Plastic injection molding is the most common production process for simple plastic parts with thin walls. It is fast, cheap, and ideal for mass production. However, an injection molding machine is a complex piece of equipment, and the process is prone to a few specific problems that can lead to part defects.Injection molding defects can significantly impact the quality and performance of manufactured products — or render them completely unusable and destined for the scrapheap. This can in turn lead to increased production costs, reduced efficiency, and compromised product reliability. For manufacturers, addressing these issues is key to maintaining quality standards and ensuring customer satisfaction.Understanding plastic injection molding defects involves identifying their causes, diagnosing their presence, and implementing preventive measures. This article looks at some of the most common injection molding defects, examining why they occur and how to prevent them.<h2 dir="ltr">What Are Injection Molding Defects?</h2><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1733143119052-yellow_black_plastic_parts.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="parts">Because they are made quickly and affordably, molded parts can exhibit defectsInjection molding defects are imperfections or anomalies that occur during the manufacturing process of molded products. These defects can manifest in various forms, such as surface blemishes, structural inconsistencies, or dimensional inaccuracies. They can undermine the functionality, aesthetics, and durability of the finished products, often leading to increased waste and production costs.[1]Proactively identifying and mitigating defects can save resources, reduce operational costs, and lead to high-quality parts. By prioritizing defect management, manufacturers can enhance their competitiveness and foster sustainable production practices.<h2 dir="ltr">Common Types of Injection Molding Defects</h2>Injection molding is a highly efficient manufacturing process, but it is not without its challenges. Defects can arise at various stages of production, affecting the functionality, aesthetics, and overall quality of the final product. Below are some of the most frequent defects encountered in injection molding, along with their causes and implications:<h3 dir="ltr">Sink Marks</h3>These are shallow depressions or dimples that form on the surface of molded parts, often around thicker sections of material. Sink marks occur when the material inside the part cools and shrinks unevenly, pulling the surface inward. They are commonly caused by insufficient packing pressure, inadequate cooling time, or poor mold design features such as inconsistent ribs.[2]<h3 dir="ltr">Warping</h3>Warping is the unwanted bending or twisting of molded parts after ejection from the mold. It is primarily caused by uneven cooling rates across the part, leading to residual stresses that distort the shape. Warping can also result from improper material selection, as some polymers are more prone to shrinkage and deformation than others.<h3 dir="ltr">Short Shots</h3>A short shot happens when the molten material does not completely fill the mold cavity, resulting in incomplete or missing sections of the part. This defect is often caused by inadequate injection pressure or obstructions within the mold. It can also occur if the mold is poorly vented, preventing the material from flowing freely.<h3 dir="ltr">Flash</h3>Flash is an excess layer of material that seeps out of the mold cavity along the mold parting line or around ejector pins. This defect can occur if the mold is not clamped tightly enough or if the clamping force is uneven. Flash can also result from excessive injection pressure or worn mold components that allow material to escape.<h3 dir="ltr">Burn Marks</h3>Burn marks are darkened or charred areas on the surface of molded parts, typically caused by trapped air overheating during the injection process. These marks are usually found near sharp corners, flow path ends, or areas where air cannot escape the mold cavity. Factors contributing to burn marks include high injection speeds, insufficient venting, or improper gate design.<h3 dir="ltr">Flow Lines</h3>Flow lines are visible streaks or patterns on a molded part’s surface, caused by the cooling and solidification of material as it flows through the mold. These defects are often linked to inconsistent injection speeds, material temperature, or poor mold design. Although flow lines are typically cosmetic, they can indicate potential weaknesses in the part.<h3 dir="ltr">Delamination</h3>Delamination refers to the peeling or separation of surface layers on a molded part, resulting in a flaky or brittle texture. This defect is sometimes caused by contamination of the material, such as moisture or foreign particles. It can also occur if incompatible materials or additives are used together or if the material experiences excessive shear stress during molding.<h3 dir="ltr">Jetting</h3>Jetting appears as wavy, worm-like lines on the surface of molded parts, caused by irregular material flow of the molten plastic. This defect occurs when molten material is injected too quickly or at an improper angle, leading to turbulence rather than smooth filling. Jetting can also result from incorrect gate design or insufficient mold temperature. Proper flow rate and gate positioning can help mitigate this issue.<h3 dir="ltr">Voids</h3>Voids are small cavities or air pockets that form inside molded parts, often reducing their structural integrity. They typically occur due to uneven cooling, excessive material shrinkage, or trapped air during the molding process. Poorly designed runners or gates and insufficient holding pressure can exacerbate the issue. Adjusting cooling profiles and improving mold venting can help prevent voids.<h3 dir="ltr">Knit Lines</h3>Knit lines, also known as weld lines, are visible seams where two flow fronts of molten material meet but fail to fully fuse. This defect is often caused by insufficient material temperature or pressure, long flow paths, or improper gate placement. While sometimes purely cosmetic, knit lines can compromise strength. Enhancing material flow and optimizing mold design can reduce their occurrence.Recommended reading: <a href="https://www.wevolver.com/article/the-pros-and-cons-of-3d-printing-low-run-injection-molds" target="_blank">The pros and cons of 3D printing low-run injection molds</a><h2 dir="ltr">Root Causes of Injection Molding Defects</h2><h3 dir="ltr">Material-Related Causes</h3><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1733143131103-colorful_plastic_pellets.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="injection molding materials">Some injection molding materials are more defect-prone than othersThe type and quality of plastic materials used in injection molding play a role in determining the success of the process. Factors such as moisture content, contamination, and material compatibility can directly influence the occurrence of defects.<ul><li dir="ltr">Moisture Content: Excess moisture in raw molding materials can lead to defects like voids, bubbles, or delamination in the finished product. Certain plastics, such as polycarbonate and nylon, are hygroscopic and require proper drying before use to prevent moisture-related issues.</li><li dir="ltr">Contamination: Foreign particles or impurities in the material can cause surface blemishes, inconsistent textures, or reduced structural integrity. For instance, contamination with incompatible polymers or dust can result in brittle or uneven parts.</li><li dir="ltr">Material Selection: Some materials are simply more prone to certain defects than others. For example, polypropylene may exhibit sinking, fiber-filled plastics may warp, and moisture-filled nylon can sputter and create various defects.</li></ul><h3 dir="ltr">Process-Related Causes</h3>The parameters used during the injection molding process also greatly affect the quality and consistency of the final product. Variations in temperature, pressure, and injection speed can introduce defects if not carefully controlled.<ul><li dir="ltr">Temperature: Inconsistent or incorrect material temperatures can lead to issues such as burn marks, short shots, or material degradation. For instance, excessive melt temperature can cause thermal degradation, resulting in discoloration or reduced material strength.</li><li dir="ltr">Pressure: Insufficient or excessive injection pressure (back pressure and/or holding pressure) can lead to defects. Low pressure may cause short shots or incomplete filling of the mold cavity, while excessive pressure can lead to flash or damage to the mold.</li><li dir="ltr">Injection Speed: The speed at which material is injected into the mold impacts the flow and cooling dynamics. High injection speeds may trap air within the mold, causing burn marks, while low speeds can lead to flow lines or incomplete filling.</li></ul><h3 dir="ltr">Design-Related Causes</h3>Product and mold design are important factors in the success of the injection molding process. Poor design choices can lead to a variety of defects, impacting both the structural integrity and aesthetic quality of the molded part.<ul><li dir="ltr">Wall Thickness: Uneven or excessively thick walls can cause defects such as sink marks, warping, or voids. For example, parts with inconsistent wall thickness may cool unevenly, leading to residual stresses and dimensional inaccuracies.</li><li dir="ltr">Rib Design: Improper rib placement or dimensions can result in defects like sink marks or weld lines. Ribs that are too thick relative to the surrounding walls can create localized shrinkage, causing surface imperfections and weakened structural areas.</li><li dir="ltr">Gate Location: The placement of gates in the mold affects the flow of molten material. Poorly positioned gates can lead to defects such as flow lines, air traps, or incomplete filling. Researchers have argued that gate location is one of the most important considerations for minimizing wastage and energy costs and consequently increasing sustainability.[3]</li></ul>Recommended reading: <a href="https://www.wevolver.com/article/what-are-injection-mold-sprues-runners-and-gates" target="_blank">What are injection mold sprues, runners, and gates?</a><h2 dir="ltr">Identifying, Diagnosing, and Predicting Defects</h2><h3 dir="ltr"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1732650534151-mold-and-inserts-large-1920x1080-v2.jpg" style="width: 100%px;" class="fr-fic fr-dib" alt="moldflow">Flow simulation tools like Autodesk Moldflow can prevent defects (image credit:&nbsp;<a href="https://www.autodesk.com/ca-en/products/moldflow/" target="_blank" rel="noopener noreferrer">Autodesk</a>)Visual Inspection</h3>Visual inspection is a fundamental step in identifying defects in molded parts. By systematically examining parts after production, manufacturers can detect and address quality issues early.<ul><li dir="ltr">Examine Surface Quality: Look for visible imperfections such as sink marks, burn marks, or flash. These defects often indicate problems with material flow, temperature, or mold clamping.</li><li dir="ltr">Check for Dimensional Accuracy: Measure critical dimensions to detect warping, short shots, or shrinkage. Variances in size can compromise the fit and functionality of the part.</li><li dir="ltr">Inspect Weld and Flow Lines: Observe areas where material flows meet or change direction. Flow lines may appear as streaks or discolorations, while weld lines can signal weakened structural points.</li><li dir="ltr">Assess Overall Consistency: Compare parts from the same production run to identify variations. Inconsistent quality across parts can highlight issues with process parameters or mold design.</li></ul><h3 dir="ltr">Advanced Diagnostic Tools</h3>Advanced diagnostic tools play a crucial role in identifying and analyzing defects in injection molding processes (or predicting them in advance). These technologies provide deeper insights into the root causes of defects, enabling manufacturers to make informed adjustments and improve quality.<div dir="ltr" align="left"><table><tbody><tr><td>Tool</td><td>Description</td><td>Benefits</td><td>Limitations</td></tr><tr><td>Thermal Imaging</td><td>Detects temperature variations across the molded part and within the mold during the injection process. Identifies areas prone to uneven cooling (e.g., warping, sink marks).</td><td>Non-invasive&nbsp;Real-time analysis&nbsp;Easy identification of thermal inconsistencies</td><td>Limited detection of internal defects&nbsp;Cannot identify material-related issues</td></tr><tr><td>X-ray Inspection</td><td>Examines the internal structure of molded parts, detecting voids, inclusions, or incomplete filling not visible externally.</td><td>High precision&nbsp;Assesses material integrity</td><td>High cost&nbsp;Requires specialized equipment and expertise</td></tr><tr><td>Flow Simulation Software</td><td>Models the flow of molten material within the mold, predicting issues like air traps, weld lines, or improper filling. Optimizes mold design and process parameters.</td><td>Prevents defects proactively&nbsp;Reduces costly trial-and-error processes</td><td>Requires accurate input data&nbsp;Demands significant computational resources</td></tr></tbody></table></div><h1 dir="ltr">Material Quality Assurance Checklist</h1>Prevention of injection molding defects largely comes down to skilled part design and machine operation. However, choosing the right materials and ensuring their proper handling can also help to prevent injection molding defects. Material properties such as viscosity, thermal stability, and moisture absorption can significantly impact the quality of molded parts.Some best practices when obtaining and handling materials for injection molding include:<ul style="list-style-type: circle;"><li dir="ltr">Verify material certification and supplier quality standards.</li><li dir="ltr">Inspect raw materials for signs of contamination, discoloration, or damage.</li><li dir="ltr">Test moisture content before processing and ensure it meets the manufacturer’s specifications.</li><li dir="ltr">Conduct small-scale trial runs to confirm material performance under intended processing conditions. Adhering to these practices helps ensure material integrity and minimizes the likelihood of defects during injection molding.</li></ul><h1 dir="ltr">Conclusion</h1>Effectively managing injection molding defects requires an understanding of their causes and the proactive implementation of preventive measures. Manufacturers can enhance product quality by selecting the appropriate materials, optimizing injection molding processes, and designing molds thoughtfully. These efforts not only minimize production costs but also ensure the reliability and consistency of molded parts.Recommended reading: <a href="https://www.wevolver.com/article/3d-printing-vs-injection-molding" target="_blank">3D printing vs injection molding: process, materials, applications</a><h1 dir="ltr">Frequently Asked Questions (FAQs)</h1>Q: What are the most common injection molding defects?A: Common defects in injection molded parts include sink marks, warping, short shots, flash, burn marks, and flow lines. Each arises from different factors such as material properties, processing conditions, or mold design.Q: How does material selection impact defect prevention?A: Material properties such as moisture absorption, thermal stability, and viscosity significantly affect defect risks. Selecting materials suited to the application and process conditions is essential for defect prevention.Q: What role does process monitoring play in reducing defects?A: Process monitoring helps detect anomalies in real time, ensuring consistent quality. Tracking parameters such as temperature, pressure, and cooling rates allows for early adjustments to avoid defects.Q: Can flow simulation software help prevent defects?A: Yes, flow simulation software models the material's behavior within the mold, predicting potential issues like air traps, weld lines, or incomplete filling. This helps optimize mold design and processing parameters.&nbsp;Q: Why is mold design critical to defect prevention?A: Mold design determines how material flows, cools, and solidifies. Features like gate placement, wall thickness, and rib design directly impact defect risks and product quality.<h1 dir="ltr">References</h1>[1] Chen YM, Liu JJ. <a href="https://www.sciencedirect.com/science/article/pii/S0736584599000058" target="_blank">Cost-effective design for injection molding</a>. Robotics and computer-integrated manufacturing. 1999 Feb 1;15(1):1-21.[2] Gruber DP, Berger G, Pacher G, Friesenbichler W.<a href="https://www.sciencedirect.com/science/article/abs/pii/S0142941811000717" target="_blank">&nbsp;Novel approach to the measurement of the visual perceptibility of sink marks on injection molding parts</a>. Polymer testing. 2011 Sep 1;30(6):651-6.[2] Huszar M, Belblidia F, Davies HM, Arnold C, Bould D, Sienz .<a href="https://www.sciencedirect.com/science/article/pii/S2214993715000093" target="_blank">&nbsp;Sustainable injection moulding: The impact of materials selection and gate location on part warpage and injection pressure</a>. Sustainable Materials and Technologies. 2015 Sep 1;5:1-8.

Injection molding problems like sink marks and flash can be prevented by addressing their most common causes. This article serves as a basic troubleshooting guide.

Injection Molding Defects: Causes, Identification, and Prevention

Joined by Adam Tipper, Managing Director and Co-owner at Next Gen Makers, our host Alex Edwards seeks to explore the experiences faced by apprentices and the best practices companies can deliver to retain young talent and rebuild the engineering workforce.

Manufacturing Apprenticeships: How can we rebuild the workforce?

Did you know that injection molding is transforming the medical device industry? This advanced process empowers designers to create high-quality and cost-effective products, ranging from common medical items to highly regulated devices. As products move through various stages of development—from initial prototyping to full-scale production—they must consistently meet stringent compliance, safety, and functionality standards. This ensures that each medical device aligns with critical industry requirements at every step.If you’re considering taking the next step in medical injection molding, this article will guide you through 4 key considerations in medical injection molding, from understanding device classifications and regulations to selecting suitable materials and preparing your design.<h2 dir="ltr">Key Considerations in Medical Injection Molding</h2><h3 dir="ltr">1. Regulatory Compliance: Meeting Corresponding Standards</h3>&nbsp;Food and Drug Administration (FDA) guidelines in the U.S. mandate rigorous tracking and documentation at every production stage to guarantee the traceability of each component. Meanwhile, Medical Device Regulation (MDR) standards in the EU emphasize consistent product safety across the device’s entire lifecycle, pushing manufacturers to follow stringent standards.Medical devices are divided into three classifications, by both FDA and MDR, based on associated risk, each with specific regulatory requirements:Class I Medical Devices: These low-risk devices pose minimal harm to users, often including items like bandages, gloves, and hand-held surgical instruments. Regulatory requirements are relatively basic, focusing mainly on general safety and quality.Class II Medical Devices: Moderate-risk devices, such as syringes, infusion pumps, and diagnostic equipment, require additional regulatory controls. These may involve special labeling, performance standards, and post-market supervision.Class III Medical Devices: High-risk devices, including pacemakers, defibrillators, and implants, require the highest level of regulatory supervision. This includes rigorous premarket approval, extensive testing, and clinical trials to confirm safety and effectiveness.For instance, a diagnostic device used for detecting infectious diseases needs each plastic component to withstand various sterilization processes without degrading or releasing harmful substances. Even minor contamination could compromise the device’s accuracy or pose risks to patients, underscoring the importance of these strict regulatory standards. Ensuring regulatory compliance is essential in medical injection molding, as incorrect categorization or non-compliance can lead to delays, increased costs, and a longer time to market.<h3 dir="ltr">2. Certifications: Guaranteeing Quality and Safety</h3>Certification is a standard, ensuring the products meet or exceed industry requirements. Key certifications in the medical industry include:ISO 13485: This certification ensures a quality management system is in place, maintaining consistency across production batches. For example, if producing IV systems or ventilators, ISO 13485 certification is critical.ISO 10993: For parts that come in direct contact with bodily fluids or tissues, ISO 10993 ensures biocompatibility. This certification is essential when manufacturing parts such as catheter tips or implantable device housings, where material safety directly impacts patient health.ISO 14644: This cleanroom certification is crucial for preventing contamination. A cleanroom-certified facility, for instance, can safely produce surgical device components that require a sterile environment, ensuring they meet hospital and surgical standards.<h3 dir="ltr">3. Material Selection: Biocompatibility and Durability</h3>Choosing materials for medical applications involves considerations beyond standard injection molding. Examples include:<ul><li dir="ltr">Polycarbonate (PC): Due to its strength and transparency, often used for housing devices requiring internal visibility, such as blood analyzers.</li><li dir="ltr">Polyethylene (PE):&nbsp;Known for chemical resistance and flexibility, PE is used in IV bags and tubing, ensuring durability and low moisture absorption.</li><li dir="ltr">Polypropylene (PP): With strong impact resistance and sterilization stability, PP is used in syringes and medical containers, offering long-term reliability.</li><li dir="ltr">Polystyrene (PS):&nbsp;Widely used for disposable labware, PS offers rigidity, transparency, and easy sterilization, making it suitable for laboratory applications.</li><li dir="ltr">Polyether Ether Ketone (PEEK):&nbsp;Widely used in implantable devices due to its strength, stability under sterilization, and biocompatibility.</li><li dir="ltr">Thermoplastic Elastomer (TPE):&nbsp;Its flexibility makes it suitable for soft-touch surgical instrument handles that withstand repeated sterilization.</li></ul>Every material choice has specific trade-offs. For instance, while PE and PP are cost-effective and chemically resistant, they might lack the strength needed for parts exposed to high-stress environments. Therefore, understanding these nuances helps in material selection, optimizing for both performance and cost.<a href="https://www.rpworld.com/en/resources/blog/what-materials-work-best-for-your-medical-device-development.html">&nbsp;Click Here</a> to explore more material choices.<h3 dir="ltr">4. Prototyping to Production: Ensuring a Smooth Transition</h3>Transitioning from prototypes to full-scale production isn’t always straightforward. During prototyping, designs may feature thinner walls or more complex geometries than standard injection molding processes can easily reproduce at scale. For example, a prototype with sharp corners that’s achievable created by the vacuum casting process, but requires design optimization, such as adding radii, and adding draft angle for efficient injection molding without sacrificing quality.When scaling up, an experienced injection molding partner with expertise and capabilities can help optimize these designs for manufacturability without compromising on quality. At RPWORLD, we assist clients in this crucial transition, helping optimize part design, select the most suitable materials, finishing options and more to support efficient and regulatory-compliant production.<h2 dir="ltr">How RPWORLD Injection Molding Accelerates Your Medical Development</h2>At RPWORLD, we integrate material expertise, one-stop manufacturing services, in-depth DFM analysis and ISO-certified process to help bring medical devices to market faster. Our services cover the entire lifecycle—from prototyping to mass production—tailoring to meet the unique needs of each medical device.Our Injection Molding Services Include:<ul><li dir="ltr">20+ years of experience in medical device injection molding, from prototyping to end-use production.</li><li dir="ltr">Mold flow analysis, and in-house tools design and fabrication.</li><li dir="ltr">Design for Manufacturing (DFM) guidance, including design optimization, material selection, finishing selection and more to avoid costly rework and save time up to 80%.</li><li dir="ltr">A wide variety of post-processing options to perfect your parts.</li><li dir="ltr">State-of-the-art quality inspection equipment and stringent quality control including real-time process monitoring to ensure consistency.</li></ul>

Photo by National Cancer Institute on Unsplash

If you’re considering taking the next step in medical injection molding, this article will guide you through 4 key considerations in medical injection molding, from understanding device classifications and regulations to selecting suitable materials and preparing your design.

From Prototype to Production - 4 Critical Considerations for Safe and Compliant Medical Injection Molding

Injection molding vs. 3D printing doesn’t have to be an either/or proposition. Some projects use both processes during a product’s lifecycle. Traditionally, 3D printing has been used for prototyping and injection molding has been used for production. Additive manufacturing has advanced, however, and 3D printed parts aren’t limited to prototypes anymore.Today, there are 3D printing technologies that can create production-quality components – and in the volumes you may require. These technologies include <a href="https://bmf3d.com/" target="_blank" rel="noopener">Projection Micro Stereolithography (PµSL)</a> from Boston Micro Fabrication (BMF), a form of microscale 3D printing that supports the use of plastics, metal-plated plastics, ceramics, hydrogels, and composites resins.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1730085049022-Metal-plated-turbine.jpg" style="width: 100%px;" class="fr-fic fr-dib">Metal-plated 3D printed plastic parts<section id="isPasted">3D printing has many advantages, but there’s often a part volume – a crossover point – where injection molding is used. With plastic injection molding, tooling that costs tens or even hundreds of thousands of dollars can be amortized across these high production volumes. Quantity is just one consideration, however, so consider these ten factors when comparing injection molding vs. 3D printing for your project.<ol><li>Lead Times</li><li>Setup Costs</li><li>Volumes</li><li>Materials</li><li>Part Size</li><li>Part Tolerances</li><li>Part Strength</li><li>Design Maturity</li><li>Design Complexity</li><li>Surface Finish</li></ol>The following sections explain.</section><section><h3>#1 Lead Times</h3>The steel or aluminum molds that are used with injection molding can take weeks or months to machine. The injection molder then sends a customer part samples for functional testing and dimensional measurements. If the initial samples aren’t suitable, the mold maker may have to adjust the tool, which extends project timetables.3D printing has shorter lead times. Unlike injection molding, there’s isn’t a metal tool that needs to be CNC or EDM machined. Customers still need part samples, but there isn’t a mold to modify if changes are required – and the settings on a 3D printer can be adjusted. Using 3D printing, it’s even possible to produce low-volume injection molds. &nbsp;For high volumes in a single run, however, injection molding is faster.</section><section><h3>#2 Setup Costs</h3>Most injection molding costs are associated with the tool. Steel costs more than aluminum, and both metals cost more than the 3D plastics that are used to build some low-volume molds. Production molds cost more than prototype molds as well. With injection molding, tooling costs also vary with mold size and complexity. 3D printing eliminates these costs and the variability that comes with them.</section><section><h3>#3 Volumes</h3>There are four volumes of parts to consider when comparing injection molding vs. 3D printing: initial order quantity, annual order quantity, total quantity, and crossover volume. Standard parts have a crossover volume in the low thousands. Small, high-precision parts have crossover volumes in the tens of thousands, and that’s part of the reason <a href="https://bmf3d.com/ultra-high-resolution-3d-printers/">BMF’s microscale 3D printers</a> are used instead of micro injection molding.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1730085117712-1730085117712.png" class="fr-fic fr-dib"><section id="isPasted"><h3>#4 Materials</h3>Injection molding and 3D printing support many of the same materials. Examples include ABS, acetal, acrylic, PEEK, PEI, polycarbonate, polyethylene, and PTFE. The end-use properties of injection molded and 3D printed materials aren’t the same, however, and injection molding supports some materials that 3D printing does not, and vice versa. With BMF’s open material system, designers can print with the materials of their choice (including non-plastics) or with BMF’s own specially formulated polymers.</section><section><h3>#5 Part Size</h3>Micro injection molding can produce small parts, but with high tooling costs and practical limitations such as the size of the mold, the capabilities of the machine, and the part’s minimum wall thickness. Most 3D printers can’t produce microscale components, but PµSL technology can print parts that are <a href="https://www.zdnet.com/article/exclusive-zdnet-interview-bmf-ceo-john-kawola-on-3d-printing-parts-smaller-than-a-human-hair/">smaller than a human hair</a>, which is roughly 70 microns across. PµSL doesn’t just rival precision injection molding in terms of size, however. This form of 3D printing can also achieve extremely tight tolerances.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1730085142908-MicroScrew4-scaled.jpg" style="width: 100%px;" class="fr-fic fr-dib">Micro Nut and Bolt with M0.3 Threads<section id="isPasted"><h3>#6 Part Tolerances</h3>For non-critical applications, the <a href="https://www.fictiv.com/articles/injection-molding-tolerances-7-questions-for-designers">tolerance of injection molded parts</a> is usually ± 0.1 mm. For critical components, such as those used in medical applications, ± 0.025 mm is typical. With PµSL technology, manufacturing tolerances are measured in terms of microns instead of millimeters (mm). Given that 1 micron equals 0.001 millimeter, PµSL printing tolerances of ± 10µm ~ ± 25µm are especially tight.</section><section><h3>#7 Part Strength</h3>Injection molded parts tend to be stronger than 3D printed components. Mainly, that’s because injection molded parts are made are made of a single layer of material. By contrast, 3D printing produces parts layer by layer. Material selection matters, however, and <a href="https://bmf3d.com/blog/injection-molding-vs-3d-printing-ten-considerations/P%C2%B5SL">BMF materials</a> such as RG resin are durable engineering materials that can be used to produce functional end-use parts.</section><section><h3>#8 Design Maturity</h3>Injection molding is ideal for manufacturing parts with mature designs in high volumes. Once manufacturing begins, however, design changes are impractical. 3D printing readily supports design changes from prototyping through production. In other words, it’s easier to identify and correct problems without scrapping tools or wasting materials, a key consideration for designs that are still maturing.</section><section><h3>#9 Design Complexity</h3>Compared to injection molding, 3D printing supports greater complexity. From holes in the middle of parts to intricate shapes or spoke-like features, there’s greater design freedom with this form of additive manufacturing. With injection molding, the tool limits part design. For example, parts with right angles may break during ejection and ribs are needed for support.<a href="https://bmf3d.com/wp-content/uploads/2020/06/chip-array-socket2.jpg" target="_blank"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1730085185905-chip-array-socket2.jpg" style="width: 100%px;" class="fr-fic fr-dib">Chip Array Socket with Arrays of 130µm Through Holes</a></section><section id="isPasted"><h3>#10 Surface Finish</h3>Finally, comparisons of injection molding vs. 3D printing need to account for surface finish. Generally, 3D printed parts have a rougher surface finish; however, post-build smoothing can be used. Injection molded parts can have a fine finish, but with higher tooling costs. With plastic injection molding, parts are also subject to surface defects such as mold flash.</section><section><h2>Comparing Injection Molding vs. 3D Printing</h2>Injection molding is ideal for high-volume production and for projects with longer turnaround times. Although it can be used with parts of various sizes, injection molding offers less design freedom. 3D is better for low-volume production runs, designs with frequent changes, and projects with quick turnaround times.There are many types of 3D printers, but PµSL technology from Boston Micro Fabrication (BMF) lets designers get prototypes and production-quality parts in small sizes – and without the high costs of micro injection molds.</section></section></section>

Injection molding vs. 3D printing doesn’t have to be an either/or proposition. Some projects use both processes during a product’s lifecycle. Traditionally, 3D printing has been used for prototyping and injection molding has been used for production.

Injection Molding vs. 3D Printing: Ten Considerations

<h2 id="isPasted">Introduction</h2>Polyether Ether Ketone (PEEK) is a high-performance engineering thermoplastic renowned for its outstanding mechanical properties, chemical resistance, and thermal stability. It finds utility in stringent sectors such as aerospace, medical, and electronics due to its robustness. While injection molding stands out as the most effective manufacturing method for crafting precise PEEK components, mastering this technique requires a deep understanding of both the material and the process, especially when using compact injection molding systems. <h3>1. Material Properties of PEEK</h3>PEEK is favored for high-performance applications owing to its distinctive characteristics:High Temperature Resistance: PEEK endures continuous exposure to temperatures as high as 250°C, making it suitable for components that experience high thermal loads.Chemical Resistance: Its resistance to a wide array of chemicals ensures durability in aggressive environments.Mechanical Strength and Toughness:&nbsp;PEEK offers superior strength and stiffness along with excellent wear resistance, which is crucial for parts subjected to high mechanical loads.Biocompatibility: Its compatibility with bodily tissues makes it ideal for medical implant applications.<h3>2. Challenges in Injection Molding PEEK</h3>Any injection molding machine, designed for precision and small-scale production, must be carefully calibrated for PEEK due to its high melting point (343°C) and unique processing requirements:Processing Temperatures: Optimal mold temperatures range between 160°C and 200°C, which helps achieve desired crystallinity. The injection temperatures should be maintained between 370°C and 400°C to facilitate smooth flow.Cycle Time: PEEK's inherent properties necessitate longer cooling times compared to more conventional thermoplastics, potentially impacting production efficiency.Mold Design: Given PEEK's minimal shrinkage, the mold must be designed with high precision to ensure accurate dimensional outcomes.<h3>3. Critical Mold Design Considerations</h3>Effective mold design is vital:Gate Design: Small, uniformly-sized gates such as pin or edge gates are recommended to minimize residual stresses.Ventilation: Proper venting is crucial to prevent gas entrapment and eliminate burn marks.Mold Surface Finish: A highly polished mold surface enhances flow, reducing friction and improving the quality of the finished parts.<h3>4. Injection Molding Parameters</h3>Tailoring the injection machine settings is crucial for optimal results:Injection Pressure: High pressures are necessary to adequately fill the mold.Injection Speed: A slow to moderate injection speed helps prevent shear heating and material degradation.Cooling and Crystallization: Effective cooling management is essential to control crystallization and prevent warping or deformation.<h3>5. Post-Molding Processes</h3>To further enhance the properties of PEEK parts, certain post-processing treatments may be required:Annealing: This heat treatment relieves internal stresses and enhances dimensional stability.Surface Treatments: Techniques such as polishing or coating can significantly improve the surface quality of the components.<h3>6. Common Defects and Troubleshooting</h3>Understanding common defects can aid in troubleshooting:Warping and Shrinkage: Maintain proper cooling rates and ensure uniform mold temperature control.Bubbles and Voids: Fine-tune injection pressure and verify material drying processes prior to molding.Burn Marks: Ensure sufficient venting and consider reducing the injection speed if necessary.<h3>Conclusion</h3>Mastering PEEK injection molding demands precise control over material properties, mold design, and processing parameters. By meticulously attending to these critical aspects, manufacturers can consistently produce high-quality, reliable PEEK components for advanced applications.#peekparts #injectionmolding #apsxllc #peek #medicalparts #biomedical

While injection molding stands out as the most effective manufacturing method for crafting precise PEEK components, mastering this technique requires a deep understanding of both the material and the process, especially when using compact injection molding machines.

Critical Aspects of PEEK Injection Molding Process

From accelerating production timelines to ensuring unmatched quality control, the adoption of APSX machines can redefine operational performance for businesses of all sizes from an inventor/entrepreneur alone to global companies around the world.1. Revolutionizing Manufacturing Efficiency with AutomationAPSX machines are built with automation at their core, reducing manual intervention and optimizing every stage of production. They incorporate CNC capabilities, allowing for precise execution of complex parts and simple injection molding process for making real plastic functional parts instead of fragile 3D printed parts. This translates into shorter production cycles, lower lead times, and a dramatic reduction in product development and production costs.By integrating APSX machinery, businesses can achieve substantial efficiency gains, minimizing downtime due to long lead times and ensuring continuous production. These systems also enable manufacturers to schedule operations 24/7, maximizing output and enhancing the overall production capacity without compromising quality.2. Scalable Solutions Tailored for SMEsFor small and medium enterprises (SMEs), balancing capital investment with production output is critical. APSX machines provide a cost-efficient solution, featuring modular designs that scale with business growth. Unlike traditional machinery, APSX systems have a low total cost of ownership (TCO), owing to their energy-efficient operations, minimal maintenance requirements, and a reduced need for expensive tooling.This scalability ensures that SMEs can start with a smaller setup and expand their manufacturing capabilities as demand increases, without the need for a complete overhaul of their production infrastructure. The flexibility and affordability of APSX solutions make them ideal for companies looking to innovate while maintaining profitability.3. Enhanced Versatility Across Multiple SectorsOne of the standout features of APSX machinery is its adaptability to various manufacturing needs. From automotive components to medical device production, these machines are engineered to handle a broad spectrum of materials, including metals, plastics, and composites. This versatility is supported by advanced programming options and customizable mold designs that allow for seamless transitions between different product specifications.For industries requiring precision and consistency—such as aerospace and electronics manufacturing—APSX machines provide unparalleled control over complex geometries and intricate detailing, ensuring that each output meets stringent industry standards.4. Accelerated Prototyping for Rapid Product DevelopmentIn today’s competitive market, speed-to-market is a critical success factor. APSX machines empower businesses to rapidly prototype new designs using subtractive and additive manufacturing techniques. By leveraging CNC milling or 3D printing capabilities, companies can iterate quickly on product designs, making necessary adjustments in a fraction of the time required by traditional methods.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1727718506442-27.09.2024_12.21.09_REC.png" style="width: 100%px;" class="fr-fic fr-dib">This rapid prototyping capability reduces the time between concept and market-ready product, enabling manufacturers to respond swiftly to consumer feedback and changing market trends. Moreover, the ability to produce functional prototypes allows for comprehensive testing, ensuring that final products meet all performance and reliability criteria before mass production.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI3NzE4MzI0NTY1LUFQU1gtUElNX0hvbWVQYWdlXzEwMDAuSlBHIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" style="width: 100%px;" class="fr-fic fr-dib">5. Precision Engineering for Superior Product QualityPrecision and repeatability are the hallmarks of APSX machinery. Using state-of-the-art software and premium components, these machines deliver exceptional accuracy, maintaining tight dimensional control even in high-volume production runs. This capability is essential for industries where product uniformity and reliability are non-negotiable, such as medical device manufacturing and precision engineering.APSX machines utilize closed-loop feedback systems, ensuring real-time adjustments that prevent deviations and guarantee that each part produced is identical to the next. This high degree of precision reduces the incidence of defective products, enhances quality assurance, and minimizes material waste, ultimately leading to improved profitability and sustainability.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI3NzE4MzUwODEwLXN3aXNzLWJhbm5lcl8xLnBuZyIsImVkaXRzIjp7InJlc2l6ZSI6eyJ3aWR0aCI6OTUwLCJmaXQiOiJjb3ZlciJ9fX0=" style="width: 100%px;" class="fr-fic fr-dib">6. Sustainability Through Resource EfficiencyEnvironmental responsibility is becoming a priority for manufacturers worldwide. APSX machines contribute to sustainability by incorporating energy-efficient drives and low-waste manufacturing techniques. With programmable precision, these machines optimize material usage, minimizing scrap rates and reducing the overall carbon footprint of the production process.In addition, the adoption of APSX technology aligns with green manufacturing practices by supporting the use of recyclable materials and facilitating the remanufacturing of worn components, extending the lifecycle of products and reducing industrial waste. #injectionmolding #cncmachining #prototyping #sustainability

APSX machines represent a significant breakthrough in modern agile manufacturing, designed to boost efficiency with easy setups, precision for injection molding over 3D printing, and scalability across diverse industrial sectors due to their low initial investment and small sizes. 

Top Benefits of Leveraging APSX Machines for Industrial Optimization

Flame test with a lighter on an FDM ULTEM 9085 part

This article delves into flame-retardant plastics typically used to produce parts through 3D printing, CNC machining, and formative manufacturing technologies. It also covers the complexities of flame retardancy and industry standards, such as the UL 94 rating.

Flame Retardant Plastics & UL 94 Flammability Standards In Parts Manufacturing

This article overviews CNC machining and injection molding as popular manufacturing technologies to produce mechanical parts, such as connectors, heat sinks and housings, for end-customer electronics devices.

CNC Machining and Injection Molding to Produce Mechanical Parts for the Electronics Industry

Whether you call it design for manufacturability (DFM), design for manufacturing and assembly (DfMA), or the latest acronym, design for additive manufacturing (DfAM), learning and following its principles is a sure-fire way to improve manufacturing processes and produce higher quality products at a lower cost.At first glance, it can seem like a lot to take in. That's because manufacturing is a deep subject, and there's much to know before people consider themselves experts.<h2 id="isPasted">Testing the DFM Waters</h2>Fortunately, we can simplify the process and ease some of the pain customers might feel when struggling with DFM principles through our intuitive digital quoting platform. &nbsp;<a href="https://www.protolabs.com/en-gb/ecom/get-a-quote/" title="Get A Quote" target="_blank">Begin a project</a> on our website and experience it yourself!Once you've selected the desired manufacturing process—CNC machining, 3D printing, or injection moulding—you'll be asked to upload a CAD file. After that, you'll need to answer some questions about the raw material, surface finish, part quantity, and so on.Depending on the selected process, you might receive an immediate price and "Ready to Order" notice, but it's more likely that your quote and DFM analysis will arrive within an hour or so. With them, you might also receive one or more design advisories.It's essential to read them and follow their recommendations. Design advisories provide helpful advice about the part’s manufacturability. Even though the part design might be okay as is—meaning it’s manufacturable—it could be improved. That's why it's crucial that if you have any questions or concerns, you should contact one of our customer service representatives for help.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1725355780031-3dp-dfm-1.jpg" style="width: 600px;" class="fr-fic fr-dib"><h2 id="isPasted">Dealing with DfAM</h2>At the risk of stating the obvious, the “A” in DfAM stands for additive. As anyone familiar with the technology will attest, 3D printing offers greater design flexibility than any other manufacturing process. It does, however, present some challenges. Check out some of our other <a href="https://www.protolabs.com/en-gb/resources/design-tips-library/?filter=3dprinting&amp;utm_source=wevolver&amp;utm_medium=referral&amp;utm_campaign=dfm-guidelines-0924&amp;utm_content=wevolver-0924" target="_blank" rel="noopener noreferrer"></a><a href="https://www.protolabs.com/en-gb/resources/design-tips-library/?filter=3dprinting" title="Design Tips Library" data-anchor="?filter=3dprinting" target="_blank" rel="noopener noreferrer">design tips</a>, and you'll discover a wealth of information about common mistakes, size and geometry constraints, and ways to improve part cost, quality, and lead time.For example, holes smaller in diameter (about 1.5mm to 2.8mm) can be challenging with any manufacturing process, and 3D printing is no exception. The same can be said for narrow slots and tall walls, especially if they're many times deeper than they are wide. A design advisory might flag these areas as “Review and Accept”, while others throw up a big red “Remove from Quote” flag. Both of these indicate the feature’s level of non-manufacturability.But what’s perhaps most unique about additive manufacturing (the “AM” part of DfAM) is its need for support material to keep part layers from curling or sagging during the print process. Exceptions exist, and part orientation plays a significant role in the number and spacing of these scaffold-like structures. Still, the fact remains that support management—though not strictly a DfAM consideration—is one area where a quick chat with one of our applications engineers can lead to better parts and fewer surprises.<h2>DFM for Chipmaking</h2>Additive manufacturing brings benefits in terms of complexity and ease of manufacturing, but one DFM rule that any designer should live by is this: If the part is easily machined, go with that production method. In fact, thick, blocky parts like hydraulic manifolds and the threaded fittings that go into them might be unprintable due to the amount of heat they acquire during the build. The bottom line is that if you can machine, mould, stamp, or form it, that’s probably the route you should take.Speaking of screw threads, here's another tip that might not fall into a purist's DFM bucket but is a common reason for faults: avoid modelling that 1/4-20 tapped hole or 1/2-13 external thread. Yes, Solidworks and Fusion 360 make it easy to do it, but machine shops everywhere—us included—prefer a simple UNC or UNF-style thread callout.There’s lots more to know about DFM for <a href="https://www.protolabs.com/en-gb/services/cnc-machining/?filter=cncmachining&amp;utm_source=wevolver&amp;utm_medium=referral&amp;utm_campaign=dfm-guidelines-0924&amp;utm_content=wevolver-0924" target="_blank" rel="noopener noreferrer"></a><a href="https://www.protolabs.com/en-gb/services/cnc-machining/?filter=cncmachining" title="CNC Machining" data-anchor="?filter=cncmachining" target="_blank" rel="noopener noreferrer">CNC machining</a>. Don’t make tolerances any tighter than necessary. Square internal corners on vertical walls add significant cost. Text does, too, especially if it’s raised. Oh, and don’t choose titanium when steel or aluminium will do. Another thing to keep in mind is that very deep pockets and holes may make the part unmanufacturable. Also, just as with injection moulding and 3D printing, thin walls tend to bend or break.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1725355847410-protolabs-sheet-metal-process-illustrion-click-to-enlarge-1225-x-793.jpg" style="width: 600px;" class="fr-fic fr-dib"><h2 id="isPasted">Moulding and Beyond</h2>Last but certainly not least on the DFM list is <a href="https://www.protolabs.com/en-gb/services/injection-moulding/?filter=injectionmolding&utm_source=wevolver&utm_medium=referral&utm_campaign=dfm-guidelines-0924&utm_content=wevolver-0924" target="_blank" rel="noopener noreferrer">injection moulding</a>. This champion of high-volume plastic part production has its own volume(s) of manufacturing guidelines, some of which contradict those already mentioned. For instance, thin walls won’t deflect during the moulding process like they will during machining and 3D printing, but the molten plastic might not flow into the mould’s harder to reach areas, leading to what’s called a short shot.But make those walls too thick and you might experience a phenomenon called sink, which is just as big of an issue. Also, as with over-tolerancing of any manufactured part, overly smooth surface finishes drive up part cost.Conversely, rough surfaces tend to reduce processing time with machining and 3D printing, but with injection moulding they can lead to dreaded ejection problems. Then, there are parting lines to contend with where mould halves meet, not to mention undercuts, gate placement, and more. Here's one area where a short chat with a moulding expert can pay big dividends later in the project.It may seem daunting initially, but don’t worry! The good news is that, despite the seemingly huge number of DFM guidelines that apply to this and the other manufacturing processes, the design rules built into our quoting process will help to steer you in the right direction. The design advisories that accompany your quote, along with our extensive library of design tips, will also help. And if you need support, you know where to find us. You can speak with one of our application engineers at +44 (0) 1952 683047 or <a href="mailto:customerservice@protolabs.co.uk" target="_blank">customerservice@protolabs.co.uk</a>.

How DFM guidelines save money, reduce lead times, and deliver better products.

The Benefits of Design for Manufacturability Advisories

APSX Machines are relevant to the IMTS 2024 audience because the IMTS (International Manufacturing Technology Show) is a major trade show that showcases the latest advancements in manufacturing technology, including machine tools, robotics, and automation equipment. APSX Machines, which specializes in advanced manufacturing solutions, would be of interest to the IMTS audience, consisting of industry professionals, manufacturers, and engineers looking to explore new technologies and innovations that can enhance their manufacturing processes and productivity.&nbsp;<h2>Smart Manufacturing: The Role of APSX Machines at IMTS 2024</h2>As the manufacturing industry continues to evolve, smart manufacturing has emerged as a key trend. APSX Machines play a crucial role in this transformation by offering advanced, automated solutions that enhance productivity and efficiency. At IMTS 2024, attendees will have the opportunity to see and hear firsthand how APSX Machines integrate cutting-edge technology to streamline manufacturing processes.<h2>APSX machines are available to purchase with listed pricing and they are in stock to be shipped</h2>One of the key advantages of APSX Machines is their availability. Unlike many other industrial machines that require long lead times, APSX Machines can be purchased quickly, with transparent pricing listed upfront (visit <a href="http://www.apsx.com/" target="_blank">www.apsx.com</a>). This allows businesses to make informed decisions and plan their budgets effectively.Moreover, APSX Machines are in stock and ready to be shipped, reducing the wait time. This immediate availability ensures that manufacturers can quickly integrate these machines into their production methods, accelerating the transition to more efficient operations.<h2>Great opportunities for rapid prototyping and production by using the APSX machines</h2>APSX Machines offer equipment like CNC machines and injection molding machines that are ideal for rapid prototyping. This allows manufacturers to quickly create prototypes and iterate designs, significantly reducing development time and costs.APSX Machines are designed to facilitate rapid prototyping and production, making them ideal for businesses looking to innovate and bring new products to market swiftly. Their advanced capabilities allow for the quick creation of prototypes, enabling iterative testing and refinement without significant delays. Short setup times, quick learning curves lead to real and functional parts faster and cheaper.&nbsp;This rapid prototyping capability not only speeds up the development process but also reduces costs associated with traditional prototyping methods. By using APSX Machines, manufacturers can achieve a faster time-to-market, giving them a competitive edge in the industry.<h2>APSX machines allows you to adapt to flexible and responsive production needs</h2>The machines are versatile, allowing for a wide range of materials and applications. This flexibility is crucial for IMTS attendees who work in diverse industries and need equipment that can adapt to various manufacturing needs.In today's dynamic market, the ability to adapt to changing production needs is crucial. APSX Machines offer the flexibility and responsiveness required to meet these demands. Whether it's scaling up production in response to increased demand or customizing products to meet specific customer requirements, APSX Machines provide the necessary agility.Their versatile design and easy reconfiguration make it possible to switch between different production tasks seamlessly. This adaptability ensures that businesses can respond quickly to market changes, maintaining their competitive edge and meeting customer expectations.<h2>APSX machines offer minimum initial investment and ongoing operational costs</h2>APSX Machines are designed to be cost-effective, which makes them accessible for small to medium-sized enterprises (SMEs). For example, their compact injection molding machines can produce parts in-house, reducing the need for outsourcing and cutting down on production costs.Investing in new manufacturing equipment can be a significant financial commitment. However, APSX Machines are designed to minimize initial investment and ongoing operational costs. Their cost-effective pricing model allows businesses to acquire high-quality machinery without breaking the bank.Additionally, APSX Machines are built for efficiency, reducing energy consumption and maintenance requirements. This not only lowers operational costs but also contributes to a more sustainable manufacturing process. By choosing APSX Machines, manufacturers can achieve long-term savings while maintaining high levels of productivity and efficiency.<a href="https://www.linkedin.com/feed/hashtag/?keywords=cncmachining&highlightedUpdateUrns=urn%3Ali%3Aactivity%3A7233571251003269120" data-test-app-aware-link="" target="_blank" id="isPasted">#cncmachining</a> <a href="https://www.linkedin.com/feed/hashtag/?keywords=injectionmolding&highlightedUpdateUrns=urn%3Ali%3Aactivity%3A7233571251003269120" data-test-app-aware-link="" target="_blank">#injectionmolding</a> <a href="https://www.linkedin.com/feed/hashtag/?keywords=rapidprototyping&highlightedUpdateUrns=urn%3Ali%3Aactivity%3A7233571251003269120" data-test-app-aware-link="" target="_blank">#rapidprototyping</a> <a href="https://www.linkedin.com/feed/hashtag/?keywords=swisslathe&highlightedUpdateUrns=urn%3Ali%3Aactivity%3A7233571251003269120" data-test-app-aware-link="" target="_blank">#swisslathe</a> <a href="https://www.linkedin.com/feed/hashtag/?keywords=productdesign&highlightedUpdateUrns=urn%3Ali%3Aactivity%3A7233571251003269120" data-test-app-aware-link="" target="_blank">#productdesign</a>

Discover how APSX Machines are transforming the manufacturing landscape and what IMTS 2024 attendees can look forward to.

APSX Machines: Key Highlights for IMTS 2024 Attendees

Our Insight video series will help you master digital manufacturing.Every Friday we’ll post a new video – each one giving you a deeper Insight into how to design better parts. We’ll cover specific topics such as choosing the right 3D printing material, optimising your design for CNC machining, surface finishes for moulded parts, and much more besides.So join us and don’t miss out.<iframe src="https://fast.wistia.net/embed/iframe/ux935q0x3d" width="900" height="450" allowtransparency="true" frameborder="0" scrolling="no" class="wistia_embed fr-draggable" name="wistia_embed" allowfullscreen="" mozallowfullscreen="" webkitallowfullscreen="" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> TranscriptHello and welcome to this week’s Insight.&nbsp;Today we’re going to take a close look at cutting corners. But before you get too concerned, I’m talking about the corners on injection moulded parts.&nbsp;Now I like a right angle the same as anyone else, but sometimes it can be a bit too sharp for its own good.<a href="https://www.protolabs.com/media/eymh3apg/implementing-corners-in-injection-moulded-parts-large.jpg" target="_blank" rel="noopener noreferrer">Image</a>As an engineering or product designer you need to be aware of the pitfalls of being too square when developing your parts for injection moulding. If you don’t have the right amount of corner rounding and filleting, then part accuracy, strength and aesthetics can suffer.Generally, it’s important to have smooth rounded edges, but there are a number of factors that can affect even a well radiused part.Some plastics are more forgiving of sharp cornered parts than others, so talk to your supplier.The thickness of your walls will also play a role. Beefing up adjacent walls can absorb some of the stress that you get from sharp internal corners, but beware because that beefed up wall can cause other design issues.And part geometry can be important. Some parts are simply more mouldable than others.All of these factors can affect the amount of corner radius that you need on a part design, it’s a question of balancing them, because Injection moulding is a complex process.But what about when you are sitting in front of your CAD? Well there are two types of radius that we need to think about: internal and external. Just so that you know, when I talk about filleting, I’m talking about radii that are found at the bottom of each compartment where the walls meet the floor of a box. &nbsp;You don’t want to make these corners too sharp, so put in a radius that is at least half as thick as the adjacent wall thickness.As for the radii at the top of those walls, well they should be rounded to about one and a half times the thickness of the wall.&nbsp;Why is this? Well it allows the molten plastic to flow more easily and gets rid of the residual stress that twists thin walled workpieces. It also prevents cracking that could lead to your part or product failing.The material that you select can also make a difference. If you’ve used injection moulding before, then you may have seen gaps along the top of some of the compartments or on the outside of a case. It’s almost as if there wasn’t enough plastic to complete the part. But It’s not because your supplier has been skimping on you, the culprit is more likely to be the raw material itself.When you force plastic through an injection mould, it does not behave like an amorphous easygoing blob. It creates long chains of molecules that link with adjacent molecules and they don’t like being cramped into a tight corner or having to flow around a sharp edge caused by posts or wall intersections.It means that the material might not reach every nook and cranny in your mould cavity and you are left with some gaps.&nbsp;Even if the material does flow where it’s meant to, the stress caused by all that molecular bending and twisting can result in warp and bow on the moulded part.Obviously neither of these scenarios are great.There are two things that you can do. Generally, the problem is worse for glass- and fibre-filled materials because their greater strength and molecular integrity make them less likely to go with the flow than unfilled plastics.The second one is to get the mould design right, proper radiusing will go a long way to avoiding this.You also need to realise that there are certain machining limitations that can prevent you having the sharp corner that you want. The internal corners in any mould cavity can’t be smaller than the end mill used to machine them.Now you can get around this by using other manufacturing methods such as electrical discharge machining, but this is slow and will cost you more money. Plus of course you run the risk of the complications that I’ve already talked about when it comes to the injection moulding itself.Moving on, I mentioned about beefing up your walls to help you get sharper corners… well it’s not just about making them thicker, because this can lead to sink, shrink and bubbles.&nbsp;You are far better to strengthen the wall by introducing a honeycomb pattern on thin sections or have a series of short vertical ribs to help prevent bending.&nbsp;Now if all of this rounding and filleting sounds like a right hassle, don’t worry; your CAD system should help and your supplier should pick up on any potential problems when they check your design using their design for manufacturability analysis.

Your masterclass in product design and development

Injection Moulding - Don't Be Too Sharp

The Protolabs Insight video series will help you master digital manufacturing, covering cover specific topics such as choosing the right 3D printing material, optimising your design for CNC machining, surface finishes for moulded parts, and much more.<iframe src="https://fast.wistia.net/embed/iframe/0uc9w8pu8r" width="900" height="450" allowtransparency="true" frameborder="0" scrolling="no" class="wistia_embed fr-draggable" name="wistia_embed" allowfullscreen="" mozallowfullscreen="" webkitallowfullscreen="" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe>TranscriptHello and welcome to this week’s Insight.This time around we’re going to be delving into an important area of <a href="https://www.protolabs.com/en-gb/services/injection-moulding/?utm_source=wevolver&utm_medium=referral&utm_campaign=uk-insight-video-0919&utm_content=insight-core-cavity-placement-0724" target="_blank">injection moulding</a>, which is working out the best core and cavity placement for your parts.<img border="0" width="601" src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzIxNzIzNzY2NDM3LTE3MjE3MjM3NjY0MzcucG5nIiwiZWRpdHMiOnsicmVzaXplIjp7IndpZHRoIjo5NTAsImZpdCI6ImNvdmVyIn19fQ==" class="fr-fic fr-dii">Now, one of the goals of rapid injection moulding is to produce your parts cleanly and quickly. It’s easy to just throw things together and plan on iterating as you go along, but spending a little bit of time on a proper design helps ensure that you’re going to be getting good parts right from your very first run.Determining how the part will be placed in the mould is a small but really very critical part of this. Our overriding consideration in this is that the part must stay in the mould half that contains the ejector system.Let me explain. In a typical injection moulding machine, one half of the mould – which we’ll call the A-side – is attached to the fixed side of the press, and the other half of the mould – the B-side – is attached to the moving clamp side of the press.The B-side contains the ejection actuator, which controls the ejector pins. The clamp forces A and B together, molten plastic is injected into the mould and allowed to cool, the clamp pulls the B-side of the mould away, the ejection pins are actuated, and if all goes well the part releases from the mould. Simple, right?Well, it depends.Let's use a mould for a plastic drinking cup as an example. To ensure that the part stays in the mould half with the ejector system, we’d like to design the mould so that the outside of the cup is formed in the cavity and the inside would be formed by the core. As the plastic cools, the part begins to shrink away from the A-side of the mould and shrink onto the core in the B-side.When the mould opens, the cup should release and stay on the B-side. There, it can be pushed off from the core by the ejector system.However, if the mould design were reversed – if we didn’t plan it right – the outside of the cup would shrink away from the cavity in the B-side. Instead of staying on the side with the ejector pins to easily release it, it would stick to the A-side, where there are no ejector pins.And if this happens… we have a problem.Of course, in the example of the cup, it isn’t hard to think through the process and work out where you want things to end up. However, not every design is quite that simple. On some parts, it is difficult to predict in advance which side of the mould the part will stick to, but well thought-out part design ensures that the part will naturally stick to the correct side of the mould.Let's consider a rectangular enclosure, like a little box, with four through holes, for example.The outside of the enclosure will be a cavity in the A-side of the mould. The inside will be a core on the B-side, and that’s where we want it to end up. Okay?Design for the holes, however, could be handled in two different ways. They could be drafted toward the A-side, requiring cores in the A-side of the mould, but this might cause the part to stick to that side, which is something we want to avoid. Rather than that, we should probably draft the cores to the other direction, which would help with ensuring that the part sticks to the B-side of the mould.On top of this, we have to think about any tabs or strips sticking from the part or spanning an internal hole. These should also be drafted to the B-side, to prevent sticking in the A-side and bending or tearing off when the mould opens.Finally, we need to take into account any texturing on the surfaces. If we have a rough pattern or texture on the outside of a part without adequate draft we need to think carefully about its location as it could cause the part to stick in the A-Side.If you’re concerned about these factors when you’re designing a part, your manufacturer should have both the software tools and the experience on hand to ensure you make the correct choice.Watch other Protolabs Insight videos <a href="https://www.protolabs.com/en-gb/resources/insight/insight-video-library/?utm_source=wevolver&utm_medium=referral&utm_campaign=uk-insight-video-0919&utm_content=wevolver-insight-library-0724" target="_blank">here</a>.

When designing for rapid injection moulding, one of the main goals is producing quick and clean parts. We’ll discuss considerations such as designing for holes, tabs or strips sticking up from the part or spanning an internal hole and surface texturing.

Injection Moulding: Core and Cavity Placement

Injection molding is a widely used manufacturing process for producing plastic parts. One crucial aspect of designing these parts is incorporating a draft angle. But what exactly is a draft angle, and why is it so important? In this article, we'll explore what draft angle in injection molded parts is, its benefits, and five key strategies for effectively incorporating it into your designs.<h2 dir="ltr">What is Draft Angle in Injection Molded Parts?</h2>A draft angle is a slight taper added to the vertical surfaces of a part design. Plastic injection molded parts must be removed from molds after they cool and solidify, this angle facilitates the removal of the part. Without the drafts, it becomes challenging to remove these parts from molds, causing costly and time-consuming production delays.<h2 dir="ltr">Advantages of Adding Draft Angle in Injection Molded Parts?</h2>Beyond facilitating the removal of parts from molds, adding a draft angle to your injection molded parts offers several benefits:1)&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;Reduces Surface Damage:&nbsp;Minimizes friction during the ejection process, protecting the part's surface.2)&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;Ensures Surface Uniformity:&nbsp;Maintains the integrity of textures and finishes.3)&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;Prevents Deformation:&nbsp;Reduces part deformation caused by unsmooth ejection.4)&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;Decreases Mold Wear:&nbsp;Lessens wear on molds, lowering the risk of damage.5) &nbsp; &nbsp; &nbsp;Shortens Cooling Time: Simplifies ejection setups, potentially reducing overall cooling time.<h2 dir="ltr">5 Key Draft Angle Strategies for Better Injection Molded Parts</h2><h3 dir="ltr">1. Essential Rules for Draft Angles</h3>1) The draft angle is generally 1 to 2 degrees.2) Parts with high dimensional accuracy requirements should use smaller draft angles.3) The draft angle for convex features should be larger than that for concave features to facilitate ejection.4) For parts with thicker walls, the molding shrinkage increases, so the draft angle should be larger.<div dir="ltr" align="left"><table><tbody><tr><td>Feature Depth</td><td colspan="4">Minimum Thickness/Draft Angles</td></tr><tr><td>0.25 in.</td><td>0.040 in./0.5°</td><td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td></tr><tr><td>0.5 in.</td><td>0.040 in./1°</td><td>0.060 in. /0.5°</td><td>&nbsp;</td><td>&nbsp;</td></tr><tr><td>0.75 in.</td><td>0.040 in. /2°</td><td>0.060 in. /1°</td><td>0.080 in. /0.5°</td><td>&nbsp;</td></tr><tr><td>1 in.</td><td>&nbsp;</td><td>0.060 in. /2°</td><td>0.080 in. /1°</td><td>0.100 in. /0.5°</td></tr><tr><td>1.5 in.</td><td>&nbsp;</td><td>&nbsp;</td><td>0.080 in. /2°</td><td>0.100 in. /1°</td></tr><tr><td>2 in.</td><td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td><td>0.100 in. /2°</td></tr></tbody></table></div>&nbsp;&nbsp;<h3 dir="ltr">2. Draft Angles for Injection Molded Materials and Structures</h3>Materials with higher hardness require larger draft angles. Surfaces that are not smooth also need larger draft angles. Additionally, parts with complex shapes, higher shrinkage rates, and reinforced plastics should all use larger draft angles. Please refer to the table below for draft angles of some common materials and features.<div dir="ltr" align="left"><table><tbody><tr><td>Material</td><td>Minimum Draft&nbsp;</td><td>Recommended Draft&nbsp;</td></tr><tr><td><a href="https://www.fictiv.com/articles/nylon-injection-molding" target="_blank">Nylon</a></td><td>0°</td><td>1°</td></tr><tr><td><a href="https://www.fictiv.com/articles/polyethylene-injection-molding" target="_blank">Polyethylene (PE)</a></td><td>0.5°</td><td>1.5°</td></tr><tr><td><a href="https://www.fictiv.com/articles/pvc-injection-molding" target="_blank">Polyvinyl Chloride (PVC)</a></td><td>0.5°</td><td>1.5°</td></tr><tr><td><a href="https://www.fictiv.com/articles/polypropylene-injection-molding" target="_blank">Polypropylene (PP)</a></td><td>1°</td><td>2°</td></tr><tr><td><a href="https://www.fictiv.com/articles/polycarbonate-injection-molding" target="_blank">Polycarbonate (PC)</a></td><td>1.5°</td><td>2°</td></tr><tr><td>Ribs</td><td>0.25°</td><td>0.5°</td></tr><tr><td>Textures</td><td>3° (light textures)</td><td>4-5° (heavy textures)</td></tr></tbody></table></div><h3 dir="ltr">3. The Degree and Direction of the Draft Cannot Affect the Functional Realization of the Product</h3>When two parts have a motion relationship, the size and direction of the draft at the mating point need to be considered so as not to affect the realization of product functions. The picture below is the structural cross-section diagram of the button and panel on an electrical product. The function of the button is to trigger the electrical switch, and it is necessary to ensure that the button will not get stuck and shake during movement. Therefore, the upper and lower gaps at the mating surface are required to be consistent, and the movement path of the button is a linear motion. In the original design, the upper and lower gaps at the mating surface of the button and the panel are inconsistent. The button will shake during movement, and it might get stuck in the panel in serious cases, causing the button to fail to trigger the switch. In the improved design, the upper and lower gaps at the mating surface of the button and the panel are consistent, the movement path of the button is vertical, and the button will not get stuck.<h3 dir="ltr">&nbsp;4. Design Side Cores</h3>A draft angle typically helps in the removal of the part from the mold, but if functionality dictates that a surface must be vertical or have specific orientation that does not allow for a draft, a side-action core (or side cores) must be incorporated into the mold design.Side-action cores are mechanisms that slide into the mold cavity to form undercut features or vertical faces that are not parallel to the mold opening direction. It's impossible to realize with a straightforward open and close motion of the mold. However, incorporating side-action cores makes the mold design more complex and significantly increases the cost.<h3 dir="ltr">5. Leverage DFM Analysis</h3>PRWORLD offers free but in-depth DFM analysis for every part design. By simply uploading your 3D CAD model, you'll gain valuable design feedback, including design optimization suggestions, including suggested modifications to improve moldability and ensure quality production. You can also benefit from the expertise of our engineering team and avoid common design pitfalls such as inadequate or missing draft angles, reducing production time and cost.

In this article, we'll explore what draft angle in injection molded parts is, its benefits, and five key strategies for effectively incorporating it into your designs.

5 Key Draft Angle Strategies for Better Injection Molded Parts

Whether you’re a designer, manufacturer, or just curious about the world of plastic parts, this insight will provide you with the knowledge to ensure color consistency in your projects.<h2 data-counter-attr="value0">Color Systems in Plastic Injection Molding</h2>In plastic injection molding (IM), the application of color goes beyond mere appearance. It signifies brand identity, function, and quality. Several color systems are available to help manufacturers achieve precise and consistent coloring.<ul><li>Pantone Matching System (PMS): Widely used for branding strategy and marketing, PMS allows for exact color matching across various materials.</li><li>CIE L*a*b System: A color-opponent space that quantifies color sensations, enabling precise color communication and control.</li><li>RAL Color System: This is a European color standard used mainly in architecture, construction, and industry, known for its comprehensive and accurate color representation.</li><li>HSB (Hue, Saturation, Brightness): A cylindrical-coordinate system representing color in terms of human perception.</li><li>RGB and CMYK: These systems are commonly utilised in digital printing and display, focusing on red, green, blue, and the combination of cyan, magenta, yellow, and black.</li></ul><h2 data-counter-attr="value1">L*a*b Color System in Plastic Injection Molding</h2>The<a href="https://www.researchgate.net/figure/The-CIELAB-color-space-diagram-The-CIELAB-or-CIE-L-a-b-color-system-represents_fig1_338303610" target="_blank" rel="noreferrer noopener">&nbsp;L*a*b color system</a>, also known as CIE L*a*b, stands at the forefront of precision in color representation. It operates on three dimensions: L* for lightness, a* for green to red, and b* for blue to yellow.By quantifying color sensations, the L*a*b system creates a standardised color-opponent space, making it indispensable for industries needing exact color matching.A vital benefit of the L*a*b system is its device-independent nature, meaning that colors remain consistent across different devices or displays.&nbsp;Its mathematical foundation ensures that any color within human vision can be described, a crucial aspect in plastic injection molding where color precision is paramount.Various online tools like this fix sensor are available for converting color values to the L*a*b system.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1717059374051-CIE-Lab-Colour-Space.webp" style="width: 100%px;" class="fr-fic fr-dib">CIE L*a*b* Color Space<h2 data-counter-attr="value2" id="isPasted">The RAL Color Standard in Injection Molding</h2>The<a href="https://www.ralcolorchart.com/about-ral-colors#:~:text=RAL%2520is%2520a%2520color%2520matching,Ausschu%25C3%259F%2520f%25C3%25BCr%2520Lieferbedingungen%2520und%2520G%25C3%25BCtesicherung'." target="_blank" rel="noreferrer noopener">&nbsp;RAL color system</a>, stemming from the German Reichs-Ausschuß für Lieferbedingungen, is a widely recognised European color standard. With over 2,300 colors, it’s extensively used in architecture, construction, and injection molding industries.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1717059392224-RAL-colour-palette-1024x610.webp" style="width: 100%px;" class="fr-fic fr-dib">RAL color paletteUnlike the L*a*b system, RAL focuses on categorising colors into collections, like Classic, Effect, and Design. It’s renowned for its accurate color representation, particularly in industrial applications.<h2 data-counter-attr="value3">Comparative Analysis: L*a*b vs. RAL</h2>While both systems have their unique strengths, comparing them reveals distinct differences:<ul><li>Universality: L*a*b’s mathematical approach makes it more universal, while RAL’s categorised collections cater to specific industries</li><li>Precision: L*a*b offers device-independent accuracy, whereas RAL’s physical color representations may differ across devices</li><li>Application: L*a*b is broader, while RAL is often favoured in European industrial contexts</li></ul>The choice between L*a*b and RAL depends on the specific requirements of the plastic injection molding project. Understanding their intricacies will help select the system that ensures color uniformity, satisfying technical demands and aesthetic preferences.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1717059410271-Red-round-injection-moulded-parts.webp" style="width: 100%px;" class="fr-fic fr-dib">Red round injection molded parts<h2 data-counter-attr="value4" id="isPasted">Achieving Color Uniformity in Plastic Injection Molding</h2><h3 data-counter-attr="value5">Design Tips for Color Consistency</h3>When it comes to maintaining color uniformity in plastic injection molding, the design stage plays a critical role. Here’s how to make it work:<ol><li>Material consideration: Understanding the material’s characteristics is crucial, as different engineering plastics react differently to colorants</li><li>Colorant selection: Utilising high-quality colorants that match the polymer used helps achieve consistent shades</li><li>Simulation and prototyping:&nbsp;Testing colors through simulation and prototypes ensures that the final product will match the desired tone</li><li>Consider environmental impact: Different lighting conditions and environments can affect color appearance. Design with the end-use environment in mind</li></ol><h3 data-counter-attr="value6">Selection Guide for Uniform Colors</h3>Choosing suitable materials and methods is paramount for color uniformity in injection molding. Here’s a guide to follow:<ol><li>Understand the project requirements: Identify the exact color specifications and the intended application of the part</li><li>Choose the right color system:&nbsp;Select between systems like L*a*b or RAL based on the project’s needs and industry standards</li><li>Select appropriate colorants:&nbsp;Work with suppliers who provide industry-certified colorants, ensuring quality and consistency</li><li>Consult with professionals:&nbsp;Engage with experienced engineers or color specialists who can guide you in achieving the exact shade</li></ol><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1717059431593-Injection-moulded-orange-corner-brackets.webp" style="width: 100%px;" class="fr-fic fr-dib">Injection molded orange corner brackets<h3 data-counter-attr="value7" id="isPasted">Sending a Sample to the Manufacturer: A Must-Do Step</h3>A practical and often overlooked solution to ensuring color uniformity is sending a sample to the manufacturer. This sample, a 50 x 50 mm flat surface, can be a cut piece of material from a targeted color or a part you’d like to match with newly manufactured parts.This practice of sending a sample to Xometry or the respective manufacturer allows for precision in color matching. It eliminates guesswork, reduces the risk of inconsistencies, and ensures that the final product aligns perfectly with the customer’s expectations.<h2 data-counter-attr="value8">Conclusion</h2>In the multifaceted world of plastic injection molding, color uniformity is more than a visual aspect; it symbolises quality, brand identity, and customer satisfaction.&nbsp;Through a detailed understanding of color systems like L*a*b and RAL, meticulous design planning, strategic selection, and sending a sample to the manufacturer, achieving precise color tones becomes an attainable goal.&nbsp;These principles, rooted in technical expertise and collaboration, ensure that the final product resonates with the desired vision, paving the way for success in any plastic molding endeavour.Xometry provides a wide range of manufacturing capabilities, including plastic injection molding and other value-added services for all of your prototyping and production needs.

Colour uniformity in plastic injection moulding is more than just an aesthetic concern; it is a vital part of product quality. In this article, we'll unravel the complexities of different colour systems used in injection moulding and the importance of specifying colour tones numerically.

Injection Molding

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