How PLA Temperature Resistance Compares to Other 3D Printing Materials

In the context of 3D printing—or any manufacturing process for that matter—temperature resistance is one of the most important material properties to be aware of. The thermal properties of a material ultimately determine the working conditions that the printed product can withstand and influences its overall longevity and performance. For example, you wouldn’t use a material that deforms in boiling water to make a component for a kettle or a mug. It just wouldn't make sense. This article is looking specifically at PLA temperature resistance and contrasting it with other popular 3D printing materials to help you better understand the thermal properties of 3D printing filaments and know what types of applications they can be used for.

What is Temperature Resistance in 3D Printing?

To start, let’s first cover what we mean when we talk about temperature resistance. Temperature resistance, often referred to as heat resistance, is an essential property of any material used in manufacturing. In the simplest terms: a material's resistance to temperature indicates its ability to maintain structural integrity under varying degrees of heat exposure.

While all materials can withstand some level of heat, they each have a defined point at which their structure begins to degrade. For plastic 3D printed objects, exposure to temperatures above their temperature resistance can lead to issues like warping, melting, or even total failure of the printed structure. All that to say: you don’t want to be using a material with low temperature resistance to print a part that will be exposed to high temperatures. 

To further elaborate, temperature resistance refers to the maximum temperature a material can withstand before it begins to degrade structurally. This property is typically measured in degrees Celsius (°C) or Fahrenheit (°F).

How is temperature resistance determined?

A material's temperature resistance is often determined through various testing procedures. These typically involve exposing the material to progressively higher temperatures until visible structural changes occur. For instance, a common sign of reaching a material's temperature resistance limit is the onset of softening, where the material becomes pliable and loses its rigid form.

Notably, temperature resistance isn't a standalone factor in determining a material's suitability for a specific application. Other properties such as strength, flexibility, and durability also come into play. However, it is a key consideration when printing parts that are expected to endure elevated temperatures.

How does temperature resistance influence 3D printing?

In the context of 3D printing, temperature resistance influences several factors. One of these is printability. Materials with a higher temperature resistance typically require higher extrusion temperatures. Another factor is the working conditions that a printed part can withstand. For example, a printed component with high temperature resistance would be more suitable for use in environments exposed to significant heat, such as the engine compartment of a vehicle.

In the printing process itself, temperature resistance factors into what print settings you will work with. For example, the melting point of a material, which directly correlates with its temperature resistance, influences the extrusion temperature settings on the 3D printer. A material with a high temperature resistance, such as ABS, would require a higher extrusion temperature to properly melt and form the desired shape. While materials like PLA, which require a lower printing temperature, have a lower thermal resistance threshold.

Furthermore, the temperature resistance of a material can significantly affect the dimensional stability of a printed object. This is particularly evident when the printed object is subjected to heat after the printing process. A material with low temperature resistance, such as PLA, tends to deform or warp when exposed to high temperatures post-printing. This behavior can affect the dimensional accuracy and overall performance of the printed object. In contrast, a material with high temperature resistance maintains its form and structure even when subjected to heat, ensuring the durability and longevity of the object in more extreme conditions.

Lastly, it is important to note that while temperature resistance is a significant factor in material selection, it is not the sole consideration. Other factors such as tensile strength, flexibility, and the intended application of the final product also contribute to the selection of the appropriate 3D printing material.

PLA Temperature Resistance

Polylactic Acid (PLA) is the most commonly used type of thermoplastic filament in 3D printing. This popularity is owed to a few reasons: PLA is very easy to print, even for beginners, it is affordable, and because it is made from plant-based resources it is more ecological than petroleum-derived thermoplastics. That said, PLA has relatively low temperature resistance compared to other thermoplastics (part of why it is so easy to print), which presents some limitations in terms of the applications it is suitable for. 

PLA tends to deform or warp at temperatures around 60-65°C, far lower than materials like ABS or Nylon. This attribute is linked to PLA's glass transition temperature, which is the temperature at which a plastic changes from a hard, glassy material to a soft one. This relatively low temperature resistance impacts how and where PLA can be used. 

PLA is a thermoplastic material derived from plant-based resources, like corn starch.

Introduction to PLA

Polylactic Acid (PLA) is a thermoplastic polyester derived from renewable resources like corn starch or sugarcane. It has gained popularity in 3D printing due to its ease of use and environmentally friendly characteristics.

PLA has a lower extrusion temperature compared to many other 3D printing materials, usually around 200-220°C, making it suitable for low-cost, hobby-grade 3D printers. It also exhibits minimal warping during the printing process, even without a heated print bed, resulting in high print success rates.

In terms of mechanical properties, PLA exhibits good tensile strength but lacks in flexibility, making it brittle under strain. This means the material is not often used for functional applications where parts require load bearing or stress resistant properties. PLA is also not known for its chemical resistance: in fact, the material is soluble when exposed to solvents such as ethyl acetate. However, the property of interest in this context is temperature resistance. While PLA's relatively low temperature resistance might seem like a drawback, it aligns perfectly with certain use-cases, particularly those that do not involve exposure to high temperatures.

Recommended reading: PLA bed temperature & print temperature settings

Characteristics of PLA's Temperature Resistance

PLA’s glass transition temperature typically lies in the range of 60-65°C.[1] This relatively low glass transition temperature contributes to PLA's modest temperature resistance. When exposed to temperatures above this range, PLA tends to soften and deform. When heated to even higher temperatures (180-220°C), the thermoplastic will begin to melt. (The specific temperature at which PLA begins to melt varies depending on the exact composition of the PLA blend.)

It's also worth noting that temperature resistance can be affected by other factors such as the rate of heating, the duration of exposure, and any physical stresses the material may be under. For example, a PLA object subjected to a rapid increase in temperature or prolonged exposure to high temperatures may deform more significantly than one subjected to a gradual increase in temperature.

PLA's temperature resistance has significant implications for its use in 3D printing. For example, objects printed from PLA are not suitable for use in high-temperature environments. On the other hand, the low glass transition temperature makes PLA easier to print with, as it requires a lower extruder temperature. Moreover, since PLA does not warp significantly during the cooling process, it is possible to achieve a high level of detail and accuracy in PLA prints.

Comparing PLA with Other 3D Printing Materials

In this section, we’ll be comparing PLA with other commonly used 3D printing materials to better understand how its thermal properties stack up and what types of applications the material is best suited for. 

ABS Temperature Resistance

Like PLA, Acrylonitrile Butadiene Styrene (ABS) is among the most popular materials for FDM 3D printing. It is a thermoplastic polymer derived from petroleum and is known for its robustness and high-temperature resistance.

ABS has a glass transition temperature around 105°C, considerably higher than PLA. This higher transition temperature means parts made from ABS can withstand higher temperatures before starting to deform. It is this feature that often makes ABS a preferred choice for applications where the printed objects might be exposed to high temperatures or direct sunlight, like automotive parts or outdoor tools.

As a consequence to its thermal resistance, ABS requires a higher printing temperature than PLA. ABS begins to melt at approximately 220°C (though the material itself is amorphous so does not technically have a melting point), and benefits from a heated print bed. The higher temperature required to print ABS as well as the need for a heated bed, make the material less straightforward to print than PLA.

The higher temperature resistance of ABS comes with other considerations. ABS parts are prone to warping during the cooling process due to the significant difference in contraction between the material at high temperature and room temperature. This warping can result in print defects if not managed correctly. Also, ABS releases potentially hazardous fumes during printing that require adequate ventilation or air filtration.

Overall, ABS offers superior temperature resistance to PLA, but comes with caveats, like the higher risk of warping and the need for a well-ventilated workspace. These factors, along with the specific requirements of a project, will influence the choice of material for 3D printing.

Recommended reading: ABS print temperature considerations: Nozzle, bed, enclosure

PETG Temperature Resistance

Polyethylene Terephthalate Glycol (PETG) is another 3D printing material that is often compared to PLA due to their similar ease of printing and general-purpose utility. However, the materials also have important differences, particularly when it comes to thermal properties and temperature resistance.

The glass transition temperature of PETG is about 85°C, which is significantly higher than PLA’s 60°C glass transition temperature. This means objects 3D printed using PETG filament can withstand higher ambient temperatures before deforming. For projects where the final product may face moderately high temperatures, such as components inside electronic devices, PETG might be a better choice than PLA.

PETG also has a significantly higher melting temperature than PLA, around 260°C. This again opens up more application opportunities for PETG, because the material can be used in a wider range of environments. At the same time, however, the higher melting temperature necessitates higher extruder temperatures during the printing process.

Similar to ABS, PETG is prone to warping and shrinkage due to its temperature characteristics. However, these issues are less pronounced with PETG compared to ABS, making PETG easier to print with while still benefiting from increased temperature resistance compared to PLA. Furthermore, PETG offers increased durability and impact resistance, making it suitable for objects subject to mechanical stress. This resistance is an additional advantage when coupled with its superior temperature resistance compared to PLA.

Recommended reading: How PETG melting point influences 3D printing

Nylon Temperature Resistance

Nylon, also known as Polyamide, is another popular material in the 3D printing world, valued for its impact resistance, flexibility, and durability. In terms of its temperature resistance, Nylon has a glass transition temperature of around 60-80°C and a melting point around 220°C. The material’s optimal 3D printing temperature is around 250°C.

A notable feature of Nylon is its low thermal expansion coefficient. This means that Nylon parts undergo minimal dimensional changes when exposed to different temperatures, leading to improved dimensional stability compared to PLA. The low thermal expansion rate can be critical in applications that involve high temperatures and require precision, such as mechanical parts.

One unique characteristic of Nylon is its hygroscopic nature. This means it absorbs water from the air, which can lead to a change in its properties.[2] If not properly stored in an airtight enclosure, the material will retain moisture, which can lead to complications during printing, like steam bubbles that create voids in the printed object.

Nylon also benefits from a heated bed (in the range of 70-100°C), which helps prevent warping and improves adhesion. An enclosed print chamber can also help maintain a consistent temperature and prevent the absorption of moisture during printing.

Nylon's superior temperature resistance, coupled with its toughness and flexibility, make it an excellent choice for parts that need to withstand high temperatures, mechanical stresses, and wear. However, the challenge of handling its hygroscopic properties and the need for high print temperatures require additional consideration when choosing it as the printing material.

Recommended reading: Printing with Nylon filament: Tips and applications for printing with nylon filament

Evaluating the Impacts of Temperature Resistance

Impacts of Temperature Resistance on Material Performance

Temperature resistance is a crucial factor affecting the performance of 3D printed materials. It determines how a part will behave when subjected to varying temperatures during its life cycle, from manufacturing to end-use.

A material's glass transition temperature (Tg) is the temperature at which the polymer transitions from a hard, glassy state to a rubbery state. Above this temperature, the material becomes more pliable and less able to maintain its shape under load, impacting its mechanical strength. PLA has a relatively low glass transition temperature implying that parts made from the material may start to deform in hot environments, such as a car parked in the sun. ABS, on the other hand, which has a glass transition temperature around 105°C, remains stable at higher temperatures, thus is more suitable for high-temperature applications.

A material's melting point is also a vital consideration. It signifies the temperature at which the material will change from solid to liquid. During the 3D printing process, this is the temperature at which the filament must be heated to create a print. PLA has a lower melting point, making it easier to print with, however this also means PLA parts are less capable of withstanding high temperatures.

The coefficient of thermal expansion (CTE) is a material property that measures how much a material expands or contracts per degree change in temperature. A high CTE means a material will undergo more significant dimensional changes with temperature fluctuations, affecting the dimensional stability and tolerances of printed parts. PLA has a relatively low CTE (68µm/m-K) compared to ABS (~90µm/m-K), meaning PLA parts are less prone to warp under temperature changes. PETG and PLA have similar CTE values. 

Lastly, a material's thermal conductivity impacts how quickly heat is transferred through the material. This is particularly important when the printed part is expected to function in an environment where it's subjected to varying degrees of heat. Like most thermoplastics, PLA has low thermal conductivity, in the range of 0.13W/(m.K). This indicates that it does not dissipate heat quickly. If thermal conductivity is important, there are some specialty 3D printer filaments with enhanced heat transfer properties.

Due to its low temperature resistance, PLA is commonly used for prototypes and non-functional models.

Impacts of Temperature Resistance on Print Quality

Temperature resistance also influences the quality of the end product in 3D printing, particularly when it comes to dimensional accuracy. As materials react to temperature changes, their dimensional stability is affected. While PLA has a low CTE and is not prone to warping within a certain temperature range, parts made from the material will not retain their shape or integrity when exposed to temperatures above 60-60 degrees Celsius. 

Another critical aspect is the aesthetic quality of the printed part. PLA's lower melting point allows for smoother extrusion during the printing process, often resulting in parts with superior surface finish. On the other hand, materials with higher melting points like ABS and Nylon might offer increased resistance to deformation over the long term, preserving the aesthetics of the final product even under high-temperature conditions.

Mechanical performance is another crucial determinant of end product quality. Materials with better temperature resistance often provide superior mechanical properties. For instance, the heat deflection temperature (HDT) indicates the temperature at which a material starts to deform under a certain load. PLA has a relatively low HDT between 53-56°C, meaning that PLA-based parts can start to deform under stress in hot environments. On the contrary, materials like ABS and Nylon, with higher HDTs (up to 100°C and greater than 175°C, respectively), maintain their mechanical integrity at higher temperatures and under stress, delivering better performance in applications demanding high temperature resistance.

Temperature resistance can also influence the post-processing potential of the printed parts. Materials with higher temperature resistance and good chemical resistance, like ABS and Nylon, may be more suitable for certain post-processing techniques such as vapor smoothing, which involves exposure to heat and solvents and could cause deformation in materials with lower temperature and chemical resistance like PLA.

In essence, the temperature resistance of the material used in 3D printing directly affects the quality of the final product, from its dimensional accuracy and aesthetic appeal to mechanical performance and post-processing capabilities. Therefore, the selection of material should always consider the temperature conditions the end product will face.

Considerations for Choosing the Right Material

One of the first things to think about when choosing an FDM filament, are the environmental conditions in which the final printed part will be placed or used. For instance, if the printed object will be used outdoors, it should be able to withstand varying temperature ranges, including potentially high temperatures during the summer months. Similarly, if the part is intended for use inside vehicles or near heat-producing electronics, it will require a material with high-temperature resistance.

At the same time, the functional requirements of the printed part also dictate the need for certain thermal properties. For load-bearing parts or those subject to stress, materials with high heat deflection temperature (HDT) like ABS or Nylon could be more suitable. HDT indicates the temperature at which a material deforms under a specific load, and a higher HDT means the part can withstand higher temperatures before losing its structural integrity.

Additionally, it's necessary to take into account the heat generated during the operation of the printed part. For components that come into contact with heat-producing elements or that generate heat themselves due to friction or other factors, it's crucial to select a material with high thermal resistance.

Lastly, it's worth considering the potential exposure of the part to sudden temperature changes. Rapid temperature fluctuations can induce thermal stress in materials, leading to warping or cracking. Hence, for environments with abrupt temperature changes, materials with lower coefficients of thermal expansion (CTE) should be considered, as they expand less when heated and contract less when cooled, thereby resisting deformation better.

Consider all these factors as you choose the most appropriate material for a specific application.

Other Factors to Consider

In addition to thermal properties like temperature resistance, there are numerous other factors that must also be taken into account to ensure the best material choice is made.

• Mechanical properties: The mechanical properties of the material are crucial, especially in terms of strength and flexibility. Depending on the intended application, one might need a material with high impact resistance and strength, or conversely, something more flexible, such as Nylon or TPU. PLA specifically has an interesting range of mechanical properties, including a high tensile strength (about 50 MPa). However, because the material is very brittle, the material ultimately has a low impact resistance compared to materials like ABS, which technically have lower tensile strengths.

• Chemical Resistance: Chemical resistance is another important aspect to look into. The ability of the material to withstand exposure to various substances without degrading or changing properties can be paramount. For example, Nylon is known for its resistance to many solvents, while PLA may be adversely affected by exposure to certain chemicals and can dissolve when exposed to solvents.

• Printability: Ease of printing is also a relevant consideration. Different materials require different printer settings, with some being more challenging to print with than others. PLA, for example, is often praised for its printability, with a low printing temperature range of 180-220°C and no need for a heated bed. This makes it an excellent choice for beginners. In contrast, materials like ABS or Nylon are more challenging to print due to their higher warping tendency and the need for a heated bed and high print temperatures.

• Cost: It should go without saying that another important factor is the cost of the material. Commonly used materials like PLA and ABS are usually more affordable than specialized materials like Nylon or PETG. The cost-effectiveness of a material is a crucial factor, especially for large-scale printing or prototyping, where the material cost can significantly affect the overall budget.

• Biocompatibility: Biocompatibility can also be a critical factor for certain applications, particularly where contact with skin is involved. For instance, certain grades of PLA are biocompatible and can be used for creating wearables or prosthetics.

• Sustainability: Last but not least, the environmental impact and biodegradability of 3D printing materials may also come into play. Some filaments, like PLA, are derived from renewable resources and have biodegradable properties, meaning they will eventually decompose under the right conditions. For many, this is a benefit over non-renewable filaments like ABS.

Ultimately, choosing the right material for 3D printing is a multifaceted decision, involving not only temperature resistance but also a wide array of other factors. Understanding these aspects can lead to more informed material choices and ultimately to the successful production of 3D printed parts that meet their intended applications' specific needs.

How to Enhance PLA's Temperature Resistance

PLA, despite its numerous advantages, suffers from relatively low temperature resistance, which can be a limitation in certain applications. However, there are methods to enhance its temperature resistance, which can make it suitable for a wider range of applications.

Post-processing Techniques

Specific post-processing techniques can be used to enhance the temperature resistance and strength of PLA. 

• Annealing: One such technique is annealing, which is a heat treatment process. In the annealing process, the PLA part is gradually heated to a temperature near its glass transition temperature. The part is then kept at this temperature for a certain period of time, before being slowly cooled down. This process allows the polymer chains to reorganize and crystallize, which improves the heat deflection temperature of the part. Typically, PLA parts are annealed at temperatures between 60-70°C for about 30-60 minutes. It's crucial to ensure the cooling process is gradual to prevent warping or dimensional changes.

• Coatings: Another post-processing method that can enhance heat stability and resistance is the application of coatings to a PLA print. Coatings such as epoxy resins can form a heat-resistant layer on the surface of the part, improving its temperature resistance. We should note, however, that coatings will affect the dimensional accuracy of the final part. 

While post-processing techniques can improve PLA's temperature resistance, they might not be enough for some applications that require very high-temperature resistance. In such cases, it might be necessary to consider other materials with inherently superior thermal resistance, such as ABS, Nylon, or PETG. For even more demanding applications, hardy engineering-grade plastics like PEEK, could be a good solution.

High-Temp PLA 

While you can improve PLA’s temperature resistance independently using the aforementioned processes of annealing or coatings, it is also possible to seek out specially engineered PLA-based filaments that are enhanced for heat resistance and toughness. 

Some filament brands offer special high-temperature PLA. For example, Proto-Pasta HTPLA Filament can withstand temperatures up to 140°C after annealing.[3] These high-temp PLA materials do, however, tend to be higher in cost and require annealing to unlock their benefits.

There are also a variety of PLA materials reinforced with chopped carbon fibers. These materials, typically with 10-20% carbon fiber reinforcement, are more rigid than neat PLA, but can often be more brittle.[4] Due to the abrasiveness of the fibers, they can also require more hardy 3D printer nozzles to print.

Final Thoughts

As we’ve seen, temperature resistance is a fairly complex topic, influenced by a range of factors such as the crystallinity of the material, the rate of heat transfer, and the nature of the heating process. And it's clear that while PLA has many advantages, its low-temperature resistance limits its applications in certain fields. It's also crucial to consider other factors such as mechanical properties, biodegradability, and cost when choosing the right material for a specific application.

Frequently Asked Questions (FAQs)

Q: What is the melting point of PLA?

The typical melting point of PLA is between 170 to 180 degrees Celsius. However, it's important to note that the glass transition temperature (Tg), the temperature at which the material becomes soft and pliable, is much lower, at around 65 degrees Celsius.

Q: Can PLA withstand boiling water?

Given that the boiling point of water is 100 degrees Celsius, which is higher than PLA's glass transition temperature, PLA will become soft and pliable when exposed to boiling water. It is therefore not suitable for applications that require exposure to boiling water without modification or post-processing to enhance its temperature resistance. The material can also not be cleaned using boiling water because it will start to soften.

Q: Can the temperature resistance of PLA be enhanced?

Yes, the temperature resistance of PLA can be improved through various techniques such as the annealing process, which involves heating the material to just below its melting point and then slowly cooling it. Other methods include material modifications such as copolymerization, blending, and the use of nanocomposites.

Q: What other factors should I consider when choosing a material for my application?

Apart from temperature resistance, it's crucial to consider factors such as the mechanical properties (strength, flexibility, hardness), biodegradability, the intended use of the product (for instance, whether it will be used indoors or outdoors, whether it will be exposed to chemicals or UV radiation), and cost. Ultimately, the best filament choice will depend entirely on the application at hand.

References

[1] Bergström JS, Hayman D. An overview of mechanical properties and material modeling of polylactide (PLA) for medical applications. Annals of biomedical engineering. 2016 Feb;44(2):330-40. 

[2] Nylon and Moisture Absorption [Internet]. NYCOA. June 2020. Available from: https://nycoa.com/recent-news/2020/moistureinnylon 

[3] Proto-Pasta HT PLA Filament [Internet]. Lulzbot, 2023. Available from: https://lulzbot.com/store/proto-pasta-ht-pla-filament#product-description 

[4] Carbon Fiber Filled [Internet]. Simplify3D, 2023. Available from: https://www.simplify3d.com/resources/materials-guide/carbon-fiber-filled/