If you’re venturing into the world of 3D printing, you’ve probably heard about PLA, or Polylactic Acid. It’s one of the most popular materials for 3D printing, especially among beginners. But to get the best results, understanding its melting point is crucial. Let’s dive into the key insights about the melting point of PLA and how it impacts your 3D printing projects.
What is PLA?
PLA, or Polylactic Acid, is a biodegradable thermoplastic derived from renewable resources like corn starch or sugarcane. It’s known for being eco-friendly and easy to print with, making it a favorite among hobbyists and professionals alike.
PLA 3D Printing Properties
| Property | Details |
|---|---|
| Extruder Temperature | 190 – 220°C |
| Heated Bed | Optional |
| Ultimate Strength | 65 MPa |
| Stiffness | 7.5/10 |
| Durability | 4/10 |
| Maximum Service Temperature | 52°C |
| Coefficient of Thermal Expansion | 68 µm/m-°C |
| Density | 1.24 g/cm³ |
| Price (per kg) | $10 – $40 |
| Printability | 9/10 |
| Recommended Build Surfaces | Painter’s Tape, Glue Stick, Glass Plate, PEI |
| Other Hardware Requirements | Part Cooling Fan |
4o mini
Why is the Melting Point Important?
Understanding the melting point of PLA is crucial for a few reasons:
- Print Quality: Printing at the correct temperature ensures smooth extrusion and good layer adhesion, leading to higher-quality prints.
- Avoiding Clogs: Printing at too low a temperature can cause clogs in the nozzle, while too high a temperature can lead to oozing and stringing.
- Material Properties: The melting point can also affect the mechanical properties of the printed object, including its strength and durability.
What is the Melting Point of PLA?
The melting point of PLA typically hovers around 175°C (347°F). This temperature is where PLA transitions from a solid to a liquid state, allowing it to be extruded through the 3D printer’s nozzle. However, the exact melting point can vary slightly depending on the specific formulation of the PLA filament you’re using.
| Parameter | Details |
|---|---|
| Temperature | PLA softens at ~60°C and melts between 170°C and 180°C. Print between 180°C and 220°C. |
| Bed Temperature | Typically 40°C to 60°C, beneficial for larger prints or colder environments. |
| Cooling | Use active cooling fans after initial layers to prevent issues like sagging. Increase to 100% after strong layer adhesion. |
What Happens When PLA Melts?
PLA is a thermoplastic, meaning it can be melted and solidified repeatedly without losing its properties. When PLA melts, its intermolecular bonds stretch but stay intact, allowing it to become fluid-like. In 3D printing, PLA is heated in the “melt zone” of the hot end, turning it into a molten state that can be extruded through a nozzle and laid down in layers on the build plate.
How to Find the Perfect PLA Melting Temperature?
While the melting point of PLA is around 175°C, the ideal printing temperature is usually a bit higher, typically between 190°C and 220°C. This range allows for optimal flow and bonding of the layers. Here are some tips for finding the perfect temperature for your specific PLA filament:
- Start with the Manufacturer’s Recommendations: Most PLA filaments come with a recommended temperature range, often between 180°C and 220°C. Start at the lower end and gradually increase if needed.
- Test Prints: Print a small object, like a temperature tower, which helps you see how the filament behaves at different temperatures. This can show you where your sweet spot is.
- Watch for Signs: If your prints are under-extruding or the layers aren’t sticking well, increase the temperature slightly. If you notice stringing or oozing, decrease it a bit.
The Role of the Print Bed Temperature
PLA also benefits from a heated bed, though it’s not always necessary. If you use one, keep it around 60°C. This helps the first layer stick better and reduces warping. However, PLA can print well on a non-heated bed with proper adhesion aids like blue painter’s tape or a glue stick.
Cooling Fans and PLA
PLA benefits from good cooling during printing. Using a cooling fan can help solidify the layers quickly, leading to better print quality and sharper details. Most 3D printers have a cooling fan that you can adjust through the printer’s settings.
How is PLA Melting Point Determined?
The most common method for determining the melting point of PLA is Differential Scanning Calorimetry (DSC). DSC measures how a material’s heat capacity changes as it is heated or cooled. Here’s a step-by-step look at how DSC works for PLA:
- Sample Preparation: A small sample of PLA is placed in a DSC pan.
- Heating: The sample is heated at a controlled rate. For PLA, this is usually between 10°C to 20°C per minute.
- Measurement: As the sample heats up, the DSC measures the amount of energy absorbed or released.
- Melting Point Identification: The DSC produces a graph (thermogram) showing peaks that indicate phase transitions. The peak corresponding to the melting point shows the temperature at which PLA transitions from a solid to a liquid state.
In addition to DSC, there are simpler, more practical methods used by hobbyists and professionals in the 3D printing community to determine the working melting point of PLA:
- Extrusion Testing: This involves gradually increasing the temperature of the 3D printer’s extruder while monitoring the flow of PLA. The temperature at which PLA starts to flow smoothly and consistently is considered its working melting point.
- Hot Plate Testing: PLA samples are placed on a heated surface, and the temperature is gradually increased. The temperature at which PLA starts to melt and form a liquid pool is noted as the melting point.
Factors Influencing PLA Melting Point
Several factors can influence the melting point of PLA, making it a bit variable:
Purity of the Material
The purity of PLA significantly impacts its melting point. PLA with fewer impurities tends to have a more consistent and predictable melting point. Impurities can disrupt the polymer structure, causing variations in melting behavior. High-purity PLA ensures reliable performance, which is crucial for precision printing tasks.
Molecular Weight
Molecular weight refers to the length of the polymer chains in PLA. Higher molecular weight PLA has longer chains, which generally results in a higher melting point. This is because longer polymer chains require more energy to move past each other and transition from solid to liquid. Therefore, PLA with higher molecular weight is often more robust and better suited for demanding applications.
Crystallinity
PLA can exist in either a semi-crystalline or amorphous state, and this affects its melting point. Semi-crystalline PLA has regions where the polymer chains are highly ordered, and these crystalline regions melt at a distinct temperature, giving it a clear melting point. In contrast, amorphous PLA, where the polymer chains are more randomly arranged, results in a broader melting range rather than a sharp melting point. Amorphous PLA is generally easier to print with but may not have the same strength as semi-crystalline PLA.
Additives
Various additives are incorporated into PLA to enhance its properties, and these can also influence its melting point. Plasticizers make PLA more flexible but can lower its melting point. Colorants, such as dyes and pigments, can slightly alter the melting point depending on their chemical composition. Additionally, fillers and reinforcements like wood, carbon fiber, or metal particles added to PLA can change its thermal properties, including the melting point.
Why Does PLA Melt Inside a Hot Car?
PLA prints can deform inside a hot car because, while the car’s internal temperature may not reach PLA’s melting point, it can easily reach PLA’s glass transition temperature of 60 to 65°C. At this temperature, PLA loses its rigidity and becomes more viscous. This makes it prone to warping or deformation. Therefore, PLA prints are best kept indoors and away from direct heat to maintain their shape and integrity.
Can PLA Withstand 100℃?
PLA (Polylactic Acid) generally cannot withstand temperatures as high as 100°C. PLA has a glass transition temperature of around 60 to 65°C, at which point it starts to lose its rigidity and becomes more pliable. Exposing PLA to temperatures above this range, especially around 100°C, can lead to significant deformation or melting.
For applications requiring higher temperature resistance, other materials like ABS, PETG, or Nylon might be more suitable.
Common PLA Melting Point Problems in 3D Printing
Even with a good understanding of PLA’s melting point, you might still encounter some issues. Here are a few common problems and how to address them:
- Stringing: If you notice fine strands of plastic between parts of your print, try lowering the temperature or adjusting the retraction settings.
- Warping: If the edges of your print lift off the build plate, increase the bed temperature or use a brim or raft to help with adhesion.
- Poor Layer Adhesion: If your layers aren’t sticking together well, increase the print temperature or slow down the print speed.
BOYI: Your Partner for 3D Printing
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Conclusion
Understanding the melting point of PLA and how it interacts with your 3D printer is essential for achieving high-quality prints. By starting with the right temperature settings and making adjustments as needed, you can take full advantage of PLA’s user-friendly properties. Whether you’re a beginner or a seasoned pro, mastering the nuances of PLA printing will undoubtedly enhance your 3D printing projects.
More Resources:
pla print speed – Source: BOYI
abs vs pla – Source: BOYI
FAQ
PLA (Polylactic Acid) begins to deform at its glass transition temperature, which is typically around 60 to 65°C. At this temperature, PLA loses its rigidity and becomes more pliable. For significant deformation or softening, temperatures above this range should be avoided.
PLA+ (PLA Plus) is an enhanced version of standard PLA designed to offer improved mechanical properties and higher temperature resistance. The melting point of PLA+ typically ranges from 200°C to 230°C, depending on the specific formulation and manufacturer.
200°C is generally considered within the higher end of the recommended extrusion temperature range for standard PLA. While PLA typically prints well between 180°C and 220°C, printing at 200°C is usually acceptable and can be beneficial for achieving good layer adhesion and flow.
PLA (Polylactic Acid) does not melt in boiling water, but it does soften. PLA has a glass transition temperature of around 60 to 65°C, which is lower than the boiling point of water (100°C). While PLA will not fully melt in boiling water, it can become soft and lose its rigidity.
Catalog: Materials Guide
This article was written by engineers from the BOYI team. Fuquan Chen is a professional engineer and technical expert with 20 years of experience in rapid prototyping, mold manufacturing, and plastic injection molding.
