PLA Melting Point: Detailed Guide for 3D Printing Plastic

If you work with 3D printing, you’ve probably used PLA (Polylactic Acid) at some point. It’s one of the most popular 3D printing materials because it’s easy to use and environmentally friendly.

But to get the best results, you need to understand its melting point and how it affects 3D printing. This guide will explain what PLA is and why PLA melting point matters in 3D printing.

What is PLA?

PLA (Polylactic Acid) is a biodegradable plastic made from renewable resources like cornstarch or sugarcane. Unlike other plastics, it breaks down naturally over time that’s why it is a great choice for eco-friendly 3D printing.

It is safe, easy to print, and has good mechanical properties. However, PLA is sensitive to heat, that’s why it’s important that you know its melting point.

Key Properties of PLA

Here’s a quick look at the important properties of PLA:

What is the Melting Point of PLA?

PLA has a melting point between 150 to 160 °C (302 to 320 °F). However, in 3D-печать, the glass transition temperature is also important because it is where the PLA softens. This affects print stability and heat resistance.

If you print at too low a temperature, the filament won’t melt properly, leading to poor layer bonding. If the temperature is too high, stringing and oozing can occur.

How is PLA Melting Point Determined?

The melting point of PLA is measured using a process called Differential Scanning Calorimetry (DSC). This test heats the material gradually and tracks when it transitions from solid to liquid.

However, PLA’s melting point can vary based on additives, crystallinity, or manufacturer’s variations. Different brands produce PLA with slightly different properties, so always check the recommended temperature settings.

Importance of Melting Point in 3D Printing

PLA melting point is key to achieving high-quality prints and preventing issues. Let’s tackle this further below.

• If PLA doesn’t melt enough, the layers won’t stick together properly, leading to weak and brittle parts. The right temperature ensures strong bonds between layers.
• The filament must be heated enough to flow smoothly but not so much that it overheats.
• Setting the right temperature prevents under-extrusion (weak prints) or over-extrusion (blobby, messy prints).
• Since PLA has a low glass transition temperature, prints can deform if exposed to temperatures above 60 - 65 °C. This is why PLA parts should not be left in hot cars or direct sunlight.

Factors Affecting PLA's Melting Point?

PLA melting point is not always the same– it can change depending on several factors, including the following:

Чистота

High-purity PLA has a consistent melting point, which makes printing more reliable and this is important for precision printing.

On the other hand, PLA with impurities can have an unstable melting point, leading to inconsistent extrusion and print defects. Impurities can disrupt the polymer structure and make the melting point vary.

Molecular Weight

Molecular weight refers to the length of the polymer chains in PLA. The longer these chains, the higher the molecular weight, which directly affects the melting point because it requires more energy to break apart. This leads to a higher melting point and better mechanical strength.

Lower molecular weight PLA has shorter chains, which melt more easily but can be weaker and less durable. For standard 3D printing, most commercially available PLA filaments work just fine.

Crystallinity

PLA can exist in two structural forms: semi-crystalline and amorphous. The level of crystallinity affects how PLA melts.

Semi-crystalline PLA has highly ordered molecular chains. This gives it a sharp, well-defined melting point. It’s stronger and more heat-resistant so it is harder to print.

Amorphous PLA has randomly arranged chains, which means it softens over a range of temperatures rather than melting at a fixed point. It has a gradual melting behavior so it is easier to print. Most PLA filaments in the market are amorphous because of this reason.

If your prints need better heat resistance and strength, look for PLA blends with enhanced crystallinity.

Добавки

Many PLA filaments contain additives that change their properties, and these can also affect the melting point. Some filaments include plasticizers to make PLA more flexible, but these can also lower the melting point and make the material easier to print at lower temperatures.

Colorants, such as dyes and pigments, can slightly change the melting behavior depending on their chemical makeup. Fillers, like wood fibers, carbon fiber, or metal particles, can also impact how PLA melts.

For example, wood-filled PLA may need a slightly higher temperature because the wood fibers affect heat transfer. Carbon fiber PLA is stronger and more heat-resistant, so it usually requires a higher melting temperature than standard PLA.

Before printing, always check the recommended temperature settings for your specific PLA type, as different additives may require adjustment to your print settings.

Common PLA Melting Point Problems in 3D Printing

Below are some melting point issues that affect prints and how to fix them.

Oozing and Stringing

If you notice blobs or extra plastic where the nozzle moves, that’s oozing. When these issues happen, your PLA is likely too hot. High temperatures make filament flow too easily, causing extra material to ooze from the nozzle.

If you see thin, wispy strands of filament between parts of your print, you have a stringing issue. This is because of incorrect retraction settings and poor cooling.

To fix this, lower the print temperature by 5°C at a time, increase retraction settings, and use cooling fans to solidify PLA faster.

Under-extrusion (Thin or Missing Layers)

If your print has thin, weak, or missing layers, your printer isn’t pushing out enough filament. This happens when PLA is too cold, the nozzle is partially clogged, or the extruder isn’t gripping the filament well.

Increase the print temperature slightly, clean the nozzle using a cleaning tool, and check that the extruder gear is gripping the filament properly.

Poor First Layer Adhesion

If the first layer doesn’t stick to the bed, the entire print may fail. This can happen if the bed is too cold, the nozzle is too far from the bed, or the print surface is dirty.

Set the bed temperature to 50-60°C, adjust the nozzle height with proper leveling, and clean the print bed with isopropyl alcohol to remove dust or grease.

Clogged Nozzle

If the filament stops flowing or comes out inconsistently, the nozzle may be clogged. This happens when PLA is printed too cold, when dust or moisture in the filament causes blockages, or when burned filament builds up inside.

Fix it by increasing the print temperature, using high-quality, dry filament, and cleaning the nozzle regularly with a cleaning filament or small needle.

Applications of PLA Based on Melting Point

PLA melting point is useful in many industries. Here are some common applications:

Food Packaging: PLA is food-safe, so it’s often used for containers, drinking cups, bottles, trays, and bags.

Medical Equipment: PLA has been used in healthcare for over a decade because it is biodegradable and biocompatible. It’s commonly found in bioabsorbable implants, covering membranes, and tissue engineering scaffolds.

Textiles: PLA resists UV light and absorbs little moisture. It’s a good choice for shirts, sportswear, bedding, mattresses, and carpets.

3D Printing: PLA is widely used in filament production for 3D printing because it’s easy to print and environmentally friendly.

Automotive and Electronics: Although PLA is new in these industries, its high strength and impact resistance make it suitable for front panels, door trims, pillar covers, floor mats, and ceiling materials.

Can PLA Withstand 100℃?

No, standard PLA cannot stand 100℃. It starts to soften around 60-65℃ so at 100℃, regular PLA will become very soft and may lose its shape.

However, annealed PLA can handle higher temperatures, sometimes up to 120℃, depending on the brand and crystallinity of the filament.

If you need a material that can handle 100℃ or more, consider alternatives like ABS, PETG, or heat-resistant PLA blends.

Заключение

To get strong, high-quality prints, you need to understand PLA’s melting point. The right temperature prevents issues and always check your filament settings to know the purity and the additives that may affect how PLA melts.

At DEK, we help you get the best 3D printing results using PLA and other materials. Contact us today and get a free quote.