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Can You Mix PLA and ABS Filaments?

3D printing is a fantastic technology that allows total freedom of creation, and knowing about the types of materials you use when 3D printing ensures optimal results. For example, you might consider mixing materials if you begin a printing project with what was left of your PLA filament but realize you don’t have enough to complete the project. But do PLA and ABS filaments mix?

PLA and ABS filaments can mix, but it’s not recommended. These are thermoplastics, which are plastics that solidify and melt at different temperatures. Not only that, they have different compositions, melting points, toxicity, odors, and durability. When mixed, they may not stick together properly.

This article will explore why mixing certain filaments is not the best idea by exploring the differences between PLA and ABS.

Why You Shouldn’t Mix PLA and ABS Filaments

Though possible, it is not recommended to mix PLA and ABS filaments when 3D printing. 

Here’s why:

Theoretically, it makes sense to mix the two filaments because they have varying strengths that the other doesn’t. For instance, ABS is robust but also very brittle. On the other hand, PLA is much more forgiving but weaker.

Understanding the differences between these two filaments will help make the right choice for which filament to use. The two materials have advantages and disadvantages, respectively.

Differences in PLA vs. ABS

To understand why you shouldn’t mix PLA with ABS, you need to know how each material works. 

For example, PLA is known to have a much lower melting point, which is why it’s not ideal for use outdoors. 

Similarly, ABS, though durable, will crack under cooler temperatures. 

Let’s take a closer look at some of their key differences below.

Composition

PLA is biodegradable since it is made of plant starches and sugars. In addition, it is plant-based and non-toxic. 

ABS is a terpolymer, a polymer composed of three monomers. The composition is usually 50 percent styrene and 25 percent butadiene and acrylonitrile.

Temperature

PLA melts at a lower temperature than ABS does. Mixing the two filaments means that by the time you’ve gotten the ABS to melt, the PLA is starting to degrade from higher heats than it needs. 

ABS also needs higher temperatures on the heating bed under your piece than PLA does. This is because using the temperature settings for ABS would warp the PLA.

Enclosing Your Printer

ABS filaments require you to enclose your printer to trap the heat and keep out external airflow. This is because ABS is sensitive to temperature changes and my crack during printing. 

This is unnecessary for PLA, though you can still enclose your printer for optimal printing.

Fumes

PLA is a plant-based material and, as such, does not release toxic fumes when being heated. 

ABS, on the other hand, produces a powerful and toxic odor. Therefore, make sure to use proper ventilation at all times when printing.

Durability and Strength

PLA will not crack in a cooler environment but will melt quicker in a hot climate. ABS generally is more durable, but it will crack in cooler temperatures because it shrinks as it cools. 

ABS has a bit more flexibility when heated than PLA and is slightly less brittle.

PLA is not suited for outdoor applications due to its low melting point.

ABS is a durable filament used in many applications such as Legos.

Check out this video for more information:

Pricing and Variations

PLA is generally less expensive than ABS. There are also more variations on colors and diameter tolerance. 

However, both are relatively cheap and widely available.

Vapor Smoothing

ABS has a stellar reputation for easy vapor smoothing or the beautiful shiny surface you get after an acetone treatment. The ABS dissolves into the acetone mixture, and those printer lines disappear.

PLA, however, doesn’t react to acetone. The purer the PLA composition, the less effect acetone has on it. 

This also implies that an ABS/PLA blend might work, seeing as a diluted or less pure form of the PLA would have some reaction to the acetone. Working with pure PLA filament will have you hand-sanding pieces to smoothness.

Tips for 3D Printing With PLA and ABS

Though you may produce an adequate print with a blend of PLA and ABS, chances are it will have some blemishes. So instead, buy composite blends or layer your projects with an ABS base and PLA layers above that.

Some other tips for printing with these filaments include:

  • You can purchase premixed PLA/ABS composite material such as this ABS/PLA blend.
  • Use the same brands of filament as different brands may have other melting points and compositions.
  • You should have different extrusion nozzles to prevent jamming when going from PLA to ABS.
  • Though it may be challenging to splice and create a fully integrated PLA/ABS blend, you can begin with an ABS base and build a PLA component on top.
  • It is not recommended to build a PLA base and add ABS.
  • Print at the slowest recommended speed for your printer.
  • Never heat filaments with an open flame as you cannot control the temperature and can burn or boil the filament.
  • Neatly cutting the ends of the filament helps with joining the materials together.
  • Pay attention to your ABS and PLA temperature properties as you may find certain brands have products with closer temperature ranges.

Final Thoughts

3D printing is a fantastic technology that lets you create anything from simple materials. Those materials are different in many aspects, such as melting points, composition, durability, flexibility, price, and variations.

PLA is a cheap and easy material to use, but it does not have ABS’s strength as a filament. ABS is durable but very sensitive to temperature changes when heated and requires stable temps to print correctly. 

Since these two materials are composed of very different things, melt at different temperatures, and have different levels of durability and strength, they do not work well when mixed.