Polypropylene is less commonly used as 3D printer filament, but it does have unique properties. Learn how to master 3D printing with PP!
, or PP, is one of the most common polymers that you’ll find around the house. It’s great for its translucency as well as its resistance against chemicals and fatigue. Being both food- and microwave-safe, it’s often used in household plastic containers.
For 3D printing, PP is great for anything that needs to be light, water-tight, or durable. Case hinges, for example, represent a very popular use, as PP can bend repeatedly without breaking.
While PP’s excellent durability makes it an appealing material to print, it is notoriously difficult to handle. Let’s take a look at the material’s challenges as well as a few ways to get around them.
Polypropylene’s main problem is that it doesn’t like to stick to things. While this may be great for some applications, it’s not so great for the 3D printing process. It makes getting your prints to stick to the print bed very difficult, resulting in frequent failures.
An added challenge is that polypropylene has a semi-crystalline structure. For printing, this means that high warping stresses are generated, peeling off any first layers that might have had the luck of sticking to your print bed.
As bed adhesion and warping are our primary enemies, we’ll run through how you can address them for success printing with polypropylene.
Tape is often used as an adhesive aid on print beds, with Kapton tape and blue painter’s tape being classic choices. Unfortunately, these classic options won’t work so well here, as PP simply doesn’t like to stick to other materials.
Thankfully, PP loves to stick to itself, and most packing tapes are made of polypropylene. Therefore, instead of using the above tapes, try printing onto some clear packing tape. (Just make sure it’s made of PP.) You’ll likely see a dramatic improvement in bed adhesion.
To combat polypropylene’s high warping stresses, try printing with a large brim or raft. Both methods increase the surface area of the first layers of your prints, reducing concentrated points of warping stresses and increasing the likelihood of your prints succeeding. After printing, they simply snip or peel off.
With PP, you may have to increase the brim or raft size beyond what you might typically use for other materials. Generally, the two can be used interchangeably, though you may find yourself preferring one over another.
Another way to mitigate warping is to turn up the bed temperature. This will prevent the PP from cooling down too much, thus reducing the amount of contraction. By keeping contraction down, you can reduce the number of warping stresses that are generated.
A good place to start is your printer or filament manufacturer’s default settings for PP, if available. Otherwise, start at 85 °C and turn up the bed temperature 5 °C at a time until you find an optimal temperature. The sweet spot should be somewhere between 85 and 100 °C.
Enclosing your 3D printer to keep in additional heat and prevent temperature fluctuations may also be beneficial, though certainly not necessary. If your printer doesn’t have one, we have some tips for making your own enclosure.
Want to try PP but don’t yet have the material? Check out the following vendors for some of the most popular brands!
As it’s less common in the 3D printing world, you’ll struggle to find any blends or variations, but the raw material is already quite impressive in and of itself.
License: The text of "3D Printing Polypropylene: How to 3D Print with PP" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.
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