Polypropylene

Finding a good build surface can be very challenging when you need to print with Polypropylene. The low surface energy of polypropylene makes it extremely difficult to get good bed adhesion even with heated beds. We have found that polypropylene adheres well only to itself. Thankfully, packaging tape is a readily available surface that is also Polypropylene based, so it can be a great option. A thick strip of packing tape along with a heated bed can greatly improve the success of your first layer with this material. Some packing tapes melt around 90 ºC so it is important to keep the heated bed at a temperature slightly less than the melting point of the tape.

Polypropylene prints can sometimes bond too well to the packaging tape on the surface of your bed, which makes it hard to separate the tape from the finished part once the print is complete. This happens because the high temperature of the heated bed allows the tape and the part to slightly fuse together. To avoid this, consider using a raft for your prints. The raft will act as an interface between the hot build surface and the bottom of your part. Once the print is complete, the raft can be discarded, so even if it partially fuses to the tape, this will not affect the final part. Version 4.0 of Simplify3D added several new features that use less time, less material, and create rafts that are far easier to remove, so consider giving this option a try if you are having trouble with the parts bonding to the tape.

Having a good build surface may not be enough to prevent printing issues. Since we know that Polypropylene can warp quite heavily, it helps to have an enclosure of some sort to trap the heat around the print. Using a printer that has a heated chamber will help eliminate warping. Temperatures of 45-60 °C for a heated chamber will usually work well. Having a standard enclosure can also significantly control warping when used with the heated bed, since the bed will help heat the air around the part, which is contained by the enclosure. However, be careful to control the heated bed temperature to avoid damaging the packaging tape as mentioned above.