PP
The lightest and most chemically inert filament there is — and the only FDM material that gives you a living hinge worth the name.
Quick Reference
- Material properties
- Engineering / Chemical Resistant
- Polypropylene (PP)
- None
- 28 MPa
- No Break (Izod notched, ASTM D256)
- 100 % (50–200 %)
- 92 °C @ 0.455 MPa
- 0.90 g/cm³ — floats on water
- Excellent — acids, bases and solvents
- 0.02 % — effectively none
- 230–240 °C
- 85–95 °C
- PP tape or a PP build sheet — PP sticks to PP
- Recommended — shrinkage is 0.8–1.5 %
- Welds to itself; will not take paint or glue
Material Property Profile
Values scored 0–10 from measured mechanical data and print process behaviour. Select a material above to compare properties.
Key Properties
What polypropylene actually does — and the two numbers that decide whether it is the right answer.
Machine Requirements
PP is not hard to melt. It is hard to make stay on the bed — and these are the thresholds that decide the print.
| Requirement | Minimum Spec | Recommended |
|---|---|---|
| Nozzle Temperature | 220 °C | 230–240 °C |
| Bed Temperature | 80 °C | 85–95 °C |
| Build Surface | PP packing tape | Dedicated PP build sheet |
| Enclosure | Draught-free | Enclosed (warp control) |
| Part Cooling Fan | 20 % | 30 % — PP crystallises slowly |
| Print Speed | 25 mm/s | 30–40 mm/s |
| Retraction | 1 mm | 1–2 mm, direct drive |
PP only sticks to PP. No glue stick, no hairspray and no PEI sheet will hold it. Print onto polypropylene packing tape or a PP build sheet and the adhesion problem disappears; use anything else and the first layer lifts before the part is 10 mm tall.
Applications — By Industry
Consumer / Packaging
- Living hinges
- Snap-fit lids and cases
- Waterproof enclosures
Chemical / Laboratory
- Chemical tanks and funnels
- Laboratory fixtures
- Fluid handling components
Medical
- Orthotic devices
- Prosthetic components
- Device housings
Industrial
- Acid-resistant components
- Battery housings
- Chemical-resistant gaskets
Tensile Strength — FDM Materials (MPa)
Heat Deflection vs Tensile Strength
Available Materials
When to Use PP — and When Not To
Use PP when
- The part needs a living hinge — nothing else survives the cycles
- Chemical resistance decides the job (acids, alkalis, solvents)
- You want the lightest possible part: 0.90 g/cm³
- The part lives in water or constant humidity
- You want a tough part that dents rather than cracks
Avoid PP when
- Stiffness matters — PP is ductile, not rigid
- You cannot print onto a PP surface (adhesion will fail)
- Tolerances are tight — shrinkage is high and variable
- The part must be painted or bonded — PP has very low surface energy
- The part carries sustained load at temperature (creep)
DfAM Tips for PP
Design rules that get a printed polypropylene part to behave like a moulded one.
Living hinge: 0.3–0.5 mm, and mind the orientation
Lay the part out so the extrusion runs ALONG the hinge axis, not across it. A hinge printed the wrong way round splits on the first close; printed the right way it will run thousands of cycles.
Wall thickness ≥ 1.0 mm
Three perimeters for anything structural. PP is ductile, so thin walls flex rather than break — but they also warp more.
Min hole diameter 1.5 mm — and oversize the bore
Shrinkage runs 0.8–1.5 %, well above ABS. Add 0.2–0.3 mm to any bore that has to fit something.
Put a brim on every flat part
A 5–8 mm brim on PP tape is the difference between a flat base and a taco. Large footprints want a raft.
Max overhang 45°, max bridge 12 mm
With cooling held down at 30 % PP bridges poorly. Support anything past 45° from vertical.
Printers Compatible with PP
PP wants a heated bed, a draught-free chamber and a build surface it will actually stick to. Dragon, Twin Dragon, Julia Advanced and Volterra all qualify.
Ready to print in PP?
Order Fracktal PP filament — 1 kg spools, 1.75 mm.