PL · engineering plastic
Polyphenylene Sulphide PPS (unfilled and 40% GF)
Hard, brittle and dimensionally stable. The filled grade is very abrasive on tooling; unfilled PPS cuts cleanly but is more brittle than PEEK and chips at a sharp edge.
Quoting this material
- Typical lead time
- 10–18 working days
- Condition
- Compression moulded or extruded stock
- Achievable finish
- Ra 1.6 µm typical · Ra 0.8 µm best
Machined in-house to your drawing: see the precision CNC machining service and the machine and inspection capability it runs on.
Machinability
Our own 1–10 shop ranking, not a published index: 10 is free-cutting brass C360, 1 is Inconel 718. It ranks how a material behaves on the floor - cycle time, chip control and tool life together. Where a published index exists it is quoted in the note.
Hard, brittle and dimensionally stable. The filled grade is very abrasive on tooling; unfilled PPS cuts cleanly but is more brittle than PEEK and chips at a sharp edge.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 75 | MPa |
| Modulus of elasticity | 3.5 | GPa |
| Hardness | 85 | Shore D |
| Continuous service temperature | 200 | °C |
| Thermal conductivity | 0.30 | W/m·K |
| Density | 1.35 | g/cm³ |
Hardness, tensile and thermal figures are typical published values for the condition stated. Actual mill certificates govern; send the specification with the drawing and we confirm against the certificate before the material is cut.
Condition
Compression moulded or extruded stock
Heat treatment
No heat treatment. Its dimensional stability comes from a rigid aromatic backbone and near-zero moisture absorption, not from any conditioning step.
Achievable surface finish
Ra 1.6 µm
Ra 0.8 µm
Cuts to a clean edge with sharp tooling; a brittle chip means the tool geometry has to be positive rather than neutral.
Tooling and cutting parameters
Cutting speed
- 150–350 m/min (sharp uncoated carbide)
Feed
- 0.08–0.25 mm/rev turning · 0.08–0.20 mm/tooth milling
Tooling
- Sharp uncoated carbide; diamond-coated for the 40% glass grade
Coolant
- Air or mist
Starting points for carbide on a rigid setup, not a guarantee. The right numbers depend on the machine, the toolholder and the fixturing - ask and we will say what we would actually run.
Typical applications
- Chemical process components
- Automotive under-bonnet parts
- Electrical connectors and switches
- Pump housings and impellers
- High-temperature insulating parts
DFM notes for this grade
- Excellent chemical resistance and a 200 °C service temperature at a lower price than PEEK - the usual reason it is specified
- Brittleness is the handling risk: a thin section in PPS chips rather than deforming, so the design should avoid sharp internal corners
- The 40% glass grade is one of the most abrasive materials we machine; tool life, not the material price, drives the cost
Questions buyers ask
- PPS or PEEK for a chemical part at 150 °C?
- PPS if the chemistry suits it - it is cheaper and holds 200 °C. The exceptions are strong oxidising acids, where PEEK is more resistant, and anything needing toughness, where PPS brittleness is the limiting factor.
- How bad is glass-filled PPS on tooling?
- It is among the worst plastics for tool wear. Glass-filled grades need diamond-coated tooling for any sort of production run, and the finish deteriorates as the coating wears - so tool condition is a quality control item, not just a cost item.
Grades we would quote instead
PEEK
5/10Machines cleanly for a plastic but it holds heat at the cut and the swarf will not break.
PEI (Ultem)
5/10A hard, stiff, amber-coloured plastic that machines like a tough wood: clean chips, crisp edges and good dimensional stability.
PSU (Polysulfone)
6/10A transparent, sterilisable high-temperature plastic that machines cleanly.