PSU (Polysulfone) Plastic Machining

Your guide to PSU Plastic Machining



A family of transparent thermoplastics

Tough and stable at high temperatures

Semi-crystalline polymer

A semi-crystalline polymer, PSU is rigid and highly resistant to mineral acids, alkalis and electrolytes. It has good machinability, making it straightforward to keep tight tolerances.

This guide will take you through the main attributes, common applications, notes for designers and suitable finishing and treatments, as well as UK stock sizes and property tables. Don't forget to bookmark the page so you can refer back later.

If you are interested in PSU machined parts, please scroll to the bottom of the page for more information about our service and to request a quote.

PSU Guide: Properties, Applications and Design Considerations


What is PSU plastic?
Polysulfone (PSU) is a family of transparent thermoplastics known for their toughness and stability at high temperatures. A semi-crystalline polymer, PSU is rigid and highly resistant to mineral acids, alkalis and electrolytes.

Polysulfone has good machinability, allowing close tolerances without great difficulty.

You may also see PSU referred to as:

  • Polysulfone
  • Polyarylsulfones
  • Quadrant® PSU 1000
  • Sustason® PSU
  • Ensifone®
  • Thermalux®
  • Udel®
  • Unifone® PSO
  • Hydex® 6201

Industry Examples: Electronics | Medical technology | Mechanical engineering | Food industry | Chemical | Automotive | Aerospace


Typical Components & Applications: Sterilisation cases and trays | Dental and surgical instruments | Medical devices | Aircraft interiors | Airline catering trolleys | Hot water fittings | Plumbing manifolds | Food service trays | Bearings | Precision gears | Connectors | Coil bodies | Flanges | Tubes | Pump components | Inspection windows | Instrumentation | Bushings

Main Attributes:
  • Good chemical resistance (mineral acids, alkali, salt solutions)
  • Flame retardant
  • High strength & stiffness
  • Excellent dimensional stability
  • Lubricated
  • High heat resistance
  • Broad temperature range capability
  • Good creep strength
  • Good resistance to hydrolysis and steam
  • High mechanical strength
  • Good insulating and dielectric properties
  • Semi-transparent
  • Typically has an amber tint
  • Food grade variations available
  • Not UV resistant and poor weatherability  – unsuitable for outdoor applications
  • Not suitable for esters, chlorine and aromatic hydrocarbons
  • Subject to stress cracking

Note For Designers:

The cost of PSU is higher than many engineering plastics and it should therefore only be selected where its specific properties are required.

If the higher temperatures or superior chemical resistance is not required, polycarbonate may be considered as a less costly alternative.

Stock material is transparent however if faces are machined, a secondary polishing process is required to regain optical clarity.

Finishing & Treatments:

When a face of PSU has been machined, its transparency is lost. A polishing process such as vapour/solvent polishing will need to be carried out in order to restore clarity if required.

See our Finishing Processes page for further information on services that we can facilitate.

Can we meet your PSU plastic machining needs? Contact us now
Get a Quote


PSU Plastic Machined Parts


Penta Precision provides the following plastic PSU machining services: 
  • CNC milling
  • CNC turning
  • Prototypes and batch runs
  • Insert installation
  • Part marking
  • Manual milling
  • Manual turning
  • Machining design advice
  • Design for manufacture service

Want to know more?


Find out how we can help you


Plastic Machining


Plastic Machining


Industry Sectors


Industry Sectors


Commitment To Quality


Commitment to Quality

Get A Quote