PSU (Polysulfone) Plastic Machining

Your guide to PSU Plastic Machining

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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

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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
TECASON® S
Quadrant® PSU 1000
Sustason® PSU
Ensifone®
Thermalux®
Udel®
Unifone® PSO
Hydex® 6201

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

UK Stock Sizes

PSU UK Stock Sizes

Here are the standard stock sizes for PSU in the UK. Please note we do not supply stock material, the information provided is purely for design and research purposes.

Stock sizes vary by supplier. Only stocked items are listed but non-stocked items may be available. Please get in touch to discuss further.

The standard unfilled grade of PSU is amber and typically available in lengths of 3000mm.

PSU Rod/Round Bar

Stock Size (mm)	Tolerance (mm)
Ø10	+0.10/+0.80
Ø20	+0.20/+0.90
Ø30	+0.20/+1.20
Ø40	+0.20/+1.60
Ø50	+0.30/+2.00
Ø60	+0.30/+2.50
Ø80	+0.40/+3.00
Ø100	+0.60/+3.80

PSU Plate

Stock Size (mm)	Tolerance (mm)
20 x 500	+0.30/+2.50
40 x 500	+0.50/+2.50

Technical Properties

PSU Technical Properties

Here are the properties for TECASON S natural which is an unfilled, unreinforced PSU brand. Reinforced and modified grades will have different properties.

TECASON PSU Properties

Mechanical Properties	Value	Parameter	Norm	Notes
Modulus of Elasticity (tensile test)	2700 MPa	1mm/min	DIN EN ISO 527-2	For tensile test specimen type 1b
Tensile Strength	89 MPa	50mm/min	DIN EN ISO 527-2
Tensile Strength at Yield	89 MPa	50mm/min	DIN EN ISO 527-2
Elongation at Yield	5%	50mm/min	DIN EN ISO 527-2
Elongation at Break	15%	50mm/min	DIN EN ISO 527-2
Flexural Stength	122 MPa	2mm/min, 10 N	DIN EN ISO 178	For flexural test: support span 64mm, norm specimen
Modulus of Elasticity (flexural test)	2600 MPa	2mm/min, 10 N	DIN EN ISO 178
Compression Strength	15/28/75 MPa	1%/2%/5% 5mm/min, 10N	EN ISO 604	Specimen 10x10x10mm
Compression Modulus	2300 MPa	5mm/min, 10 N	EN ISO 604	Specimen 10x10x50mm, modulus range between 0.5 and 1% compression
Impact Strength (Charpy)	175 kJ/m²	max. 7.5J	DIN EN ISO 179-1eU	For Charpy test: support span 64mm, norm specimen
Notched Impact Strength (Charpy)	4 kJ/m²	max. 7.5J	DIN EN ISO 179-1eA
Ball Indentation Hardness	167 MPa		ISO 2039-1	Specimen in 4mm thickness

Thermal Properties	Value	Parameter	Norm	Notes
Glass Transition Temperature	188°C		DIN EN ISO 11357	Found in public sources
Service Temperature	180°C	short term		Found in public sources. Individual testing regarding application conditions is mandatory
Service Temperature	160°C	long term
Thermal Expansion (CLTE)	6 10^-5 K^-1	23-60°C, long	DIN EN ISO 11359-1;2
Thermal Expansion (CLTE)	6 10^-5 K^-1	23-100°C, long	DIN EN ISO 11359-1;2
Specific Heat	1.2 J/(g*K)		ISO 22007-4:2008
Thermal Conductivity	0.21 W/(K*m)		ISO 22007-4:2008

Electrical Properties	Value	Parameter	Norm	Notes
Specific Surface Resistance	10¹⁴ Ω		DIN IEC 60093
Specific Volume Resistance	10¹⁴ Ω*cm		DIN IEC 60093

Other Properties	Value	Parameter	Norm	Notes
Water Absorption	0.06/0.1%	24h/96h (23°C)	DIN EN ISO 62	Ø ca. 50mm, h=13mm
Resistance to Hot Water/Bases	+			+Good resistance
Resistance to Weathering	-			- Poor resistance
Flammability (UL94)	V0	Corresponding to	DIN IEC 60695-11-10	Corresponding means no listing at UL (yellow card). The information might be taken from resin, stock shape or estimation. Individual testing regarding application conditions is mandatory.
Density	1.24 g/cm³