Machining PEI | Machined PEI Parts | Penta Precision       +44 (0) 2392 668 334

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PEI Machining

A Guide to PEI CNC Machined Parts: Properties, Applications and Design Considerations

What is PEI?

PEI (Polyetherimide) is a high performance amorphous thermoplastic which is typically transparent amber in colour.

PEI is commonly used for structural components requiring high strength and rigidity at elevated temperatures as well as broad chemical resistance.

Please see our PSU (Polysulfone) page for an alternative high performance thermoplastic which has similar characteristics but is cheaper and more readily available.

Main Attributes of PEI:

  • High mechanical strength
  • High rigidity
  • Very good dimensional stability
  • Relatively high long term service temperature
  • Flame resistant
  • Good chemical resistance
  • Excellent electrical properties
  • High strength to weight ratio
  • Glass-filled grade available
  • Low thermal conductivity
  • Highest dielectric strength of any thermoplastic
  • Transparent amber
  • High tensile strength
  • Semi transparent
  • Good UV resistance and weatherability
  • Most grades suitable for use with food
  • Can withstand dry heat sterilisation at 180°C, ethylene oxide gas and gamma radiation


Need a part machined by an experienced and reliable components manufacturer? Simply complete our short form to receive your no obligation quotation.

Detailed information about PEI for designers including UK stock sizes and technical properties can be found in the tabs below. Please note: this information is provided as a guide only. All information is based on our present knowledge and is given in good faith. No liability will be accepted by Penta Precision in respect of any action taken by any third party in reliance thereon.

Similar or obsolete designation and trade names

You may also see PEI referred to as:

PEI Components, Applications & Industries

Here are some examples of the industries and components for which PEI is appropriate. This is by no means an exhaustive list. Please do get in touch if you are considering using PEI and we can talk through your project with you.

Typical Components & Applications:
  • Reusable medical devices
  • Electrical/electronic insulators
  • Manifolds
  • Surgical probes
  • Clamps
  • Radomes
  • Thermostat housings
  • Bezels


      • Reflectors
      • Lamp sockets
      • Fuses
      • Gears
      • Bearings
      • Switches
      • Connectors
        Industry Examples:
        • Instrumentation
        • Electrical/Electronics
        • Food technology
        • Aerospace
        • Medical
        • Pharmaceutical
        • Automotive
        • Telecommunications

        PEI Machining Service - PEI Milling & Turning

        Penta Precision provides highly accurate PEI machined parts. Customers turn to us when they have had quality and delivery issues with their existing suppliers and need a reliable precision machining partner.

        Penta Precision provides the following PEI machining services: 

        • CNC PEI milled parts – prototypes & large batch runs
        • CNC PEI turned parts – prototypes & large batch runs
        • Insert installation
        • Part marking
        • Manual milling
        • Manual turning
        • Machining design advice
        • Machining drawing service

        Reasons to Choose Penta:

        • ISO 9001:2015 quality assurance
        • Consistent high quality machined parts
        • Reliable delivery dates - our track record speaks volumes
        • Exceptional customer service and communication
        • Machining design advice
        • Extensive experience in our field
        What Makes Penta Different?

        There are 3 key elements that run through the core of our company and staff at every level to ensure we deliver an exemplary service that goes above and beyond. We like to call these our 3 C's:

        • We Communicate well 
        • We take Care at each stage
        • Our service is Consistent

        See our ‘Proven Process’ page to find out more

        We are regularly machining high performance thermoplastics for customers all over the UK. Our customers depend on our machining expertise as well as our outstanding delivery performance, to machine the highest quality parts. If you'd like to discuss how we can help you with your PEI machining requirements, here's a list of ways to get in touch with us.

        Can we meet your
        PEI machining needs?
        Call our engineering team on
        +44 (0) 23 9266 8334
        or contact us via our email form

        "It has been a pleasure to work with Penta Precision with clear, concise and accurate communication and products exactly meeting our specification."Anthony - Quality Manager

        Tel: +44 (0) 2392 668 334

        Fax: +44 (0) 2392 668 335

        Connect with us:

        Penta Precision Engineering Ltd

        Aspen House

        Airport Service Road



        PO3 5RA

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