CNC Milling

CNC milling is a precision machining process that uses computer-controlled rotating cutting tools to remove material from a solid workpiece. It is ideal for producing complex engineering-plastic components with flat surfaces, pockets, slots, holes and features across multiple faces while maintaining tight tolerances and consistent quality.

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How the Process Works

1. Design review

We review your CAD drawings to see if CNC milling is the best manufacturing option.

2. Material Selection

We help you choose the right material for your performance and cost goals.

3. Milling Process

The raw material will be clamped onto the machine and the cutting tools will begin to carve out the details in your design.

4. Inspection and Certification

Your component(s) are then fully inspected and sent to you with a CoC.

  • When would you choose this method?

    Choose CNC milling when a component requires complex, non-cylindrical geometry such as pockets, slots, holes, contours, or features across multiple faces. It is particularly suitable for prototypes and low-to-medium production volumes where tight tolerances, material flexibility, and avoiding mould-tooling costs are important.

    Here are components that are CNC Milled:

    • Manifolds and valve blocks
    • Mounting brackets
    • Wear plates and guide plates
    • Electrical insulators
    • Machine guards
    • Pump and valve components
    • Housings and enclosures
    • Jigs, fixtures and tooling plates
    • Gears and sprockets
    • Slide rails and linear guides
    • Sealing plates and gaskets
    • Semiconductor handling components
    • Medical-device components
    • Custom prototypes
    • Parts with pockets, slots, holes or complex profiles
  • Why choose this method?

    CNC milling is often chosen for engineering-plastic components with complex, non-cylindrical geometries, including flat surfaces, pockets, slots, contours, drilled holes and features positioned across multiple faces. Multi-axis milling can produce intricate components to tight tolerances while providing considerable flexibility during prototyping and design development.

    Compared with CNC turning, milling is better suited to square, rectangular, irregular or three-dimensional parts. Turning is generally faster and more efficient for rotationally symmetrical components such as bushes, sleeves, rollers and sealing rings, whereas milling provides greater freedom when a component cannot be produced by rotating the workpiece around a central axis.

  • The benefits of this method:

    • Complex geometries: Produces pockets, slots, contours, threads, holes, and features across multiple faces.
    • Tight tolerances: Delivers accurate dimensions and consistent results for demanding applications.
    • No mould tooling: Eliminates the cost and lead time associated with injection or compression moulds.
    • Ideal for smaller quantities: Cost-effective for prototypes, one-off components and low-to-medium production runs.
    • Design flexibility: CAD designs can be modified quickly without replacing dedicated tooling.
    • Wide material selection: Suitable for numerous engineering plastics, including PEEK, POM, nylon, PTFE, PEI and PPS.
    • High-quality finishes: Creates clean surfaces and accurately finished features, often requiring minimal secondary processing.
    • Repeatable production: Computer-controlled machining produces consistent components from one batch to the next.
    • Rapid lead times: Parts can be manufactured directly from stock material once the design and machining program are approved.
    • Reduced material risk: Components can be produced from certified stock shapes with full material traceability.
    • Multi-axis capability: Advanced machines can manufacture intricate features from several angles with fewer setups.
    • Scalable production: Suitable for initial prototypes, replacement parts, and ongoing production batches.

CNC Milling's Axes

CNC milling machines operate along multiple axes that control the movement of the cutting tool and workpiece. A standard three-axis machine moves from side to side along the X-axis, front to back along the Y-axis and vertically along the Z-axis, making it suitable for machining flat surfaces, pockets and holes. Four-axis machines add rotation around one axis, allowing multiple sides of a component to be machined without manual repositioning, while five-axis machines introduce a second rotational movement so the tool can approach the workpiece from almost any direction. This multi-axis capability is particularly valuable because it enables complex contours, angled features and intricate geometries to be produced in fewer setups, reducing handling time and alignment errors while improving accuracy, consistency and surface finish.

Which materials can be CNC Milled?

Suitability depends on a component's material

Can be CNC milled

Polyether Ether Ketone (PEEK), Polyacetal (POM), Polyamide (PA), Polycarbonate (PC), Polyetherimide (PEI), Polyimide (PI)

These materials have sufficient stiffness and dimensional stability to hold tight tolerances, while producing relatively clean cuts and good surface finishes.

Polyphenylene Sulphide (PPS), Polyvinylidene Fluoride (PVDF), Polyvinyl Chloride (PVC), Polypropylene (PP), Polyethylene (PE), PEEK GF30

These materials require more careful machining because they may soften, deflect, form stringy chips, crack or cause increased tool wear.

RENY MXD6, Perfluoroalkoxy (PFA), polytetrafluoroethylene (PTFE), PA66 GF60

PTFE and PFA are extremely soft and prone to creep, while the other materials, being highly glass-filled grades, are abrasive and can cause rapid tool wear, chipping, and fiber breakout.

Cannot be CNC milled

Ceramic Alumina (Al₂O₃), Ceramic Zirconia (ZrO₂),

Once fully sintered, these ceramics are too hard and brittle for conventional cutting tools and normally require green-state machining or specialist diamond grinding.