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CNC Milling
CNC milling of prototype parts
CNC milling is ideal for functional prototype parts, as well as one-offs or small batches for machine builders and manufacturers of low-volume, high-value products. We CNC machine parts in metals, alloys and engineering plastics.
Quick and cost-effective, CNC (computer numerical controlled) milling is considerably more accurate than 3D printing. Our quoted general tolerance of ±0.1mm is quite wide, but that’s just a starting point for estimating before we get tied up drawing. In reality, the machine tools hold much tighter tolerances. Ask us if you need specific tolerances on critical dimensions, as we can normally comply.
Another advantage CNC milling has over 3D printing is that the material is isotropic, whereas 3D printed material properties can vary relative to build orientation. This can be critical for functional prototype parts, especially those with complex geometries.
Note that we also have CNC lathes, so we can meet all CNC machining requirements for prototype parts.
What is CNC milling?
Starting with a solid block of material (a ‘blank’) in the machine vice, the milling machine uses rotating tools to cut profiles, pockets and other features to the required depths. It is simple to produce through holes, blind holes and tapped holes, as well as slots, keyways and undercuts.
Parts with complex geometry can be machined on our five-axis vertical machining centres. If necessary, we can make fixtures for holding workpieces in our three- or five-axis machines.
Toolpaths for complex 2D profiles, 3D surfaces and other features are generated automatically by our offline programming software, Mastercam, using the geometry data from the X_T, STEP or IGES file.
Once our engineer has finalised the CNC program, it is downloaded to the machine. The automatic tool changer is populated with the correct cutting tools, the material is clamped in the vice and the machine is started. Because the machines are fully automatic, they can be left to run unattended, overnight if need be.
What materials and finishes are available for CNC milled prototype parts?
The most popular materials for CNC milling prototype parts are aluminium, stainless steel, acetal and clear acrylic. See our page about materials for CNC machining for more information about these materials and the many others we routinely work with.
Other materials are available (subject to supplier lead times).
All CNC milled parts are deburred, cleaned, degreased and inspected. We also offer a wide range of finishing options for CNC machined parts.
CNC milling machines for prototype parts
We continually invest in our CNC workshop to ensure our capability matches customers’ requirements for machined parts. Today we have two Haas VF-2SSYT five-axis vertical machining centres with Schunk air vices and Haas robot packages three Hardinge-Bridgeport GX 480 vertical machining centres, one Bridgeport VMC 600 vertical machining centre and three Haas Mini Mills. See our CNC turning page for information about our turning centres.
The maximum milling machine bed size is 450 x 350mm. However, for our three-day Express CNC service, customers need to select from one of the materials that we hold in stock in specific sizes (see below).
CNC milling for low-volume manufacturing
CNC machining benefits from excellent repeatability and a high level of automation. These two factors make the technology particularly useful for low-volume manufacturing. Our two newest machines, the five-axis Haas vertical machining centres (VMCs), are equipped with automatic tool changers, programmable vices and robots for continuous loading and unloading of parts. Consequently, they can machine parts without an operative having to reposition the workpiece in the vice, and the robots can load blanks and unload finished parts automatically so the machines can produce batches of parts unattended.
Inspection of CNC milled parts
All CNC milled parts are inspected visually and key dimensions checked with callipers or a micrometer. We also have thread gauges, other handheld metrology instruments and, unlike many of our competitors, a co-ordinate measuring machine (CMM). Read more about our in-house inspection facilities.
Service levels
We offer three service levels for CNC milling, depending on your technical requirements and project timescales: Express, Standard and Economy. Parts are shipped in as little as three working days with our Express Service. There is more information about the Service Levels and Dispatch times on our Service Levels page.
Talk to us
What are your CNC milling requirements for prototype parts? Talk to us about your project on 01763 249760 or complete the enquiry form below to request a quote.
CNC Machining team
Our CNC machining team produce accurate, high quality parts with an excellent finish from our suite of CNC machines. Request a quote for your next prototype part.
Ian Reinemann
Senior CNC Manager
David Brassington
Quality Inspector
Michal Mikolajczyk
CNC Team Leader
Ricky McMillan
CNC Operator / Setter
Dan Summerfield
CNC Programmer
Glenn Watts
CNC Operator / Setter