CNC Machining

CNC machined parts with an inspection report


World-class computer numerical control (CNC) machined parts delivered to your door in days. A wide variety of CNC materials and secondary finishes available from our manufacturing partners.

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We’re proud to be partnered with 180+ highly vetted CNC partners, who have a proven track record of making high-quality mechanical parts for customers all over the globe. With our partners’ expertise, our engineers’ attention to detail and our entire team’s commitment to exceptional quality assurance at every stage, you can rest assured that with Geomiq, you’ll receive the perfect CNC Machined parts – the first time, every time.



Our diverse, global supply chain offers an extensive range of capabilities. Whether you are looking for one-off prototypes or large-scale batch manufacture, we can deliver repeatedly on quality and lead time. Our partners operate virtually every kind of CNC machine, including mills, lathes, mill-turns, multi-axis machines, sliding head lathes and bar fed lathes. We also offer CNC grinding and EDM processes. This allows us to utilise the correct tool for the job to meet requirements at a competitive price.


With our standard tolerance being +/- 0.127mm on all CNC Turned parts and the ability to refine that even more, Geomiq offers only the best CNC Turning services. With 1400+ machines in our network, we guarantee a great price while maintaining the highest level of quality and fastest delivery possible. So if you are looking to have parts turned with a high level of accuracy and need parts made right the first time, you have come to the right place.


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Rapid turnaround

We’re committed to reducing friction at every stage, so you can be as delighted with the speed of your CNC Machined parts’ arrival as you are with their exceptional quality. Order now to receive your parts in as little as 5 days!

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High accuracy

Our standard CNC tolerance is +/- 0.127mm, and when you use our tolerance configurator, you can expect precision machining down to +/- 0.005mm.

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Unmatched scalability

Whether you’re after a one-off prototype or 10,000 units at the most competitive price, Geomiq’s world-class supply chain can deliver.

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The perfect finish

We offer high-quality finishing processes for most CNC Machined parts; from anodising, polishing and plating, to powder coating and more.

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A wide variety of materials

We offer over 100 plastic and metal materials, and take great care to ensure the right material is used for every part. Please get in touch if the material you require is not listed.

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A wide range of industries

With customers in every industry, from aerospace, defence, robotics, medical and automotive to electronics, Geomiq has a wealth of experience meeting a diverse range of requirements. Calling on our world-class supply chain, we can meet any requirements.

Quality assurance at every stage

We’re committed to providing the best quality assurance in the business. We employ highly skilled engineers to triple-check all of your files and parts from initial quote to final inspection – ensuring that you’re happy with your results the first time, every time.

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From prototype to production in days

At Geomiq, we know your time is valuable – and we’re passionate about helping you save more of it. When you upload your files, we’ll get you a quote within one business day – and our network of highly experienced partners will ensure the finished CNC products are of the highest quality with short lead times.

Leverage the expertise of our global partner network

We partner with 180+ highly vetted and experienced CNC manufacturers from a number of countries, so that you can benefit from a world-class supply chain, offering greater capabilities and the highest standards in the world – all from a single access point.

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CNC Machining materials

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Available aluminium varieties:

  • Aluminium – Grey (6061)
  • Aluminium – Grey (6082)
  • Aluminium – Grey (7050)
  • Aluminium – Grey (7075)

Available stainless steel varieties:

  • Stainless Steel – Grey (303)
  • Stainless Steel – Grey (304)
  • Stainless Steel – Grey (304L)
  • Stainless Steel – Grey (316)
  • Stainless Steel – Grey (316L)

Copper – Red/Bronze

  • Brass – Yellow (CZ 121)
  • Brass – Yellow (CZ 131)

Magnesium – Grey (Magnesium AZ31)

Steel Alloy – Grey (Allow 4140)

Titanium – Grey (Grade 5 Ti6AI4V)

  • ABS, Black
  • ABS, White
  • ABS, Natural
  • ABS, Clear
  • ABS/PC, Black
  • Copolymer, Grey
  • Copolymer, Natural
  • Homopolymer, Black
  • Homopolymer, Natural
  • Homopolymer, Black 20% glass fibre-UV
  • Homopolymer, Black UV stabilisted
  • CVPC on request
  • HDPE, Natural
  • LDPE, Natural
  • PA6, Natural
  • PA6, Black 30% Glass Fibre
  • PA6, Natural 30% Glass Fibre
  • PA6/6, Natural 20% Glass
  • PA6/6, Black 25% Glass
  • PA6/6, Black 30% Glass Fibre
  • ABS/PC, Black
  • PEEK, Natural 
  • PEI, Black
  • PEI, Natural 
  • PET, Natural 
  • PMMA, Clear 
  • PMMA, Frosted
  • PP, Homopolymer Black
  • PP, Homopolymer Natural
  • PP, Copolymer Natural
  • PP, Natural 
  • PP, Natural 20% Glass
  • PPSU, Black
  • PS, (HIPS) White
  • PSU Natural
  • PTFE, White
  • PVC, Grey
  • UHMW

Post-processing and finishing options

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This is the finishing option with the fastest turnaround. If you opt for as-machined finishing, your parts may be left with visible tool marks and potentially sharp edges and burrs, but we can remove these upon request.

Coating services:

  • Galvanic zinc
  • Nickel and chrome
  • Anodising (hard and colour)

Surface finishing options:

  • Polishing
  • Blasting
  • Painting and powder coating

Heat treatment options:

  • Quenching and tempering
  • Normalising and tempering


CNC Machining is a form of subtractive manufacturing. This means CNC Machining starts with a block of material (called a blank), and uses fast-moving cutters to quickly carve away material and create the finished part. This involves the automated control of machining tools (such as drills, boring tools and lathes) by means of a computer. These CNC machines process each piece of material to meet specifications by following a coded programmed instruction, and once programmed can manufacture the part autonomously.

What are the benefits of CNC Machining?

The key advantages and disadvantages of CNC technology are summarised below:

  • CNC machining offers excellent accuracy and repeatability and can produce parts with very tight tolerances, making it ideal for high-end applications.
  • CNC materials have excellent and fully-isotropic physical properties and are suitable for most engineering applications.
  • CNC is the most cost-effective manufacturing process for producing low-to-medium numbers of metal parts (from one-off prototypes, up to 50000 units)
  • Due to the subtractive nature of CNC machining, specific geometries are either very costly or impossible to manufacture.
  • The start-up cost of CNC machining is high compared to 3D printing, so CNC is less suited for low-cost prototyping (for example, comparing metal and plastic). 

The lead times of CNC machining (10 days) are longer than the lead times of 3D printing (2-5 days), as CNC machines are not as widely available since they require expert knowledge to operate.

How to improve your CAD designs for CNC machining

CNC Design Rules and Tips

When designing 3D CAD parts that are going to be CNC programmed using CAM software, a few rules or pointers can be followed to allow the part to be machined on a CNC machine. 

For example, one needs to remember that the cutting tool used is round, so you cannot have square corners in some places, so one needs to be aware of the cutting tools used.

Here are some rules to follow when designing for CNC machining to prevent the CNC programmer from redesigning your part when they are doing the programming. 

1. Maximum part size

Maximum part size depends on your machine size; giant machines can produce parts bigger than 2mx0.8mx1m, five-axis CNC machines have a smaller volume.

2. Take note of wall thickness.

  • Metals: Minimum 0.8mm Plastics: Minimum 1.5mm
  • Absolute minimum 0.6mm

Thin walls on a part allow for more opportunity to break, no matter what the material. Wall thickness is proportional to the stiffness of the material, so thinner wall thickness leads to vibrations when machining. As a guideline, keep this in mind: for metals, try not to go below 0.8mm, and plastics not less than 1.5mm. Try to design your part from sheet metal instead or use another manufacturing method if required.

3. Height of tall features

  • Typically Maximum: 4 x part length

Vibration becomes a problem when machining tall features. Try to work by the ratio of max height is 4 x the length to minimize machine vibrations.

4. Try not to use too many tolerances in your design.

  • Standard: ±0.125mm
  • Minimum: ±0.001mm

Tolerances are necessary for a design; excess tolerancing only increases machining time and cost. Tight tolerances should only be specified where essential and should keep with the CNC machines tolerance ability. Some standard tolerance to stick by for most CNC machines is ±0.125mm, whereas down to ±0.001mm is feasible. Tolerances should be defined on all critical features.

5. Holes should have accurate length to width ratios.

  • Maximum: Hole length = 4x Hole diameter

Try to work with the ratio hole diameter is less than 4 x the length of the hole. If the hole is too deep, this results in the tool deflecting and makes it difficult to remove the chips, leading to tool fracture. An example is a hole 10mm wide that should not be more than 40 mm deep. Deeper holes need to be machined with larger diameter cutting tools; bear this in mind.

6. Limit thread length

  • Maximum thread length=3 x hole diameter
  • Recommended: M6 or higher
  • Smallest: around M2

Strong threads are formed in the first few turns, so long threads are pretty unnecessary; as a rule of thumb, try to design your thread three times longer than the hole diameter. Choose larger threads if possible; they are easier to machine.

7. Avoid designing features that can’t be machined

Not all features can be machined on a CNC. If one sticks to some simple guidelines when designing, the part will be redesigned before machining.

One needs to understand the machine’s capability; for example, A 3 axis machine cannot machine negative angles. Another example is one cannot machine curved holes on a CNC; to do this, one would have to split the part into two and reattach the two halves. EDM is a better process for this.

8. Try to design functional parts that can be machined.

When designing, try to think about the machining processes involved in creating the part; one needs to think practically about how the machine will move and if the part is to be machined on a three-axis or five-axis machine. Three-axis machines can only work with simple geometry and curves, whereas five-axis machines can manage more complex parts.

9. Size of small features

  • Minimum: 2.5mm
  • Smallest: 0.100 mm

Most CNC machines use a minimum of a 2.5mm tool diameter; this can be considered when designing. It is feasible to develop features smaller than 0.1mm, although this should be avoided.

10. Design restrictions

One needs to think of the surfaces that can be machined with the CNC tool, internal geometries such as a curved hole are impossible to machine, and such a part would need to be split into two separate parts machined separately and then combined to produce that geometry.

The vertical parts of a machined part will always have a radius due to the tool geometry – drills are always round and can only cut radii.

The geometry of the part decides how it is held in the CNC machine; this impacts the cost; if it can’t be bolted down, it would need to be clamped in place, which could add to a positional error when completing subsequent runs.

Workpiece stiffness can change when thin walls are machined into the parts leading to the vibration of the part. Take this into account when designing.

Read Geomiq’s CNC Design Guide > 

CNC Locations

CNC Machining London
CNC Machining Sheffield
CNC Machining Birmingham
CNC Machining Bristol
CNC Machining Glasgow
CNC Machining Manchester
CNC Machining Essex
CNC Machining Ireland
CNC Machining Leicester
CNC Machining Scotland