CNC milling service

A UK-based CNC milling service delivering accurate, repeatable components where quality, consistency and supplier confidence matter.

From drawing review to inspection, Penta supports milled components with practical engineering input, controlled production and clear communication.

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ISO 9001 Certified
JOSCAR Registered
Cyber Essentials Plus
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Ben
Aerospace & Industrial
Penta Precision delivered an excellent service with a standard turnaround. The work was of a sublime level and the level of communication right from the start was outstanding.
Simon
Industrial & Marine
Penta provide an excellent service from start to end. Friendly and knowledgeable consultant and advice, superb communication throughout, outstanding attention to detail, flawless engineering and machining, on time supply, transparent pricing, clear and accurate paperwork. A genuine pleasure to do business with.
Steve
Steve, Scientific and Technical
Excellent service, friendly and helpful staff. Never had a non-conformance on our system for Penta Precision.
David
Aerospace & Industrial
Overall excellent service, parts are delivered on time to an acceptable standard. Sales and quotation team are very responsive to our enquiries.
Russell
Medical and Pharmaceutical & OEM
Customer service is always very professional with everything done to a great detail expertise. Final product is also to a very high standard.
David
Aerospace
Overall excellent service, parts are delivered on time to an acceptable standard. Sales and quotation team are very responsive to our enquires.
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Proven. Certified. Trusted.

A CNC milling service supported by certified quality systems.

Our CNC milling service operates within ISO 9001-certified quality systems and is JOSCAR registered, giving procurement and engineering teams confidence in compliance, traceability, and delivery reliability on every order.

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British Assessment Bureau ISO 9001 Quality Management Accreditation
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Technical CNC milling expertise

Our CNC milling service supports complex features, tight tolerances and repeat production requirements. We review drawings, material, workholding and inspection needs before machining, so risks are addressed early.

  • CNC milling across aluminium, stainless steel, brass, copper, plastics and other engineering materials
  • 3-axis and 5-axis milling capacity for complex profiles, pockets, faces and drilled features
  • Inspection support for consistent quality and clear evidence

Materials we mill

Aluminium

Arrow
Lightweight, corrosion-resistant, and highly machinable

Plastic

Arrow
Lightweight and chemically resistant with good electrical insulation

Stainless steel

Arrow
Strong and durable with excellent corrosion and heat resistance

Titanium

Arrow
Commercially pure unalloyed titanium, corrosion-resistant, high strength-to-weight ratio

Copper

Arrow
Excellent thermal and electrical conductivity, good corrosion resistance

Brass

Arrow
Free-machining and dimensionally stable with good corrosion resistance

Bronze

Arrow
Hardwearing and corrosion-resistant with excellent load-bearing properties

Guidelines for CNC machining

Lead times

CNC tolerances

Finishing processes

Max dimensions

Tab one

Order Type Quantity Range Typical Lead Time Additional Info
Prototype 1–5 parts 1–4 weeks* May vary based on complexity and material, but is flexible to the part requirements. Contact us early to discuss.
Small Batch Production 6–25 parts 6-8 weeks Can occasionally be reduced to 2–3 weeks depending on capacity and material lead time.
Medium Batch Production 26–100 parts 6-8 weeks Best suited to scheduled or call-off ordering for consistency
High Volume Production 100+ parts 6-8 weeks Longer lead times. Kanban or call-off ordering strongly advised
Kanban / Call-Off Orders Varies 24–48 hours dispatch* Stock held at Penta. Dispatch triggered by usage or schedule. Order is invoiced or paid upon call-off.
Tab two

Process
Range of Tolerances Achievable
Notes
Milling >±0.01 mm Dependent on part geometry, material and setup. 5-axis offers tighter tolerances and better repeatability.
Turning >±0.01 mm High-precision turning across billet and bar work, supported by modern multi-axis machines.
Geometric Tolerances >±0.010 mm* *Depending on material, finishes, and the geometry of the part.
CMM Measurement Verification to ±0.002 mm Achieved using our CNC CMM with 2.3µm volumetric accuracy and temperature compensation.
Tab three

Finishing Process Purpose Additional Information
Hard Anodising Adds a protective oxide layer to aluminium parts. Usually 25–30 microns thick. Typically used for parts designed for the outdoors and general engineering for corrosion resistance. This finish requires hole masking and machining allowance, so use only if needed.
Sulphuric Anodising Adds a decorative layer to aluminium. Less than 5 microns thick. Won’t offer any protection and minimal corrosion resistance. For decorative or aesthetic purposes only.
Bead Blasting Creates a uniform matte finish that removes tool marks. Ideal for reducing reflectivity and improving surface uniformity.
Powder Coating Provides a hard, colourful coating that is tough and wear-resistant. Commonly used on enclosures, brackets, and consumer-facing components.
Chromate Conversion Plating Enhances corrosion resistance while retaining electrical conductivity. Often applied to aluminium components used in electronic assemblies. Commonly referred to as Surtec or Iridite.
Polishing Achieves a smooth, high-quality surface for aesthetic or functional use. Used in medical, optical, or high-spec applications where surface finish is critical.
Nickel Plating Applies a thin layer of nickel to improve corrosion and wear resistance. Provides a bright, uniform finish. Often used for decorative parts or where moderate hardness and conductivity are needed.
Ultrasonic Cleaning Removes fine particles, oils, and machining residue using high-frequency sound waves. Commonly used as a pre-finishing or pre-assembly process. Ideal for complex geometries and internal features. Leaves no residue.
Assembly Combines multiple components into a finished or semi-finished assembly. Used to streamline production workflows. May include press fitting, fasteners, inserts, or other mechanical joining methods.
Tab four

Process Maximum Dimensions Notes
Milling Up to X: 1000 mm, Y: 600 mm, Z: 550 mm Based on Doosan and Matsuura 5-axis machines. Max Ø350 mm × 300 mm height for 5-axis work.
Turning Max billet Ø380 mm × 580 mm length
Max bar Ø65 mm × 1100 mm length		 Applies across Mazak, Doosan Puma, and CMZ lathes. Includes Y-axis and driven tooling.
Tab five

Examples of our high-quality CNC milled components

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Sealing die

Aluminium machining
CNC Milling
Coated aluminium 6082 T6
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Space Component - Tray on 3U/6U Satellite

Aluminium machining
CNC Milling
Aluminium 7075
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Heatsink

Aluminium machining
CNC Milling
Aluminium
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Sensor Block

Copper machining
CNC Milling
Copper C101
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Bar Seal Die

Brass machining
CNC Milling
Brass
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Brass Block

Brass machining
CNC Milling
Brass
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Milled Aluminium Bracket

Aluminium machining
CNC Milling
Aluminium 7075
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Enclosure

Aluminium machining
CNC Milling
Aluminium nickel bronze
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Black anodised speaker component

Aluminium machining
CNC Milling
Aluminium 6082 T6 with black anodising
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Baffle cage support bracket

Plastic machining
CNC Milling
Nylon
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Electronic enclosure lid

Aluminium machining
CNC Milling
Aluminium 6082 T6 with Cerakote coating

What our clients say

David
Aerospace & Industrial
Overall excellent service, parts are delivered on time to an acceptable standard. Sales and quotation team are very responsive to our enquiries.
Simon
Industrial & Marine
Penta provide an excellent service from start to end. Friendly and knowledgeable consultant and advice, superb communication throughout, outstanding attention to detail, flawless engineering and machining, on time supply, transparent pricing, clear and accurate paperwork. A genuine pleasure to do business with.
Steve
Scientific and Technical
I have used Penta Precision for 4 years and have never had any issues with quality or the service we have received. I would have no hesitation in recommending them as a supplier of precision parts.
Nadiya
Medical and Pharmaceutical & OEM
Highly recommended and customer orientated company. Professional team which meet requests in a timely manner, supportive and cooperative.
Russell
Medical and Pharmaceutical & OEM
Customer service is always very professional with everything done to a great detail expertise. Final product is also to a very high standard.
Mark
Scientific and Technical
I'm very grateful to have a supplier like Penta that we can rely on to deliver high quality, precision parts...Please keep up the good work.
Ben
Aerospace & Industrial
Penta Precision delivered an excellent service with a standard turnaround. The work was of a sublime level and the level of communication right from the start was outstanding.
Nick
Marine & Subcontract Machining
Penta Precision have consistently provided us with excellent service...which is reinforced by their attentive and customer focused team, who maintain a high standard of communication throughout the process.
Martin
Defence & Electronics
Our first order was professionally executed to the required standard. Communication was good.

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CNC Milling 101: What engineers need to know about capability, risk and repeatability

11 Jun 2025

CNC milling is a subtractive manufacturing process in which material is removed from a billet of raw material to create a metal component. It's an important part of the modern manufacturing process and is typically used during machining.

Common questions

How much does CNC milling cost?
Is there a minimum order quantity (MOQ)?
What is the fastest lead time you can offer?
What file formats do you accept?
What are the maximum and minimum part sizes you can mill?