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Best CNC Milling Services for Your Custom CNC Milling Parts

Custom CNC milling services delivering tight tolerances, smooth surface finishes, and fast lead times. We offer 3-axis, 4-axis, and 5-axis milling for prototypes and production parts in over 50 metals and plastics with 15+ finishing options. Get instant quotes and rapid delivery with ISO-certified quality.

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Certifications
ISO 9001:2015 | ISO 13485:2016 | IATF16949

Precision CNC Milling Services - Customized CNC Milling Solutions for Your Milled Parts

Whether it’s a basic 3-axis system or increasingly complex 4-axis or 5-axis systems, our powerful manufacturing capabilities provide unparalleled precision and craftsmanship, with tolerances as low as ±0.01.

3 Axis CNC Milling

If your part has a relatively simple structure but requires high precision, then 3-axis CNC milling services are the best choice. At the same time, it is also very suitable for small-batch production and prototyping.

4 Axis CNC Milling

When your design evolves from a simple, single structure to a multifaceted one, in most cases, 4-axis CNC milling can effectively turn your ideas into reality.

5 Axis CNC Milling

When your design evolves from a simple, single structure to a multifaceted one, in most cases, 4-axis CNC milling can effectively turn your ideas into reality.

CNC Milling Design Guidelines and Capabilities

For decades, Lingjun has earned its reputation by holding fast to strict CNC machining tolerances. Working with critical dimensions day after day has sharpened the consistency of our results. We follow ISO 2768-m for metals and ISO 2768-c for plastics—clear standards that demand years of discipline to uphold. This steady commitment is what secures our clients’ trust and strengthens our presence in search visibility.

Maximum Dimensions

Maximum depth that can be milled is 2 in. (50.8mm) from either side of part. For specific milling dimensions by material, see maximum part extents for machining.

 MaterialUSMetric
3-axis**
  • ABS
  • Acetal
10 in. x 14 in. x 1.75 in.254mm x 356mm x 44.5mm
3-axis**
  • ABS
  • Acetal
  • Nylon
22 in. x 14 in. x 0.75 in.559mm x 356mm x 19.1mm
3-axis**
  • Aluminum 
22 in. x 14 in. x 3.75 in.559mm x 356mm x 95.3mm
5-axis
  • Hard metals*
  • Brass
  • Copper
10 in. x 7 in. x 1.75 in.254mm x 178mm x 44.45mm
5-axis
  • Aluminum
10 in. x 7 in. x 3.75 in.254mm x 178mm x 95.3mm
5-axis
  • Stainless Steel 304
4.25 in. x 3.25 in. x 3.75 in. 107.95mm x 82.55mm x 95.25mm

*Hard metals: Titanium (6Al-4V), Stainless Steels (303, 316, 17-4PH), Steel Alloy (4140)

**Denotes two-sided machining only

 USMetric
Size0.25 in. x 0.25 in6.35mm x 6.35mm
Nominal Thickness0.040 in.1.02mm

In the Protolabs automated factory, we currently support UNC and UNF threads from #2 up to 0.5 in., and metric threads from M2 to M12. Avoid modeling internal threads on your part design.

We also offer the following for milled parts:

Coil inserts
Key inserts

Standard Tolerances
For parts that don’t require a technical drawing we typically can hold a machining tolerance of +/- 0.005 in. (0.13mm). Part features are recommended to be thicker than 0.020 in. (0.51mm) in all regions and a nominal part thickness above 0.040 in.

High-Requirement Tolerances
For additional tolerance requirements, we require a technical drawing at time of upload. Linear tolerance quoted to ISO 2768-1-1989-f, standard hole tolerance of +/- 0.005 in. (0.13mm) and hole and bore-style tolerance on specified features may be +/- 0.0005 in. (0.01mm).

Sharp inside corners on a part will be radiused (rounded) as a natural result of the CNC machining process. Resulting radii will be the minimum allowable tool radius.

Protolabs’ fully automated factory allows you to design in engraving.  We allow:

  • Plastic and soft metals: Minimum width of 0.018 in. (0.457mm), depth of 0.0118 in. (0.3mm). Example text size would be 16 point Arial Rounded MT font.
  • Hard metals: Minimum width of 0.033 in. (0.838mm) and depth of 0.0118 in. (0.3mm). Example text size would be 22 point Arial Rounded MT font.
  • If design permits it, opt for recessed text versus raised

Protolabs also offers Laser Part Marking and Ink Stamp for our semi-automated factory capability as well as via Protolabs Network website. 

Ink StampSpec
Black InkMIL-A-A-208,  13pt. (1/8″) Characters
Black Epoxy InkMIL-A-56032, 13pt. (1/8″) Characters 
White InkMIL-A-A-208, 13pt. (1/8″) Characters 
White Epoxy InkMIL-A-56032, 13pt. (1/8″) Characters 

Kindly ensure to explicitly denote the customized tolerance values on the engineering blueprints.

CNC Milling Materials

Besides plastics and metals, we offer a wide range of CNC milling materials to meet your specific requirements. Contact us to obtain customized materials to meet your needs.

Metal

  • Aluminium
  • Brass
  • Inconel
  • Tool Steel
  • Bronze
  • Titanium
  • Alloy
  • Stainless steel
  • Copper
  • Magnesium

Plastics

  • Nylon
  • ABS
  • PMMA (Acrylic)
  • PET
  • PEI
  • PEEK
  • Polycarbonate
  • Polyethylene
  • POM
  • Polypropylene
  • HDPE
  • PVC
  • LDPE
  • CPVC

Custom CNC Milling Surface Finishes

Surface treatment is crucial. It not only refines finished custom CNC milled parts but also removes surface imperfections, improves the product’s appearance, and, through physical or chemical means, provides a protective layer to increase the durability and strength of your parts.

Anodized

This highly durable finish offers a broad spectrum of color dyes and adjustable luster, ranging from uniform matte to brilliant gloss. The achieved oxide film thickness is tightly controlled, typically ranging from 2 µm to 40 µm.

Polishing

Our Polished Finish achieves an exceptionally smooth, high-gloss surface. Engineered for optical reflectivity, it meets a strict surface roughness standard of Ra 0.8μm (Ra 32 micro-inches).

Bead Blasting

Applicable across diverse metallic and plastic substrates, this process yields a uniform satin finish and subdued luster. Crucially, it is non-destructive, guaranteeing dimensional integrity with negligible material removal.

Black Oxide

Black oxide is a chemical conversion coating applied to ferrous metals. It delivers a uniform, non-reflective matte black aesthetic while providing mild corrosion resistance and enhanced lubricity (often requiring a supplementary oil).

Powder Coating

Suitable for metal parts, this finish provides matte, glossy, or textured surface options in fully customizable colors. Typical material removal ranges from 0.05 mm to 0.15 mm, delivering a clean and uniform appearance.

As Machined

As Machined means maintaining the original surface condition after machining, without any additional treatment. At Lingjun, this is an optional surface treatment option for parts, to avoid any misunderstandings regarding surface treatment.

Brushing

Brushing is a fantastic and widely used surface treatment process. Precision brushing imparts a refined satin finish to components, producing a smooth, uniform surface while subtly masking minor surface imperfections.

Electroless Nickel Plating

The electroless nickel plating process deposits a consistent, dense coating on metal surfaces, delivering superior corrosion protection while enhancing hardness and wear resistance for extended service life.

Chromate Conversion Coating

The resulting surface exhibits either a smooth or matte appearance, sometimes displaying a subtle clear or pale yellow hue. During the process, an extremely fine layer—ranging from 0.25 to 1 micrometer—is precisely removed, ensuring a uniform and controlled finish across the part.

E-Coating

Designed specifically for metal components, this surface treatment is available in both matte and glossy options, with black being the predominant choice due to its versatility and aesthetic appeal.

Painting

This surface treatment is suitable for both metal and plastic components, offering a range of finishes including matte, gloss, or textured. Precise color matching can also be achieved to meet specific design requirements or brand standards.

Heat Treatment

Through precisely controlled cycles of heating and cooling, heat treatment significantly improves the mechanical properties of metal components, enhancing hardness, tensile strength, toughness, and wear resistance, while also optimizing microstructural characteristics for superior performance in demanding applications.

Get a Milled Parts & Surface Finishes Quote Today

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Why Choose Lingjun CNC Milling Services

High Quality

Our commitment to quality is absolute: We deliver unmatched precision in every project, enforce rigorous, end-to-end quality control, and consistently earn universal client satisfaction upon delivery. We guarantee every aspect.

Fast Lead Time

Lingjun's confidence in delivering rapid project turnaround is rooted in our state-of-the-art facilities and immense manufacturing capacity. We leverage a high volume of machine assets to ensure every client order is processed efficiently and quickly.

Quality Guaranteed

We have obtained ISO 9001:2015, ISO 13485, IATF 16949:2016, and AS9100D certifications. Furthermore, we have implemented a complete and comprehensive quality control process from the development stage.

What is CNC Milling Service?

CNC milling is a subtractive manufacturing process that shapes metal or plastic parts by removing material with a rotating cutting tool. It excels at producing detailed features such as pockets, channels, threaded holes, and complex 3D profiles, using 3-axis, 4-axis, or 5-axis machines.

3-Axis Milling – Performs linear motion along X, Y, Z.
4-Axis Milling – Adds a single rotary axis for angled cuts.
5-Axis Milling – Incorporates two rotary axes, ideal for deep contours and complex surfaces.

The workflow begins with a digital CAD model, which is translated into machine instructions (G-code). After the raw material is fixed in place, the spindle follows these programmed toolpaths, removing material layer by layer to achieve the final geometry with reliable precision.

Advantages of CNC Milling Services

1. Strict tolerance control

2. Reduced scrap rate

3. Machining complex geometries

4. Continuous operation

5. Optimized toolpaths

6. Perfect batch matching

7. Reliability

8. Broad material compatibility

9. Minimizing material waste

10. Reducing indirect costs

Applications of CNC Milling

1. Aerospace Components

2. Automotive Prototyping

3. Medical Implants & Devices

4. Tooling, Molds, and Dies

5. Consumer Electronics Housing

6. Energy Sector Components

7. Robotics and Automation

8. Defense and Military Hardware

9. Custom Jigs and Fixtures

10. Architectural Elements

11. General Rapid Manufacturing

FAQ's About CNC Milling Service

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