Machining Services


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Produce precision parts that exceed industry standards.


Create and test products quickly to bring them to market.

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Empower to innovate faster, maximizing performance.


Innovation in enclosures for low-volume production.

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Deliver machinery that beats the competition.

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Speed up innovation and development.

Medical Devices

Build prototypes and products that adhere to medical safety.


Improve efficiency with precise, fast, and constant part quality.


Drive time-to-market through on-demand production.

CNC Machining for Aerospace

The extremely high level of precision needed within the aerospace industry makes CNC machining a suitable manufacturing process for the sector.


This article provides you with a complete guide to aerospace machining and its importance.



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Select from 30+ surface finishing options.


Choose from 50+ metals and plastics for your project.

CNC Machining eBook

If you want to produce high-quality machined parts with a sleek appearance, it’s essential to consider some critical factors related to CNC machining. 


Here, we’ve gathered some basic information and important considerations to help you achieve the desired results.

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Instant Quote for Sheet Metal Fabrication and New Homepage

Exciting news from RapidDirect!  We’ve rolled out two exciting updates to enhance your manufacturing journey. 

  • Instant Quote for Sheet Metal Fabrication
  • A brand-new Homepage Experience

Custom Online CNC Milling Services

On-demand CNC milling services for rapid prototypes and production parts. Get custom milled parts from various high-quality metals and plastics. Tight tolerance of 0.01 mm. Milled parts as fast as 1 day.

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Online CNC Milling Services for Custom Parts

From 3-axis basics to intricate 5-axis projects, our precision CNC milling makes your designs come alive with unmatched accuracy and craftsmanship.
3-Axis CNC Milling Services

3-Axis CNC Milling

With 3-axis CNC milling, precision meets affordability.  It’s your go-to for simple parts that still demand accuracy.

4-Axis CNC Milling services

4-Axis CNC Milling

Think of a design, and 4-axis milling can probably make it. Multi-sided machining just got a whole lot simpler.

5-Axis CNC Milling services

5-Axis CNC Milling

For those complex and intricate parts, 5-axis milling is the master key. Bring your most ambitious designs to life.

CNC Machining Solutions

Low and High-Volume Production

Whether you need small batches or large-scale production, we can offer you both. With stringent tolerance controls and comprehensive capabilities, we adapt to your volume requirements without compromising on quality.

CNC Milling Materials

At RapidDirect, our CNC milling service offers a diverse range of materials, ensuring precision and durability. This vast selection empowers our clients with optimal choices for their unique projects, boosting their product’s quality and performance.

CNC Milling Surface Finishes

Gain access to quality surface finishing for custom CNC milled parts to remove aesthetic flaws and improve the appearance of your products. We also provide rigid protection and additional resistance and strength to your parts through superior surface finishes.

As Machined  

As machined (Ra1.6)
As machined finish leaves the surface straight from the CNC machine, providing a cost-effective option with tool marks.


Anodizing Type II (Black, Glossy)
Anodizing increases corrosion resistance and wear properties, while allowing for color dyeing, ideal for aluminum parts.


Ra0.2 (Mirror polish)
Polishing achieves a high gloss finish, reducing surface roughness and enhancing the aesthetic appeal of metals.

Sand Blasting

Sand blasting (#220)
Sand blasting uses pressurized sand or other media to clean and texture the surface, creating a uniform, matte finish.


Tumbling smooths and polishes small parts by friction and abrasion in a barrel, offering a consistent but slightly textured finish.


Electropolish is a chemical process that smooths and brightens surfaces while improving corrosion resistance.


Alodine (Chemical film:Conversion) Yellow
Alodine coating provides corrosion protection and improves paint adhesion, mainly used on aluminum surfaces.
Heat Treatment
Vacuum Heat Treatment
Heat treatment alters the mechanical properties of metal to increase its hardness, strength, or ductility.

Brushed Finish

Brushed (#220)
A brushed finish creates a unidirectional satin texture, reducing the visibility of marks and scratches on the surface.

Powder Coating

Powder Coating (Black)
Powder coating applies a thick, wear-resistant layer with excellent color and texture options, suitable for a variety of surfaces.


Nickel Electroplating (Glossy)
Electroplating bonds a thin metal layer onto parts, improving wear resistance, corrosion resistance, and surface conductivity.

Black Oxidize

Black Oxidize
Black oxidize is a conversion coating for ferrous metals that improves corrosion resistance and minimizes light reflection.

Tolerances for
CNC Milling

RapidDirect ensures precision with our CNC Milling Tolerance standards. We commit to exact measurements, benefiting clients with consistent, high-quality results, optimized for search visibility. Our standard tolerances for CNC milled metals are ISO 2768-m and ISO 2768-c for plastics.

Maximum Part Size1000 x 500 x 500 mm1000 x 500 x 500 mm4000×1500×600 mm
Minimum Part Size5 x 5 x 5 mm5 x 5 x 5 mm5 x 5 x 5 mm
General Tolerances±0.1 mm±0.05 mm±0.1 mm
Lead TimeDelivery of simple parts can be as fast as 1 day.5 bussiness days for most projects.5 bussiness days for most projects.

CNC Milling
Design Guidelines

Recommended Size
RadiiInternal radii should be at least 1/3 of the cavity depth. Use larger radii whenever possible.
Threads and Tapped HolesDiameter Φ 1.5-5 mm, depth: 3 times the diameter.
Diameter Φ 5 mm or larger, depth: 4-6 times the diameter.
RapidDirect can produce threads of any specification and size as required by the customer.
Minumum Wall ThicknessFor metals: 0.8 mm; For plastics: 1.5 mm. Thicker walls ensure better structural integrity.
TextCNC Milling: Minimum width of 0.5 mm and depth of 0.1 mm.
RapidDirect can create standard text via CNC engraving or laser engraving as per customer requirements.
HolesMinimum diameter of 1 mm. Hole depth should not exceed 4 times the diameter for best results.
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CNC Machining Project

Kickstart your project with our easy-to-use online quoting platform. Upload a CAD file to receive instantly quotes, lead time, and DFM details for your CNC components. Specializing in CNC machining for metals and plastics, we provide adaptive production and shipping solutions to align with your product development needs.

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With RapidDirect’s CNC milling service, you’re investing in more than just machinery. You get the promise of impeccable precision, adherence to tight schedules, and the support of seasoned professionals.
High Quality

Experience unparalleled precision in each undertaking. Our advanced milling processes ensure components adhere to tight tolerances, as tight as ±0.01mm, resulting in seamless assembly and operational excellence.

Fast Lead

Accelerate your manufacturing cycle. RapidDirect domestic workshops and state-of-the-art machinery guarantee fast turnaround times, helping businesses maintain momentum and meet critical deadlines.


No matter you whenever and whereever, navigate your CNC milling projects with confidence. Our seasoned specialists offer insightful guidance at every step, maximizing design optimization and output quality.

How CNC Milling Works?

CNC milling is a precise manufacturing process that involves removing material from a workpiece using rotating cutting tools. The process begins with a digital design, typically created in CAD software. This design is then converted into a CNC program, which dictates the movements of the milling machine.

The workpiece is securely fastened to the machine’s table, and the cutting tool, mounted on a spindle, rotates at high speeds. The machine follows the programmed path, making precise cuts to shape the material into the desired form. CNC milling can create complex shapes and features, such as slots, holes, and contours, with high accuracy.

Three-axis milling moves the tool along the X, Y, and Z axes. Four-axis milling adds rotation around one axis, while five-axis milling allows rotation around two axes, enabling more intricate designs. This versatility makes CNC milling essential in various industries, from aerospace to medical devices.

Untitled design

Advantages of CNC Milling

CNC milling offers numerous advantages for manufacturing:

  • High Precision: CNC milling machines can produce parts with very tight tolerances, ensuring high accuracy and consistency in every piece.
  • Complex Geometries: With the ability to move in multiple axes, CNC milling can create intricate and complex shapes that are difficult or impossible to achieve with manual machining.
  • Efficiency: Automated operation allows for continuous production, reducing lead times and increasing productivity. Multiple parts can be produced with minimal downtime.
  • Flexibility: CNC milling can work with a wide range of materials, including metals, plastics, and composites. This versatility makes it suitable for various applications.
  • Repeatability: Once a design is programmed, the machine can reproduce identical parts over and over, ensuring uniformity and reducing the risk of human error.
  • Cost-Effective: While the initial setup can be expensive, the efficiency and precision of CNC milling reduce overall production costs, especially for large quantities.
  • Safety: CNC machines operate with minimal human intervention, reducing the risk of accidents and enhancing workplace safety.

Applications of CNC Milling

CNC milling is widely used to produce a variety of precision parts and components:

  • Engine Components: Used in the manufacturing of engine blocks, cylinder heads, and pistons, ensuring high performance and durability in automotive and aerospace industries.
  • Gear Components: Essential for producing gears, splines, and shafts with tight tolerances, used in machinery and automotive applications.
  • Medical Implants: Creates precise and high-quality implants such as hip joints, dental implants, and surgical screws for the medical field.
  • Electronic Housings: Produces enclosures for electronic devices, ensuring proper fit and protection for circuit boards and components.
  • Custom Prototypes: Allows for the rapid development and testing of prototypes, helping designers refine their products before mass production.
  • Tooling and Dies: Essential for creating molds, dies, and cutting tools used in various manufacturing processes.
  • Complex Aerospace Parts: Used for producing turbine blades, brackets, and other intricate parts that require high precision and strength.


At RapidDirect, we have a variety of CNC milling machines to meet diverse manufacturing needs. Our inventory includes 3-axis, 4-axis, and 5-axis CNC milling machines.

The 3-axis machines are perfect for simple operations, handling basic cutting tasks along the X, Y, and Z axes.

Our 4-axis machines add an extra rotational axis, allowing for more complex geometries and more efficient production of parts with features that require continuous machining around a fourth axis.

Finally, our advanced 5-axis CNC milling machines offer the highest level of precision and versatility, enabling the creation of intricate parts with complex shapes and angles.

These machines are capable of machining in five different axes simultaneously, reducing the need for multiple setups and ensuring exceptional accuracy and quality in every component we produce.

RapidDirect offers comprehensive CNC milling capabilities tailored to various industry needs. We can machine parts with maximum dimensions of 4000 x 1500 x 600 mm and minimum dimensions of 5 x 5 x 5 mm, accommodating a wide range of project sizes. Our milling machines can work with various materials, including metals, plastics, and composites. We achieve tight tolerances, typically ±0.01 mm for 5-axis milling, ensuring precision and consistency. Our lead times are competitive, ranging from 3-7 days for simpler 3-axis tasks to 7-14 days for more complex 5-axis projects. We also provide additional services such as surface finishing, heat treatment, and quality inspection to ensure that every part meets the highest standards of quality and performance.

CNC milling and CNC turning are both subtractive manufacturing processes, but they differ in how the material is removed.

In CNC milling, the workpiece is stationary, and the cutting tool moves across multiple axes to remove material and create the desired shape. This process is ideal for complex parts with various features such as slots, holes, and contours.

On the other hand, CNC turning involves rotating the workpiece while a stationary cutting tool removes material. This method is best suited for producing cylindrical parts, such as shafts, rings, and bolts. While milling can handle more complex geometries, turning is typically faster and more efficient for producing round parts.

CNC milling and CNC routing both involve cutting materials using computer-controlled machines, but they serve different purposes.

CNC milling machines are designed for precision work with metals, requiring high rigidity and the ability to handle significant cutting forces. They are used for producing intricate and complex parts with tight tolerances.

CNC routers, however, are typically used for softer materials like wood, plastics, and composites. They operate at higher speeds and are ideal for cutting larger sheets into parts with less emphasis on precision. Routers often feature a gantry-style design, allowing for quick and efficient handling of large workpieces, while milling machines focus on detailed, accurate machining.

When a 3D model or drawing does not specify a particular fillet size, standard practice is to add fillets with a radius that balances strength and machinability.

Typically, fillets with a radius of 1/3 to 1/5 of the cavity depth are added. For general purposes, a fillet radius of around 1 mm to 3 mm is commonly used. This size helps to reduce stress concentrations and improve the overall durability of the part.

However, the exact size can vary based on the material being used and the specific requirements of the part. Larger fillets are often preferred for softer materials, while smaller fillets may be used for harder materials to ensure structural integrity without compromising precision.

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