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CNC Machining Services

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CNC Machining Services

Fathom’s CNC machining experts deliver high-quality parts by way of modern machining methods while incorporating additive technologies to drive more outstanding results. Highly skilled machinists support this hybrid approach and a diverse setup of industry-leading equipment to accommodate many types of applications at any given time. Companies trust Fathom with CNC machining projects that are time-sensitive, short production run related, involve high-complexity and/or require high-precision.

CNC Machining Services

Fathom offers CNC Machining services for the manufacture of precision plastic or metal parts. Utilizing high-speed CNC machines and the latest software programming, Fathom can produce complex pieces directly from 3D CAD data with detail-oriented precision using 3-axis, 4-axis and 5-axis CNC machines, including vertical milling machines, horizontal milling machines and lathes.

Fathom employs CNC machinery that performs complex operations such as turning, milling, drilling, tapping and deep-hole boring. Fathom supports all processes in precision machining with an effective quality control program. We use our engineering expertise, experience, state-of-the-art equipment and in-depth knowledge to serve a variety of different industries, including medical, aerospace, defense, automotive and consumer goods.

From rapid prototypes—both cosmetic and functional—to low-volume production parts, Fathom’s CNC machining team is part of its secure facility and follows processes to protect a company’s IP (e.g., NIST 800-53 Compliant). Customers can choose from a wide variety of metal and plastic material options or can make special material requests. The team offers a tolerance accuracy range from +/-0.001″ to 0.005″ and can support even faster lead-times for on-demand reorders.

CNC Machining Parts and Images


Work with Fathom on Your CNC Machining Project

Fathom is ready to help you produce a high-quality product that meets your project’s exact specifications and deadlines. Over many years and thousands of projects, Fathom has worked with numerous satisfied clients from multiple industries and now we are ready to tackle your project. Our SmartQuote online platform will allow your team to quickly upload a design to our system, keep track of the progress being made and stay in touch with Fathom experts.

What is CNC Machining?

Computer numerical control (CNC) machining is a manufacturing process during which a pre-programmed computer software directs the movement of factory machinery and tools. CNC machining can control a variety of complex machinery, from mills and routers to grinders and lathes. Using CNC machining allows three-dimensional cutting tasks to be accomplished with a single set of prompts. This process has become popular because there is no need for a live operator to push levers, buttons and wheels. Once a CNC machine has been activated, the cuts are programmed into the software and then communicated to the tools and machinery which perform the task, similar to a robot.

CNC machining is ideal for projects requiring production-grade materials and rapid prototyping of tight tolerance plastic and metal parts with excellent surface finishes. The repeatability of the process also opens up the possibility of producing high volume manufacturing of parts using CNC machining.

How Does CNC Machining Work?

CNC machining can be simplified into a 3-step process.:

  1. An engineer produces a computer-aided design (CAD) model of the part to be made.
  2. A machinist translates the CAD file to a CNC program and prepares the machine.
  3. The CNC program is initiated and the machine produces the part.

Advantages of CNC Machining

There are many ways your project can benefit from CNC machining. These include:

  • Precise parts
  • Large, scalable volumes
  • Variety of shapes, sizes and textures
  • Reduced demand on workers
  • Increased worker safety
  • Easy reorders
  • 24/7 machine operation

Lower costs and greater efficiencies

CNC Machining Design Limitations

There are several key considerations to keep in mind when designing your product for CNC machining.

  • Workholding: A part’s geometry will dictate how it will be positioned on the CNC machine and the amount of setup required. If a part must be manually repositioned, this can result in a small positional error. This can also impact the cost of the project in addition to part accuracy.
  • Tool stiffness: The tool used to cut the part may vibrate while operating. Tool stiffness may result in looser tolerances.
  • Workpiece stiffness: Temperatures and cutting forces developed during machining may cause the workpiece to vibrate or even cause deformities. There are a minimum wall thickness and a maximum aspect ratio of tall features that the part must have to prevent workpiece stiffness.
  • Tool geometry: CNC machining cutting tools have a cylindrical shape and a flat or rounded end. This can restrict the CNC machined parts geometries. The inside vertical corners of the part produced will have a radius, even if a small cutting tool is used.

Tool access: If the cutting tool is unable to reach a surface, it cannot be CNC machined. This places a limitation on parts that require hidden internal geometries and sets a limit on the maximum depth of an undercut.

Conventions Used to Describe CNC Procedures

Your project may likely be described as:

  • 2 Axis: the cutting takes place on the same plane. The cutter does not have any capability of movement in the Z plane.
  • 5 Axis: the cutting occurs entirely in planes parallel to the main plane, but not always at the same height or depth. The cutter may move on the Z plane to switch levels, but not at the same time as the X or Y movements.
  • 3 Axis: the project requires cutting with simultaneous controlled movement along the X, Y, Z axes.
  • 4 Axis: means the above plus 1 rotary axis movement is included. This may be 4 axis simultaneous interpolation or 4th axis positioning where the 4th axis repositions the part between 3 axis operations, but does not move during machining.
  • 5 Axis: rotary axis movements of 2, 2.5, 3, or 4 plus 2. Additionally, it may be 3 and 2, 2 separate axes positioning and 3 axis machining, or 4 plus 1, or continuous 4 axis machining plus 5th axis positioning.

Different types of CNC Machines

A CNC machine follows a coded program to modify a piece of material to meet specifications. The code is written by a person or translated from CAD or CAM software. They often use G-code or M-code. Some of the most frequently used CNC machines include:

  • CNC Mills: The most basic mills consist of an X, Y, Z system and newer mills with three axes. Most CNC Mills run on programs following letter and number-based prompts that instruct pieces to move certain distances. Face milling, tapping, drilling, turning and shoulder milling are all functions of a mill. On a CNC mill, the workpiece is held in place. Cutting tools or drills attached to a spindle remove pieces of material from the workpiece.
  • Lathes (CNC turning): Lathes deliver circular cuts with precision and high velocity. Lathes are commonly used for complex designs not possible with a manual machine. Most CNC lathes have two axes, X and Z. Some models have more than two axes, which allows them to do more advanced jobs. On a lathe, the material is held on a rotating spindle. The non-rotating cutting tool or drill traces the perimeters of the part, forming the geometry or shape.
  • Plasma Cutters: Material is cut using a plasma torch. Plasma cutters are mainly used for metal materials, but other materials may be used. The machine generates heat and speed by using compressed-air gas and electrical arcs.
  • Electric Discharge Machines (EDM): Two workpieces are cut and shaped by using electrical sparks. Two electrodes on the machine discharge sparks. As the space between these electrodes shrinks, a current passes through, which removes a portion of the workpiece. This method is sometimes called die sinking, spark machining, spark eroding, burning, or wire erosion. Subtypes include Wire EDM and Sinker EDM.
  • Water Jet Cutters: High-pressure water jets are used to cut hard materials such as metal or stone. Water jets are often employed when the material cannot bear high-heat.
  • Other tools with CNC variants include CNC routers, 3D printing, induction hardening machines, surface grinders, milling machines and more.

CNC Materials

From Fathom to ICOMold, the Fathom brands provide leading CNC machining services across geographies offering both metal CNC machining and plastic CNC machining.

METALS OPTIMAL QUANTITY TOLERANCES (+/-) ADVANTAGES & CONSIDERATIONS FINISH & APPEARANCE
Stainless Steel 1-1000 +/- 0.005″
  • High strength
  • High corrosion resistance
  • High weldability
  • Standard machined finish
  • Tumbled
  • Bead blasted (sand or glass)
  • Polished
Low Carbon Steel 1-1000 +/- 0.005″
  • Common steel
  • High machinability and weldability
  • Can be hardened
  • Not corrosion resistant
Aluminum 1-1000 +/- 0.005″
  • High strength, low weight
  • High machinability
  • Low cost
Brass 1-1000 +/- 0.005″
  • Corrosion and chemical resistant
  • High density and strength
  • Non-conductive
PLASTICS OPTIMAL QUANTITY TOLERANCES (+/-) ADVANTAGES & CONSIDERATIONS FINISH & APPEARANCE
HDPE 1-100 +/- 0.008″
  • Medium impact strength
  • Flexible (Shore D70)
  • FDA compliant
  • No water absorbsion
  • Standard machined finish
  • Tumbled
  • Flame or vapor polished (acrylic only)
PC 1-100 +/- 0.008″
  • Medium tensile and high impact strength
  • Maintains properties over range of temperatures
  • High optical clarity (clear)
ABS 1-100 +/- 0.008″
  • Medium tensile and high impact strength
  • Electrical insulator
  • High machinability
  • Low cost
Acrylic 1-100 +/- 0.008″
  • High tensile strength
  • Can be polished for high optical clarity
Nylon 6/6 1-100 +/- 0.008″
  • High tensile and medium impact strength
  • Maintains properties over range of temperatures
Acetal (Delrin®) 1-100 +/- 0.008″
  • Medium tensile and medium impact strength
  • Holds machining tolerances well
  • Good wear and fatigue resistance
ULTEM® 1-100 +/- 0.008″
  • High tensile strength
  • High working temperature range (335°F)
  • Electrical insulator
  • High optical clarity (clear)

History of CNC Machines

Modern-day CNC machines are robotic or automated systems with multi-axis and tooling capabilities. During the late 40s, the original numerically controlled machine was made by John T. Parsons while working with MIT and the defense industry. Technology had been progressing up to this point throughout history from the 18th century steam-powered machine automation and as far back as 700 B.C. Italian craftmans.

CNC Machining Questions Answered

Q: What language is used by CNC machines?

A: CNC machines are primarily programmed using G-code though M-code is also acceptable.

Q: Are CNC and VMC the same?

A: No. A computer controls CNC machines. A VMC is a kind of CNC machine used to cut metal.

Q: What is the difference between PLC and CNC?

A: Programmable Logic Controller (PLC) is sequential, while CNC is conditional.

Q: Who invented CNC machining?

A: John T. Parsons

Q: What is the significance of CNC machining?

A: As the process is automated, it increases efficiency, lowers costs and increases accuracy.

Q: What materials can be used in CNC machining?

A: Depending on the application, common materials include stainless steel, copper, brass, aluminum, titanium, foam, polypropylene, ABS, POM, PC, Nylon and more.

Q: What are the five different CNC machines?

A: CNC lathe machine, router machine, milling machine, laser cutting machine and plasma cutting machine.

Q: What is the difference between DNC and CNC?

A: A direct numerical control (DNC) system uses a mainframe computer to operate multiple machines. DNC refers to the networking of more than one CNC machine.

Q: What is an NC machine?

A: Numerical Control (NC) machines receive instructions from a punch card, whereas a CNC machine receives instructions from a computer.

Q: What industries use CNC machining?

A: Aerospace, medical device, photonics, defense, electronics, transportation and more.

Q: What type of finish is produced by CNC machining?

A: Some CNC machines, such as the CNC mill, may leave visible tool marks. Because of this, an additional step may be required to finish the part.

Q: What are the standard finishes for CNC parts?

A: Bead blast, anodized, chem film, passivation, powder coat, electropolishing, electroless nickel plating, silver plating and gold plating.

CNC Machining Quotes

Quickly get a quote in as soon as one hour on any CNC project today with our SmartQuote platform.


Fathom’s metal part finishing options include the standard machined finish, a tumbled finish, a bead-blasted matte finish that appears matte-like or a finely polished finish leaving your part with a smooth gleam.

Plastic finishes include the standard machined finish, tumbled finishing and flame or vapor polishing for acrylic only. If you aren’t sure what finish is best for your metal or plastic parts, talk with a Fathom expert directly.

Comprehensive Capabilities for Rapid Manufacturing

At Fathom we offer a unique advantage of speed and agility-our experts help companies go from concept to prototype to manufacturing in ways not previously possible. 

3D Printing / Additive Manufacturing
90+ Machines  
SLS / / Two-day  SLA / / Next-day 
FDM / / Next-day DMLS / / Three-day 
PolyJet / / Same-day MJF / / Two-day
Injection Molding

30 Second Quotes

Prototype Tool / / As soon as 10 days

10K Parts / / 10 days

Production Tool / / As soon as 3 weeks

CNC Machining

3 & 5 Axis Milling & Turning
(Plastics, Composites and Metals)

Tolerance Accuracy Range
from +/-0.001″ to 0.005″

Urethane Casting

Injection Molding Adjacent
without High Costs of Metal Tools

Most Commonly Used for High-Volume
Prototyping & Bridge to Production

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Fathom is driven by advanced technologies and methods that enhance and accelerate today’s product development and production processes.

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