When it’s time to create a prototype for a design, there are two main options for you to consider: 3D printing and CNC machining. The two processes are fundamentally different. 3D printing is additive which means that a prototype is created by adding material. This process often uses plastic. CNC machining (computer numerically controlled machining) alternatively, is subtractive; the prototype is crafted by removing material over an extended material from a larger base material. Although it’s possible to use a variety of materials for CNC machining, it most frequently uses metal.

For creating a functional prototype, CNC machining is often the best option. It provides precise, efficient, and fast production. Additionally, because of the consistency, once the prototype is finalized, production can easily be scaled to a higher volume. There are many reasons that CNC machining is most effective when considering how to create a prototype. Let’s examine a few of them.

It’s Possible to Use a Range of Strong Materials

CNC machining offers a range of compatible materials to craft a prototype, such as zinc, brass, copper, aluminum, stainless steel, and numerous types of plastics. If a prototype has a mechanical purpose, it’s critical to ensure that it is as similar to the final part as possible. Using strong metals that allow the prototype to behave in a way similar to the final product facilitates an easy transition to final production, as adjustments don’t have to be made to account for a different material.

Although creating a prototype using CNC machining can be more expensive than 3D printing, it’s worth the working knowledge of how the part functions in its final material.

Quality and Consistency for Prototypes

Because CNC machines are controlled by a computer program, the tolerance for errors is within a fraction of a millimeter. Consequently, there’s the certainty that the prototype and the final product will match. Although it may be possible (and less expensive) to create a prototype with a 3D printer, sometimes items that are made with 3D printers cannot actually be manufactured in the correct material. 

Accuracy and Complexity

When designing a complex item, such as a component for a turbine or a medical tool, you want to produce a prototype that allows you to understand effectively what the final product will look like. 3D printers are mostly accurate; however, they do tend to have a larger margin for error than CNC machining. Additionally, 3D printers are often not as quick as CNC machines can be.

What Types of Processes May Be Used to Create the Prototype?

All CNC machining processes have similar basic production stages. The first step is to design a CAD model and export the CAD model into a CNC program in a compatible file. CAM software then converts the CAD file into directions (using G Code) that the CNC machine can read and follow. Prior to the operator running the program via the machine, they affix the necessary part to the machine and then set up the worktable or vise. Once everything is set up appropriately, the operator uses the machine interface to execute the operation.

  • CNC Milling:
    CNC milling involves using the tool that the operator attached to the machine to remove material to a larger block in order to create the appropriate part and is used for parts where the machine only needs to access one side of the part.
  • CNC Turning: CNC turning functions nearly exactly as it sounds. Material is placed on a rotating rod, and excess is removed. This type of process is especially effective with prototype parts that have round cross-sections.
  • 5-axis CNC Machining: There are multiple axes of CNC machining that are possible. 5-axis CNC machining is similar to CNC milling; however, the tool is able to move along multiple axes and therefore can be used for even more complex prototypes.

Whether a prototype requires CNC milling services, CNC turning services, or a more complex 5-axis or 6-axis CNC machining service, it is certain to be the most functional and accurate prototype for a vast array of devices needed by multiple industries. The ease of adjusting design in CAD means that new prototypes can be easily produced, offering a seamless process from prototype to larger production.