Sheet Metal Fabrication vs. CNC Machining: Choosing the Right Process for Your Custom Prototype

When it comes to prototyping a custom part or enclosure, selecting the right manufacturing process can make all the difference for your project. Two of the most popular methods – sheet metal fabrication and CNC machining – each offer distinct advantages. Depending on your specific requirements, you can choose the method that best suits your needs. At ProtoSpace Mfg, we can custom manufacture your part or enclosure using either method, and best of all, we can do it in just 2-3 days.

In this blog, we’ll guide you through the key factors to help you decide between sheet metal fabrication and CNC machining.

The Basics

Sheet Metal Fabrication involves shaping thin sheets of metal through cutting, bending and assembling.

CNC Machining (short for Computer Numerical Control machining) uses software-driven tools to cut material from a solid block with incredible precision.

Design Complexity

The complexity of your prototype's design will largely determine which method is best:

Sheet Metal Fabrication: Suited for simpler, flat designs or prototypes with angular shapes, it’s therefore an ideal choice for box-like enclosures, as well as chassis and housings with bendable or folded structures.

CNC Machining: Best for highly detailed designs, which have intricate geometries and blind features. For example, if your enclosure needs tight tolerances or integrated features like threads or grooves, then sheet metal fabrication might not be the right fit.

Durability and Strength

Both manufacturing methods produce durable prototypes, but their applications differ:

Sheet Metal Fabrication: Produces strong, resilient parts, ideal for general use cases. However, sheet metal parts may not provide the same level of durability as machined parts for high-impact applications.

CNC Machining: Offers superior strength with tighter tolerances and better surface finishes. Machined enclosures are more robust and better suited for harsh environments, such as aerospace applications, and offer excellent protection against water and moisture.

Integrated Features

Consider the type of features you need in your prototype:

Sheet Metal Fabrication: Ideal for adding perforations, vents, or access panels. Moreover, it's great for lightweight designs that require ventilation cutouts or fasteners, latches, and hinged panels.

CNC Machining: Allows for high-precision, single-structure parts with integrated features like heat sinks, gaskets, or complex pockets for electronics.

Speed of Manufacturing

We understand that tight deadlines are common while prototyping. While CNC machining typically takes longer due to programming and setup, our High Velocity Mass Customization (HVMC) process ensures lead times of just 2-3 days for fully finished custom parts and enclosure, whether you choose sheet metal fabrication or CNC machining. However, note that the complexity of the machining process can impact lead times (check our parent company Protocase's guide for more information). So, plan accordingly.

Material Options

At ProtoSpace Mfg, we stock a wide range of materials to match your project’s requirements:

Sheet Metal Fabrication: Steel, galvanneal, stainless steel, aluminum, copper and perforated sheet metal.

CNC Machining: Aluminum, cold-rolled steel, stainless steel, as well as plastics like Delrin, acetal, UHMW, acrylic and polycarbonate.

Making the Right Choice

Ultimately, the choice between sheet metal fabrication and CNC machining depends on the specific needs of your custom prototype. Here’s a quick summary:

Sheet Metal Fabrication: If your design features flat, folded, or modular shapes and doesn’t require tight tolerances.

CNC Machining: If your prototype needs precision, tight tolerances, or is a solid block.

Need Help Deciding?

If you’re still unsure which process is best for your project, our team is here to help. For more design advice, reach out to us through the contact page on our website.