Protocase Resources

The information below is intended to be helpful for customers who wish to learn more about enclosure design. Also, please use our online support if you have questions for our expert design staff.


Frequently Asked Questions

CNC Milling

What is CNC Milling?

CNC Milling is the removal of metal with a rotary cutter or other rotating cutting tool. Our 3-axis milling feature a 30,000 RPM spindle which allows us to cut at high speed with smaller cutters, and features an automatic tool changer which decreases total time to cut a part.

How large of a part or panel can be CNC machined?

The maximum size sheet metal parts we are able to mill in a single setup is 4' x 8'. The maximum size bar stock that we are able to mill in a single setup is 26" x 16" x 12".

What is the smallest part or panel that can be CNC machined?

The minimum sheet metal part that can be vacuum-chucked without clamps is 5" x 5". Vices can be used for smaller parts. Please email for more details.

What materials can be CNC machined?

CNC milling is most commonly performed on aluminum and copper. Steel and stainless steel may also be milled, but cycles are longer due to the inherent cutting characteristics of these metals. View all of our bar stock for CNC Machining.

What kind of work holding do you offer for CNC Machining?

Protocase offers a number of different ways to achieve proper workholding for your CNC machining needs, including vacuum chuck, vices, clamps and custom jigs. Visit our CNC Machining page for more information, or contact us to discuss your project.

Can you lathe parts?

Yes, we offer CNC Turning (Lathe), as well as CNC Machining with 5-Axis, 3-Axis and CNC Routers. View our CNC machining page to learn more about what we offer.

What is the tolerance of your CNC machining?

We specify a standard dimensional tolerance of +-0.005" for CNC machined parts. However, it is possible to achieve a tighter tolerances on our routers, lathes, 3-axis mills and 5-axis mills. If you require a tighter tolerance, please contact us, as tighter tolerances may increase the cost of your project and have to be clearly defined upon ordering. Learn more about our CNC machining tolerances here.

Can I use self-clinching fasteners in my CNC machined design?

Yes. Machined parts are generally used with concealed head 'PEM ®' brand self-clinching fasteners. Inserting these fasteners into blind holes has the extra benefit of a smooth finish on the opposite sides of sheet metal after the fastener is installed. These 'PEM ®' brand self-clinching fasteners can be used in sheet metal as thin as 0.075". View our CNC Milling page for a full list of stocked self-clinching fasteners for blind milled holes.

What kind of a finish does CNC machining leave?

Due to the spinning motion produced by the CNC milling machine's cutter, the surface finish of CNC machined parts will have visible toolmarks. If you require a smooth, unblemished finish to your part, we recommend choosing a secondary finish: grained finish (can only be applied to the outside of machined enclosures due to geometry) or powdercoat.

Can CNC machined parts be powdercoated?

Yes. All of our stock powdercoat colors are available for powdercoating CNC machined parts as well (non-stock powdercoat colors are available with additional cost and lead time). Powdercoat paints with texture (Sandtex Polyester and Textured Polyester) will cover toolmarks with no additional finishing operation. Non-textured paints (Smooth Polyester, Smooth Epoxy and Smooth Polyester-Epoxy Blend Hybrid) will not cover toolmarks, therefore an additional finishing operation such as grained finish will need to be performed before powdercoat painting.

Why was my CNC order quoted thicker than I intended?

The material used to CNC machine your design will always have a standard thickness tolerance, so it is part of our standard procedure to quote your design with some extra thickness. Visit our Fabrication Tolerances resource to learn more.