Design for CNC Machining Parts

CNC machines are a marvelous technology that offer a range of possibilities for accurate parts, but your end-product is only as good as the design you set out with. There are some major considerations one has to make when developing any machined part, taking into account its full geometry.

As of yet, such guidelines are more rules of thumb than real protocols set in stone. Industry-wide standards are rare and the technology is always in flux, coming up with new and exciting innovations that push the envelope in terms of what is and isn’t possible. However, there are many practices that have become tried and true rules to live by. Here are some of the restrictions and considerations that come with designing parts for CNC machining.

Basic rules

Generally, it is best to design parts so that tools of the largest diameters possible can machine them. This helps avoid the need for specialist tools and ensures faster processing. It’s also best not to design cavities that are more than four times deeper than their width. It’s vital to make sure the features of the design align with the principal directions your machine allows. This involves keeping in mind the number of axes one is machining with.

When trying to machine text or letters, it is best to use engraved text rather than embossed. Embossed text can end up using a large amount of material that needs to be removed throughout the process. Using a sans serif font with a minimum size of 20 points is also recommended to avoid small, unwanted features within the engraved text.

It’s best to submit a technical drawing when working with a machinist. These need to have a very specific format but can greatly help work through the design of the part and bring out its best qualities.

Machine Type

Before you consider the specifics of the part, it’s important to note the limitations and strengths of the type of CNC machine you have. This may seem basic, but various types of CNC machines offer better control over certain forms and shapes.