Why 2D Drawing Is Still Important For Manufacturing CNC Machined Parts

2D drawing for CNC machinied parts

The 3D CAD technology makes the parts design and manufacturing process faster. Engineers design the CNC machined parts using CAD software, and send the 3D digital files to the CNC machine shop and the parts will be produced directly from the 3D files using digital manufacturing techniques. No 2D drawing is needed in this design to manufacturing process.

Does that mean 2D technical drawings are not necessary, or the 2D drawings are obsolete in the custom CNC machined parts manufacturing industry? No, 2D technical drawings are still very important in the manufacturing process. It specifies the detailed information on CNC machined parts, this is very helpful for manufacturers to meet the dimensional requirement so that to ensure the fit and functionality.

Why the 2D technical drawing is important when manufacturing the CNC machined parts? Check out the below reasons:

1. Reduce errors when producing the custom CNC parts.

2D drawings help the manufacturer to understand important part characteristics, such as critical dimensions, tolerances, GD&T, and surface finishing requirements, they will use suitable manufacturing processes to meet the detail specs, therefore reduce the manufacturing errors, ensure the functionality and good for assembling.

2. Portability.

The 2D technical drawing can be printed out on paper, it is easy to carry, share and read. The staff of the CNC machine shop can use it to identify critical tolerances, outline the assembly steps, identify the points of measurement, and proceed with the inspection. It is more simple to look at a printed 2D drawing rather than load the 3D model on a computer, on the shop floor of most factories, it is not always have a computer for looking at the 3D CAD files, neither any good way to print out a 3D model with all the necessary notes.

3. Concise.

A 3D CAD model includes all geometry, a concise 2D technical drawing can show the critical dimensions tolerances that need to be met, important assembly features which deserve attention, provide necessary inspection points for quality control purposes.

4. Easy to communicate certain aspects of the design of the parts.

The 2D engineering drawings are the best way to discuss certain aspects of your design. For example, if there is a 3/4” hole in the parts, is it a through hole for a 3/4” bolt? Or a tight tolerance hole for a 3/4” bearing? If it is a tapped hole, what is the tap size and depth? Finishing requirements can be called out, the 2D drawings should also include the tolerances of critical dimensions, especially those that mate with another part in an assembly.

5. Saving cost.

If you specified a tight tolerance (eg. 0.01mm) on the 3D file of a part, the machinist needs to ensure every dimension is machined to that tight tolerance, it will increase the machining cost a lot. However, if you create a 2D technical drawing to show the tight and loose tolerances, critical and not critical features respectively. It will help the manufacturer to focus on the key dimensions and features, shorter the manufacturing lead times, as a result of saving machining cost.


Due to the reasons listed above, it is worth spending some time preparing the 2D technical drawings for the 3D files, it will not only help to lower the design errors, but also help the manufacturer to produce the part as expected and faster. In our experience, the customers who provide both 3D files and 2D drawings are more satisfied with the parts they receive.

If you have any CNC machined parts need to quote, we are here to help, submit your request for quote or Email us with 2D drawings and 3D files.