Clean up after anything is not usually an especially enjoyable endeavor, even where subtractive or additive manufacturing processes are concerned. This is where post processing comes in.
The Problem with CAD In Subtractive Manufacturing
To cut parts using a CNC cutting machine, it has to be programmed with the path of the desired shape or nest of shapes. Most parts are designed with a CAD program where they are saved in a CAD drawing format, such as DWG, STEP, or several others.
But you can’t just take the CAD file and send it to a cutting machine. It has to be interpreted first, so the CNC on the cutting machine can understand it. The problem with CAD file formats is that:
- They usually contain a lot of information that the CNC cutting machine doesn’t need or would find confusing, such as title blocks, Bills Of Material, dimension lines, borders, welding symbols, etc.
- They usually have multiple layers, some of which are useful to the CNC and some of which the CNC needs to ignore.
- They sometimes have many parts in one file, some of which might need to be cut on the CNC cutter, and some might need to be machined, cast, or sent to an EDM.
- They don’t have all of the information needed by a CNC machine. Machines need to be told when to turn a process on and off, how to lead-in and lead-out from a part, etc. All of this information is referred to as the process technology.
Post Processing For Subtractive Machining