2007-Dec-2 - CAD Design Process

When designing something complex in CAD you will find there is a bit of a process.  First you design parts. Then you build the parts into Sub-Assemblies.  Next you build sub-assemblies into Groups.  Then you build the groups into the machine.  It is a logical pyramid process.  You can also think of it like a file structure inside of a computer. CAD CAM is one of those processes you need to master with DIY CNC.

Designing Parts
Parts are your building blocks. Without this level, nothing could be produced or CNC controlled in your shop.  The part level breaks the entire “thing” down to its simplest form.  You also manufacture at the part level.  You make parts, and then assemble them into other things.Parts are generally made out of raw materials. Think of a differential on the rear axel of a car.  The differential is made up of gears and a housing.  Each of these are parts of the differential and the differential is the assembly of these parts. There are plenty of CNC terms to learn that will help you with this design process.

Designing Sub Assemblies with Hobby CNC
Sub Assemblies are the next level up and I am guessing you are getting the idea.  You first design parts, then put them together into sub assemblies. In the car example above the differential is a sub assembly in the axel “Group” of the car.  Sub Assemblies are put together to form CNC Machining groups.