Building your own unit

If you are thinking of building your own unit, you must be even more selective. The following are some example considerations:

• What is the recommended holding torque for your motors?
• Can you locate the right leadscrews with the right pitch? Are you going to need a Delrin (a type of low-friction, high-wear-resistance plastic) leadscrew nut or a brass one? BumbleBee uses Delrin nuts, but my 3018s all use brass nuts. The difference is often dictated by design and expected wear.
• What power/RPM spindle will you use? Is a plastic mount sufficiently rigid, or will you need a metal one?
• If you are building a desktop unit, you will likely have a worktable that moves. If you are building a unit with a larger work area, the entire gantry will have to move along y. Are you going to use belts, and is that motion system likely to have binding problems (I have seen some of the belt-driven systems get hung up because the belt gets trapped in the frame extrusion slots and wears down very quickly, or loses tension very easily)? Look at the motion system closely and play the devil’s advocate to see where the potential for wear is and whether you will be servicing the machine more often than you would like.

Regardless of whether you are building or buying your CNC machine, you will have to go through some setup processes before confidently working on a project.