Having worked the past two years on the school’s Shop-Bot, I have become the person to use it the most and I am most familiar with it. CNC milling is not something that most people will have run in with by now necessarily, but it is a nice skill to have. It is perfect for cutting very precise things but if you don’t know what you’re doing it it can be difficult to get those things precise.

1. The program you’re using to view what you’re cutting is probably right. When using a program like V-Carve (the software that comes with the Shop-Bot) its 3D model is normally very accurate so when something seems off in placement or depth or anything else, viewing the model can help. Chances are if everything in the program looks correct, with a problem like that, something in the process of either digital or physical setup was the mess up.

2. The machine can probably do more than you think but that is dependent on knowing your material. The Shop-Bot can be an incredibly fast moving machine to the point where it is surprising each move doesn’t break the bit installed in it at the time, but that’s only going to apply to softer materials that cut well, like wood. Knowing that metal is much denser having it move slower and take off less at a time is a necessity, otherwise you can end up with six broken bits from making one part. For materials that can fuse together using something that can remove that material as it cuts, it is also useful to avoid letting a wadded mass of your material to get left behind.

3. Be creative with holding down your materials. The amount of strange ways that have been used to hold down something that just regular clamps couldn’t reach is insane. Several of the methods involved holding down the material by clamping a 2×4 across a section of it, drilling holes into the board below it and using a series of pegs and wedges, and just plain screwing down every part that wouldn’t be touched by the machine.

CNC milling may not be for everyone, but for those either just started or learning hopefully these tips can be useful in helping you avoid what can be expensive mistakes. There’s still a lot more that can be learned and hopefully you can find those experiences through your own learning process as you find out what it may have to offer.