Absolute beginner - trying to understand what went wrong!

Projects
1

Good Morning Everyone,

I’m a total beginner here to the world of CNC.

I was attempting to cut a base for a stand in a scrap bit of ply, nothing complicated (at least I didn’t think so!)

The machine cut the center hole for the dowel rod perfectly, and then went on to cut the base, the first pass went perfectly, but on the second pass, it bit skewed off and started cutting inside of the original cut. Sorry, I may not be using the right terminology :slight_smile:

Is it putting too much strain on the bed perhaps? It’s a cheap 3018 CNC router with a 24V Motor, I tried adjusting the plunge depth from 1.6mm to 0.8mm in the hope that the material was hard and the steppers were struggling to cut. But I still got the same result. (not always in the same place tho)

IMG_1933
IMG_1933480×640 99.9 KB

This is one of the results. I’m hoping someone can point me in the right direction, Happy to supply whatever figures you think might help diagnose (I don’t know exactly what might be needed)

Anyway, thanks for reading, really looking forward to getting this to work properly, appreciate the machine isn’t the best :slight_smile:

Thanks Again
Chris

2

Your machine lack the power/rigidity to perform the cutting loads applied to it. That is the short answer :slight_smile:

What bit, how many flutes, what RPM, what feed rate did you go with? Going shallower give you greater tolerances with the above.

Try same cut with 0.2mm depth per pass.

3

Thanks :slight_smile: I’ll give that a go.

The bits are Genmitsu CNC router bits, 2.2mm size, RPM is the default in Easel at 12000, I had the feed rate set to 800mm/s as well as lowering the depth per pass to 0.8mm

I’ll try lowering it to 0.2mm

Thanks again :slight_smile:

Chris

4

These?
If so, such burr bits are unusable for wood.

5

Yes, the exact same set.

I didn’t realise this, they mentioned they were OK for wood :face_with_raised_eyebrow:

Would you happen to have a recommendation as to suitable bits to use?

6

Any of these or similar will do much better:
Buy where conveniant to you :slight_smile:

For cut-out I use 3mm and 6mm primarely but larger bits for surfacing (19mm or 3/4")
For engraving I use 20-90deg V-bits
For 3D surfaces I use ball mills or tapered bits, depending on desired outcome.

For making / cutting out PCB’s from FR4 boards I’d use the burr bits you got :slight_smile: