Diamond bits on plywood - vibrations

Mostly Printed CNC - MPCNC Troubleshooting
1

I was cutting some wood and plywood with 1 flute simple bit and it was working fine.

Some time ago I found that people prefer Diamond Bits for the plywood because they produce more clear cuts on the top. I tried a couple of bits (3.17, 2.4, and 2.1) but comparing to 1 flute 3.17 I am getting serious vibrations.

Do you have any quess what is the reason and what am I doing wrong?

My build is quite stiff, every single bearing is really tightened. But on these bits I am having very serious vibrations. The top of the part is better (no hair), but the cut itself is having slight wobble. (on the screenshot below left was cut by 1 flute, and right ones is Diamond 2.1mm)

[attachment file=46075]

Sorry no luck to embed the video from YouTube - Video shows sound I get. Some resonance?

 

IMG_20171015_174340.jpg
IMG_20171015_174340.jpg1360×599 104 KB

2

Is the diamond bit a 2 flute? I think you just need to slow down your RPM’s, or cut deeper per pass.

Do you have a link to the bit, I’m not sure what it is.

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3

Ryan, so sorry, due to some reason thought these are called diamond bits, but these are CORN type bits!

Here is the lot: https://www.banggood.com/10pcs-11_522_53mm-Carbide-End-Mill-Cutter-PCB-Drill-Bits-p-1090388.html?rmmds=myorder

Just noticed that price is a bit…mmm… cheap, even for chinese made)) But the geometry looks fine

Do you think what you said above could be right for these bits?

 

P.S. I think I had around 10 000 RPM, and 1.5mm depth that time

4

Those are drill bits, best for pushing down into wood and not so good for pushing sideways.

5

Hmm… Are you sure you are looking at the right link? (or you’re referring to the name Chinese decided to give to the goods?)

They do not look like a drill ones. I’ve heard they are used for the brittle materials like PCB, Carbon, and Plywood

 

 

cornbit.png

6

I wouldn’t use those for plywood, they’re really made for pcb(fiberglass) or carbon fiber panels. The ones you linked to will gum up with wood and glue. Plain old 1 or 2 flute endmills work best for plywood. Plywood really is a shitty material to cut no matter what though. The glues they use are really hard on the end mills.

1 Like
7

Thanks guys,

Seems like I will forget about these, and will contunue to deal with 1 flutes… (and sleep well)