What causes whiskers

[rdagger]

This is my 3rd sad attempt at milling pcb's. My first 2 looked like mashed potatoes. I'm using a Romaxx hs1 with a 60° vbit and I've been using millpcbs.com as a reference. I measured the runout on my Ryobi spindle at about .002. What steps should I take to address the whiskers?

[plasmator]

Is your spindle mount stable? Did you measure the spindle runout while mounted, or off the machine?

If everything is solid, you might play with different feeds and speeds.

[Kipper]

Is the cutter sharp....and turning in the right direction?

[rdagger]

The cutter is sharp and brand new although it is a cheap eBay purchase. I tried both a 60 and a 45. I assume the direction is correct because there is no way to change the direction on the Ryobi.

I measured the runout while the spindle was mounted on the machine. Is .002 bad?

The mount seems very solid. The Ryobi only has 1 speed but I will try to lower the feedrate.

[sch]

What rpm are you running the spindle at? Small bits need very high speeds.
For consideration, what sort of results would one get get running a 1" carbide
cutter at 20 rpm?

[rdagger]

My Ryobi TR45K only has 1 speed: 25,000 RPM at no load.

[chuck99z28]

Looks to me like its just too many ipm.
How fast are you traveling?
It looks like is just plowing through the copper.

[Jay C]

Not sure what you are etching into, but that doesn't look very level. What parameters are you using for bit size (assuming PCB-Gcode output). The bit isn't cutting the copper or PCB, it's tearing it. How old is the PCB material?

Also, the circles for the mounting holes don't look round. Do you have backlash in your axis? Have you successfully cut other materials?

[rdagger]

Here are my PCB-GCode settings:
isolation default .0001, maximum .0001, step size .006
etching tool size .005
z high .5, up .1, down -.005, drill depth -.07, drill dwell 1
Feed rates xy 20 ipm, z 10 ipm

I rushed home after work to try another pcb. I set the Mach3 feedrate to 20% instead of changing the values in PCB-GCode. I also bought some new PCB's. I was using old scraps for my first test. The results are better although it's still looking more like Picasso than a pcb. It got worse when I went to drill. It was going fine and then it just tore across the board.

[Jay C]

Try these settings:

Spot drill holes: -.005

Isolation
Default: .001
Maximum : .008
Step: .002

Tool size: .003

Z Down: -.003
XY Feed: 24
Z: 5 - too fast and you can snap the tip off of those V-Bits


Also, post a close -up/macro photo of the bit you are using ... the tip especially.

-Jay

[Jay C]

Oh, and post your G-Code so I can see what it looks like. That second photo looks like major backlash to me...the circles are horrid.

[rdagger]

Here's the original code and a pic of the bit. I'll try your settings in the morning. If I change the tool change position z from 0 to .5, will that prevent my previous drill disaster?