Dertermining depth of copper

Thread Starter

spinnaker

Joined Oct 29, 2009
7,837
I am going to start milling PCBs soon. I will need to know the depth of cut. I have a bunch of PCBs around here but no idea what weight they are. Is there anyway to determine the thickness of the copper other than just experimenting?
 

mcgyvr

Joined Oct 15, 2009
5,394
measure with a caliper..
You may have to mill off some assuming copper all the way to the edge and measure then..
Personally I'd just set it to .010-.015 deep and go for it..

Hope you bought carbide tools.. the fiberglass is tough/abrasive on tools..
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,837
Those tool bits look to have a pretty long cutting relief on them, makes them a little weaker. That type of bit is commonly called a "D" bit.

RepRap has a wiki with a lot of different PCB software on it, even some that work with some of the PCB schematic programs. And it has a lot of general PCB milling info.
http://reprap.org/wiki/PCB_Milling#Engraving_Tips

Does not say too much about bit length unless I am missing something.
 

shortbus

Joined Sep 30, 2009
7,236
Does not say too much about bit length unless I am missing something.
I was going by the picture in the link. That type of bit is commonly called a 'wax milling bit', due to its way of being made it is usually to fragile to with stand much side force when in use. You'll see that they brake pretty easy,especially the very tip, the part you need.

At work for engraving, both in a pantograph and CNC they used a 'pyramid bit'. When you see them they have a much more robust point and basically four cutting edges not one. they can even be used on soft ferrous metals and most non-ferrous metals and plastics. Where I worked the cutter grinder made them up for us as needed. The first link I found - http://www.ebay.com/itm/6mm-0-1-Carbide-Steel-60-Degree-Router-Pyramid-Engraving-Bit-for-CNC-Machinery-/291229278418?hash=item43ce9e20d2:g:bpcAAOSwq7JT~lMN
 

kubeek

Joined Sep 20, 2005
5,650
2oz copper is just 0.003" thick. Does your machine even have enough accuracy to keep that level? I think you should simply test how much depth you need to get reliable separation.
 
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