Homebrew_PCBs

Hi Sage,

I’m not sure the spring loaded bit holder will work by itself.  It would need some means of limiting the cut depth.

There are several PCB routing machines that use a spring loaded motor and spindle (or “floating” head) so they can route warped PCB materials, but this is different I think.  On these machines the routing bit is held firmly in the spindle, with a cylindrical plastic “spacer” over the end of the motor and spindle to set the cutting depth.  The whole motor and spindle is then spring mounted (or sometimes just uses the weight of the motor itself with no spring).  The cylindrical spacer is often connected to a vacuum system to remove swarf as it’s cut and before it ends up under the end of the spacer.

I’ve been wondering how to make a spring loaded spindle with depth adjustment that can fit in that Morse tapered tool holder of my CNC machine since it doesn’t have a spring loaded motor/spindle. 

Making a spring loaded engraving bit holder is easy.  Making the depth spacer that’s easily adjusted is the problem!

Cheers,

Mark

For those that CNC mill their own PC boards I know there is autolevelling software out there to control the engraving depth, but I was wondering if the spring loaded engraving bit holders work instead of going through the whole process of probing the board etc. I can imagine having the holder run over the swarf would cause problems with the height but if you keep everything very clean as you go,  don't these devices work? Is there something else making their use undesirable?

Sage

Mark,

If the spacer is threaded it could just be given a slight turn to adjust the depth.  There could be either thread friction or a clamping collar to keep it from rotating.

Bertho

From: Mark

Thanks Bertho,

Good suggestion!

Mark

Mark,

If the spacer is threaded it could just be given a slight turn to adjust the depth.  There could be either thread friction or a clamping collar to keep it from rotating.

Bertho

From: Mark

Thanks for the link.

Looks good but it appears in this design that the depth nosepiece rotates with the engraving tool.  It could get pretty hot from friction in a high speed spindle and melt, or simply wear away on the sharp edges of the tracks and the abrasive fibreglass swarf.  Maybe I’ll try a similar design for ball bearings on the nose so it doesn’t have to rotate.

I guess the one without the depth control relies on the cutting speed to limit the cut depth, especially as they are designed for very hard materials like glass and granite.

Cheers,

Mark

Seems like what I described is available from the company I linked to in my last post. I just didn't look far enough in the site. Great minds think alike I guess.

So, has anyone tried one of these for milling PCB's?

http://www.2linc.com/engraving_depth_overview.htm

Sage