Re: [CAD_CAM_EDM_DRO] brushless servo amp

----- Original Message -----
From: "William Scalione" <scalione@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Sunday, May 21, 2000 11:47 AM
Subject: Re: [CAD_CAM_EDM_DRO] brushless servo amp

Great, thanks for giving it a shot
I've backplotted the files but haven't had a chance to get into the Haas
at work to try them on a board yet
I wasn't happy with all the jumping from place to place either,
the files were generated automatically from the artwork and didn't
come out with any kind of efficiency in mind I've been playing with
the software to try and improve the way it generates the toolpath
but for a small number of boards it would take more time to edit
the trace file into a continuous path than would be saved
the tool called out in the software is a 0.3mm carbide engraving mill
but it gets sent to the tool info file as zero width ,I will have to
change it in the machine definition file and documentation
PCB milling is very hard on tools, and its not just the fiberglass
pure copper likes to build up on the cutting edge and then flake
off ,taking small chips of the tool with it
the information I've found so far sez that the cutters normally used
for board milling can range from 0.1mm to 0.8mm with minimum
recommended trace isolation width being 0.2mm
I will be trying a single flute 90deg countersink bit set so that the tip
just breaks thru the copper
more info on PCB milling can be found at
http://www.lpkf.de/home_us.htm LPKF homepage
under rapid PCB prototyping
and
http://lpkf.herrlich-ramuschkat.de/artikel/view/examples.html
shows some realy small work with 5 milled traces running
between standard IC pads and 2 between SMT pads
they also have a new laser milling system for even finer work

Brian
http://home.earthlink.net/~bfp/


Bill wrote

> Brian,
>
> I milled the traces for your power amp board today on my router.
> They seem to be ok. I am not sure that I will build one, I was just
> seeing if my machine would be able to do it (read playing). I was
> unable to figure out what size tool to use so I tried a small 1/4 round
> engraving bit to start but it was too big so I used a 1/8" dia Dremmel
> conical rotary file. It doesn't leave a very nice finish but a quick
> sanding of the board when it's done cleans it up nicely.
> I imagine cutting the fiberglass will dull the bit pretty quickly.
> What is the normal tool used when cutting circuit board material?
>You have some pretty small traces there so it needs to be quite small.
>The code is not very efficient as it goes from one end of the board to
> another cutting fragments of traces here and there. They all connect
>up in the long run though.
> Nice job
>
> Bill