On Friday 15 May 2009, Rob Jansen wrote: >Gene, Gary, > >I use double sided tape a lot for milling EPS/XPS foam and sometimes for >PCB milling. >There is a problem with the tape wrapping around the mill when you mill >through the tape, not that much of a problem for PCB material with a >spade mill but it could be a problem with one of those combined >engraver/drill bits for PCBs. Surely tape is a problem with foam, the >tape will stick on the sharp edges and influence the quality of the cut. > >A vacuum table is the better solution and easy to make yourself. >Although I don't like Andrew's design (it does not allow you to use >smaller PCB material) it is nicely made. >Check out this link >http://www.cnczone.com/forums/showthread.php?t=33585&page=2 ><http://www.cnczone.com/forums/showthread.php?t=33585&page=2> in the >cnczone, it shows photo's of a home made grid type vacuum table. Nice >thing on the grid type is that you can use a silicone or rubber band to >create a smaller vacuum area. >Made out of PVC it is not expensive, not too heavy and very forgiving in >case you drill or mill too deep.
And I have several feet of HDPE 1/2" thick, that would be just the ticket. Sounds like a plan to me. >And yes, you do need a vacuum pump and the litter wonder that Gene has >is a very nice humming pump. Most membrame type of compressor like used >in a refrigerator are also a nice, they don't make as much noise as my >vane pump (mostly being used to vacumize large 70" x 20" carbon forming >molds). Fridge compressors aren't diaphram types, but usually the inner/outer meshed gear variety, like an auto engines oil pump, but the basic Gast design with moving vanes is also used. The suction noise is contained in the housing. We only hear it in the Gast vane pumps like these because one end of it is connected to the air we hear with. With the right lube & decent air filters, they'll easily run for 40 years. No diaphram type can do 10% of that due to diaphram fatigue. [...] -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Murphy was an optimist. ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
