2009/10/27 Gene Heskett <gene.hesk...@gmail.com> > On Tuesday 27 October 2009, Chris Epicier wrote: > <...> > >- I have a parallel port based 3 axis mill driven by emc2 2.3.3 (soon > > 2.3.4) - I have a vacuum table, that is well enough even (I remill the > > surface when the wear plate needs to be replaced) - x and y are also > > repeatably within reference distance from home position - If I would add > a > > small metal plate (say alu) into my vac table (could veven be on an > spring > > mount), connect it to a wire, I could close an electric circuit when the > > tool touches that plate. > > I would not recommend using alu for that due to the oxide coat that forms > on > the alu about 100 microseconds after it is scratched to expose the metal. > To > use it that way would require enough contact force to penetrate this oxide > layer and actually make a connection at 3 to 4 volts of applied voltage. > That contact pressure could be sufficient to damage the edge of the bit, > reducing its life. > > A gold or silver plated copper contact would be hundreds of times more > reliable at touch pressures that would not damage the surface or the bit. > <...>
The touch of plates I have been using for years are normal steel, both standard and stainless. They are spring loaded. works like a charm. Regards, Sven ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
