On Friday 02 January 2009, Dean Hedin wrote: >My current 3 axis is a former PCB router. I added a z axis and more > powerful steppers. > >I kept the original spindle motor. It takes about 70 volts DC and spins >around 50k rpm. There is no gear box. It is really nothing special, other > than having precision roller bearings. It's about 4 inches long and about > 1.5 inches in diameter. > >I believe a good substitute might be some of the R/C electric motors that > spin around this same rpm. > Unforch, I just spent 15 minutes googling for those, and found absolutely zero real information on those motors. And I don't buy pigs in a poke I can't see through.
For pcb cutting, I'd think about a little 50k rpm air motor that Grizzly sells quite reasonable, but it needs 7 scfm at 90 psi, and my compressor isn't quite up to that level of delivery, only about 3 horse. I'd assume that it might need a lube mist in the feed too, although we used to spin quadruplex video tape heads at 14,400 with dry air for tens of thousands of hours of spin time, but with 3 phase motors, the air was just for the bearings. Maintenance of the air compressor for something like that should be budgeted into the job cost though. >----- Original Message ----- >From: "Chris Radek" <[email protected]> >Subject: Re: [Emc-users] PCB routing on a CNC mill > >> On Fri, Jan 02, 2009 at 05:14:03PM -0500, [email protected] wrote: >>> 1. Very fine line routing will be disappointing, it tends to push the >>> coper out of the way rather than cut. This is in part due to the low >>> spindle speeds. The velocity of a 1/32 or smaller mill at the cutting >>> surface is quite low. A high speed spindle will help immensely. For >>> wider lines the resolution is good enough and it is quick. >> >> So true. Spindle speed and runout are very important. I have good >> results at 20krpm but feed rate is limited by the spindle speed. >> 30krpm would be better. >> >>> 2. The best method, at least for me, is to use a toner transfer >>> technology to produce an etched circuit and use the CNC mill to drill the >>> holes and cut out the board. This process has a number of limitations >>> but gives me decent boards fairly quickly. >> >> Interesting! I have found that this process works pretty badly and is >> finicky compared to routing. Maybe I never found the right material >> to print on. I only tried a couple times. > >---------------------------------------------------------------------------- >-- _______________________________________________ >Emc-users mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/emc-users -- 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) Simon: "It's okay to leave them to die." --"Serenity" ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
