On Friday 04 July 2014 11:43:41 Jon Elson did opine And Gene did reply: > On 07/04/2014 12:24 AM, Gene Heskett wrote: > > I've broken several of those 1/32 SC mills, trying to cut deeper than > > 1.5 thou per pass and faster than 2.5 ipm. Brass sheet (door kick > > panel from ACE Hdwe) is 1/32 thick so I'm doing 25 passes to get 45 > > thou down in case > > Hmmm, I'd think the feedrate should be higher, and I'd > expect to be able to > cut more than 1.5 thou / pass. I'm more familiar with > aluminum, but usually > cut with a 1/8" carbide end mill at 2720 RPM (as fast as my > mill goes without > overspeeding the motor) and do about .050 steps down when > plowing > full width. That would be about .010" steps down on the > 1/32" cutter.
I can do that in harder alu. I just ejected that mill, looked it over and found a chip out of one cutting edge corner, so that probably explains why it was also throwing up a burr 3 or 4 thou high. Checking the next one in the box, its good. Yet. Guess I'd better call MCS Monday & get another box. I tightened up the gibs a bit, x was sloppy as heck, I could grab the table when it was somewhat left of center to balance out the motor weight, after putting an indicator adjacent to the end of the gib, and rotate it on the Y sled, showing around 7 thou of slop. Bout half a thou on both ends of the gib now, but its dragging enough to make the motor tone more audible. Probably a bent gib yet, I spent several hours about a year ago straightening both as best I could, (OEM they was bowed about 1/8" in the center) but hammering out that last thou is a cast iron bitch. Same on the Y but only about 3 or 4 thou of play. Tightened that up too. That bit of tightening brought up more backlash, so now its set at about .0021 in both directions. Small balls, loose thrust washers, nut actually moving against the well crushed felt used for a wiper. Don't know which, or all of the above. Pick an excuse, I can probably use them all. :) OTOH, I expect its now at least twice as accurate. > I generally run 10 - 15 IPM feeds. Again, that would scale > down for the > smaller cutter. You want to keep the cutter advancing > through the material as fast as possible, to prevent > localized heating. > > You want to use an air blast to keep the chips from piling up. I usually blow it clear about once a minute. My air compressor is outside, sitting under the eave of the building with a tarp on top, plus half a sheet of that orange ply used for sheathing to help direct wind driven rain away. To run a steady blast from that nozzle, I'd have to uncover it else the compressor cylinder would get too hot. Way too hot. Carbonize the oil hot. Thanks and Cheers Jon, time for us to go start the grill I expect, Gene Heskett, hoping he has enough gas in the grill cylinder. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Open source business process management suite built on Java and Eclipse Turn processes into business applications with Bonita BPM Community Edition Quickly connect people, data, and systems into organized workflows Winner of BOSSIE, CODIE, OW2 and Gartner awards http://p.sf.net/sfu/Bonitasoft _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
