On Sunday 21 April 2019 14:07:55 Jon Elson wrote: > > On Sun, 21 Apr 2019 at 03:34, John Dammeyer <jo...@autoartisans.com> wrote: > >> I used the Machinist toolbox to figure out what sort of speed and > >> feed I needed but ended up running the mill faster (thought I'd > >> read it should be 3000 but it was supposed to be 2000). Typo > >> error. OK. So tool bit 0.09375. Two flutes. HSS. Chip load > >> 0.00551. Aluminium bar. SFM set at 40 which called for 2000 RPM and > >> about 22 ipm > > .094 tool at 2000 RPM is 50 SFPM, really slow for aluminum. > 600 SFPM is recommended. > chip load for HSS end mills should be .010 * end mill > diameter, so .010 * .094 = about .001". > At these settings, feed rate should be 4 IPM. > > I have stopped using all HSS in the smaller sizes, I buy > 10-packs of 1/8" solid carbide end mills for about $3 each, > and they last a LONG time. Crummy "HSS" tools from China > last about 5 minutes before dulling begins to show. > Name-brand M42 HSS tools seem to last at least 3 times > longer, maybe even up to 10 X better. And, they rarely cost > more than $1 extra over plain HSS. > > One of the tricks with aluminum is to keep the cutter > moving. So, take a shallow cut and keep the feedrate up, > and always do climb milling if possible. Higher feeds keep > the heat from being concentrated in one spot on the workpiece. > > Using a 1/8" carbide end mill at about 3000 RPM (limit of my > mill), I would plow full-width cuts at a depth of .062" > (half diameter) at about 4 IPM, then cut the sides at 10-15 > IPM with a side step over of about 0.25 - .050, and a final > dimension pass taking off .010 on the side at 8 - 12 IPM. > This is with a 4-flute cutter. As long as you keep the > cutter moving right along, you won't have a problem with > gumming up the cutter. > Printed for shop use, thanks Jon. > And, flood coolant REALLY helps with the heating problem. I > have a throttle valve on my coolant system, and use the > smallest LocLine nozzle, and throttle it down to a little > jet pointed right at the cutter. So, it just spreads out a > little puddle on the top of the part. > > Jon > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users
Cheers, Gene Heskett -- "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> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
