On 23 Feb 2017, at 05:46, Jon Elson wrote: > On 02/22/2017 10:08 PM, Todd Zuercher wrote: >> Yuck, if I don't ever have to mill that crap again it will be too soon. >> Started out dry and trying to mill .12 deep per pass. 1st try (1" long ramp >> in) tool ramped in to full depth nicely and then promptly snapped, 400imp >> @18krpm is too fast. 150imp went about 2 inches, gumming up badly
A polished carbide tool will not allow aluminium to stick to the cutter. Standard endmill finish gums up in seconds, as do most coated cutters. Clean the cutters by immersing them in caustic soda solution. >> . Half a dozen bits later, having some success with a .06" cut depth >> @120imp and soaking it with WD-40. >> >> > 18000 RPM might be too fast for a 1/4" tool, but then I read > this book about high speed machining where they were running > 75 HP on a 1/2" end mill at 80,000 RPM, and removing 640 cu > in of aluminum per minute. > CNCcookbook.com has a free trail speeds and feeds calculator. Needs slowing a little on a less than perfectly rigid machine, but worth the free trial. > But, of course, this particular aluminum may just be pure > trouble. 2024 and 6061 seem to machine really well. Choice of grade of aluminium is very important, with 6*** and 7*** series being great for machining, and others being sticky and basically not at all nice to machine. > Are you > climb milling? That is really important to prevent the tool > from rubbing before it breaks the surface. Climb milling is > with the edge of the cutter striking the uncut surface, so > the cutting edge of the tool is moving in the same direction > as the material moving past. On 6*** and 7*** series, it is easy to get a finish that looks a lot like chrome, especially using climb milling or at least a last finishing pass climb milled. Rigidity is important, as with all metal machining. Marcus > > Jon > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
