On Saturday 24 September 2016 12:11:34 Jon Elson wrote: > On 09/24/2016 03:04 AM, john mcintyre wrote: > > Good Day All, > > Problems with machining sticky material. > > I find wd40 or crc penetrating fluid in the pressure pack and use > > the fine tube nozzle to direct the spray right onto the cutting tip > > . > > This is good for all sticky materials as it stops the material (soft > > aluminium) building up on the cutting edge. > > The best fix for this is to keep the tool moving along the > workpiece. Don't take a deep cut slowly, take a light cut > and keep the feed rate up. This prevents localized heating > of the workpiece material. Also, I don't use any plain HSS > tools, I use M42 or higher Cobalt HSS, which keeps a sharp > edge MUCH longer. For the small stuff, I use 1/8" solid > carbide end mills, these work really great. > > Jon > And for alu, if the spindle can do it, all the rpms it can muster. This reduces the time between the passage of a cutting edge for the oxide to form on the freshly cut surface before the next cutting edge comes by, as does some spray misted, oxygen free oil (safflower is nice) to keep the surface sealed behind the cutting edge as much as possible.
That alu oxide forms behind the cutting edge in free air in about 1 millisecond, and its the 2nd hardest substance known to man. And its that oxide that eats our tools for lunch. Even carbide succumbs eventually. For long jobs where the work gets hot? A goodly portion of that heat is from the chemical reaction of the alu burning and forming the oxide on its freshly cut surface. Reducing its access to the oxygen in the air, or in the water mix you may be using for coolant, will cool the workpiece by a considerable amount. Messy in the shop, but your tooling will thank you by lasting many times longer. You don't need much oil, but you do need enough continuous air to feed the mister. If you can see the oil spray, thats way too much. An once an hour is enough to make the shop air foggy if not vented outside. Hard to get off your glasses too. > ---------------------------------------------------------------------- >-------- _______________________________________________ > 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
