John, I always use single flute router-style cutters (Accupro, from MSC Industrial at www.mscdirect.co.uk) which are specifically designed for machining aluminium and are highly polished so the aluminium will not stick to the flutes. These are jolly expensive cutters, and other makes are available, etc. I would not use an 'ordinary' endmill on aluminium (unless you keep your jar of caustic soda handy to dissolve the welded-on chips in the flutes).I would use a 10 or 12mm cutter at 2000-3000 rpm, so the tooth peripheral linear speed is a bit faster than your speeds. I am not using flood coolant, for the same reasons as you, but do use neat cutting oil around the area being cut. Running at the same feedrate as you, I would probably take a cut of 50 to 100% of what you are taking, for roughing, although bear n mind that is a tooth loading of twice what you are using (1 tooth versus 2). Linear speed around the same as you, at 120 - 200mm/min. All cuts are climb cuts, in aluminium.
Marcus On 4 Nov 2021, at 06:34, John Dammeyer wrote: > I used the big 1/2" one for the large pocket and the smaller 5mm one for the > smaller pocket and profile. The surface finish, given my crappy cast > aluminium, was really nice. > > My mill does have a coolant pump but I don't know if I use the mill often > enough to fill the reservoir with coolant that then goes mouldy and stinky. > So I'm working on a compressed air mist coolant system. But maybe having a > secondary reservoir that pumps out the main one and adds an aquarium bubbler > would work for the flood system. So in the last 12 years I've never used > coolant. > > John > > >> -----Original Message----- >> From: andrew beck [mailto:andrewbeck0...@gmail.com] >> Sent: November-03-21 10:52 PM >> To: Enhanced Machine Controller (EMC) >> Subject: Re: [Emc-users] Project Progress >> >> What cutters are you using? >> >> As a sideline here in New Zealand I buy and sell tooling so I'm always >> testing the limits. >> >> And can probably advise a bit >> >> On Thu, 4 Nov 2021, 11:29 John Dammeyer, <jo...@autoartisans.com> wrote: >> >>> I've been using LCNC quite a bit (for me). In the photo there are two >>> steel spring collars that were entirely done with the mill. I could have >>> left them as large disks with just a stepped hole and the set screw holes >>> but what's the fun in that. >>> >>> >>> http://www.autoartisans.com/mill/SpindleControl/TrialFitOnSpindleCover-1.jpg >>> >>> The spindle cover casting (10lbs of scrap aluminium) was machined in the >>> places I needed flat surfaces and to get rid of a bit of sag in the casting >>> mostly for looks. I'd occasionally spray a bit of WD-40 but mostly just >>> held the shop vac to clean up the chips. >>> >>> http://www.autoartisans.com/mill/SpindleControl/SpindleCoverplate-4.jpg >>> >>> Essentially between 1000 and 2000 RPM, 2 flute 1/2" end mill, 25% step >>> over, about 2.5 to 5 IPM IPM and a depth of cut of about 0.1" for each >>> pass. This created chips that did not melt onto the tool bit and left a >>> quite nice smooth finish. >>> >>> But with those parameters it did take quite a while. OTOH, it ran >>> automatically and other than check on it periodically and vacuum or blow >>> away chips I could do other things nearby. >>> >>> If I enter the parameters into Machinist Toolbox with a target RPM of 1500 >>> I see it suggests a tool feed rate of 21 IPM. I think that would melt the >>> chips without flood coolant. Since I didn't want to screw it up and have >>> to cast it all over again I was very conservative. >>> >>> Was I too conservative on this? It's been suggested by a friend who runs >>> MACH3 that he dials in a much faster feed and spindle rate and then hauls >>> back on the sliders to reduce it to very slow and then in small steps bumps >>> up the speed until it feels right. >>> >>> >>> >>> Suggestions are welcome. >>> Thanks >>> John >>> _______________________________________________ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> >> >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users
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