On Tuesday 18 February 2020 22:32:24 Marshland Engineering wrote: > I've long gone off HSS as Carbide is so cheap from China. > > Starting point - 4 Flute - 1000 rpm - 100 mm min and cut in 2 passes. > 65 m/min, 0.025 mm per tooth. > All depends on machine rigidity. > > For HSS maybe 1/2, 500 rpm and 50 mm min. > > This is where I like my hand wheels, I can feel the cut pressure. > If the spindle is DC controlled so the motor currant can be monitored, I found that an ammeter to display motor currant to be very helpfull, showing me how hard it was working, and has saved me $40 in those little 5x20 slow blow fuses since.
That teeny little bare chassis motor controller that comes in the smallest hf mill they were selling 20 years ago, has a very stiffly controlled speed, so stiffly controlled I had to rig an ammeter so I could see how close I was to blowing a 1.5 amp fuse. But eventually the pass transistor in it failed. I looked up the part number to see what sort of a critter it was, compared that to what was in a dead computer psu, and the computer transistor was rated at 10x the currant and 2x the volts. Since those better specs implied quite a bit more gate capacitance to drive it, I was concerned with its much smaller driver, but watching it with an ir thermometer showed I needent be concerned. Later I took it out of the gearhead and put it in a plastic box with a PMDX-106 so linuxcnc could control it in both directions. Its been there, working great for all of the last decade, until the y screw ignored the limit switch and unscrewed itself from the nut, and I cannot find the bag of oversized balls I put in those screws I got from Stuart almost 20 years ago. So I used the stepper kit and psu in the 6040 after I found its motor supply was folding back to about 13 volts when the A axis was plugged in. Now all the electronics in the 6040 have been replaced. Now the 25 or 30 ipm xy moves at 200 ipm. Same motors although it could use a bigger z, that water cooled spindle is close to too heavy as it can only make 30 going up. Teeny little motors. > -- > Thanking you > Wallace Weideman > Marshland Engineering > 704 Marshland Road > Styx > Christchurch > 03 3237449 > www.marshland.co.nz > > On 19/02/2020 at 3:45 p.m., [email protected] wrote: > >Send Emc-users mailing list submissions to > > [email protected] > > > >To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.sourceforge.net/lists/listinfo/emc-users > >or, via email, send a message with subject or body 'help' to > > [email protected] > > > >You can reach the person managing the list at > > [email protected] > > > >When replying, please edit your Subject line so it is more specific > >than "Re: Contents of Emc-users digest..." > > > > > >Today's Topics: > > > > 1. Feeds and speeds (John Dammeyer) > > > > > >--------------------------------------------------------------------- > >- > > > >Message: 1 > >Date: Tue, 18 Feb 2020 18:45:21 -0800 > >From: "John Dammeyer" <[email protected]> > >To: "'Enhanced Machine Controller \(EMC\)'" > > <[email protected]> > >Subject: [Emc-users] Feeds and speeds > >Message-ID: <[email protected]> > >Content-Type: text/plain; charset="utf-8" > > > >I've got Mecsoft AlibreCAM generating the tool paths for this in the > > attached > > photo. It's Cold Rolled steel 3/16" thick. I'm using a 1/4" HSS end > mill. I'm trying to figure out, using Machinists tool box, exactly > what feeds and speeds could be used for milling the slot. > > >I was thinking 30 SFM and with a 4 flute end mill doing 0.003" per > > flute the > > toolbox comes out with 460RPM, 5.5ipm for S460 and F5.5 and 10% of > tool diameter for depth per pass so 0.025" > > >Is that too conservative or likely to break something? Doing it > > manually I'd > > do it by feel but once it's automatic it's harder to decide SFM and > chip load. > > >Thanks > >John > > > > > >-------------- next part -------------- > >A non-text attachment was scrubbed... > >Name: image001.png > >Type: image/png > >Size: 29705 bytes > >Desc: not available > > > >------------------------------ > > > > > > > >------------------------------ > > > >Subject: Digest Footer > > > >_______________________________________________ > >Emc-users mailing list > >[email protected] > >https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > >------------------------------ > > > >End of Emc-users Digest, Vol 166, Issue 90 > >****************************************** > > _______________________________________________ > Emc-users mailing list > [email protected] > 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
