The attached photo shows the general idea of what I'm trying to build. Although the slots could probably have been easily cut with the unbent HRS held at an angle with a manual mill, the CNC adds the ability to make it fancy.
I'll clamp a test piece into the vice and give it a try. John > -----Original Message----- > From: dave engvall [mailto:[email protected]] > Sent: February-18-20 11:00 PM > To: [email protected] > Subject: Re: [Emc-users] Feeds and speeds > > Hi all, > > By hot roll I assume you mean something like A36. Alloy comp not > controlled just mechanical. It tends to be low alloy scrap plus 4140. > > Using a� TiAlN coated 1/4 carbide I can� use 2200 rpm and 11 ipm, doc > 0.05, any more and it screams at me. This is basically slotting, on a > side cut same rpm,� and feed, .7 doc for radial of only .025.� Makes for > a lot of passes. This� is on a Cinci contourmaster 1963 vintage, > converted to servos. Going deeper and slower doesn't seem to help. Since > TiAlN likes to run hot I machine dry. It is not unusual for small jobs > to run for a couple of hours. > > On a machining site someone recommended ... increase the feed until you > break a mill, then back off 10%. Pretty aggressive. > > Rumor has it that AlCrN coated carbide� with flood coolant lasts a long > time; and that was in a production environment. If ... (when) I get my > big machine up I'll give more serious stuff a go. > > I do a lot of A36 because it is cheap and OK for experimental work but > CR machines like a dream by comparison. HTH > > Dave > > > On 2/18/20 10:09 PM, John Dammeyer wrote: > > > Thanks everyone. The trouble with the machinist workshop program and > some of the others is they are targeted at production speeds. I'm not even > sure about the alloy of Hot Rolled Steel which is what will be used here. > > > > The part is designed to hook around the ears of a pipe crucible so accuracy > isn�t that big a deal and at the moment, HSS is all I have. With manual > machining, as Wallace said, you can turn the hand wheels and get a feel for > what it should do. And yes the machine is pretty rigid. > http://www.autoartisans.com/milton.htm This picture was when it first > arrived. > > > > I do have a coolant pump but have yet to use it. Not sure what kind of > coolant to use. A large part of my machining has been aluminium castings. > I've not yet set up mist coolant. Any suggestions for what type of coolant to > use for a machine that is only used occasionally? > > > > All things considered the CNC conversion is the easy part. My heart is > always in my throat a bit when first start running a CNC program. That's the > really hard part. > > > > John > > > > > >> -----Original Message----- > >> From: Stuart Stevenson [mailto:[email protected]] > >> Sent: February-18-20 7:04 PM > >> To: Enhanced Machine Controller (EMC) > >> Subject: Re: [Emc-users] Feeds and speeds > >> > >> John, > >> > >> Do you have flood coolant or mist coolant? > >> > >> I would be inclined to try the cut full depth if you have flood or mist > >> coolant. 1/4 inch is on the borderline of having the strength necessary to > >> make a full depth cut. I would think 5.5ipm might be a little aggressive > >> but I would leave it programmed at that feed and speed and turn the > >> feedrate to about 20% to start the cut. After you get into the cut I would > >> move the feedrate up about 10% to see, hear and feel how mill is cutting. > I > >> would keep moving the feed up until I saw, heard or felt the mill working > >> too hard. I would then start turning the speed up a little at a time to see > >> how the mill responds. > >> I think 30sfm might be a little slow but you can adjust the speed after > >> entering the cut. > >> If you can adjust the feed and speed to make the full cut sound good and > >> you have another part to run I would change your program to enter the > cut > >> as you did the first time but the add lines to make it more aggressive > >> after you have entered the cut. > >> If you are leaving a little material to clean up the you can drastically > >> increase the speed and feed after you turn around at the end of the slot. > >> Is the slot you are cutting wide enough to allow at least .010 thou. for a > >> finish pass and maybe a spring pass. > >> I would make the finish pass and spring pass in a conventional cut rather > >> than a climb cut. > >> Stuart > >> > >> > >> On Tue, Feb 18, 2020 at 8:47 PM John Dammeyer > <[email protected]> > >> wrote: > >> > >>> 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 > >>> > >>> > >>> _______________________________________________ > >>> Emc-users mailing list > >>> [email protected] > >>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>> > >> > >> -- > >> Addressee is the intended audience. > >> If you are not the addressee then my consent is not given for you to read > >> this email furthermore it is my wish you would close this without saving or > >> reading, and cease and desist from saving or opening my private > >> correspondence. > >> Thank you for honoring my wish. > >> > >> _______________________________________________ > >> Emc-users mailing list > >> [email protected] > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users
_______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
