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  • Cutmaster 42 CNC conversion

    Well, thanks to Scott V, I was able to get ahold of Victor Technologies and discuss the signals in the CM42 and their suitability for CNC. While they didn't really offer a lot of help, and it wasn't really expected since I'm knowingly modifying the machine to do something it wasn't intended to do, they did confirm that I had the right signals and their locations. Of course, the info I had was right out of the service manual. For those who want to do this, but don't have the downloadable service manual, or don't understand it, well, maybe this isn't something you should be tackling. But if you do, here is what I can tell you'll need from the machine.

    Trigger - J14 - either pins 1/2 or 3/4. I can't tell for sure yet, so I'll have to ohm them out and find the right pair. The table in the manual lists 1/2 as the gun switch signal and 3/4 as the cup test signal. Another drawing on the site appears to show 3/4 as the trigger and PIP signal.

    Ok to move can be taken from J9 - 1.

    Arc voltage is available on J10.

    In theory, it looks like you could insert a current setting in your program and then use an analog output to control the current by varying the voltage on J2 - 1, from 0-4 VDC. No idea how linear it is, though.

    It took a lot of looking on Google images to figure out the connectors. Maybe there are some clues on the ones in the unit, but I didn't see any.

    The Trigger connector, J14, is compatible with an old AMP connector, now TE Connectivity. It isn't the same, but it works, and I couldn't find an exact match. The TE p/n for the female (wire end) is 2132781-4. The crimp pins are 1123721-2. The header is 1-1123723-4. All of these are available from Mouser. I found that 1744036-4 looks more correct, but the pitch is differnt, so I'm not sure if there is another one that works better or not.

    For now, I am not messing with the arc voltage because I don't have THC. So, I'll only be using the trigger and the pilot arc current feedback signal. The pilot arc signal appears to use a connector either made by JST or compatible with them. I'll know for sure when the connectors I ordered arrive later this week. The one that appears to be it is the JST XH series connector. The female side looks to be the XHP-3 using SXH-001T-P0.6N crimp pins. The header appears to be B3B-XH-A. These I ordered from Digikey and will be here later this week for me to try out.

    I ended up using a GX-16/5 connector from Ebay. They list it as an aviation connector - sure! Anyway, it seems like it will work okay, at least for now. I'll see if I end up outgrowing it. It doesn't have enough thread to span the rear panel thickness, so I machined a rectangular adapter plate with a double-D hole and thinned out center so it fits well and looks right at home.

    Once I get this up and running, I'll try to remember to update this with any additional things I learn.

    Dave
    Still building my new old truck - see the progress!
    http://www.ford-trucks.com/forums/65...-coe-idea.html
    http://www.hobartwelders.com/weldtal...ad.php?t=27017

    Square Wave TIG 200 - Woot!
    MM180
    SP125+

  • #2
    I was able to confirm that all of the connectors I ordered work with what is in the machine already. Going to have to either make a wire harness or rout a board now to split the connections.

    Also confirmed that the trigger is pins 1 and 2.

    Dave
    Still building my new old truck - see the progress!
    http://www.ford-trucks.com/forums/65...-coe-idea.html
    http://www.hobartwelders.com/weldtal...ad.php?t=27017

    Square Wave TIG 200 - Woot!
    MM180
    SP125+

    Comment


    • #3
      Originally posted by whateg0 View Post
      I was able to confirm that all of the connectors I ordered work with what is in the machine already. Going to have to either make a wire harness or rout a board now to split the connections.

      Also confirmed that the trigger is pins 1 and 2.

      Dave
      Dave,
      good info, and it will be of great help to others following that path..

      Post some pics of your setup when you have it up, and running..

      Comment


      • #4
        Dammit! Ordered the wrong crimp pins for the bigger connector. I know what happened, but dang it!

        The right pins should be: 1744144-1.

        So, now it will be next week before it is cutting on its own.

        Dave
        Still building my new old truck - see the progress!
        http://www.ford-trucks.com/forums/65...-coe-idea.html
        http://www.hobartwelders.com/weldtal...ad.php?t=27017

        Square Wave TIG 200 - Woot!
        MM180
        SP125+

        Comment


        • #5
          Originally posted by whateg0 View Post
          Dammit! Ordered the wrong crimp pins for the bigger connector. I know what happened, but dang it!

          The right pins should be: 1744144-1.

          So, now it will be next week before it is cutting on its own.

          Dave
          I just got around to trying out my Cutmaster 42...

          Some info if you are interested... The 9-0091 tip is good for 20-35 amps. It will be the go to tip for 120 volt use. Smallest kerf on any air plasma I have seen.True meaning of fine cuts. The 9-0094 tip (40 amp) will be best for CNC standoff work in general. I used the SL-40 torch on my 120 amp Victor with the 9-0091 tip, and the machine turned down all the way. 30 amps in the book specs, but sure looks like less.. This is 19 ga. SS with a feeler ga to check the Kerf width.
          Attached Files

          Comment


          • #6
            That's good info to have on the tips. I am considering running the machine on 120 some so, knowing that I can get a thin kerf out of it will be useful on a couple of jobs I have waiting in the wings. I need to get a second 220 circuit added so I can run the air compressor and the plasma cutter at the same time. As it is now, I can't do jobs with a lot of cutting without pausing somewhere in the middle to pump up the compressor again. At least it's a 60 gallon tank, so it does last awhile. With my table only being 2x2, there is only so much a guy can cut at once anyway.

            I got the breakout board in the machine last night, so I am hoping to make some test cuts today and see how it does on the table. Should do a lot better than the old plasma cutter. Next task will be to get the arc ok line to the software so I don't have to babysit as much, and then later down the road, I'll deal with the THC.

            Dave
            Still building my new old truck - see the progress!
            http://www.ford-trucks.com/forums/65...-coe-idea.html
            http://www.hobartwelders.com/weldtal...ad.php?t=27017

            Square Wave TIG 200 - Woot!
            MM180
            SP125+

            Comment


            • #7
              Dave,
              I did a few test cuts with the 20-35 amp consumables. Hooked up to my MQ-6000 generator and small Hitachi [email protected] psi/13 amp 4 gal compressor. Cuts 3/8 beautiful. and will sever 5/8 very slow. Max on 120 volt input.
              The compressor keeps up with the smaller tips just fine.. Also the generator too..120 volt on each machine on a different leg of power.. Cuts a bit better with the plasma on 240,and the compressor on 120 volt. Tried up to the max of the smaller tips..35 amps.. here is the 120 volts cuts..(27 amps) Expect better performance out of the generator/air compressor at sea level.. I am at 4200 ft .. So even more impressive..
              Attached Files
              Last edited by Scott V; 12-08-2014, 04:33 PM.

              Comment


              • #8
                What would you estimate your travel speed to be on that 3/8 cut?
                Still building my new old truck - see the progress!
                http://www.ford-trucks.com/forums/65...-coe-idea.html
                http://www.hobartwelders.com/weldtal...ad.php?t=27017

                Square Wave TIG 200 - Woot!
                MM180
                SP125+

                Comment


                • #9
                  Originally posted by whateg0 View Post
                  What would you estimate your travel speed to be on that 3/8 cut?
                  Probably similar to the Hypertherm 30 XP.( have not used that one yet) and Esab 400.(all on 120 volts) I will have to double check to see if my hunch is correct. I used the 20 amp nozzles on a Thermal 42 before, but only at 20 amps.(120 volts input) Standard Hypertherm 30 at 30 amps. Esab was maxed at 30 also on 120 volts too. I did not realize you could turn the 42 up with the 20 amp nozzles to 27 amps.. New hypertherm 30 xp runs fine cuts at 25 amps. Bet they are all real close to 8-12 ipm (best quality) Main thing is a clean low bevel cut. The little SL-40 torch does a nice job there. I would think you will run very close to the plate in cnc use. More like a Hypertherm, then a standard SL-60 torch. My guess anyway, to get the arc to transfer well/etc...

                  Comment


                  • #10
                    It's cutting again

                    Well, it was cutting again. I welded the contacts in my relay that I was using to trigger the torch, so it is offline for the moment. The replacement will be here today, so I'll get it replaced. Then, I should be back up and running again. Without the Arc OK line, I had to insert an extra "tool change" to allow enough time for the purge that the TD does then pierce time. I had a bit of a bevel on my cuts the other night, so I picked up new tips and electrodes. Hopefully that takes care of that.
                    Still building my new old truck - see the progress!
                    http://www.ford-trucks.com/forums/65...-coe-idea.html
                    http://www.hobartwelders.com/weldtal...ad.php?t=27017

                    Square Wave TIG 200 - Woot!
                    MM180
                    SP125+

                    Comment


                    • #11
                      Originally posted by whateg0 View Post
                      I had a bit of a bevel on my cuts the other night, so I picked up new tips and electrodes. Hopefully that takes care of that.
                      The torch standoff cutting height/thickness vs amps cut at, plus speed of cut can have a great influence on bevel. I can tell the SL-40 cuts at a low bevel. (Pretty high arc density) so consumables will be a good thing to change out..

                      My Victor is in the shop getting looked at. Seems the Pilot arc is not working.Heard there was some of the newer Victor 42 with board problems. China messing around on suppliers/etc..... I bought mine mostly for the way the 42 torch works on my A-120, so the machine is just a bonus.. (Sort of): The new ground cable on the new ones that took a hit. Nice on the older Thermal models, and stiff as a board on the new Victor. Cut it off and put a female dinse on it, so problem solved with my other quality ground leads laying around.. Ground lead is buried in the machine to stick a whole new American whip on it, so a dinse is a good way to go..

                      Comment


                      • #12
                        Were you guys able to get any further here? I've got a Cutmaster 42, also, and am interested in seeing how easy it would be to get going on a CNC rig.

                        Comment


                        • #13
                          I do have it mostly working. I have the trigger line connected and wiring in place for the Arc OK line. But I don't have the arc voltage ported out yet. I ran out of pins, thinking the Arc OK and trigger used a common ground. They don't. So, I have ordered 8-pin connectors and am hoping to get that side completed soon. I have been wanting to implement THC, but haven't wanted to part with the money or figure out how to integrate it into LinuxCNC. That's the motivation now.

                          I'm redesigning the table right now to allow my 2'x2' cutting area to cut from a full sheet. Nothing like taking a working design and complicating it!
                          Still building my new old truck - see the progress!
                          http://www.ford-trucks.com/forums/65...-coe-idea.html
                          http://www.hobartwelders.com/weldtal...ad.php?t=27017

                          Square Wave TIG 200 - Woot!
                          MM180
                          SP125+

                          Comment


                          • #14
                            That sounds awesome. Home built table? I have a CM42 and like it (using PlasmaHelper.com's stuff) but there's nothing like CNC. As I get more into CNC, and know that you can run it via LinuxCNC, I was interested in seeing my options.

                            Do you have any pictures of everything?

                            When looking at the CNC equipment on http://candcnc.net/, it looks like they hardwire just the switch. You're trying to debug the voltage control on the torch to implement THC?
                            Last edited by xnzrhl; 07-23-2015, 07:56 AM.

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                            • #15
                              The CM42 has all of the necessary signals on the control board. They just aren't ported out of the box, like on the A40. So, I just built a wire harness that plugs into the control board and has breakout connectors to plug the original wiring into. Then I have a harness that comes out to the rear panel. I was thinking of making a few and seeing if others were interested in them, but decided for the first one to just use some perf board. Ended up being a usable prototype.

                              I was a little scared of implementing THC, but have been reading a lot lately and found a LinuxCNC config that has all the necessary files in place already, so I'm hoping to try that out with a mock THC controller. I haven't ordered a THC controller/system yet because I didn't fully understand what I needed to do to make it work. I was hoping to try out the new config this week, but the week is getting short, and I still have a long to-do list.

                              I have a couple things to cut when I get a chance, so I'll try to get some pics then. It is all homemade. Everything from the bearing trucks, to belt adjustment, to the frame. I'd like to redo it with fewer machined parts next time.
                              Still building my new old truck - see the progress!
                              http://www.ford-trucks.com/forums/65...-coe-idea.html
                              http://www.hobartwelders.com/weldtal...ad.php?t=27017

                              Square Wave TIG 200 - Woot!
                              MM180
                              SP125+

                              Comment

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