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Building YET another laser cutter.

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  • Building YET another laser cutter.

    With that Rofin CO2 laser fixed I need something to put it on, so a friend and I decided to put it on his CNC router. It was a huge machine made from 80/20, 5' x 24' table. We took off half of it and now it's just 5x12'. It was pretty terribly designed by some company up in the Seattle area and the company had it built for drilling holes in aluminum extrusions for door and window frames. The Long Y axis was driven by rack and pinion with a single dc servo motor on one side that also connected to the other side though a 1" shaft that ran through the center of the 3" 80/20 extrusion and the pinions were hanging off 3/8" shafts connected to that, massively overhung and tended to just break off from fatigue. The short X axis was slightly better but the Z was a horrible squeaking mess. It also had the awful Gecko servo drives.

    So I am redoing all of that. Now using Yaskawa Sigma 5 servos and gearboxes, one on each side of the Y axis and replaced the motor on the X. Replacing the Z with a commercial linear slide.

    Since I remade the side plates where the X axis connects I made it to hold another piece of 3" 80/20 and built up another X axis that will be belt driven from another motor. Z for for the laser is a small Hiwin ballscrew slide with a animatics smartmotor which is a little brushless servo motor with a built in driver. Also reusing a lot of parts from the old laser welder.

    Router, stuff everywhere on it, partly disassembled.

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    The awful Y axis drive. DC servo drove the big timing belt pulley which drove the pinion not installed.

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    New servo motors and 10:1 gearboxes from china. The seem to be pretty good considering the price, about $105 a piece.

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  • #2
    The cutting head I plan on using attached to the crash switch from the old laser welder.

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    X axis drive and motor for laser X axis

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    The 6x3/8" I used for this was anything but flat. Flattened as much as I can with the press and then bedded the trucks in with some Hysol 1C and used some graphite spray as a mold release.

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    X installed, you can see the siding the beam covers I reused from the laser welder. The gray box holds the turn mirror and will connect the beam line bellows together as well.

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    Last edited by macona; 11-15-2021, 06:02 AM.


    • #3
      Waiting for parts now for the laser X axis. Sent them out to oshcut for laser cutting. It will support the beam bellows seen in the last picture and connect it to the X axis fold mirror box which will end up connecting to the Y axis bellows. I picked up the bellows off of ebay, they came off a trumph laser cutter. Still need to order the lenses and a couple other optics.

      Also made up boards to connect the servo drive to the kflop we will be driving the system with.


      • #4
        This laser can cut metal?


        • #5
          Maybe. It does 225W and has peak power somewhere around 600W so it should be able to cut thin steel with oxygen assist. Not certain, ill find out eventually.


          • #6


            • #7
              The laser cut parts I ordered from OSHCut showed up Saturday and stuck them together and test fit it on the machine. Couple little goof, the holes to mount them to the 80/20 were 1/8" out of position horizontally and I made the cuts for the angle to support the bellows. I threw the parts on the mill and cut out the holes into slots and cut the aluminum angle to fit in the recesses. Now I need to weld up the parts and either paint or powder coat them.

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              Attached Files


              • #8
                Cool project. You get to play with some interesting stuff.


                • #9
                  Originally posted by macona View Post
                  It also had the awful Gecko servo drives.
                  It seems like only a few years ago (has it been that long?) the Gecko servo drives were a very popular solution. I see you mention KFLOP, which is also new to me. Obviously I've fallen behind on this stuff, but it is good to see improved tech.

                  Thanks for sharing.


                  • #10
                    Yeah, the gecko servo (not stepper) drives were really the only cheap servo drives around for a long time and they really just kind of suck. It was a bang-bang type servo loop where the motor just bounces between each encoder pulse so sitting at a standstill the were rather noisy. To tune them you need a scope which is just kind of annoying. Modern servos, especially the ones I use are so, so much better with real time auto tune and no need for scopes. At this point in time i can get a 400w mitsubishi J2S or yaskawa sigma V series drive and motor for about $2-300 and those come standard with 131072 line encoders.

                    kflop is actually getting pretty old now, I think pushing 10 years old. It works pretty well, pretty versatile since you can program it in C to do whatever you want and has a Mach3 plugin as well as it's own CNC interface as well. There are a bunch of accessory boards too like for driving servos, analog io, and digital IO. It does have a pretty steep learning curve but the forum is active and there is quick support from the creator.


                    • #11
                      Interface board for kflop to yaskawa drives. Line drivers drive the servos for higher pulse speeds. I hate dealing with MDR connectors.

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                      • #12
                        Got the bellows end plates welded up and I went ahead and powder coated them. Asked a friend what color I should powder coat them and he said purple. So purple they are.

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                        • #13
                          Did a but more work on the laser cutter. Found I made a little mistake on the interface PCB and fixed that.

                          Bored out the gear and broached them for the Y axis. Found I had a used 2J E-Collet and bored it out to hold the gears. Came out nice, using some green Loctite to hold them in place, should be fine.

                          IMG_2555 by Jerry Biehler, on Flickr

                          IMG_2556 by Jerry Biehler, on Flickr

                          IMG_2563 by Jerry Biehler, on Flickr

                          Made up an idler pulley for the Laser X axis and got one belt on, I was about 2" short so I need to order more belting. Whoops. There are supposed to be two 3/8" belts side to side.

                          IMG_2551 by Jerry Biehler, on Flickr

                          IMG_2564 by Jerry Biehler, on Flickr

                          Drilled out and attempted to tap for screws to hold the bellows rails. Tapped one hole. Went to the second hold and the tip of the tap fell off. WTH... So that will have to wait.

                          Figuring electrical requirements now. We are going to run a small sub panel to the back of the shop to bring three phase back. We need 3 phase for the laser, compressor, and chiller among other things. Cables for the servos are ordered too.

                          Next week I am off for a plant shut down so it will give me an opportunity to get down to the steel yard and pick up some tubing for the Y axis bellows track. Then I can send out to have the supports for that laser cut.