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  • Suggest some parts for an Acorn Lathe build?

    As noted elsewhere, Centroid finally launched the lathe software for their Acorn board, and I ordered one along with thyeir all-in-one touchscreen PC. (I needed both a new Win10 PC and a touchscreen, and that was an inexpensive solution.)

    I currently have my Logan running on a pair of MicroKinetiks controllers and a power supply, but I've been considering removing the entire assembly- everything from the WinXP PC all the way to the connections to the steppers- as a complete, running unit.

    That means I'll need two new stepper drivers and a power supply. Gecko seems to be a 'name brand' for controllers, but they have a pretty wide range of options, and the more I read, the more confused I get. Can anyone make any recommendations? The 540 seems the widely accepted choice, but I don't need four axes. (No, I have no plans for a turret or live tooling- if I go that far, I'll buy a lathe with a turret already installed.)

    And to power the steppers, do I need a "switching" power supply, or a "linear" one? Or is there any real difference?

    The lathe is currently fitted with... I think it's a NEMA 23 270 oz-in, and a NEMA 24 (or 26?) 570 oz-in.

    Doc.
    Doc's Machine. (Probably not what you expect.)

  • #2
    You are a businessman, not a hobbyist, why not just order the Tormach lathe?
    As for power supplies, linear are simpler, easier to get the higher voltages and current needed. Switching power supplies are what’s inside your PC. Analog vs Digital.

    Comment


    • #3
      I like the Leadshine DM542 like this one https://www.amazon.com/Leadshine-Dig...eadshine+DM542 I ended up with Longs Motor DM542 clones because I got a deal on them but dunno how they'll pan out long term.

      Centroid has the Acorn/DM542 wiring schematic on their downloads page so it takes away some of the head scratchin'. Supposedly the linear power supply is better but there are tons & tons of switchers being used successfully. I'm going to use a 36v switching PS on the ORAC lathe because I have it and just plain doesn't need blinding speed to do my stuff. I have a big fat toroid & related parts going into the new mill since it has 3 axes and more travel. Extra speed will be nice on it.
      Milton

      "Accuracy is the sum total of your compensating mistakes."

      "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

      Comment


      • #4
        Originally posted by RB211 View Post
        You are a businessman, not a hobbyist, why not just order the Tormach lathe?
        -I would love to, and likely will in the relatively near future. There's two problems though: First and foremost being cost- the Tormach lathe, with turret, with shipping, and with a modicum of tooling, knocks on the door of twenty grand. Even a bare-bones build, skipping semi-essentials like coolant and an enclosure, is still ten grand.

        And two, as has been noted in other recent threads, at the moment I have no idea whatsoever on how to use it. The idea was to build the CNC conversion on my Logan for relatively cheap (I have about a grand into it so far) and use it to start learning the basics of CNC. The Mach 3 system, however, is famously limited in threading capability thanks to it's single-pulse encoder, and of course also lacks anything you could call a "conversational" interface.

        The current slightly modified plan is to switch over to the new Centroid setup, which can take proper encoders, and has professional-level conversational capabilities, to make the converted Logan hopefully much more usable by a near-total CNC noob like me.

        THEN, if all goes well, save and sell product as I learn, in perhaps a year or so, buy the Tormach.

        Switching power supplies are what’s inside your PC. Analog vs Digital.
        -Ah, I see. That's helps, thanks.

        Doc.
        Doc's Machine. (Probably not what you expect.)

        Comment


        • #5
          What DOC said!


          Tormach's little turret looks sweet.
          Last edited by lakeside53; 10-21-2017, 10:03 PM.

          Comment


          • #6
            Originally posted by Doc Nickel View Post
            As noted elsewhere, Centroid finally launched the lathe software for their Acorn board, and I ordered one along with thyeir all-in-one touchscreen PC. (I needed both a new Win10 PC and a touchscreen, and that was an inexpensive solution.)

            I currently have my Logan running on a pair of MicroKinetiks controllers and a power supply, but I've been considering removing the entire assembly- everything from the WinXP PC all the way to the connections to the steppers- as a complete, running unit.

            That means I'll need two new stepper drivers and a power supply. Gecko seems to be a 'name brand' for controllers, but they have a pretty wide range of options, and the more I read, the more confused I get. Can anyone make any recommendations? The 540 seems the widely accepted choice, but I don't need four axes. (No, I have no plans for a turret or live tooling- if I go that far, I'll buy a lathe with a turret already installed.)

            And to power the steppers, do I need a "switching" power supply, or a "linear" one? Or is there any real difference?

            The lathe is currently fitted with... I think it's a NEMA 23 270 oz-in, and a NEMA 24 (or 26?) 570 oz-in.

            Doc.
            Doc, might I suggest Teknics Clearpath SDSK brushless servos with the servo driver built into the motor as well as great auto tuning software? Coupled with Centroid CNC Acorn, a great combination. Another suggestion might be DMM technologies AC servos and DYN drives.

            I will be doing a video series on my YouTube channel on the conversion on my Emcoturn 120 CNC lathe as soon as they arrive. martyscncgarage
            I believe Centroid already has schematics on line for both to get you started.
            Marty
            Mesa, AZ
            Jack of All Trades, Master of None

            Comment


            • #7
              You can certainly suggest them.

              But, and I'm not asking this facetiously, what would that gain me?

              I'm very new to both CNC (at least in a direct, hands-on way) and designing and building CNC machines, so I've been trying to keep this build both simple and on a budget.

              I understand the servos have built-in encoders, more power, etc. but my planned work for this machine is relatively small aluminum parts in fairly short runs. I don't need huge power and lightning-fast rapids. I need a fairly simple, relatively inexpensive machine that I can learn on, and will be easy and also relatively inexpensive to fix when I crash something.

              As noted above, this conversion is basically a trainer. Once I'm reasonably comfortable with it, and have a better grasp on the software and tooling minutiae, I'll likely then pick up a ready-built machine, most likely the Tormach slant-bed.

              Doc.
              Doc's Machine. (Probably not what you expect.)

              Comment


              • #8
                Originally posted by Doc Nickel View Post
                You can certainly suggest them.

                But, and I'm not asking this facetiously, what would that gain me?

                I'm very new to both CNC (at least in a direct, hands-on way) and designing and building CNC machines, so I've been trying to keep this build both simple and on a budget.

                I understand the servos have built-in encoders, more power, etc. but my planned work for this machine is relatively small aluminum parts in fairly short runs. I don't need huge power and lightning-fast rapids. I need a fairly simple, relatively inexpensive machine that I can learn on, and will be easy and also relatively inexpensive to fix when I crash something.

                As noted above, this conversion is basically a trainer. Once I'm reasonably comfortable with it, and have a better grasp on the software and tooling minutiae, I'll likely then pick up a ready-built machine, most likely the Tormach slant-bed.

                Doc.
                Closed loop motors, no frustration with lost position.

                We'll, then Geckodrive stepper drivers and appropriately sized stepper motors.
                Another option are the newer closed loop steppers and drivers. I happen to like to use automationtechnologiesinc.com for my steppers and drivers. They have some of the closed loop Nema 23 & 34 steppers. I have one and will buy 2 more to try out on my next Dyna DM2400 build.

                Marty
                Jack of All Trades, Master of None

                Comment


                • #9
                  Doc,

                  Since you're taking suggestions (just messing with you).

                  Seriously, I think you should reconsider getting a used serviceable cnc lathe up here. There have been several opportunities and one was virtually free for the taking. Yes, the free one was bigger than you want but it didn't have any serious issues according to the owner. He was willing to give it away rather than put it in storage. Yes! Yes! I know space is very limited in your shop but where there's a will there's a way. I worked with a guy that put a Hurco cnc mill in a 10' X 12' insulated and heated shed next to his house and used it that way for several years before moving it to his new shop.

                  Ron

                  Comment


                  • #10
                    I think I see the problem here- Perhaps I wasn't clear, the mechanical side of the build is done, and has been tested and run (such as I can) under Mach 3. I already have steppers installed on both axes, 1 270 oz-in on the cross-slide, and a 570 oz-in on the carriage (which, in both cases might be a bit of overkill, especially with a 3:1 belt reduction.)



                    The idea here is to replace the controllers. Which I admit don't necessarily need to do, the MicroKinetics controllers appear to work just fine.

                    But rather than dismantle the entire setup, swap out the existing BOB for an Acorn, etc. I'm considering removing the current, working system, everything from the WinXP PC all the way through to the cables to the steppers, as a complete unit.

                    With the Acorn and the all-in-one PC I ordered Friday evening, all I really need is two new drivers and a power supply. I already have a new enclosure, so with those, I should be able to wire everything up fresh. The old system can then either be sold off, used on a different machine, traded off, whatever.

                    I ordered a pair of DB's Leadshines- I have no idea if they're ideal for my setup, and they're likely not the best possible driver I could have gotten, but they should get me up and running, and the price was right.

                    Doc.
                    Doc's Machine. (Probably not what you expect.)

                    Comment


                    • #11
                      Originally posted by nc5a View Post
                      Seriously, I think you should reconsider getting a used serviceable cnc lathe up here. There have been several opportunities and one was virtually free for the taking.
                      -What? Which one was that?

                      The only "professional" CNC lathes I've ever seen up here was that Hardinge at the Government auction ($15K) a Tree that somebody had in Girdwood for some reason (I think he was asking $15K as well) and there was one for sale up your way earlier this summer (but with some semi-major issue and a not-free price tag.)

                      And sorry, room absolutely is an issue. A machine that size would necessarily have to be installed in the main garage are of the shop, and that's already packed much too full. And a new outbuilding would have it's own costs- both building it, heating it, running power to it, etc.

                      I do have a possible option with a buddy with a small warehouse attached to his office, if it came down to that, but really, I'm still for the moment sticking with the idea of running the Logan for a year, then selling it off and swapping the Tormach into its place.

                      Doc.
                      Doc's Machine. (Probably not what you expect.)

                      Comment


                      • #12
                        Originally posted by Doc Nickel View Post
                        I think I see the problem here- Perhaps I wasn't clear, the mechanical side of the build is done, and has been tested and run (such as I can) under Mach 3. I already have steppers installed on both axes, 1 270 oz-in on the cross-slide, and a 570 oz-in on the carriage (which, in both cases might be a bit of overkill, especially with a 3:1 belt reduction.)



                        The idea here is to replace the controllers. Which I admit don't necessarily need to do, the MicroKinetics controllers appear to work just fine.

                        But rather than dismantle the entire setup, swap out the existing BOB for an Acorn, etc. I'm considering removing the current, working system, everything from the WinXP PC all the way through to the cables to the steppers, as a complete unit.

                        With the Acorn and the all-in-one PC I ordered Friday evening, all I really need is two new drivers and a power supply. I already have a new enclosure, so with those, I should be able to wire everything up fresh. The old system can then either be sold off, used on a different machine, traded off, whatever.

                        I ordered a pair of DB's Leadshines- I have no idea if they're ideal for my setup, and they're likely not the best possible driver I could have gotten, but they should get me up and running, and the price was right.

                        Doc.
                        I see. How much current do your steppers need? As long as you ordered the leadshine drivers that can handle the current, you should be fine.

                        Does your machine have ballscrews or some sort of anti backlash nut?
                        Are you going to fit an differential encoder with line driver output at 1:1 to your spindle so you can try threading etc?

                        In any case, have fun and enjoy the learning journey!
                        Marty
                        Jack of All Trades, Master of None

                        Comment


                        • #13
                          Originally posted by Marty Escarcega View Post
                          How much current do your steppers need?
                          -Not sure. I have the specs somewhere, but I can't seen to put my hands on them right now. My existing MicroKinetics drivers are good to 5A and have been working fine, and the Leadshines DB suggested are good to 4.2A.

                          Does your machine have ballscrews or some sort of anti backlash nut?
                          -Of course. They're admittedly typical Ebay ballscrews, but they seem pretty decent.

                          Are you going to fit an differential encoder with line driver output at 1:1 to your spindle so you can try threading etc?
                          -Of course. That was one of the major (to me) drawbacks of the Mach3 setup- most of what I need to manufacture is threaded, and in some cases even dual-lead or quad-lead threaded, and M3 basically can't do that. I've already ordered a 2000-line encoder, as recommended on the Centroid Acorn discussion board, and just ordered the belts and pulleys I think I'll need.

                          Doc.
                          Doc's Machine. (Probably not what you expect.)

                          Comment


                          • #14
                            Originally posted by Doc Nickel View Post
                            -Not sure. I have the specs somewhere, but I can't seen to put my hands on them right now. My existing MicroKinetics drivers are good to 5A and have been working fine, and the Leadshines DB suggested are good to 4.2A.



                            -Of course. They're admittedly typical Ebay ballscrews, but they seem pretty decent.



                            -Of course. That was one of the major (to me) drawbacks of the Mach3 setup- most of what I need to manufacture is threaded, and in some cases even dual-lead or quad-lead threaded, and M3 basically can't do that. I've already ordered a 2000-line encoder, as recommended on the Centroid Acorn discussion board, and just ordered the belts and pulleys I think I'll need.

                            Doc.
                            Sounds good Doc.

                            You could likely drive the Microkinetics drivers from Acorn if you needed to.
                            Marty
                            Jack of All Trades, Master of None

                            Comment


                            • #15
                              Originally posted by Marty Escarcega View Post
                              You could likely drive the Microkinetics drivers from Acorn if you needed to.
                              -Undoubtedly; they take step/direction just like most everything else. And I may still do it that way- basically I'd just need to remove my BOB, add in the Acorn, run the ethernet cable, and done.

                              But, I kind of like the idea of keeping the old system, which is tried and tested, intact. Either for later reuse, use on a different machine, or just to sell it all off as a unit to another DIY'er.

                              Doc.
                              Doc's Machine. (Probably not what you expect.)

                              Comment

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