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Which CNC retrofit control?

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  • Which CNC retrofit control?

    I need to do a control retrofit on my 1980 LeBlond 19â€‌ Tape Turn Regal lathe. I would like to cut costs and do it myself. There are several things that complicate my decision on which one to get.

    A 4 position turret. Do most retrofits cover this? I found the magnetics for it. Manually tripping forward will lift and turn, then when it stops turning reverse will lock it down.

    Spindle brake. I think some lathes reverse the motor to stop the spindle but this has a brake. I don’t know how it is activated. Would this be another complication or is it not a problem once I get started?

    It has “Servo Shiftâ€‌. In normal operations when an S1 thru S12 and M3 word is called: if the spindle is running it stops, the selector knob turns to the “Sâ€‌ gear number, the spindle oscillates about 5 seconds until it drops into gear, then the spindle starts. It has two ranges to get the 12 speeds like a manual lathe. The selector knob seems to have its own servo. I haven’t dug into it to find out if there is a servo on each gear range. I think there is a separate motor just to oscillate the spindle (as though putting your hand on the chuck and rocking forward and reverse).

    I could dumb it down and eliminate all these auto features, but that kind of defeats the purpose of cnc.

    LeBlond LTD sells a retrofit kit but is it worth paying maybe twice as much to have a system all figured out? Their price on a steady rest was more than what I paid for the whole lathe. (I paid $1600, price new $80,000.00)

    Do all retrofits come with the software needed to operate? If not can you buy any software or should it be theirs?

    Super Dave

    [This message has been edited by suprdvn (edited 06-06-2004).]
    Super Dave

  • #2
    Lathes are quirky as regards conversions due to the threading capability needed.
    At the moment you have a choice of 5 controls that's easy on your pocket.

    TurboCNC can run lathe and do threading but it's a very simple program and doesn't offer much in the way of the sort of extra's you need.

    Mach2 will be able to do this but not at present, what's your time scale ?

    Microkinetics also do lathe but again don't cater for the extra's you need.

    Ajax CNC which is in another on going thread do lathe but seeing as how they charge for every extra it may be too much at the end of the day to run a turret and spindle.

    Ahha also do lathe and with their deluxe board you have plenty of inputs and outputs. It also has it's own macro language that can talk to PLC's for turrets and spindle and brake servo's
    You might find t handy to drop Bill Griffin a line at as I know he has done about 30 ful sized commercial machines using this software.

    John S.

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


    • #3
      Turbocnc can output extra points for brake,
      You can use extra axis'es to create control points and call them with axis calls.
      External I/o, brake, all available in points.
      Mach2 would work too by tricking it similar like.

      I got a woodie just looking at the lathe and thinking of the possibilities. Someday...

      I wish I was close, I'd help rewire/modernize for some lathe time. I love interesting projects. Problem now is I am chasing my tail to keep the bills paid.



      • #4
        So if I understand you correctly David, the brake would be wired to the say the "Y" axis and the servo shift to 4th axis, etc?

        I'm not in business now but would like to start one someday specializing in cnc. I've been putting it off for some time and am itching to get it done.

        Super Dave

        [This message has been edited by suprdvn (edited 05-30-2004).]
        Super Dave


        • #5
          No.. but you can trick the machine.

          EMC has a brake option. Turbocnc does too if I remember correctly. (stinking formatted brain)

          I wired my brake on my mill to a output, and the estop, and the selector switch next to the pneumatic speed control. Emc recognizes these outputs but Mach2/turbocnc does not. When I hit the estop and the brake switch is activated it turns on the brake and I can change tooling. I won't grab the spindle without the hardwire estop being in.

          You can fool the output several ways, by thinking it is a drive, you can use the fwd/rev pulse pin to toggle items.. you just have to remember when you do code.

          Opto-22 does not care whether it is 5vdc or a 120vac module in a slot, it will energize it. They are all 5vdc on the logic side.

          I got a case full of the old classic modules. I really like the old style since it is simpler.

          John got a big kick outa my pictures of my mill during the last time I wired it but:
          This is a simple opto rack. it has the input terminals on the top for direct connection to a parallel cable. The bottom connections can operate outputs of varied voltages. Simple and cheap on ebay.
          In configuration you set the extra drive axis pin dir say to (2f8 address, pin 3) and when you toggle that drive in the positive manner it turns on that pin, toggle it reverse and it goes the other way. It retains the logic to be -preset- for the next move. you have to be able to preset the pins so the drive knows which way it must go, usually ms before pulsing the step pin.

          The Mach2 manual is the best I have ever saw. One of the easiest to understand. (Has external clock program that helps time waveforms) Understanding how it works lets you set turbocnc up in a flash also.
          The EMC manual is out of date. when you read about it you are reading about releases three years old or more. They are working on it. It runs on RT linux or rta.. (external clock program with software calls)
          Turbocnc is self explanatory, has a pretty good manual. No graphics, no external driver, it runs in dos as a single tasking program. Not as fast as either of the above.

          It is much harder hardwiring logic then to just rely on software. But all estop logic should be hardwired not dependent on the software. I also did all my limits like that. I remove power from the axis drives/spindle.

          The rocking back and forth has me intrigued. Perhaps apply the brake? then to m03/m05/m04/m05? and watch for external input to cease macros? Perhaps to setup the drive to follow freq? and just output logic direct like it is another axis.
          I had to recently add the wire for reverse on my spindle. till now I have depended on the inverter to get my turn-down speed. With a 1 1/4 drill I had to switch to the low range. I used the fwd reverse pins/logic positions from emc bridgeportIO setup logic.


          [This message has been edited by ibewgypsie (edited 05-31-2004).]


          • #6
            Are you by chance running 480 volts there?

            email me if you are..



            • #7
              It’s wired for 230 volts. I use a 20 hp phase converter for the 10 hp spindle motor. It works well.

              When I got the lathe it wasn’t working. Turns out the problem was an oil fouled electrical
              connector. Used it for about 5 months, but now more control problems.

              I have mostly figured out how the servo shift works. The dial can be turned manually or with
              the servo to a gear number at any time even with the spindle running. With the spindle stopped
              and the brake on the spindle oscillates and the gears shift hydraulically. I don’t know what
              makes the spindle oscillate yet but I don’t think it is the spindle motor. I just tried it by
              momentarily hitting the forward and rev switches, that made my shop lights dim with each
              reversal. Not a good idea.

              Every full turn of the blue servo is one notch on the dial. The whole servo box appears to be
              a bolt-on accessory. It appears as though I don’t have to hook it up for the hydraulic shift to
              work. But since it is a servo wouldn’t I be able to wire it as a 4th axis?

              I have found the magnetic for the hydraulic motor. When I select a gear and start the pump it
              will go into gear, if it doesn’t mesh then I push the spindle a bit and do it again. Worst case
              scenario I could wire a push button for the hydraulics and rock the spindle by hand.

              The spindle brake works. Even with the bad control turned off (main power on). The brake
              applies automatically just by grabbing the chuck and giving it a good pull and turns off when
              the rpm is zero.

              David, you ought to resize your pictures. The text poked a whole in the right side of my monitor.

              Super Dave

              [This message has been edited by suprdvn (edited 05-31-2004).]

              [This message has been edited by suprdvn (edited 06-01-2004).]
              Super Dave


              • #8
                I wonder.. Is the spindle drive dc too? It may be a servo type drive too. I saw something recently on a similar dc spindle on another board.

                If so, it may pulse forward and back at partial current.

                I must warn you:... I am/was real bad always about taking things apart to see how they work.. Grampa got real mad about his railroad watch when I was about 5.. If I could have found all the parts I am sure I could have put it back together and avoided "that" whipping.

                Takes a lot to "hack" a cnc machine without books, have you searched out a manual yet with schematics? I spent several days on a creeper pulling wires and tracing circuits. It was useless thou. I gutted it like a fish.


                [This message has been edited by ibewgypsie (edited 05-31-2004).]


                • #9
                  Super Dave, the rocking of the spindle is done by a gear motor with a crank shaft and rod connected to the coil on the spindle brake. The coil rocks back and forth and with the coil energiezed it drives the input shaft to and fro. I just worked on a 17" Regal and had to take it all apart for a bent shaft in the headstock housing. As far as shifting is concerned the simpleist approach would be to set it up so you get a spindle stop call when ever you need to change speeds and change the speed dial manually. It could be automated, maybe use a PLC and write a program for it. Many toolchangers on VMC use that approach. The control calls out to the PLC what to do and the control is in a hold state until the PLC sends a ready signal back to it. There should be a bunch of micro switches in that box to read the shifter position, to make sure that it is indeed all the way in gear and not stuck between gears. Possibly they can be used to detect what gear it is in on bootup. On the Regal I think they were used to inhibit the spindle from starting unless one switch from each shift shaft senser was made. This would give a simple binary output to the PLC. Good luck, keep us updated.


                  • #10
                    Them Hitachi plc bricks, I think the last one I bought was $65.. a real relay replacer.. not a real complicated item. You could chain logic in there thou.

                    Depends on how complicated you want..

                    Neat to hear from someone who has had one apart.



                    • #11
                      I do have wiring schematics for it, but don’t understand any much of it.
                      Here’s just part of a page.

                      There is more than 10 full size sheets with some reference to the servo shift,
                      (not to mention the other items that I question). The wiring continues to items
                      on other pages that in turn connect to more items on even more pages etc. until
                      everything is connected somehow to everything else. It seems a bit
                      overwhelming. Perhaps if I would read up on the symbols used I might be able to
                      follow it.
                      Does anyone know of good reference material?
                      Super Dave

                      [This message has been edited by suprdvn (edited 06-01-2004).]
                      Super Dave


                      • #12

                        I have been a electrician since the 70's..

                        Doesn't seem to be anything uniform in electrical schematics. Each company seems to draw thier own symbols. Most times things are similar, you have to study each drawing and interpert what the cad person wanted to convey. Most times enough is similar so you can figure it ou.
                        That Kinda looks like a synchronous motor in the page you posted. (a ac motor with poles that runs a preset exact speed according to frequency input)

                        The resistor-capacitor across the dual poles kinda give it away (phase shift). The lil arrows where the lines cross are just that, no connection. Like a street roadmap just follow one line at a time thinking, if (contact closed) Not (contact open) then (end result) logic.. you can build a chain of logic like that.. if this,, and not this.. and this then this turns on..

                        The squares inline with it are probably power transistors, or look for a legend. Pins are identified 1,6 & 1,5 ? Might be a reversing relay too thou. (in that case they should have drawed the contacts tho)
                        SPindle speed select? is this the servo-shift as they called it? Looks like a synch motor to me.. Directions are selectable by red/black wires going in I bet (probably not red/red-common white). It should select a different transmission cog according to? does the left have a processor somewhere with limits for each gear?
                        Damn, just enough to get interesting Now I got something else to think about all day.. HA.. better then a soap.. I wanna see the logical selector.. the cpu.. or relays/limits..
                        Possibly a latch-hold till limit made? In that case there will be a wire for each gear in the selection.. one thing about synch motors, you can stall them out without really hurting them.. turn them on and instantly they hit thier speed.. I got a whole truckload and all I can think of is to make a clock out of them. This is much more interesting..



                        • #13
                          How about trashing the whole servo shift business and putting a large motor belted to the spindle with a VFD for speed control? For very low speed maybe you could halt the program and shift to a low gear manually.

                          What are your intentions for this machine? Production machining, job shop, hobby?

                          If it's for a profit making venture, I suggest you go with one of the commercial control retrofits. A commercial control will have mucho more features than the hobby type. Features like a wide assortmant of canned cycles making programming at the machine possible for a high percentage of parts. (I own a four-CNC shop with all full featured commercial controls, close to 95% of our programming is done on the floor at the machine without need for CAM, fast and efficient way to work IMO).

                          However you go, you have to realize an older machine like yours doesn't have much market value (just a touch over scrap value) so you want to be careful in sinking a great deal into the retrofit.


                          • #14

                            A few chips on a "junk" little above scrap priced machine.

                            Unfortunatly home shop machiniests can't afford new cnc machines so they purchase older ones and "get them to work" I see over and over production shops abandon machines cause they can't afford to have them repaired. (or hire a good electrician). or the company that made the profit off them is not supporting them, bridgeport had a similar opinion. I called the support number on the mill for documentation.. the man on the phone laughed and asked "do you know how old that machine is?" I am quite sure people on the phone representing a company like that has a lot to do with them changing hands. RUn off the little money (me)

                            I can't afford a machine shop's price to do the things I want. So I do my own on my home machine.

                            Superdv: if you get tired of the lathe, call me perhaps I can give your money back.. Or, I can help as much as these wires can allow from here.



                            • #15
                              Thanks everyone for your help. I will be contacting the retro companies for quotes
                              and other questions. Can't wait to see the different responses. Will keep you up to date.

                              RE: "However you go, you have to realize an older machine like yours doesn't have
                              much market value (just a touch over scrap value)"

                              I'm not so sure about that. Especially if I did go with a commercial unit and got all my
                              accessories working. There is not much cnc available in this size lathe. Quite heavy
                              duty. I would maybe get some work that other job shops couldn't do. I’m hobby now,
                              job shop sometime down the road.

                              I have a problem with the Z axis screw, but otherwise it is mechanically like new. I am
                              quite impressed with the construction of the lathe. The bed ways can even be unbolted
                              and reground on a standard surface grinder (if need be).

                              I will be doing most of my drilling with the turret, but if I need to drill with the tailstock:
                              it has over 12" travel on the quill, two speed feed quill for deep drilling. There is a collar
                              that you slide right behind the hand wheel. The slow setting is slower than most lathes
                              so you would not get fatigued and the fast is rapid for pecking.

                              Super Dave

                              [This message has been edited by suprdvn (edited 06-01-2004).]
                              Super Dave