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  • Advice needed re surface grinder automation

    I have a torn rotator cuff, so turning that handle on the SG is no longer an option. It's a Boyar Schultz 6-12, and I would like to automate the table travel. I will use a dc motor for the table traverse (X-axis ??), and a stepper motor for the cross feed (Z axis ??).

    I have a few questions for the pros.

    1-What would be a good range of linear speeds for the table travel in X.
    2-What would be a good range of cross feed advance in Z.
    3-Should the cross feed advance after just one travel in X or would it be better to have the table traverse a selectable number of times before advancing the cross feed to ensure spark out.

  • #2
    My advice on this subject is often ignored or ridiculed but I'll give it a try.

    Your cross feed should be capable of incremental or continuous movement. Incremental, as small as a few thousandths per cycle. It should also be able to move continuously at a variable speed. The question of which to use (incremental or continuous) depends on whether you're hogging or finishing.

    For heavy material removal use the incremental.

    For finishing use the continuous (Z) movement so that the wheel travel is something less than the width of the wheel per cycle. Make several spark out passes, back and forth, not letting the wheel completely leave the workpiece. The finish on your material will give you clues if you're moving too fast.

    Gene

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    • #3
      Thanks Gene, the stepper on Z can be programmed to do small increments down to 1 thou. But do I understand correctly that when finishing the 3/4" wheel should advance +- 1/2" between passes.

      I am also figuring 3 - 4 seconds for each 12" of travel in X, that's 15-20 feet/min. does that sound right.

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      • #4
        1/2" is way high. Usually you increment somewhere around .040 to .050 a pass.

        3 to 4 seconds for 12" is high. The automatic grinder at work must move 24" in less than a second.

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        • #5
          Thanks Macona. I was replying to easymike regarding the cross feed. I increment .025 to .050 a pass manually.

          The handwheel advances the table 3" per revolution, and I usually turn it at about 1 turn every second. Wouldn't 8 rev/sec (to achieve 24"/sec) be too high?

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          • #6
            Not really. There is not much material removal going on so you can go fast. The only real issue is loading down the spindle.

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            • #7
              Originally posted by yul m6 View Post
              Thanks Gene, the stepper on Z can be programmed to do small increments down to 1 thou. But do I understand correctly that when finishing the 3/4" wheel should advance +- 1/2" between passes....
              When finishing the wheel should be continuously moving, not incrementally.

              Gene

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              • #8
                To give a comparison, my Jones&Shipman 8"x24" grinder does from 0 to .077 per pass in Z and 0 to 10feet/min X feed. Whilst it would (very) occaisionally be nice to have a coarser cross feed available, you're probably into hand feeding territory for a single finishing pass much beyond that.


                Originally posted by easymike29 View Post
                When finishing the wheel should be continuously moving, not incrementally.

                Gene
                That would apply to a cylindrical grinder, not a surface grinder.

                Regards
                Mark
                Last edited by Mark Rand; 11-07-2013, 05:48 PM.
                Location- Rugby, Warwickshire. UK

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