Rotary Welding Positioner; The Build

  1. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Well I got ******all else to do today so I'll show you lot what I've done so far.

    But first a bit of back ground, I've been after a Rotary table for sometime now. The problem is 2nd hand ones are thin on the ground, and tend to be massive and heavy. You can buy New ones from China however one of those is going to cost you 500quid even before The Customs man wants his Duty and VAT:mad:

    So been the tight Northern Monkey I am:whistle: I decided to build one.
    After some time searching for a suitable electric motor I found a guy selling off a load of Brand new Conveyor motors from a bakery. So I bought 8 of them:laughing:

    They are a lovely little motor only 14w but the important thing is they have a Reduction gear box, reducing the Motor RPM from 1400 down to 2.06 that's 630:1 :o Because of the large reduction the torque is unreal. And they work in both directions.

    So stick a variable speed controller on and off you go. NO not as simples as that, I spoke to 4 different companies who sent me their "sure it will do the job" bits of kit, only to find out the motor at slow speed would lose all its torque. No good, no good at all. Finally I found someone who knew what they were talking about, I sent them a Motor so they could make sure it would work. It did, wooho:hug:
    It turns out the motors aren't single phase but 3 phase, and because of this a small 1ph to 3ph invertor is the speed controller to use, not only that the guy tells me the motors alone would set you back 300quid each, without the reduction box:o But as they are such a low wattage the things will last for ever:clapping:

    So I bought 8 of those as well :whistle:

    Problem is I've now spent more than a yellow one would have cost me:rolleyes:

    I now have 8 motors and 8 controllers, so best start to build one.

    The frame is 12" x 12" x 14" made from 20x2mm box. Mitred corners, welds ground flat on the outside so it doesn't catch, the frame will be powder coated black once finished.

    I'm waiting on a Pillow block to support the shaft. The earth strap is from the local motor factors. No volt switch, 2 way switch , Pot and Plastic box, off tinter web. The shaft is 3/4" Dia 304 stainless I had, This will fit to a 1 1/8"x12TPI threaded head so you can fit a Myford Faceplate or Chuck. I found the round plate in a corner and been me couldn't wait for the Myford bits to turn up, so quickly knocked up this face plate for the prototype.

    So here it is, I don't like the ground clamp point so I've ordered a Female Dinse Socket. I'm also fitting a pair of adjustable armrests that will also double up as a torch holder.
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    Last edited: Feb 9, 2010
  2. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Forgot. Speed controller shaft waiting on a knob, on the right, and CW/CCW direction switch on the left
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  3. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Pillow Blocks turned up this aft, so made a bracket to fit, and welded that on. :D
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  4. astro_al Rocket Scientist

    Really excellent! I could use one too, so knock a couple up would you? ;)

  5. Dr pepper Member

    I worked at bosal exhaust, we had machines a little like that.
    Your ground strap idea looks superb, simple and cost effective, I have an issue here at work with static build on on rollers that feed paper into machinery, I've tried various expensive methods, that might be worth a try.
  6. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Orders are been taken:welder:
  7. wyn

    wyn Forum Supporter

    Posts: 2,413
    Nice. :cool:

    Will the speed control bit stick above the table so it can be adjusted on the fly ?
  8. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    The pictures don't show it too well do they

    But Yes, I put it under the control box so it didn't get broken, but you can still get to it, with either the table upright or on it's side. I'm looking at fitting a foot pedal option as well
  9. Robotstar5

    Robotstar5 Casanunda Staff Member

    Posts: 10,421
    Having used a few small (and large) positioners, have you thought of mounting your frame inside another with an arced plate with holes drilled in so you can peg the positioner anywhere between 0° and 90° for the mkII.
    Also, never seen a strap work return before (try a smear of coppaslip to aid conduction), normally use a rotating coupling (expensive) or a spring loaded carbon brush against back of faceplate (much cheaper) which we use on robot manipulators at work and seem to last forever.
  10. brightspark

    brightspark Member

    Posts: 13,275
    yarm teeside
    just done a 500v flash test on some copperslip its a good insulator not a conductor ;)if u had to silicone grease would be ok to use would stop arcing
  11. Robotstar5

    Robotstar5 Casanunda Staff Member

    Posts: 10,421
    That's odd, considering one of the biggest manufacturers of welding manipulators recommends it
  12. brightspark

    brightspark Member

    Posts: 13,275
    yarm teeside
    yes its great for slow moving parts lasts forever
  13. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    I had thought about that, but I found I never used the function. I also think the main reason they have them is because they are so heavy, thus saving your balls trying to turn it on its side.
  14. Robotstar5

    Robotstar5 Casanunda Staff Member

    Posts: 10,421
    Just thinking with my robot "hat" on as you can sometimes get better torch angles.

    Here's one I did with a 1600kG positioner welding alternator bodies

  15. BillJ Member

    Posts: 643
    I've worked both on paper handling machines and on electronic equipment production lines, both suffering from static. Ground straps of that sort are just what you need. Copper contacts connected to the chassis and contacting the ends of the roller spindles are common too.
    It's fun watching a stack of sheets levitating above each other when they've come hot and dry out of what was essentially a high-speed laser printer. Needed to keep your distance, though - it could give quite a belt:o

    Are the rollers themselves conductive?
  16. brightspark

    brightspark Member

    Posts: 13,275
    yarm teeside
    nowt like a bit of static to get u to move fast :laughing:ive seen a few on grain blowers through plastic pipe :laughing::laughing:
  17. Robotstar5

    Robotstar5 Casanunda Staff Member

    Posts: 10,421
    I've seen metal sheets levitating using an electromagnet under the stack, makes the top one "float" so it could be picked up by a press tending robot.
  18. BillJ Member

    Posts: 643
    Yep - I've seen a service engineer with a neat hole burned through his thumbnail through getting too close to fast-moving paper :laughing:
  19. hotrodder Member

    Posts: 3,859
    SE England
    cool :clapping:
  20. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    I thought so as well. Comments?
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