Stepper Motor Driven Rotary Table
Bill Chennault
Posts: 1,198
All--
Some of you have expressed interest in my ideas concerning a stepper motor driven rotary table. In and of itself, this is not a new concept, idea, or project. The only question is, How much do you want to spend?
This is exactly what I spent . . .
Part #: H5685
Description: 4" Rotary Table
Price: $109.95
URL: www.grizzly.com/products/h5685
Part #: NEMA Size 17 Stepper
Description: NEMA Size 17 Stepper
Price: $21.54
URL: www.robotstore.com/store/product.asp?pid=1367&catid=11
Part #: BS0710-USB
Description: BS0710-USB
Price: $89.00
URL: www.stepperboard.com/prod10-BS0710.htm
Part #: A 6Z23M017DF0905
Description: HTD Pitch, 17 Teeth, Polycarbonate timing pulley
Price: $5.19
URL: www.sdp-si.com/index.asp·(Use the Part# to look it up on this HUGE site.)
Part #: A 6Z23M060DF0910
Description: 3mm HTD Pitch, 60 Teeth, Polycarbonate timing pulley
Price: $7.69
URL: www.sdp-si.com/index.asp (Use the Part# to look it up on this HUGE site.)
Part #: A 6R23M080090
Description: 3mm HTD Pitch, 80 Teeth, 9mm wide Neoprene Belt
Price: $6.09
URL: www.sdp-si.com/index.asp (Use the Part# to look it up on this HUGE site.)
Part #:
Description: 12"x6"x0.25" Aluminum plate
Price: $10.00 (Approximate; buy it locally. I bought a 2' length and have a LOT left!)
Total: $239.46
My control setup consisted of a BS2 with a zapped Pin 1, a Professional Development Board, and the BS0710-USB stepper controller board from Peter Norberg Consulting. (It is shown at a URL that does not indicate Peter Norberg Consulting, above.) This stepper controller is very easy to use and will control two steppers either or both of which can be any mix of unipolar or bipolar. The little Jameco stepper I used was bipolar.
Here is a picture of the entire setup . . .
Here is a link to a side view which shows another perspective.
And here is a link to a 10Mb movie that proves something moved!
As you can see, I used a magnetic clamp dial indicator to give me a clue as to repeatability. I cranked the BS2 up, wrote the code, downloaded it to the BS2, messed with the dial indicator so that at the end of its travel it would indicate 10/1000" and let it run for 42 hours.
I noted that for about the first three hours repeatability varied quite a bit. (Well, "quite a bit" is relative: How would you term returning to within 20 to 30 thousandths of an inch to the same spot thousands of times without stop?) Then, after about three hours, repeatability improved dramatically, becoming +/- 0.003". A bit, perhaps another hour, and it improved again to less than +/- 0.001".
I attribute the initial improvements in repeatability to equipment breakin.
As you can tell if you watch the video, the stepper is running very slow, taking maybe three or four seconds to go from far out to far in. (I have not timed it.) This may be why repeatability is so good. I plan to speed it up about tenfold, while leaving enough room in the swing to ramp up and down appropriately.
Other than for my own curiosity, one may well ask, What good is this? Well, I plan to build a robot shoulder by building two setups similar to the one·above and mounting one on the other at a 90 degree angle. However, I will not use that Jameco stepper, since it is nowhere near as strong as I had hoped. (They do not even list the holding torque!) In fact, I will probably do away with the entire timing belt with gear reduction idea and simply get a stepper hefty enough (700+ in-oz) to drive the rotary table shaft directly. This will not only give me a good robot shoulder, but two stepper driven rotary tables with plenty of power for a small mill.
So, after more experimentation, I will be asking some questions on the "General" forum about stronger steppers (I think I have found it), higher current stepper boards (again, I think I have found it) and power supplies (gee, I don't have a clue). But all that is another question.
I want to thank everyone on this forum that taught me stuff and pointed me in the right directions.
--Bill
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You are what you write.
Post Edited (Bill Chennault) : 6/6/2007 11:53:58 PM GMT
Some of you have expressed interest in my ideas concerning a stepper motor driven rotary table. In and of itself, this is not a new concept, idea, or project. The only question is, How much do you want to spend?
This is exactly what I spent . . .
Part #: H5685
Description: 4" Rotary Table
Price: $109.95
URL: www.grizzly.com/products/h5685
Part #: NEMA Size 17 Stepper
Description: NEMA Size 17 Stepper
Price: $21.54
URL: www.robotstore.com/store/product.asp?pid=1367&catid=11
Part #: BS0710-USB
Description: BS0710-USB
Price: $89.00
URL: www.stepperboard.com/prod10-BS0710.htm
Part #: A 6Z23M017DF0905
Description: HTD Pitch, 17 Teeth, Polycarbonate timing pulley
Price: $5.19
URL: www.sdp-si.com/index.asp·(Use the Part# to look it up on this HUGE site.)
Part #: A 6Z23M060DF0910
Description: 3mm HTD Pitch, 60 Teeth, Polycarbonate timing pulley
Price: $7.69
URL: www.sdp-si.com/index.asp (Use the Part# to look it up on this HUGE site.)
Part #: A 6R23M080090
Description: 3mm HTD Pitch, 80 Teeth, 9mm wide Neoprene Belt
Price: $6.09
URL: www.sdp-si.com/index.asp (Use the Part# to look it up on this HUGE site.)
Part #:
Description: 12"x6"x0.25" Aluminum plate
Price: $10.00 (Approximate; buy it locally. I bought a 2' length and have a LOT left!)
Total: $239.46
My control setup consisted of a BS2 with a zapped Pin 1, a Professional Development Board, and the BS0710-USB stepper controller board from Peter Norberg Consulting. (It is shown at a URL that does not indicate Peter Norberg Consulting, above.) This stepper controller is very easy to use and will control two steppers either or both of which can be any mix of unipolar or bipolar. The little Jameco stepper I used was bipolar.
Here is a picture of the entire setup . . .
Here is a link to a side view which shows another perspective.
And here is a link to a 10Mb movie that proves something moved!
As you can see, I used a magnetic clamp dial indicator to give me a clue as to repeatability. I cranked the BS2 up, wrote the code, downloaded it to the BS2, messed with the dial indicator so that at the end of its travel it would indicate 10/1000" and let it run for 42 hours.
I noted that for about the first three hours repeatability varied quite a bit. (Well, "quite a bit" is relative: How would you term returning to within 20 to 30 thousandths of an inch to the same spot thousands of times without stop?) Then, after about three hours, repeatability improved dramatically, becoming +/- 0.003". A bit, perhaps another hour, and it improved again to less than +/- 0.001".
I attribute the initial improvements in repeatability to equipment breakin.
As you can tell if you watch the video, the stepper is running very slow, taking maybe three or four seconds to go from far out to far in. (I have not timed it.) This may be why repeatability is so good. I plan to speed it up about tenfold, while leaving enough room in the swing to ramp up and down appropriately.
Other than for my own curiosity, one may well ask, What good is this? Well, I plan to build a robot shoulder by building two setups similar to the one·above and mounting one on the other at a 90 degree angle. However, I will not use that Jameco stepper, since it is nowhere near as strong as I had hoped. (They do not even list the holding torque!) In fact, I will probably do away with the entire timing belt with gear reduction idea and simply get a stepper hefty enough (700+ in-oz) to drive the rotary table shaft directly. This will not only give me a good robot shoulder, but two stepper driven rotary tables with plenty of power for a small mill.
So, after more experimentation, I will be asking some questions on the "General" forum about stronger steppers (I think I have found it), higher current stepper boards (again, I think I have found it) and power supplies (gee, I don't have a clue). But all that is another question.
I want to thank everyone on this forum that taught me stuff and pointed me in the right directions.
--Bill
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
You are what you write.
Post Edited (Bill Chennault) : 6/6/2007 11:53:58 PM GMT
Comments
I am glad you got this up and running it looks nice and should be very powerful do you have any idea as to the internal gearing ration of the Table?
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- Stephen
I see you caught the missing space after the first character, too. Sorry about that.
I posted the 60 tooth part number wrong. I have edited it and both pulley part numbers work for me on the SPD/SI site, now.
I am now running a "high speed" test of the same setup. I will let it run for at least 24 hours and report on the setup's repeatability. The Jameco 155459 stepper is really a heapie-cheapie thing and I do not think it is appropriate except for experimentation, which is what I am using it for. I think I am going to like the Peter Norberg Consulting stepper driver board, though. However, I do not know if it will find a place in my parts bin other than as an experimental piece.
--Bill
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You are what you write.
No. I don't know the worm gear ratio. I believe it is quite low, as that is the nature of worms and worm gears. As soon as I finish my experiments, I can stick the handle back on it and easily tell you what it is by turning the handle one revolution and noting how many degrees the table turns.
--Bill
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You are what you write.
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Think Inside the box first and if that doesn't work..
Re-arrange what's inside the box then...
Think outside the BOX!