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anoah
05-12-2003, 10:20 PM
Would this work for a CNC Stepper on a small machine or does it not have enough steps.

Thanks!

Albert

PM42L-048-TIA5 by NMB Configured with 2 coils and powered with 12 volts at 1.2 amps. The outside diameter of the NMB motor is 55 mm(2") and 25 mm(1") thick. The mounting holes are on 67 mm (1-3/4") centers. At 48 steps per revolution, and a holding torque of 1800 g.cm (63 Oz?), this stepper is a perfect match for your project. The shaft is 9/16" long by 1/8" in diameter. MOT1014..

chuckknigh
05-13-2003, 12:25 PM
When I asked a similar question, I got several answers. Let me paraphrase the two best ones, here.

Of course, more steps are better. 200 steps per revolution (1.8 degrees per step) is common enough that you shouldn't have to get less than this. I salvaged 100 oz in, 200 steps per revolution steppers from some old HP laser printers -- they're easy to get, and cheap.

Work out the numbers...48 steps per revolution, directly coupled to a 1/2x13tpi screw thread gives a theoretical resolution of 624 steps per inch, or .00016 inch per step. Coupled to a 1/4x20tpi screw thread, you'll get 960 steps per inch, which means a theoretical resolution of .000104 inch per step. Your machine will FLEX more than that!

-- Chuck Knight

chuckknigh
05-13-2003, 12:28 PM
Whoops -- .0016 and .000104. Misplaced one of my decimal points! :-)

WOODKNACK
05-13-2003, 01:08 PM
Im not sure what you are getting at. I can tell you I bought a system from stepperworld and the motors were 60 oz. 12 volts .44 amps. the were 200 steps per revolution motors. For a small machine they would be ok. By small I mean 8x8 inch. I could only get 6 ipm out if it. They would skip steps anything more then that. There are alot of factors though! Like how much drag does your machine have, etc... Im not sure but I think the more steps your motors have, the more accurate cut you will get.

abasir
05-13-2003, 09:57 PM
Anoah,
Not sure your question is about step or power. As for step, my Z-axis is 48 steps motor but driven by quarter step driver for 192 steps per revs. It's a 5V 0.56A motor and with the tool I use on the axis, I could get 15ipm.

WOODKNACK
05-14-2003, 01:26 AM
Its probably the board I was running as to why i was only getting 6 IPM. This is still a new hobby to me. So I am learning here too.
so heres a question. What is the difference between a 200 step motor and a 48? And dont tell me 152! hahah. would one be more accurate? Say you had a driver board set at full step and you made a circle cut. whould the circle look better from the 200 step motor or the 48 step motor?

balsaman
05-14-2003, 08:27 PM
The more steps, the finer the smallest movement the machine can make. That said, a 200 step motor on 1/2-10 rod moves the axis .0005". That's a half of one thousands. I doubt you could see it in a circle, no matter which motor you use.

Still, since 200 step motors are cheap and plentiful, I would use them if you can.

Eric

WOODKNACK
05-15-2003, 12:31 AM
Ya but that is .0005 for a 200 step motor with 1/2-10. your right.

but now if you take that 48 step motor and couple it the the same rod 1/2-10 then it comes out to .002.

Thats 2 thousands! I guess it would depend on what you were going to do with the machine..

I would go with smaller rod. more turns per inch. Id sacrafice speed for accracy. But like I said It would depend on what you were going to do with it...

How accurate do you have to be to mill circut boards?
I never done it. Just curios.....