Random stepper questions

[chuckknigh]

Well, I looked for HPLJ printers yesterday, at my flea market. Lots of LASER printers but only 1 HP...that I wanted to pay for.

So, I got a batch of 4 printers for $5...one was an HP3, the others were just random...NEC, Lexmark, and something else.

So, since my steppers will undoubtedly not match, and will likely be of differing strengths, which axis needs the biggest one, and which needs the smallest?

So far I've gotten out 2 steppers -- a 31n-cm and a 22n-cm. In US units that's about 100oz-in and 66 oz-in, if I did my calculations correctly. And, like I said, they don't match.

I would imagine Z would need the smallest motor, since its motion can be stepped down more by choosing a different thread pitch on the screw. No penalty, since its length of travel is so short.

And, I assume the longest axis would need the strongest...same reason.

Am I assuming correctly?

-- Chuck Knight

P.S. One other thing. If I turn out to have both unipolar and bipolar motors...there's essentially a distinct driver circuit running each one, so it won't matter, right?

[WOODKNACK]

do you have any 2 that are the same? I believe you should have 2 of the same stepper for your X and Y axis. other wise it may not do certian moves right, like cut circles. as for the z axis a different one would work fine. Do you have apicture of the motors? Im just curios to see them. How many amp and volts are they?

If those steppers came out of regular bubble jet prints I dont think they are going to be powerful enough to run your machine.

[WOODKNACK]

To save you a little head ache I saw these on ebay that would be perfect for what you are doing. Id say they are worth the money. Figure all your time looking for steppers!
http://cgi.ebay.com/ws/eBayISAPI.dll...category=26209

and they are double shaft so you can mount a crank to it if you want.

[HomeCNC]

How about this place. I like the .9 deg per step motors.

http://www.herbach.com/Merchant2/mer..._Code=STEPPING

and

http://www.herbach.com/Merchant2/mer..._Code=STEPPING

[WOODKNACK]

Hey,
that looks good!I think I might buy a couple of the,4.5 VDC, 187 oz/in Torque, 400 Steps per Revolution, 0.9° Step Bi-Polar Stepping Motors. Good link..
I believe the stepper I have that I got out of lazer printers are .9 degrees and 400 steps prer revolution. but they are only 85 or 100 oz in.They are the same motors Balsaman has. The only info I could find on the net about them was this.

7)Japan Servo 85 oz-in 400 Steps/Rev . $29/ea, (- and if you want to see what a quality motor looks like inside, here is the dis-assembled motor, showing the clean design and double stack with ball-bearing construction.)
Japan Servo TYPE KP56QM2-001, with Ball Bearings on each end of shaft. (note, unless you burn out the windings, and this takes at least a little effort, the only failure mode in step motors is bearing failure - which is easy to remedy as well as rare with Japan ball bearings)
NEMA23 mounting flange: Motor Length = 75mm from flange to rear of case, Motor Diameter = 57mm. Shaft Length = 14mm, Shaft Diameter = 5.9mm
6 Wire CT windings 3.5 ohm - 0 - 3.5 ohm,
Maximum Current: Center tapped - 1.5A , Bipolar, full winding - 1.0A
note: These motors have been carefully removed from surplus assemblies - leads are 75 mm long, and may require extending for some applications. We guarantee your satisfaction with these motors !! Limited quantity available. $29/ea

[chuckknigh]

do you have any 2 that are the same?

No, I don't. So far I've retrieved 3 of the steppers from 3 of the printers...I have a large, medium, and small.

The largest is a 100 oz-in stepper, a Minibea Astrosyn 23LM-C701-01. 5.2V/phase, 1.4A/phase.

The medium is unknown so far (still google searching), a Minibea Astrosyn 23LM-S047-G1. 4.2V/phase, 1.2A/phase. Considering the almost insignificant difference between it and the first one, I expect that they're pretty close in capacity. It's 20% less voltage...maybe 80 oz-in? It's a guess, but not an entirely unreasonable one, assuming that it's a linear function.

Both of these are 1.8 deg per step, so 200 steps per revolution.

The smallest is by the same company, but has an IBM part number...thankfully it also has another number, 23LQ-C202-G2V. It has no voltage or amperage specs on it, as well as having no deg/step data. IBM didn't like their motors to be well documented, apparently. By using that number, I was able to find out it has 2/3 the torque of the 100 oz-in one, so it's around 66 oz-in, and get all the voltage and amperage specs. It's around here, somewhere.

I believe you should have 2 of the same stepper for your X and Y axis.

Well, I've still got 1 or 2 more printers, so there's still a chance! :-)

Do you have a picture of the motors? Im just curious to see them.

I'll see what I can do...I've got a digital camera, but incandescent light isn't the best stuff for photos. It's an older model...doesn't have white balance.

...

Well, they seemed to come out acceptably. Now, to figure out how to post them. Hopefully it'll show, below.

If those steppers came out of regular bubble jet prints I dont think they are going to be powerful enough to run your machine.

Big ancient LASER printers...the biggest one came from a gigantic HP laserjet III commercial grade printer. Sadly, the other printers, while heavy duty, are apparently designed for home use and have lighter duty components. Not much lighter...but lighter nonetheless.

-- Chuck Knight

[WOODKNACK]

Chuck,
One of my motors is the same as your! (The largest is a 100 oz-in stepper, a Minibea Astrosyn 23LM-C701-01. 5.2V/phase, 1.4A/phase.) I too have one of these.
Do you know what your are going to use for a board yet?

[chuckknigh]

I thought these were big enough...they're nice steppers! Now, I have 1 more printer to disassemble, before I'm done. Hopefully I'll find 2 that match...otherwise I'll make do with what I have, and keep my eyes open for an HP laserjet 1, 2, or 3...they all used the same big stepper.

As to the board, I had intended to homebuild one. The circuits look simple enough, and the chips are commonly available -- can't hurt to try. As I understand it, you build 1 board for each motor (or 3 basically distinct circuits on one board), so I can build pretty much whatever I'd like.

While buying a board might be more efficient, it's definitely not as much fun!

BTW: You posted a link to eBay...these printers that I'm disassembling have cost me $25, and one is being resold to a local garage for $20. My out of pocket expense will be $5 for 4 steppers...not too bad! Definitely better than the $60 opening bid on that auction...and especially considering my budget.

-- Chuck Knight

[WOODKNACK]

Hey Chuck,
I never said what you had were not big enough! I did not know what you had. From the way you put it, it sounded like you were taken them out of bubble jet printers!
And yes sounds like you got a good deal. I just through that ebay bid at you becouse I know how frustrating it is to collect parts some times. I also found that it is just better to pay for something you find then try to wait for ever for the best deal! I guess it depends on how bad you want to build something and how good you want it to come out.
I am currently working on my 3rd machine now. I have learned alot by building the last 2 machines. I am also learning that it is better to buy the parts you really need then try to make them out of hardware store parts. Don't get me wrong in what I am saying. Im not trying to start a fight, Im just making a statement.
If you would like some plans for a unipolar board ,just give me a email and ill send you some I found off the net a year ago. It has everything you need to build it. even a list of materials.

[chuckknigh]

Im not trying to start a fight, Im just making a statement.

Wow...no hostility from my side. I'm not trying to fight. Sorry if my tone made it sound that way...it was not my intention.

And, as to small motors, remember...I only found this forum a little over 2 weeks ago, and my first question was: "Is it possible to hook up a Dremel to my old HP pen plotter?" Boy have I come a long way!

It's a testament to this site and the knowledge contained in its members and their posts. Seriously...I started knowing zero about any of this, and now I'm designing my own CNC mill.

And yes sounds like you got a good deal.

As to getting a good deal...I just delivered that guy's LASER printer, along with an extra toner cartridge, extra RAM chip, and extra paper tray scavenged from a related model printer that I took apart.

He gave me double our agreed on price, since I brought extra parts...a pleasant surprise. I've actually managed to gather parts, AND make a profit at the same time! :-) When projects go like that, it's REALLY fun!

He got a good deal, too...it was a very nice printer...one complete one out of 2 parts machines.

I live for the art of the deal -- I think it's in my genes!

If you would like some plans for a unipolar board ,just give me a email and ill send you some I found off the net a year ago. It has everything you need to build it. even a list of materials.

Now...plans for a board. This sounds useful -- I'll send you a PM with my email.

I have learned alot by building the last 2 machines. I am also learning that it is better to buy the parts you really need then try to make them out of hardware store parts.

Well, I've been "inspired" by Cranky and his harware store CNC site. Of course, person that I am, I can't just buy plans and build someone else's design -- I have to do it myself. The good part about it is that I learn a lot more that way!

-- Chuck Knight

[balsaman]

Chuck,

Those steppers will be fine. You don't need two the same, if you aren't too fussy, because you can make up for any differences in the software setup. Circles etc. will be fine.

Z should not always nessisarily have the smallest stepper. If the router will be heavy, a larger one may be a good idea. The z is the only one that has to work against gravity. If you will be using a Dremel, then go with the smallest on z.

If any of the steppers are 4 wire, they won't work on a unipolar driver. 4 wire is a bipolar motor. Unipolar motors (5, 6 or 8 wires) can be driven by a unipolar or bipolar driver.

I have 3 of the largest of your motors. Those work very well. I am sure the other two will be fine as well.

[chuckknigh]

I'm delighted to hear that they don't have to match. I was going to size them, based on the mass they move. (moving gantry design) Since I intend to nullify the weight of the milling head through the use of either springs or a counterweight, I had not considered gravity to be an issue.

The biggest would be on my longest (X) axis, and move the entire gantry.

The medium would be on my shorter (Y) axis, and move just the router head assembly.

The smallest would be on the Z axis, and be geared down with a fine pitch thread, if I can find that material locally...less movement, but more resolution that way. Or, am I just obsessing?

The medium and large motors are 6 wire unipolar units...the small one is a bipolar 4 wire. Thanks for the heads up. I'm actually keeping my eyes open for a junker HPLJ 1, 2, or 3, so I can get another big stepper...but in the meantime I'm going to go ahead with what I have.

As I understand the driver boards, they're basically a complete and discrete circuit for each axis -- I saw one design that was literally a separate board for each axis. Because of this, I should be able to implement a board for either type of stepper, depending on what I need for each one. If I implement a backplane for power, it becomes even simpler...almost literally plug 'n play.

Of course, I haven't drawn up the schematics, yet..I'll see if I can get some samples, and then I'll design around what I get. If memory serves, Allegro Micro gives samples in Qty 4...

-- Chuck Knight