Azteeg X3 pro and stepper motor questions

I just purchased an Azteeg X3 Pro controller board which has 8 stepper drivers on the board. I haven't gotten yet but wanted to start researching and planing.

I'm planing on retrofitting a Z corp powder printer with this board and a double head extruder. The x and y axis use one stepper, and one each for the extruders. The Z axis uses four steppers, one on each corner of the bed. Total of 8 steppers. Since the board can drive 8 steppers, can I synchronize 4 drivers on the board to drive the z axis steppers?

Tim

If you trust the step signals to be synched, you could do that. Also the may be other ways. I think the old darwin reprap printer had a belt engaging all 4 corners of the Z, maybe you can use something similar. Otherwise you can check stepper coil resistance, if its low enough like ~ohms then you can even tie 4 motor coils in series and get a total 4ohms which could be manageable. You could also use one paralleled step/dir/en and with just one of each you could drive 2-4 steppers drivers, e.g. same command for all.

I have a question just out of curiosity, what is original main uC on the Z corp printer, and at which Mhz it works?

When you mention uC do you mean micro controller?

I'm not sure of all the details of the printer since it's at work so I would have to take a look at it on Monday. From what I'm told it uses a 386 motherboard, that was replaced a few years ago, I'm not sure of Mhz . We may scrap this. There are two other boards in it, one looks like a 3 axis stepper driver.

I'm not sure I could tie all four motors to one driver. The motors are a 23 frame size and my guess is they are about 2-2.5 amps each. I'll have to crawl into the cabinet with a flash light to check. The bed size on this printer is 20" x 30" and the Z is 18". It has a 3/8" aluminum main plate that another 3/8" aluminum plate drops into. We have one more powder print this week and then we're going to start cleaning it, then taking all the stuff off that's not needed and readying it for the extruders. The extruder should arrive in another 2 weeks.

Edited 2 time(s). Last edit at 02/22/2014 11:49PM by Schultz.

Hi yes, microcontroller. If it does use 386 then we assume its has some storage device, first of everything make sure you make a backup copy of that

If you put motors in series it will not need more current, still 2-2.5a for all of them because same current goes through all. But they just add their coil resistance, so resistance has to be low to start with. Might depend on the power supply also, but i think that to be a good one. But it might be better to have just 1 motor for z, with a continuous belt with 4 pulleys. However i think it might have servo motors instead of steppers, and servo drivers may have controls other than step/dir/en, in which case i dunno if there is a reprap firmware to drive that.

If i understand correctly you want to scrap an old, but otherwise working z-corp powder printer into a reprap. That has to be a first, please document it somewhere with picture and so. It would make such a great read.

Yes the 386 does have a hard drive with it. We will be sure to check out whats on it and back that up.

The unit has two power supplies: one for the computer mother board and one 24 volt for the what I'm assuming drives the motors and controls. I hope it's not servos since that would cause more work than I was planing. If it is then I'll be looking for some steppers and likely new lead screws. The ones on it have through the motor lead screws. However I could nearly double the z axis travel by not using linear actuator type motors. If I do have to replace them I'll likely take the single motor and belt option. Now you have me wondering if the x and y are servos too, since it seemed rather quiet and not the buzzing sound that steppers tend to make. Also I noticed x and y motors have an extra set of wires which I assume is an encoder, but it could be a brake too. On Monday I'll get the numbers off them and find out for sure what they are.

I'll be sure to take some before, during and after pictures and post them here.

If there are servos, IMHO leave it as is, i dunno of any firmware that will work with servos. In such for a big and heavy setup changing motors may result in drastically low performance and accelerations and if that happens may not be worth to make conversion to a lower performance setup. Besides, you could probably ebay it if its working and get quite a few repraps in return - just an opinion or a thought.

I was assuming there wasn't any value left in a ten year old printer, especially a powder printer where the models have to be de-powdered, dried, and then resin coated before you can do anything with them.

You are the judge of the value for yourself, but if it is in working condition, for me at least it would be quite nice to have something like that.

Well it was bugging me so I stopped by work and I was wrong on the size. They are 34 frame size, 4 amps each, .55ohm/phase. So they are much larger then I first thought. The X and Y appear to be 24v brushless DC motors with a 11:1 gear box and an encoder. I haven't been able to find the model number on the PIttman website.

I can easily replace the dc motors with steppers. I think they used DC for the speed on these two axis, the head zips around pretty good. For the Z axis can I just get a higher current driver and send step and direction to that from the Azteeg board?

Does anyone know how to use the DC motor and encoder with a reprap type board?

DC servos have typically much higher torque than steppers, and now a dc servo with a gearbox, that will be hard to replace with a stepper at comparable dynamic torque, you would have to go much much bigger size steppers to get that kind of torque, thats what i meant.

To use a typical reprap firmware with a servo, you would need a servo driver that accepts step/dir/en commands, that is not typical but there are some. See the original drivers input if there is "or pulse" and "en/dir" on labels, it could work directly.

There are also some "hybrid" servos, which are a stepper motor with an encoder and a driver that takes encoder counts, so it is also some sort of a closed loop system. Also just a wishful supposition, those too can be worked as is.

Edited 1 time(s). Last edit at 02/23/2014 06:12PM by NoobMan.

The phrase that comes to mind: Well if it were easy, everyone would do it!

I did find the motor on the Pittman site. Its a brushless DC that runs up to 6000 rpm, with 30-50 oz/in of torque. When coupled with the gearbox it can produce 224 oz/in of torque. To equal that in a stepper I would have to have a NEMA 23-34 with current ranging from 2.4-3 amps. These motors as you mentioned are much bigger. Looking at stepper dimensions I would estimate it about twice the diameter and length for the same power.

I will look to the controller board an see if I can make sense of it and use it along with the controller I'll have this week.

You mentioned that there is some firmware that does work with servos. If are able to point me to it that would be very helpful.

Huh, what i said in post no. 2 is that i dunno of any firmware that works with servos. I suppose it could be done, just i dunno of any, but have not looked for that either, so check it. On the other hand what i said in the previous post was a little different, and more suppositions about the motors that you have in that printer, for example if those servos were hybrid servo, those are with stepper motors instead of dc, which case would nice and happy because you could work directly with those.

just a comment
There are many servo drives out on the market that work on step and direction inputs the same as stepper drivers. just a thought