Here's the deal, I have 2 cannon 6000 bubblejet printers and 1 4100 bcj of the same make. My querry is as to whether the print head carriage motor (being a discreet stepper motor) would be able to handle and/or be useable as the x/y/z axis feed drives for something that would be using a Dremel as the powerhead. (I know we are't talking anything as industrial as the Uber Router) and if this is possible, where could I find control boards for them or how would I be able to make my own pc interface/controller/positional feedback boards. Please! any and all comments and/or satirical jabs wanted.
Well, I have for some time been collecting old printers to make some of the same attempts of a x/y table, but something else always seem to come up. Like, the last 18 months I have been deeply involved with setting up a combined TV, Telephony and Internet network for the app. 2000 people living in the buildings around here. And the last 2 months I have been sick with the flue, and head cold and what have you not. Anyway, here is what I have been thinking about. The driver chips for the stepper moters are already there, in the printer. So maybe it would be possible to locate them and reuse them Oherwise one will have to build a driver circuit for the stepper moters. I basically have that under control, as I already have a couple of H-bridges all ready that can handle different Amps. As for microcontrollers to run the whole thing, I already have some experience with AVR MCU's, and have made several serial <-> MCU interfaces. Is this the sort of info you are looking for? Alvin
You wouldn't normally use a H-bridge for stepper motors Alvin. Just 4 MOSFETs and a uC, or just a stepper motor driver/translator IC would do. I would think that those motors would only have enough torque to move the dremel in horizontal plane. To lift/lower the dremel you'd need to gear the stepper down somewhat.
About the driver for the stepper motor, all I'm saying is with the right transistor a driver can be made quite easily. MOSFET's would probably be smarter, but I have no experience with MOSFET's (yet). They also seem to be more expensive than say the BC438/BC437 or TIP120/TIP124 transistors. You are probably right about the stepper motors for the Z axis, but then one could just use some hacked servo motors or something like that, to increase the torq. So SteveyG if you have schematic for stepper drivers, will we see them? Alvin
So Wicked Li'l Bender, I suppose this is the awsome Uber Router that you are refering to? With this being the Uber Router Little Brother Doing a search here at Bit-Tech, I found that this guy may have the driver boards you need http://www.hobbycnc.com/ Hmmm..... looking at this page http://homepage.ntlworld.com/gloomy-place/cncold.htm it may be that beltdriven stuff is just not powerfull to do any metal routing. Thinking further down the line, maybe it could be strong enough to hold a lazer, for simple lazer cutting. Alvin
Thank you for your quick responses. and Yes big Pappa Kong is my insperation in all of this. As for the printer steppers, I think that a reduction pully system to drive the axis would allow the smaller steppers to power the shafts without too much problem. those steppers do have a bit of Umph! just see how big the cannon print head is and then watch how that motor slings that thing back and forth... that whole assembly moving makes my printer stand sway back and forth... So mosfets, Uc's and digital interface for the pc... anybody (obviously more experienced than me)feel like tackling the logic circuit and or helping me to get some of the electronics worked out? Remember, I am not trying to reach insane power and speeds with this... just a smaller version that can cut alu and mild steel with a dremel.. I am not expecting the head unit to break sound barriers! And again, thanks for the input... keep it coming! (Maybe Kong himself will get dragged into this thread!)
I've been parting-out printers for about two yrs, slowly approaching my goal of a fully automated Unimat. The steppers are more than strong enough to drive the bed through aluminum cutting, and seem to handle steel okay as long as I keep the feed rate low (am using a 7 to 1 reduction gearset from one of the printers). Picked up one of these control boards last year to interface to an old PC, but haven't added it to the cluster yet.
Ive been looking online at stuff about micro-stepping of steppers, and that could help out with your precision, along with the gearing down. With microstepping, and a properly coded µC you could get very high resolution. From what I understand, you put a current sense resistor in series with you FET/transistor ( I would think that you could use the Rdson of the FET if it remained constant enough) take the voltage from that run it to the - on a comparator, and hook the + lead of the comparator to a DAC which the µC controlls, and it will "chop" and keep the current in the stepper limited to what you chose. More voltage from the DAC=more current through the stepper. Letting you pause between where the steps would normaly be. I've wanted to make a robotic arm to help we with soldering of small SMD packages. I too have been eying up inkjet printers with ideas in my head. Also, from what Ive seen you wouldn't want to pay for an stepper motor controller board, it may be worth it to make your own. And, you would only need an h-bridge for a 4-wire stepper. With 5,6, and 8 wire motors, you can get away with a single FET for each phase. meh enough rambling, just seach for "homemade stepper motor controller" and "stepper motor schmatics" you'll get loads of stuff.
