PSMD (Pololu Stepper Motor Driver) Triple Axis Driver

thingiverse

A drop-in replacement for the MakerBot stepper drivers that contains all three axes on one board. You can order these from my web site: http://www.tinkerin.gs/p/psmd-pololu-stepper-motor-driver-triple.html Now you can also order these from Seeed Studio!: http://www.seeedstudio.com/depot/psmd-triple-axis-driver-p-1029.html Updated: Now smaller (same height as a Gen4 stepper driver and 1/4" wider for 3X the axes), and with dip switches to configure microstepping. Also now has a motor-power-in (or 12V out) screw terminal that can be used to drive the motors on up to 35V. I need to update the files an description. See it in action here (with an early prototype): http://www.youtube.com/watch?v=8TEvwzTABEI&hd=1 And it's not mentioned or shown, but you can see it in action in this video: http://www.youtube.com/watch?v=2iGnlqBLn5s&hd=1 This board makes your steppers run at eight times higher resolution (1/16th steps instead of 1/2 steps), making it run smoother and way quieter. I based the design on the MakerBot Stepper Driver v3.0 ( http://www.thingiverse.com/thing:760 ) but with a few notable exceptions: •) I used the Pololu A4983/A4988 ( http://j.mp/pololu-smd2 ) stepper motor driver carrier board for each axis, so three of them are required for all three axes to work. (This was originally designed fo the A4983, but the replacement A4988 works great.) •) Circuitry that is already on the Pololu board has been removed. •) The CD-ROM-style connectors from the Gen4 electronics are used. I used a horizontal-mount connector instead of a vertical mount for mostly cosmetic reasons on the Cupcake, and that may have to be changed for the Thing-o-magic or a RepRap. I'll have to modify the layout to support vertical connectors if they are needed. •) This board is etchable and hand-solderable. This means that, with the exception of the thru-hole capacitor leads, none of the lead holes are used as vias. Also, traces are reasonably far apart, all of the wiring of the thru-hole parts (except the caps) is on the back, and vias (and drilling) are avoided as much as possible. I have provided the PDF I used for toner transfer. I placed the Pololu boards vertically and with nothing under them to provide a natural flow of hot air past them. This is why the capacitors are mounted on the back. If they still show signs of overheating, there are holes at the bottom to mount a 12v CPU fan to blow air up past them and provide cooling. So far, in my testing, the steppers overheat before the drivers. More info about the RepRap testing with Pololu drivers (and my inspiration) here: http://www.reprap.org/wiki/Pololu_Electronics Update 1: Oops, I forgot to post my machines.xml. Now it's up. Update 2: I added a photo of this latest revision with the endstop connectors corrected and soldered in place. I'm working on the mechanical endstops as another thing. All of the other photos are of the previos revision of this board. Update 3: I updated the eagle files with some minor cosmetic changes, mostly to clean up the silk screen. I didn't change the version because it's all cosmetic. Update 4: I have partial build instructions up on Flickr. http://www.flickr.com/photos/giseburt/sets/72157625473951054/ Update 5: I have updated the design a little, and bumped the version number to 0.5. (I've left the 0.2 files here.) It now has 6-pin connectors that should be compatible with the Gen4 electronics. It also has a 12V in/out screw terminal, and I've added more silk-screen to help identify parts and pins. The down side is that the -pin connectors made the traces really tight, and it will be more difficult to solder a home-etched version, since some traces to the 6-pin headers are on the top side. I'm sorry, I'm currently out of kits. I am in the process of having some professionally made, but I don't currently have an ETA. The good news is that they will be completely assembled, and the only soldering needed will be of the Pololu drivers. Instructions For assembly of the older (pre-v0.6) boards, follow the directions at http://www.flickr.com/photos/giseburt/sets/72157625473951054/ keeping in mind that there are a few changes from the PCB shown that are explained in the descriptions. Mount the capacitors on the back, and if you're etching a board yourself, you'll need to solder the legs on both he back and front. Those are the only place I did that. I recommend soldering all of the surface mount stuff first. It's hard to get to with the headers an stuff in the way. This is the 13 LEDs and 12 resistors if you're not doing the extra power circuitry. There are all large-pad (non-pinned) SMD parts, and are easy to solder by hand. Technically, the LEDs and their three resistors are optional, but very helpful to see what's happening. The LEDs are in groups of two, from top to bottom. Each group of two should have one oriented one way, and the other the opposite way. So, for example, the top two would be red, one oriented to the left, and the other oriented to the right. From top to bottom, it would be: Z: 1) Red Led (to the left) 2) Red Led (to the right) 3) Green Led (to the left) 4) Green Led (to the right) Y: 1) Red Led (to the left) 2) Red Led (to the right) 3) Green Led (to the left) 4) Green Led (to the right) X: 1) Red Led (to the left) 2) Red Led (to the right) 3) Green Led (to the left) 4) Green Led (to the right) Installation - once everything is soldered and checked for shorts. I put the labels as X, Y, and Z from top to bottom, but that really doesn't matter. Each of the three are independent, and you can make them whichever axis you choose, so long as all of the connectors for each axis are matched horizontally. 0) If you're installing this on a MakerBot cupcake to replace the stock drivers, remove those first. 1) Place the Pololu drivers in the three sets of female headers, with the trimpot (little screw) to the top. 2) Mount the board. On a Cupcake, the mounting holes match the tops (or bottoms) of two consecutive standard drivers. (To do: Add a photo of it mounted so this makes sense.) 3) Connect the steppers. You can at this point decide which of the three circuits (horizontally) are for which axis. I did Z, Y, X, from top to bottom, so that my stepper cables where not too stretched. The notches on the stepper cable should be toward the plastic fingers on the connector. (If you're steppers move backward, you can probably flip them, but it's better to do that in software.) 4) Connect the ribbon cables. They have notches so you can't get them backward. Just be sure that the ribbon cables are horizontally next to the correct steppers. 5) Connect the power, at the bottom. 6) Note, this changed for ReplicatorG 22. On ReplicatorG 22 or higher: Download the file makerbot (3-axis pololu).xml and move it to the machines folder of the ReplicatorG folder. Now open ReplicatorG and skip to Step 8. On ReplicatorG 21 or lower: Install the machines.xml file. (ReplicatorG should be closed for this part.) It goes into the folder ~/.replicatorg/ (~ means your home directory. On OS X, hit Cmd-shift-G and type that in, then hit return to get to the folder, since it's hidden.) Be sure to make a backup of your old one first. If you're not connecting to a Cupcake, you may have to edit the file appropriately. This file if to account for the steps being 1/16 steps, versus the 1/2 steps with the normal drivers. 7) (No longer needed for ReplicatorG 22 or higher.) Open ReplicatorG and go to Preferences and check "Show experimental machine profiles" then click Close. 8) Under the Machine menu, choose ReplicatorG 22 or higher: Driver → Cupcake CNC (with 1/16th step Pololu Driver), or ReplicatorG 21 or lower: Driver → EXPERIMENTAL - Cupcake CNC (with Pololu Driver) 9) Now connect to the machine and test movement with each axis. You should now tune the trimpots for each axis. 10) Print! Tuning the trimpots This is the same as with the standard drivers, except the trimpots are a lot smaller. 1) Turn all three of the trim pots all the way to the left. This turns them all the way down. 2) In ReplicatorG, open the control panel and click Steppers On. 3) Now, slowly turn each trimpot to the right until you can no longer move the X and Y axes by hand. Don't push real hard, you don't want to break anything. If your belts skip, then you probably need to tighten them. Be sure to push the X-axis by the middle instead of the front or back so that you don't do any damage to the rods or the bushings. When it was at the right place for me, the steppers squealed audibly, so I went past the squeal and stopped. 4) Do the same with the Z axis, except move it up and down with the control panel until it appears to move smoothly without any binding stopping or slowing it. The goal is to have them as low as you can so that your steppers don't overheat during long builds, but no so low that you gets skipped steps. If your steppers overheat, they will lose their power (and skip a lot) until they cool back down, so don't try to adjust anything until they've cooled. If you're getting skips during prints and the steppers aren't really hot, turn the appropriate trimpot up a very little and try again. If you find that the drivers themselves are getting hot, you can add a small 12v fan at the bottom of the board with some twist ties or pull ties. I recommend pointing it up to blow past the drivers and draw the most heat off. I haven't had to do this and don't know how well it works. Enjoy!