Sunday, September 19, 2010


So with the printer shelved until either I find a fix for the relay problem, or makerbot releases a fixed firmware update, I'm back to working on my Mantis 7 DIY mill. I originally started this project in hopes of making the pcbs for the reprap that I couldn't order from makerbot, wasn't practical to send out for fabrication, and my own prototyping. The mechanical building had some small issues but I eventually got those solved out. Then came the electrical/computer parts, I chose the brute force stepper driver from the Mantis 7 Wiki but when I hooked up the design nothing happened. I tried running through it to find shorts and whatnot but couldn't find much. I then ordered a probotixs breakout broad to avoid the hassle and possible shorts of wiring my own port to individual wires. I then made boards that were controlling a single motor per board and hooked those up through the terminals on the probotix board. Again things didn't work and I didn't know why. Next I ordered a unipolar stepper driver board from probotix, and hooked that up to the controller board and the motor, still nothing. According to the original plans from mantis I was using a 12V DC external power supply to run the system. Well after picking up the project again and trying to find if all the connections worked, I noticed something that I had overlooked. What I had overlooked was that the stepper motors were only needing 4V and 1.2A, the spindle motor was the only thing that needed 12V dc, and one reason things weren't working is that my motor coils were completely saturated so there was never a change in coils regardless of what signals were sent from the controller board. So now I have to wait for the coils to de-energize completely before I can try anew without the external power supply to see if that works. I guess it would have really been helpful if the mantis site had a BOM including steppers so that everything was on the same page or if needed to be tweaked had some sort of base to calculate from. Ah well, just another day to learn things.

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