Polargraph - timing belt and spring load

thingiverse

My take on a polargraph showcased at Aarhus Mini Maker Fair in October 2016. Featuring: 1) Spring-loaded bearing that minimizes or eliminates belt slip 2) Screw mount (three parts per side) 3) Suction cup mount (two parts per side). Mirror components for mounting electronics on the left-hand side. 4) PCB for two steppers and a servo, utilizing my old EggBot PCB, which I've reused and attached for Eagle I used two aluminum single suction pads from Silverline, each capable of supporting 50kg. The specifications can be found at http://www.silverlinetools.com/en-GB/Products/Automotive/Bodywork/427574. I'm grateful to have built upon the excellent work of Sandy Noble (http://www.polargraph.co.uk/) and am running the polargraph software on my machines. Print Settings: Printer Brand: RepRap Printer: RepRapPro Infill: 40% Instructions Assembly Assembly for wood: Mount bearing on arm (large hole). Mount arm on motor mount (the low stub) - ensure free movement. Insert a 20mm M3 bolt with a holding M3 nut to secure the spring into the spring arm. Add a spring for load, as it doesn't need much force, over the bolt and fit it into the groove on the spring arm. Mount motor and adjust pulleys to be flush with the surface. Mount on wood board. Mount the Arduino in a suitable holder on the wood board (for example, http://www.thingiverse.com/thing:33327 or http://www.thingiverse.com/thing:1826386 - just pick one...). Assembly for suction pads: Mount bearing on arm (large hole). Mount arm on motor mount (the low stub) - ensure free movement. Insert a 20mm M3 bolt with a holding M3 nut to secure the spring into the spring arm. Add a spring for load, as it doesn't need much force, over the bolt and fit it into the groove on the spring arm. Mount motor and adjust pulleys to be flush with the surface. Mount Arduino on right-hand bracket. Mount plate on suction cup and mount motor mount on plate. Mount two lags (with M3 nuts inserted) onto the Arduino. Assembly of gondola: Mount servo (upside down) on the two stubs. Zip tie the timing belt onto itself, making a loop that slides freely over the two stubs on the sides. You could add an 608zz bearing if you like - I didn't and it draws fine. Insert a M3 nut into the pen ring and screw in a 20mm M3 bolt. Assemble electronics: See image of electronics and follow Using polargraph firmware (http://www.polargraph.co.uk/) with these pin settings: Motor A = Left Motor B = Right Left Enable = 2 Left Step = 3 Left Dir = 4 Right Enable = 5 Right Step = 6 Right Dir = 7 Servo = 11 Connect electronics to servo, motors, PSU, and computer. Use modular wiring so extensions can be archived very easily. My timing belt is six meters long on each side for the suction pad version and around two meters for the wood version. Wires have to fit this. Play and enjoy - it's really funny...