OoeyGUI

There are 4 stepper motors on the 3d printer: one for each axis and another for the extruder. I wanted to user a motor that could be powered with a computer power supply, was under 750ma (A3967 compatible), had a small step angle and maximized the torque. I evaluated many (too many) options, but settled on the 162027 from Jameco:

This motor is 600ma, is compatible with the A3967, has a .25″ spindle which fits without modification the sprockets from electric goldmine, and has plenty of torque to handle the

                  

RepRap uses a toothed belt which engages plastic pulleys. The toothed belt and pulleys are fairly expensive and require precision gluing. I was intrigued by the idea of using ‘ball chain’ and am considering milling custom sprockets eventually. In the mean time, Electronics Goldmine has rollerchain and sprockets for very cheap – $1.25 per sprocket, and $2.50 for 23″ of mini-chain. I used 9 Sprockets and 5 sets of roller chain. They are fairly quiet and you can’t really beat the price.

SparkFun.com sells a stepper driver based on the Allegro A3967. This chip is a microstepping stepper driver capable of driving a stepper up to 750ma. It requires lots of tuning to drive the stepper correctly (varying parameters such as step frequency, current limiting via a pot, etc). It is also subject to motor noise.
I’ve been working with Zach on from the RepRap research foundation on a higher power stepper driver based on the A3977 which will drive 2.5a and is dip switch configurable for full step or microstep. You can follow the project on SorceForge. Until that project is completed and available, this combo seems suitable for light duty FDM extrusion.

§ One Response to Drive Components

• jameco reject says:

  August 11, 2008 at 9:19 am

  if you only need a few motors your ok but dont expect Jameco to have the same part next month. They got me before. I choose not to use Jameoc because you never know what you will get