Tuesday, 6 August 2013

Stepstick re-design

The Pololu stepper motor driver carrier and the open source Stepstick are pretty ubiquitous now as stepper driver daughter boards for a wide range of 3D Printer controllers. The Pololu driver has gone through a few iterations and the latest Allegro based version is the "Black Edition" which we have been supplying for some time now. It runs significantly cooler than the older version but is more expensive.

At the same time there have been a number of variations on the Stepstick theme but these have either had a bad reputation for poor quality assembly or have not had the designs published and so were not open source.

In the quest to continue to reduce prices while keeping high quality I decided to redesign the Stepstick to use an A4982 on a 4 Layer, 2Oz copper PCB (same as the Pololu Black Edition), aiming in the design to maximise heat dissipation. At the same time I have incorporated the design changes recommended by Nophead to fix low current microstepping issues and also increased the range of current supported by the Stepstick to the full 2A that can theoretically be supplied by the A4982 chip. Schematic is below:



I have had some prototypes made and initial testing is very promising: They run a mendel 90 fine with no heatsinks, where the original Pololus on that machine needed heatsinking.




There is further testing to do and I will post an update on that shortly.

Update:  Thermal test results are in! : Stepper Driver Thermal Testing

Now available on our webstore as well as eMakershop and eBay

No comments:

Post a Comment