Setting the drivers

Getting ready for the last few electronic steps before trying to actually move things. Do I calibrate the drivers to 0.5V the same as the MPCNC? Are we still flashing RC8 or should I be doing an RC7 version instead?

I think I’ve got the wiring all set, not as clean as I’d like but should be functional. I need to print the last two pieces (two brackets at the top didn’t come with my kit) then print a spool holder to mount on the top and something to mount the LCD display. Anyone have suggestions for the latter?

Rc8 works for mp3dp but the screen is kinda slow. Hopefully there is an update soon, the bugfix branch is cuasing very random erros but the screen works perfectly…

drivers, depends on what you are using. Run them and check temps half hour in to your print.

I got things moving today with each of the drivers at 0.7V, though I haven’t tested the extruder or heat bed. The endstops are working and mostly adjusted. I’m going to make sure the bed is level, slap a layer of blue tape on the aluminum and see if I can lay down some plastic. I was moving it around today using Repetier-Host, what should I be using to take an STL file and slice it into gcode for R-H to send to the printer? I need to print my brackets, then print supports for a spool holder to sit up top, and a mount for the display (anyone have suggestions for the latter).

You can slice right in repetier. I like slic3r. I put some basic print settings on the reptier page. For a printer they are pretty conservative but should get you printing easily.

I’m a big fan of my lcd case…

I found the slic3r interface in Repetier-Host and set everything except bed heat to the examples you show for the MPCNC. It estimates 23+ minutes for the two brackets vs. 13+ with Repetier-Host defaults, so should be slow enough. Once I actually get things printing I can probably start tweaking it faster.

I like your case too, but for the printer I think I want one that mounts on the printer instead of sitting next to it. It’ll be easier when I have to move things around.

Easier to move things around but I’m not a fan of mounting things on the printer…Very easy to mess things up while it’s running. If you go to mess with the screen you might see artifacts in the print or layer shift.

Things like changing out an empty filament spool in the middle of a print get even more precarious. That is the main reason I don’t put spool holders on the frame. A little too rough and you could mess up a print.

That being said, there are plenty of times I would like them mounted on the frame…


Did you follow the Pololu instructions via the youtube to set the driver up, or did you find a short cut? I don’t have a power supply as shown on the movie and I’m trying to find a short cut, or I’m willing to pay to get it done for me.

Use your voltmeter on it’s lowest DC setting, between the ground from your power plug, to the little silver potentiometer. There are a bunch of videos on this, tom did a good one.

I did a very similar process as the video, except I used the normal power supply for the printer with the Arduino and RAMPS connected but the steppers disconnected. It’s pretty easy to connect one side of your multimeter to the board ground with a clip. Hold the positive probe to the via they show in the video and turn the pot to set your voltage at 0.7V. If you follow the instructions in the video all the way you’ll squeeze the last bit of power out of your stepper, at the cost of a lot of heat you’ll have to dissipate. At 0.7V you won’t have to worry about heat and you’ll still have plenty of power to move around much faster than you really need.

Found out I either had a bad Ramps or driver. Bought a new ramps and driver, swapped out a non suspect driver from the old ramps to the position for the extruder and my skips/gaps went away.

Great! There are a few quality issues to be found on a lot of these parts, part of the ‘make it cheap’ that we all crave.