Calibrating / Stepper Issues

[mvanderploeg]

I'm working on getting my printer up and running and I'm having some issues with the Z axis.

I have two issues happening: First is that the stepper motors aren't working when connected together. They work fine individually, but once they are both connected they just hum (very very quietly). I've tried the driver turn pots up to about 10 degrees, but it doesn't make a difference. I'm checking the readings with my meter today, but I'm assuming it may be a bad driver / turn pot.

Also on the Z axis. I'm having issues with the stepper motor / rod connection and the frame rod connection being at a different width than the carriage connection by almost 1/16 of an inch on both sides. The rods are plum, but the pinch points are causing a bow. I'm assuming this is just a PLA or mounting deviation, however, it is causing a pinch point on the bearing at the carriage creating friction and causing resistance in Z axis movement. (see attached image)

 

[GORDON.LAPLANTE]

It appears the top connector (holding the smooth rod) may not be fully tightened. This may bring in the rod slightly. I can change the top z-axis stepper motor bracket so the 4 diagonal slots are turned to run left/right. This would allow for slight adjustment in moving the motors back and forth and alleviate any pressure.

Once you replace the stepper driver let us know if you are able to print the new z-axis bracket and we can upload it.

 

[mvanderploeg]

Gordon,

Thanks for the reply. I tested the driver and it was bad so I replaced it with the spare extruder driver and it works fine now. The screw wasn't tightened all the way, but that was because I was working on it when I took the picture. I ended up shimming the bearing with two pieces of paper and it seems to be true enough now.

On another note, I'm trying to trouble shoot a slanted print issue. I'm working with the cubes and have gotten the layers, and extrusion rate really quite good. However, my print is at a consistent slant in the Y direction. (See image) Any ideas? I've worked with the driver current, but that hasn't had an effect.

Let me know if you have an idea.

Thanks!

 

[GORDON.LAPLANTE]

Researching the problem now...

Make sure your y-axis belt is tightened and its not skipping as the bed moves back and forth.

Its possible you have yet another bad stepper driver and I would hate for this to be the case. The link below had the same problem and this was the solution. We can send you one to replace it with.

Since it's a very regular skipping pattern I think its something in the gcode file or the electronics.

Same issue:
http://forums.reprap.org/read.php?1,238008,238041
http://www.kaosat.net/?p=1490

 

[GORDON.LAPLANTE]

I'm working on getting my printer up and running and I'm having some issues with the Z axis.

I have two issues happening: First is that the stepper motors aren't working when connected together. They work fine individually, but once they are both connected they just hum (very very quietly). I've tried the driver turn pots up to about 10 degrees, but it doesn't make a difference. I'm checking the readings with my meter today, but I'm assuming it may be a bad driver / turn pot.

Also on the Z axis. I'm having issues with the stepper motor / rod connection and the frame rod connection being at a different width than the carriage connection by almost 1/16 of an inch on both sides. The rods are plum, but the pinch points are causing a bow. I'm assuming this is just a PLA or mounting deviation, however, it is causing a pinch point on the bearing at the carriage creating friction and causing resistance in Z axis movement. (see attached image)

I redesigned the z-axis motor bracket by turning the diagonal slots to be left/right. This way you can adjust the motor if the z-axis is binding. Just tested it on one of our printers and I'm getting nice z-axis movement now. We will upload the file for others to try if they have any similar issues.

 

[dreadful]

I'm working on getting my printer up and running and I'm having some issues with the Z axis.

I have two issues happening: First is that the stepper motors aren't working when connected together. They work fine individually, but once they are both connected they just hum (very very quietly). I've tried the driver turn pots up to about 10 degrees, but it doesn't make a difference. I'm checking the readings with my meter today, but I'm assuming it may be a bad driver / turn pot.

Also on the Z axis. I'm having issues with the stepper motor / rod connection and the frame rod connection being at a different width than the carriage connection by almost 1/16 of an inch on both sides. The rods are plum, but the pinch points are causing a bow. I'm assuming this is just a PLA or mounting deviation, however, it is causing a pinch point on the bearing at the carriage creating friction and causing resistance in Z axis movement. (see attached image)

@Gordon
I believe his pictures might show a dimensional inconsistency with your models. I don't actually have my printer yet and his pictures may show a more dramatic bend, but I've been remodeling the gMax in SolidWorks and I do measure a ~1mm difference from center to center between the z-axis brackets and the x-axis carriage.

If you look at the pictures, the z-axis parts are designed at 30.956mm [1-7/32"] while the x-axis carriage is at a beautiful 30mm even. This might be why the acme rod and guide rod are bowed. Although I wouldn't think 1mm difference would show up so well in a photo.