Geeetech

After lots of calibrations, I feel I have my system working pretty well. I haven't done any dual extruder printing yet. But I have printed several detailed pieces with good results. I still get a little stringing, but a little sandpaper takes it right off.

So my issue is with a large piece that I have tried to print. The print job takes a little over 10 hours to print. Around 3/4 of the way thru the print, the second extruder starts hitting the left side of the piece. After several layers, the second extruder breaks the first layer bond and then the whole piece moves. Why would the second extruder be fine thru most of the print, but start touching around 80mm high?

the picture is too big to see the whole of it...maybe is the stringing thing or bad print quality in the previous layes like bending that collision with the second nozzle and changed it's coordinates. How about increase the retraction length and speed a little to reduce the stringing?

I will try changing the retraction and speed. The strings really aren't the issue, it is when the second nozzle starts hitting the piece.

these two hotends, have you leveled them?

So after more calibrations, things started working well for one piece. After that the printer started having issue around 13mm in height.

When I home the printer and let it sit there for awhile, the print head will release and go back down to the printing surface, or at least it used too. Now the z axis gets stuck on the way down. Something is wrong with the z axis motor and it is getting stuck going up and down. I removed the belt and put it back on. I loosed it up a little also. Nothing is helping the z axis motor from working properly. Is the z axis motor bad? How can I can a replacement, I ordered this from Amazon?

You can check the followings,maybe you can find what cause this issue.
Firstly,check if the smooth rod and threaded rod are crooked,or get some defect on them.And you can paint lube,then check if the Z moving can work normally.
Secondly,Measure the voltage of the driver board, normally the value should be 0.8V-1.2V, you can put the red probe of multimeter on the potentiometer, and put the black one on the GND.
If the voltage is too low or too high, the step motor will not work stable. It will lose steps or vibrates, sometimes too hot. You can rotate the potentiometer on the driver to adjust the voltage to about 1.0V and see it if works.
Hope can help you!

Meanwhile,you can refer to this Link.
http://www.geeetech.com/forum/viewtopic ... 13&t=17038
maybe can help you.

OK after some more reading and testing I found that the diagonal rods were different sizes. I heated one end and adjusted them to be all the same. I then changed the firmware to have the correct rod length. I then went thru the whole process of leveling, homing and adjusting again.

What I find is that the second hotend is slightly higher in position 1, 2 and 3, but in position 4 the 2nd hotend touchs the plate before the 1st hotend. I have the 2nd hotend higher so I can get the printer adjusted, but why is it hitting in position 4? This is the reason why I am having issues printing anything, the second hotend starts hitting the project when it gets over towards the 4th position. Is there something in the firmware that needs to be adjusted?