My first attempt at a dual head printer and print

Sadly,
It didn't turn out too well.
This is a Tevo Tarantula, updated with lots of bracing, custom bed platform and Chimera clone.


Here are my first two individual head prints. Red is left head, green is right.


With high hopes I created a two-color version of the honerable XYZ calibration cube, hopefully to show red letters in a green cube.


Yeah, not so much.
I use Simplify3D as my slicer. I watched a couple of YouTubes showing how easy it is to fuse two stl files to create a two-color print. When your printer behaves, that is. Wow, what happened? Looking at the bottom of the cube, everything looked fine and correct. Then as the print progressed it looked like "head 2" was compressing in the X axis while the Y-axis looked, well, almost fine. WTF?

Note, I had two individual prints that were fine (if underextruded), so my system is "compressing" as it moves up the Z-axis. I am wondering if I have the head one offset properly done (I measure approximately 18mm spacing in the X axis and zero in Y. Hmm, that looks suspicious. If I have that measurement off, would the error be cumulative? This is certainly what it looks like. Facinating.

Well, heck. If it were easy, this wouldn't be a very interesting hobby, would it? Has anyone seen this before and have a clue what I am witnessing?

Thanks all, just documenting a journey.
DLC

It turns out the problem is no mystery at all. I turned the printer on this morning and noticed a hesitation in the X movement after homing. Examination showed a loose pulley on the X stepper! I must not have tightened it all the way down. I am firing up another print and will report on the results.

If this works, then it is on to correcting what is obviously an under extrusion issue on both heads. These geared extruders are "fresh off the printer" so my initial steps/mm may not be fully correct yet.

[edit]
This corrected the compression issue. Tuned my extruder to give much better extrusion volume as well. The printer/printhead still delivers poor to really poor prints.I can get "ok" prints with either head, put them both together and there is no other word for it but crappy. I have done the YT tutorials on S3D for dual head printing. Wow. This program makes it really simple to create two-color prints. Sadly, my Tarantula and clone Chimera do not live up to the tutorial videos. Does anyone else have a true E3D or clone Chimera setup that works well?

On the chance that it is the printer and not the printhead, I am going to connectorize my hotend and swap in the stock one. I am using one of the Thingirob Modular X-car thing for my X carriage (https://www.thingiverse.com/thing:1438795). I will update when I get _something_ reasonable from my build!

Thanks,
DLC

Edited 1 time(s). Last edit at 06/12/2018 12:49PM by dlc60.