Rostock Max V2, z tower "sticks" on first print

[dbroome]

My son finally made it through the assembly, we debugged the wiring a bit and got everything configured. Inside Matter Control we ran the PID auto tune, did the z-height calibration and even went through several iterations of tower calibration. Everything works well. We can home all three towers, use the manual controls to move it any which way we want. No issues in movement at all.

However, when we load the fan shroud to do our first print, things get weird. The hot end and bed warm up as they should, the screen changes to "printing" and the head begins to move down towards the bed. About 5-6 inches down, the z tower just sticks, and it makes a clicking noise. Like maybe the belt is slipping? x and y seem to be moving fine.

We cancel the print and can immediately use the manual controls to home and move up and down with no hiccups, skipping or anything.

Anyone have any thoughts on what could cause this and how to troubleshoot it?

[Tincho85]

Can you extrude filament? What material and temperatures are you using?
If you manually push it, does it take too much force?

Also, what are you travel move speeds?

[joe]

Take off the arms from the cheapskates and run the print again. This way x,y and z can move independently and you watch/ listen easier. You could have a mechanical bind that won't show up until the hotend and fans are on, reducing the current to the stepper motor slightly. This would cause clicking from the stepper as it is skipping steps. Also while the arms are disconnected move the z up and down-( with power off) as well as x an y to see if it feels different. Move them slowly when moving manually so it doesn't damage the rambo.

[Tincho85]

Oh... z TOWER, not z coordinate, I misread it and thought the noise was from a clicking extruder

[dbroome]

Thanks for the suggestions guys. I have removed the arms and tried the print. The z tower stopped at about the same point. I'm going to let it cool down and I'll try to manually move them and post back tomorrow. A mechanical bind may very well be it. If I can't get it, I'll post a video that will show what is happening better than me trying to describe it.

Oh, and it is extruding. We are using ABS at 228 and 80 on the bed. No fans are running, as we are trying to print the shroud.

[dbroome]

After checking thoroughly and determining there was not a mechanical bind, I figured it had to be electrical. The only think I could think of that would make the cheapskate just stop like that was the end stop. I noticed that the manual movements I was doing was slower than the "fast" drop they were doing. I opened the advanced settings and changed the speed of the non-print movements from 300 to 100. That fixed it.

Is it possible there was some electrical interference that caused the RAMBo to think the end stop had been hit? I hate not knowing for sure what caused the problem, even if I am printing now...

[Windshadow]

Did you twist each of the end stop wire pairs? Were you sure you only had end stop wires in one of the towers (did not run them dow the extrusions wit any of the other wiring) Did you make sure the they crossed or were crossed by any other wires on the top plate by as close to 90° as possible ? they are prone to receiving spurious signals if they run next to other wiring in parallel and are not twisted.

[geneb]

It wasn't the end stop - your rapid travel speed was just too high. You can bump it up in increments of 50 until it misbehaves again and then back off 25 until it starts working properly.

g.

[dbroome]

They are by themselves in the tower, but it doesn't look like they are twisted. Maybe they picked up a signal when the exit the tower at the bottom. I'll unplug them from the RAMBo and twist them that way.

The 300 number was the default value it came with. It seemed fast to me when it went, but would a default value be too fast for the printer to work reliably?

Either way, thanls everyone for the help. We are up and running. You should have seen the crowd of family around it while it was printing the shroud. My 88 year old grandfather just stared in amazement for 30 minutes...

[geneb]

It's up to MH to change the default value and they haven't done so as of yet.

g.