Z axis acting funny

[DaGroundZero]

I have over 200 hours on my rostock, and it was printing great up until about 3 days ago where it knocked into the print and made a birds nest. I didn't think too much about it, so i restarted the print. This time it didn't wait to mess up, it did it on layer 2. I tightened my belts and made sure all my gears were tight. I figured that I better re-calibrate the printer just to make sure I didn't get it out of whack. This is where the weird part comes in. I set it fine in the middle as per instructions. I do the Z, X, and Y. I go to print and my hot end slams to the print bed. I recalibrate and it is 1.8-2 mm too high. I fix it. I try to print, and it prints about 2 mm from bed. I kill print and try again. It goes to where it should go and starts printing. Then during the print it moves to a new position and hot end hits bed again..

In between try 2 and try 3 the power supply dies. I had an extra, so a few minutes later I have the printer working again, but still acting weird.

I did notice that a few times when I "home all" that the Z axis would not go up with the other 2. Then it would some times, then it wouldn't. The X and Y would hit the end stop, come down a little, go to the top, and then z would start coming up.

I'm turning it off for a bit, asking for help. I've not updated or touched the firmware in 90+ hours, so I wouldn't think it is anything software related.

Any suggestions?

[ApacheXMD]

Maybe double check your motor wiring to make sure it's still good? Maybe a a crimp went bad at the 4 pin connector.

I had trouble for a little while homing when the 6-32 end stop screws werent hitting square to the end stop switch. It wasnt quite as bad as 1.8mm, but you might want to verify endstop operation and consistency.

[foshon]

I would start by checking the physical connections to each motor, the z waiting to move leads me to believe there may be an issue there (or perhaps with the limit switch).

When I calibrate my center z-max, I do it seperate from the towers. I start by connecting the host to the printer and adding 10mm to the max height. Then I close the EEProm and disconnect. Reconnect and drop the head to around z30, bringing it down the rest of the way manually. When I find the paper pinch point, I home the machine, do the math, change the settings in the EEProm, close it, and disconnect again. Then, finally, I reconnect re-home and drop the head to z5, followed by 5mm in manual to verify. Then and only then do I even begin to worry about the other three.

I have experienced, as have many others, EEProm burps that result in no take over of the new data the first time around. I have yet to have a failure using the disconnect/reconnect method (so far).

[DaGroundZero]

thanks for the suggestions. I will start trouble shooting the connectors and end stops. Also, I've not done the disconnect/reconnect while homing. I will start doing that to see if that elimates any burps!

The sad part, is I just got my fan mount printed out and attached about 2 weeks ago. I put the fan on it about a week ago, and it was printing like a champ before this happened! LOL Oh well, now there is something to work on.

[JohnStack]

I have experienced, as have many others, EEProm burps that result in no take over of the new data the first time around. I have yet to have a failure using the disconnect/reconnect method (so far).

Repetier out of sync? What would cause EEProm sensitivity? Chip quality?

[DaGroundZero]

Okay. I booted my mac and cycled power on the printer. I wanted to start everything from scratch.

I checked 4 pin connectors and end stops. I started playing around with home and noticed that the Z would stop every now and again a few mm away from the end stop. Hummmm? I would home again and it would go down, and stay down, or go up. some times when it was down, and I pressed home, it would shoot up hit the end stop, then go down with all of the other arms.

I captured a video of this and I'm uploading it now to youtube.

I noticed that one of my end stop wires was moving a bit while the belt was going. so I pulled it out a bit, and rerouted it over a bit. So far, I've home about 100 times and not a single issue. I can't see a crimp in the wire, but I guess it was moving it just enough to cause some type of spike or false hit on the end stop.

I'm working on trying to calibrate my printer after jacking it all up trying to calibrate it!

Here is the link to my video. http://youtu.be/o2eWAL8Tkg4

[lordbinky]

If I remember correctly, false endstop signals have been induced by running the endstops wires along with stepper motor wires. If it happens again check how your cables are routed and separate them reasonably.

[DaGroundZero]

I will give that a look, but I think I have them routed separately from the stepper wires. I will double check.

[Eaglezsoar]

DaGroundZero, I'm glad you found the problem and it was something simple.

[foshon]

I have experienced, as have many others, EEProm burps that result in no take over of the new data the first time around. I have yet to have a failure using the disconnect/reconnect method (so far).

Repetier out of sync? What would cause EEProm sensitivity? Chip quality?

IIRC it has something to do with a setting in the firmware (and EEProm). If both are set to zero the EEProm will never take, better to set one or the other to "1" (or anything not zero). I don't know if it is something one only has to change when making a change (EEProm) or changing it once makes life wonderful (firmware). Honestly, it hasn't pissed me off enough to research it further.