Rostock MAX print issues

[Blade-Breaker]

HI this is my first question of many I am sure. I just put my Rostock together and went through all the calibration steps. One problem I am having that I can not figure out is that during a print it looks like it shifts over to one side. It is very consistent in that it always goes towards about the midpoint of the X and Y posts. The part will be printing and all of a sudden it will be printing about one width over from where it should be. At the same time it may also not be going up the correct height it should to go to the next layer. Once it does this it will print fine for a while or even the rest of the print. But most times is will skip over once or twice in a print. I have attached a picture of what is happening. Is this a mechanical issue?

I am printing ABS extruder temp 220 bed 80.
Checked all the arms and they are swinging free on both ends.
Belts are tight. I tightened them more than what I thought was needed the other day to see if that was the issue.
I did adjust the print radius as described in the instructions and that worked out well ( I think ) I did this when the bed and extruder were at temp.
I just checked all the bearings and they are all snug and look fine.

There is probably something I am missing but it just seems to random to be mechanical. I have been printing the test cubes to dial in the wall thickness and those turn out great!! My kids wanted a cone and I printed that out with no issues.

Looking forward to any help you can offer.
Ryan

[Eaglezsoar]

[quote="Blade-Breaker"]HI this is my first question of many I am sure. I just put my Rostock together and went through all the calibration steps. One problem I am having that I can not figure out is that during a print it looks like it shifts over to one side. It is very consistent in that it always goes towards about the midpoint of the X and Y posts. The part will be printing and all of a sudden it will be printing about one width over from where it should be. At the same time it may also not be going up the correct height it should to go to the next layer. Once it does this it will print fine for a while or even the rest of the print. But most times is will skip over once or twice in a print. I have attached a picture of what is happening. Is this a mechanical issue?

I am printing ABS extruder temp 220 bed 80.
Checked all the arms and they are swinging free on both ends.
Belts are tight. I tightened them more than what I thought was needed the other day to see if that was the issue.
I did adjust the print radius as described in the instructions and that worked out well ( I think ) I did this when the bed and extruder were at temp.
I just checked all the bearings and they are all snug and look fine.

There is probably something I am missing but it just seems to random to be mechanical. I have been printing the test cubes to dial in the wall thickness and those turn out great!! My kids wanted a cone and I printed that out with no issues.

Looking forward to any help you can offer.

Quite often this type of problem is caused by EMI. What happens is the endstop wires are routed to close to the stepper motor wires and noise is induced into the endstop wires.
See this thread: http://forum.seemecnc.com/viewtopic.php?f=37&t=1614 The fix is near the end of the thread.
Ensure that you do not have your endstop wires running near the motor wires. Many times users will run wires in the hole the uprights have and they run the motor wires and endstop
wires in the same upright. This should never be done. Check your wiring and do what you can to separate the endstop wires away from the stepper wiring.
Another possibility is the cheapskates are not adjusted properly and the friction causes the shift in layers that you are seeing.

[geneb]

You might also want to inspect your belts - a badly damaged tooth might do this as well as a cracked drive gear if you've got one of the older plastic gears with the metal core.

g.

[Blade-Breaker]

Great suggestion. I do have my extruder motor wires running down the Z post. They are not going through the hole but are on the outside under the bearings but still could be close enough to be causing this. This may explain why it always goes away from the Z. I will move the wires and see if it changes.
Thanks for the reply.

[Blade-Breaker]

You might also want to inspect your belts - a badly damaged tooth might do this as well as a cracked drive gear if you've got one of the older plastic gears with the metal core.

g.

OK I will take another look at them. I do have a newer kit that I just received about 2 weeks ago. The pulleys are all metal. Last night I was watching each belt and pulley and did not see any problems.

Thanks for the reply.

[geneb]

Ah, ok. The new gears won't crack. (If they do, you might want to check to see if your house is still standing. )

Take a peek at the wire management outline I did in Appendix A of the manual - it's a pretty simple way to keep a handle on the stepper, hot end and accessory wiring.

g.

[Blade-Breaker]

Thanks for the help everyone. It looks like that cured it. Now to try and figure out next 1000 things. FUN!!

[Eaglezsoar]

Thanks for the help everyone. It looks like that cured it. Now to try and figure out next 1000 things. FUN!!

So what do you think cured it?

[Blade-Breaker]

Thanks for the help everyone. It looks like that cured it. Now to try and figure out next 1000 things. FUN!!

So what do you think cured it?

Sorry I guess I did not explain. The only change I made was to move the wires for the extruder motor away from the Y post where they were. I have not had that problem for a couple hours now. The wires for the switch are still inside the Y post. Must have been the EMI.

Again thanks for the help everyone.

[Eaglezsoar]

Thanks for the help everyone. It looks like that cured it. Now to try and figure out next 1000 things. FUN!!

So what do you think cured it?

Sorry I guess I did not explain. The only change I made was to move the wires for the extruder motor away from the Y post where they were. I have not had that problem for a couple hours now. The wires for the switch are still inside the Y post. Must have been the EMI.

Again thanks for the help everyone.

Glad you got it working. That's a common gotha that is really hard to diagnose because of its randomness and most people do not
think about EMI when wiring. Happy printing!