Missing Steps After Filament Binding!!!

[araiza444]

Hi,

Monday night, I decided to replace a worn .5mm hot end nozzle (due to lots of carbon fiber PLA printing) with a new .5mm nozzle on my Rostock Max V2. During the replacement process, the 2mm PTFE Bowden tube wedged it self into the new nozzle incoming port. I did not realize this had happened until 3 prints later, when I noticed that the filament was not extruding as smoothly as it usually does. I dismantled the Bowden hot end, found and repaired the failure and continued printing. Since then, I have noticed that one of my stepper motors does not produce a continuous steady hum on travel after homing all axes. I suspect that the stepper might be missing steps, but never noticed this until after the nozzle issue. Also, I have had a couple of prints fail due to the hot end shifting in and out of position in the middle of the print.

I am in the process of investigating the failure of the axis motor, and have a plan down for determining if the issue is caused by motor or driver. My question to you is, is it possible that Rambo over heating due to additional stress caused on the extruder motor by the binding of the filament may have caused one of my stepper drivers to become damaged? I only performed 3 small prints since nozzle change. Also, if a stepper driver on the Rambo did in fact become damaged, can I use one of the other unused stepper drivers on the Rambo board in place of the damaged one. If so, do you guys know of any documentation for doing this?

Also, has anyone else experienced similar issues, and if so, can you please tell me how you troubleshoot and overcame the failure?

If my Rambo did in fact becomes damaged, would it be covered under a any warranty? I purchased my Rostock Max V2 last thanks giving and have only been using it since Christmas. The LCD on the machine says that I it only has 8 days of runtime.

One last thing, I may be over estimating the failure, can you give me any suggestions on anything else I should check? I am planning to test each individual stepper motor and stepper motor drivers and wiring to each tonight once I get home.

I am planning to install a couple of additional fans inside of the base enclosure, and individual heat sinks to each driver chip and of course the controllers MCU and memory chips and one on each Stepper Motor, to ensure that everything stays cool and that fresh cool air is always circulating in there.

I’m not sure if there are any better and more precise ways to troubleshoot this. Please tell me what you think. I know that there are lots of people here who are extremely knowledgeable and experienced with this printer who may have experienced something similar to this and have a solution for the problem I am experiencing.

Ooh and by the way, I have ensured that all axis belts are tight enough to not have any linear slack, but not too tight to create binding stress on the motors and my printer is a stock Rostock Max V2, with Rambo V1.3 Driver...

Thanks!

[Mac The Knife]

I'd check the setscrews for the belt pulleys first.

[araiza444]

Hi Mac, thank you for help! I checked the belt pulley set screws and they each seem to be good! I did perform a bit of motor/driver/ investigation and I think I found my problem, which now makes a lot of sense. My extruder stepper motor is what was causing my printing issues. I believe that the additional strain caused by running the machine while the filament was binding may have killed the motor.

It just jitters back and forth now when I try to drive it manually using MatterControl. It works somewhat OK when I plug it in to faster stepper drivers but craps out when I plug it in to the extruder1 port. I also tested the extruder port by connecting a different motor to it and it worked perfectly and smoothly. So, my conclusion is to double check that the 2mm PTFE tube in the Bowden end is perfectly tucked in after each and every nozzle change.

By the way, I did tested each individual axis motor and driver and now they are all working perfectly. Reinstalling all axis connections seems to have remedied my missing step situation, so I now believe that they were due to a loose axis motor connection.

I hope my findings are able help someone else.

Thanks!

[Eaglezsoar]

araiza444, great troubleshooting and I am glad that you got everything working again.
A loose connection in the any of the steppers can definitely blow a driver on the Rambo card although it is rare.
Happy printing to you!