CTC test print results, x-axis issue?

[etang858]

Hi Guys,

I was printing a calibration print and I have attached the results.

Software: Makerbot Desktop

Firmware: Stock version 1

upgrades: Fan and y-axis pillow blocks

Layer Height: 0.1mm

Infill: 35%

Shells: 3

Extruder temp: 205

Extruder Speed: 50

Traveling speed: 70

Two main issues:

1. Circles are not circular
2. Gaps around circles and various shapes from the rest of the body exist

I’ve read this comes from slack belts. I’ve tightened up all my belts and they are taught.

I noticed on the x-axis…

• the pulley has no set screws on it and rotates on the shaft as opposed to being connected to the shaft and rotating in the bearings. Is this by design or did CTC forget set screws? (see image)
• I can slide the pulley in the y-direction freely. It seems like they were one shim short to restrict the pulley from shifting. Again, by design?

Any tips or thoughts how to make my printers better would be appreciated!

Thanks!

[MB3D]

As long as the shaft is supported by bearings (can’t see this) then you definitely should get yourself a setscrew and tighten the pulley so that the belt is lining up with the printhead

[3DPrintingBeast]

Maybe try to resemble the x-axis. you will problem find a minor problem.}}

[Mylesrbarker]

I had this problem on another type of printer. It came down to not having the right number of teeth on the pulley. Have you replaced the pulley with a new one either on the motor or the other end? If so, check that it has the right number of teeth for your machine. The problem I had was I used a gt20 (20 teeth) on a Makerbot machine that needed a gt18 (18 teeth). This caused more travel in the x direction and resulted in oval prints in the x direction. I believe that cTC machines use gt20s but it is possible that the newer models use gt16 (16 teeth). Does anyone know? Whoever sold the printer to you may have put the wrong pulley on. Check the teeth numbers are the same on the motor and the other end.

[adamcooks]

Rep 1 and ALL clones use 17t. Rep2 uses 18t pulley. But that’s the drive side, idler doesn’t matter.

[adamcooks]

No need for a set screw, it reduces the wear on the axle cup. It should be in a straight line though.

[iCloud]

The set screw on the stepper motor has a flat surface cut on its shaft and when the set screw is loose it can cause about 0.3 to 0.4 mm wobble and cause oval circles

[iCloud]

Also there is no set screw needed for the left hand side x axis idler

[neolinux]

I have the same problem, i didn’t find any solution

[Pyr_X]

Do you guys happen to know what type of bearings are on the idler side that he posted pictures of? Mine split in two when I dismantled the x-axis to find what was causing some terrible clicking sound… Let’s just say I found the cause but don’t know what to replace it with.