[Makerbot Replicator 2x] Where did this part fall from?

[jonjong...@gmail.com]

tldr: I need your guys' help identifying what part this is and where it goes.



Hi everyone. Earlier today I noticed that my bot has started to print inconsistent circles. They're coming out oval-like. As recommended, I tightened the x-axis belt. After loosening the 4 screws attached to the motor, this part fell out. It looks like a pin/dowel/barrel of some sort. Can't seem to find out what it is and where it goes. Out of curiosity, I ran a test print and while I'm still having inconsistent circles, the printer is able to print. Anyone know what it is and where it goes?

While I'm here, anything else that might address my circle-printing issue? I've already checked the allignment of gantry and tightened the x and y-axis pulley and belt but this hasn't helped.

[Daniel Newman]

On 20/02/2017 4:45 PM, jonjong...@gmail.com wrote:
>
> tldr: I need your guys' help identifying what part this is and where it goes.

roll pin.... I didn't even have to see the photo to tell you. It's a design
flaw actually since it can cut the cable it is attempting to secure....

See, e.g.,

https://www.toybuilderlabs.com/blogs/news/13039525-replicator-2-x-axis-jitters

and the discussion it links to. IIRC, that roll pin was in part of the X carriage.
(I removed mine as soon as I realized that it was there... that nearly 5 years
ago so my recollection is vague.) But you can search more on Replicator 2 roll pin.

Dan

[jonjong...@gmail.com]

Right on the money. Going to leave it out and go with the zip-tie mod. Thanks for your help!

Any suggestions regarding my other issue? Circles have recently started coming out ovular.

[Jetguy]

The backlash fault (lost motion) comes from either one of 2 known faults on that model.
The first place to check is the short belt between the Y axis motor and the upper jackshaft. That motor is on the back wall of the printer and just loosen the 2 screws and move the motor down to tighten that short belt. That is the Y axis.

X axis has a totally different fault, On the replicator 2 and 2X, the the known fault mode of failure there is the belt clam section of the extruder carriage warps from heat from the heater blocks nearby. This causes the belt to no longer be gripped tight.
This is a much harder fix and requires a replacement carriage or a creative way to clamp the belt again. I would NOT glue it as if the carriage already warped, better to replace it.
Also the X axis belt tension is made by sliding the motor by loosening it's 4 mounting screws in the right hand side.

You may or may not be able to use a replacement X axis carriage from another brand like Wanhao or Flash Forge https://ultimate3dprintingstore.com/collections/brand-new-2017/products/ultimate-3d-printing-store-parts-department-wanhao-duplicator-4-series-dual-extruders-carriage
They use a much better clamping system on the belt, but minor mods may be required to attach the extruder cooling bar. Nothing crazy, just I think a little trim to allow the bar to sit on top as there was some tabs and I know the 2X bar is much bigger.
Or, there is always Carl's trick aluminum upgrades that solve some of this too and is compatible https://shop.raffle.ch/shop/alucarriage-dual/

Also, the X axis idler shaft and pulley on the left needs inspected and greased. If that pulley seizes to the shaft, then the shaft wrecks the slot in the left arm, and then you are stuck replacing that plastic bracket.