Replacing the X-Axis motor bracket
Good morning!
I just finished assembling the MK3S kit yesterday and everything worked great! Unfortunately, during my third or fourth print, I started hearing a quiet chirping noise that I hadn't noticed in the first few prints. I ran the self test again, and it reported that the X axis belt was loose. While attempting to tighten the tension on the X End motor, I cracked the plastic mounting bracket. I've just ordered a new replacement X End Motor/Idler from the store (and some PETG so I can print my own in the future).
In the meantime, I have two questions:
First, can I continue using the printer in the meantime? Everything seems to work despite the crack. The crack is on the outer, bottom edge of screw hole for the top left screw for the motor. It is the part of the plastic that is furthest from the printer frame, and all the tension is directed away from the crack towards the belt and frame. I am still able to screw in all 3 screws into the motor, the motor feels firmly mounted, and the printer passed a self test, and seems to be printing fine. I've just printed a new 3DBenchy and the Gear Bearing from the SD card, and both prints seem fine. The 3DBenchy looks pretty much identical to one I printed before the crack, and the Gear Bearing looks clean and rotates freely.
Second, once I get the replacement piece, how do I remove the X axis rods from the motor and idler? Inserting the X axis rods was the hardest part of the entire kit build, they were really hard to insert and required about 30 minutes of very careful tapping with a hammer. They are in there REALLY tight. I don't know how I will remove them from the motor bracket that has the crack. Any suggestions?
Thank you!
RE: Replacing the X-Axis motor bracket
To answer your first question, yes, you can print with a crack. My y-axis Mount cracked when I was building the printer and it still worked just fine. To answer your second question, you could try carefully hammering the printed parts off the rods, but that sounds very risky. I’d have to check, but there might be another way to get the rods out without taking out the rods.
RE: Replacing the X-Axis motor bracket
easiest way is to take the bare x axis ( rods and ends only - no carriage) and holding the 2 x-ends gently rock the ends in a twisting motion while pulling the apart. they should slowly separate and then you can chuck the open end of a rod in a hand drill and spin it out of the other end at low speed
RE: Replacing the X-Axis motor bracket
Hmm. Will the smooth rods fit in a drill that way? Interesting idea...
I was talking with someone about it, and they suggested using a bar clamp/spreader. First reverse it to work as a spreader and exert pressure to separate the parts and pull them off the rods, then flip it back to the clamp configuration and use that to seat the rods in the new part rather than hammering. I was going to give that a try. Is there any reason that wouldn't work?
One challenge is that the outside edge of the X-axis motor bracket isn't flat but has the L shape and an angled interior edge, so there is no good flat surface to put pressure against. I was considering printing a piece that would fit with the X-axis motor bracket like two puzzle pieces, exactly matching the interior surfaces so force gets distributed pretty evenly, and with a flat outer edge to clamp on (or hammer or push on) without damaging the actual part. I'm new to designing 3d objects, so I don't know yet how easy or hard that will be.
RE: Replacing the X-Axis motor bracket
You'd need to ensure the clamp applies force at the exact center of the two rods, otherwise it will wrench and crack the housing anyway. Seat the rods one end at a time to ensure they all fit and hit bottom. Then insert the pair into the idler end, make sure they both are bottomed out. Then insert the loose ends (extruder bearings attached) into the motor end. Apply force to set the rods.
I used my hands, and a very small twisting wiggle to do the final push to seat the rods. They are a tight fit, but not a pressed fit. If you need clamps, something else is wrong.