Printer is Running Again!

Unfortunately, I needed the kick-in-the-butt of my Dad coming out for a visit to prompt me to tear down and fix my printer.

I pulled off the heated-enclosure brackets and lifted the bed in order to access the stepper motors, then put locktite on all the motor pulleys.

I also worked on the heat source for the heated chamber. Having two 150 watt bulbs right next to each other and inside a metal box concentrated the heat onto the top plate worse than I had realized. Here's the damage, viewed from below with the bulbs and fixtures removed:

To prevent this from happening again, I covered the bottom of the top plate with aluminum tape:

Later on, I'll clean it up and add some ceramic insulation around the bulb fixtures (I have to find it again - it got lost in my sea of stuff).

After a quick re-assembly (and some really quick calibration), I ran the file for "knurled bolt and nut", this time with white filament. All things considered, it turned out pretty well, though not as nice as the previous two I made.

All in all, it was some good male bonding, and Dad took the bolt and nut home as a souvenir!

Belt Failure

My first print with the new heated build chamber failed about halfway through with the X-tower belt broke in the middle of the night. The printer continued to run through the rest of the file, regardless, resulting in the spaghetti mess of filament in the top right area of the build plate:

Encouragingly, there was no warping on this part - the heated chamber did it's job. Unfortunately, the belt broke in a location that was impossible to splice. I had to order more belt from Amazon.

When I replaced the belt, I looked for the problem. It turned out I had assembled the toothed gear improperly on the X-tower stepper motor. The toothed pulley is supposed to be flush with the end of the shaft:

The misalignment made the edge of the toothed pulley bite into the belt with every movement. There was a nice pile of rubber powder below the pulley.

The other two stepper motors were correctly assembled. I made the adjustment, threaded on the new belt, and it's been running fine for nearly a month afterward.

Belt Tensioners

I picked up this model for belt tensioners specifically designed for the Rostock.

The first print failed because I was lazy and didn't do proper bed prep:

The second print succeeded.

I set up the print file with two cams in the center, and the tightening tool on the outside. Later, I printed four more cams (two for each tower).

Here's the tower without the cams:

And here's the tower with the cams.

I had to buy 3" #6 bolts to make this work. They're relatively hard to find. Fortunately, Lowes had them in stock (after checking Amazon and Home Depot).