New KITTAZ, Y axis tips, excellent prints

Finished building my first KITTAZ over the weekend. This is my first go at 3d printing, and I’m very happy. It’s just gotten through it’s sixth part. All of them are ABS and have succeeded. Here’s a 0.14mm layer rocktopus

. Only print issue has been my first two coming slightly unstuck, and this is nothing more than me getting used to how much Lulzjuice to apply to the bed and the concentration of ABS in the acetone. They rocked a bit back and forth, but stayed stuck enough to finish. Since those first two, thanks to more juice, everything has stuck solid, but also been no problem to remove. <3 Lulzjuice. Here are some things I found along the way.

The kit was missing 4 M5x14mm SHCS and 2 M5x14mm thumb screws. Lulzbot support responded the same day and is shipping the missing parts. In the meantime, I was able to find M5x16mm at a local store (they didn’t have 14mm), and used these along with some additional washers to take up the extra length. Easy fix.

During assembly i had to file out the slot of the filament idler where the bearing goes. I was scraping ABS trying to get the bearing in. A bit of filing, and all fixed. Like another forum post suggested, I used channellock pliers to squeeze the idler shaft into the printed ABS part. Alternate from side to side to squeeze it in evenly. This was also my first time manhandling parts that were 3D printed, so it took some getting used to. They’re strong. I had to remove flashing from all the holes for the 10mm rods. Also had to file the corners of the pads on the Y-axis frame mounts that fit into the extrusion channels so that they went all the way down into the channel and sat flush against the extrusion. I had to try different spacer washers on the hobbed bolt a few times, since tightening it down changed the alignment slightly.

Biggest unknown for me was how stiff / tight to make the Y axis bed travel. It’d be good to have a spec for the force needed to get it moving before attaching the belt. It took some fudging to get the two 10mm rods aligned and parallel so that the bed traveled smoothly with uniform tension across the whole travel. In the end, I came up with these steps:

With the Y bed assembled, before installing the belt:
Loosen all M5 bolts connecting to the Y corners pieces (Y Corners Left A1, Y Corners Right A1) by turning them about 1 turn away from where they start to tighten. Remember to loosen the bolts facing inward on the extruded bars. Also loosen the set screws holding the Y rods. The Y axis assembly should no longer be rigid, but have some play. Loosen all M3 screws on the Y bed plate bearing holders.
Place the whole assembly on a flat surface with all Y corners siting flat. Wiggle the assembly slightly if the corner bottoms do not sit flat
Slide the Y bed all the way toward the motor. Tighten the M3 screws on the bearing holders closest to the motor so they just begin to tighten up. Do not tighten them with a lot of force at this point.
With all Y corners sitting flat, tighten the M5 bolts and rod set screws on the Y corners closest to the motor. Tighten them all the way.
Verify that the Y bed slides smoothly on the full length of travel. Slide it back and forth a few times, keeping the Y corners flat on your table.
Slide the Y bed back to the motor and finish tightening the M3 bearing holder screws closest to the motor. Screws on the two bearing holders farthest from the motor should still be loose.
Slide the bed to the end with the idler plate, opposite the motor. Verify that the Y corners sit flat, and tighten the remaining M5 screws on the Y corners holding the idler plate.
Verify that the bed travels smoothly over the full range. If not, repeat the above steps.
With the bed in the middle of its travel, hold one of the loose bearing holders and apply a slight force to keep it snug against the rod. A slight twisting force works well for this. You do not need much force. As you hold the bearing holder snug, tighten its M3 screws. Do the same for the other bearing holder.
The bed will now take more force to move, but should have very little slop.
Check that the bed does not bind or become difficult to move at either end of the travel.

For bed leveling, don’t play games with sheets of paper. Get a cheap dial indicator and stick it on the extruder stepper with some double-sticky thin foam tape. Five minutes of using Pronterface to drive around the bed, adjusting the screws, and your done, level to a few thousandths. This also revealed that my borosillate plate had warped and was bowing 0.030" along the X axis, high in the center. This is probably from sticking on the heating pad. The adhesive across the pad pulled it up into an arc. If it looks like this matters (which so far, I don’t think it does), I’ll put thermal paste on the pad where the glue is and secure it some other way.

You must follow the firmware update instructions. Without this, Pronterface will drive the beds in the opposite direction. The slic3r configs have worked great, and I’ve only tweaked the infill and skirt. In one case, I had a high skirt and it started to get uneven, developed pretty significant bumps / stairsteps from the printhead going too fast and getting into resonance with the previous bumps. Everything survived, but I’d like to know how to slow down the speed for the skirt.

So, a new KITTAZ is born, and I’m very happy. I’ve held off on 3d printing for years, always put off by one thing or another about the printers that are out there. The TAZ4 / KITTAZ looked to have finally hit the mark. From my first prints, I think it truely has. Now I’m dreaming of dual heads and a milling attachment (with alternate base). Very exciting.


Thanks for the tips!

We’re always looking to see how we can improve things. We appreciate it. Nice looking Rockto!