Friday, January 4, 2013

MendelMax 1.5 Build Log: Part 2: X-Axis Build

The ACME lead screws and nuts showed up, along with the promised replacement parts from www.lulzbot.com.

Next steps in the rep rap Mendel Max 1.5 build- assemble the X-axis ends. I ordered the lulzbot ACME Pillow Block X-End Set 2.0. The Z-axis rods are 10mm, and the X-axis rods are 8mm.
ACME nut in the bottom half of one of the X-ends

The ACME nut didn't quite fit- trimming the socket with a X-acto knife

Perfect Fit!
Lulzbot.com was out of the extruder components, so I decided to order some from an e-bay seller. I found a seller located in Hutchenson, MN who was selling parts at a very reasonable price. I also purchased some printed endstop switch brackets, "pillow blocks", and belt clamps as well.

Additional Parts from E-Bay seller
The SDP bushings for the 8mm and 10mm rods both have the same OD, so the printed "pillow blocks" are the same for all size bushings. The printed "pillow blocks" were a bit rough on the inside, and the SDP bushings didn't fit with a reasonable amount of force. I learned my lesson on the X-carriage not to force the bushings. A round file worked great to clean out the inside of the "Pillow Block". With a little filing, the bushings pressed in place easily.

Filing Pillow Blocks

Pushing Pressed into Pillow Block

Assembled X-Axis assembly
X-Assembly in place
X-Axis in place with frame assembled
 With the X-axis assembly in place, I could start dialing in the mechanism. Unfortunately the Z-axis (vertical) wouldn't slide at all, it would easily lock up. Obviously something wasn't aligned right.

The right side of the Z-axis slide seemed to be tighter than the left. I removed one of the pillow blocks, and the assembly seemed to slide slightly easier.


One Pillow Block Removed
After inspection, it seemed the upper pillow block wasn't aligned fore and aft with the Z-axis slide. 

Adjusting Mounting hole with dremel.
Even after re-assembly the Z-axis still didn't slide right. After looking at the X-ends further, I saw that there were actually two additional Pillow Block mounting holes on the lower X-end.

See lower mounting holes on lower X-end

Pillow Block moved to lower X-end holes
The X-assembly slid much better up and down the Z-axis after moving the Pillow Blocks.

Lulzbot.com also sent the replacement lower vertices to replace the missing units from the original kit.

Replacement kit from Lulzbot.com
When I re-assembled the frame, I also took the opportunity to replace the upper cross braces with some heavy duty 8020 aluminum brackets from D&S Machined Products. The aluminum braces really stiffened up the assembly. As is, both the X and Z axis easily slide without binding.

Current State of MendelMax Frame

Current State of MendelMax Frame
Next steps:
  • Install Z-axis ACME lead screws
  • Assemble & install extruder & hot end
  • Build Y-axis sled & build platform

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