OneUpSolid

The QU-BD OneUp printer gets it's name from the fact that it has only one lead screw on the Z axis to raise the X axis. Not only does this reduce parts cost, it also eliminates the pesky need to keep the two Z axis mechanisms in sync to maintain parallelism of the X & Y axises.

The OneUp does this, quite ingeniously, by squarely attaching the one acme lead screw nut between the Z axis bearings at the outer ends of the rigid X axis. Placed anywhere between those two ends, the Z axis will lift both ends equally. Amazingly, the OneUp gets good 50 micron layer accuracy. Confusingly, the TwoUp uses the same concept, it is just a bigger printer.

Using Sketchup parts from other designs, I threw together a OneUpSolid printer design this afternoon. The more I played with it, the more I liked it. Using mini-v-wheel assemblies for the Z and X axis and 4 solid v-wheels bolted to a 8x8 Build Plate is actually cheaper than using linear bearings and linear bearing quality rods to build the same size machine. This design's build would cost about $300 including Ramps, heat bed and a 360 watt power supply, about $75 more than a comparably outfitted QU-BD's TwoUp cost for a flimsy MDF framed 6.5x6.5 build printer.

This design looks (at this stage) like it would be an easy, quick assembly, lending itself to selling semi assembled (extruder, mini v-wheel assemblies) kits.

The Sketchup file is HERE. This, and the images below, are just a concept mockup at this stage (4 solid wheels attached to Build Plate are missing, extruder has not been finished or even decided upon yet, etc). An interesting thing about this design is that the weight is behind the X axis, so the Y-axis foot is at the rear of the Y axis instead of the front.

Although the Z axis requires 20x20 extrusions for the mini-v-wheel assemblies, I've bolted 20x40 extrusions to the back sides of those extrusions - for added strength and to provide for mounting the power supply and Ramps box.