Simpler, cheaper delta

Please tell me he's posted a BOM!

Here's the development thread - http://forums.reprap.org/read.php?178,267835

I'm already thinking about how to redesign the threadless to work with this. I will plan on making a trip to the hardware store to pick up anything I might be missing. I think I have most of what I need. Might just need a little more all thread.

Yep, that's what I was looking to do.

I thought there was a problem with repeat-ability with the threadless ball screw (as in 3 of them would have 3 different rates from the same STL).

What about the possibility that instead of using horixontal force with the bearing design, you print something more like the gravity screw toy so that the bearings ride down the screw like a spiral ramp so that the force is downward instead?

I will hve to draw something up to show what I mean.

EDIT: Done

can you post some pictures of what you have made? That would be great.

I have been planning a mod of this. I like the majority of it being printed parts and inexpensive bearings. The original thread on reprap they are using expensive threaded rods though. I have redrawn this to use his hub, but changed the shoulders to use bronze sleeve bearings and thrust bearings. The parts can be purchased from McMaster Carr for $21 a column (24" shaft and bearings). Considering the rods they are using cost $65 a column, this is a considerable savings. I plan to drive this using fishing line. I have 2 goals: Cheap and easy to assemble. When I get further finished the base, motor mounts, and line pulleys, I will post more details in the projects section.

Well, from the original thread if you look on page 4 there is a description of the build volume. Nicholas shows a 200mm diameter circle that can fit into the odd shaped build area. This is up for debate in my mind. The arms should not ever reach complete vertical or horizontal angles. On a standard Rostock/delta, the arms are the only vectors that move, and hence the shoulder and end-effector offsets do not come into play with the X-Y area. But on this LISA design, the end-effector and shoulder offsets move and stay in line with the arms, thus increasing the reach. Until one is built, I would rather say the minimum diameter is 180mm.

As for Z, I plan to get 600mm hardnened shafts (24") that once you remove the 200mm for the arm, 20mm for the shoulder, roughly 15mm for the end effector and another 25mm  for getting an endstop switch and about 25mm for endplate mounting, that leaves 315mm possible height. Depending on your hot-end and heatbed will take away from this.

Edit: I have a different shoulder dimension than the original LISA. So I whipped up the numbers with the original column spacing. That is the first picture. In the second picture, I maximized the column spacing to get the 200mm diameter with what I am working on. That is picture 2. The weird shape in the middle is the actual build area. If the arm is fully upright/vertical, the hotend would be at 80mm radius from the column. If the arm is fully extended/horizontal, the hotend would be 280mm radius from the column. Cross section each column and you get that weird shape.