Tuesday, 18 October 2016

Project: Proteus Delta part 1

Or Building a large Delta from Electrical Conduit part 1:

     A couple of weeks ago, I backed DisTech Automation's Prometheus System on Kickstarter, and decided that rather than refit one of my existing printers, I'd build a new larger delta specifically for it. After building the Micro Kossel and MPCNC, I ran across the incomplete Emmett-Delta on OpenBuilds, which had some interesting ideas for using electrical conduit for the frame, rather than the usual expensive V-slot. I decided to go with a 30cm diameter build plate with 1 meter of build height, so the overall size is about 1.5 meters tall with a 50 cm per side base, making this something of a monster-sized machine.

Emmett-Delta parts waiting for assembly
     For the frame, I'm using 60 feet of 1/2 inch electrical conduit for the towers, and about 12 feet of 3/4 inch electrical conduit for the top and bottom triangles, you can see some of the 3/4 inch pieces in picture with the printed parts. On the 3D printed parts, I got in touch with the original designer, David Bunch, and he finished designing some of the missing parts so I could do a full build. For the controller, I'm using the well reviewed Duet 0.8.5 and pairing it with a 24 volt heat-bed from UltiBots, I'll have more on those in a future post.

Side bar fitted with drilling jigs
Preparing to drill with 3/16 inch bit
     For filament usage, I've gone through just over 1.5 kg so far, half of that in the lower corner brackets that clock in at 240 grams each. Once I'd finished printing the corners, cutting and drilling the electrical conduit to it's final size was next. Cutting was fairly straight forward, since I used this technique with a reciprocating saw, metal blade, and miter box. As for drilling the holes to actually bolt things together, I tried doing it by hand with a power drill and 3 days later, ended up with my holes all over the place. If I did it again, I'd invest in a drill press for faster and more accurate drilling.

Side bars waiting for installation. Note the messy holes from hand drilling
The primary assembly tools: a ball-ended hex key, and a 6" crescent wrench
     Once I got the screw holes straightened out, the actual assembly for the triangles is fairly straightforward, line up the holes, insert a bolt, loosely thread a nylock nut onto bolt, repeat at next hole. I did this until all of the sides for each triangle were loosely assembled, then went around the sides tightening each bolt in turn until all of them were snug, then gave each a tiny bit more of a twist to completely lock the frame.

Top triangle fully assembled
First side of lower triangle assembled, note the installation of the bed support bracket
    When assembling the lower triangle, it quickly became apparent that I'd need to install the brackets for the electronics and print bed during the assembly, otherwise I'd need to remove the upper bars to install them and potentially damage the alignment on one or more of the sides.

Lower Triangle fully assembled, including brackets for controller board

Brackets for Duet 0.8.5 controller with space for optional Duex4 expansion board
    Once all of the bolts were tightened, it was time to start work on assembling the towers, which I'll cover next time.

Completed triangles waiting for final assembly

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