Woodstock Delta Printer by jpickens

Last crawled date: 3 years, 1 month ago

I have been building derivative Rostock Delta printers based upon Johann's excellent design for several years. My current version, which uses magnetic ball joint arms, is derived from the original Johann Rostock, as well as several other designs posted here on Thingiverse.
Here's a Youtube video of it in action:https://youtu.be/jT24ClLlQKo
This design uses a direct drive extruder, the Titan by E3D. When they released this product, I realized that this geared extruder with a pancake stepper motor was just what I needed to chuck the bowden extruder in the bin and mount it directly on the end effector.
The whole effector with the extruder drive and E3D hotend weighs under 300grams.
Since I have modified many of these parts, I thought it would be helpful to gather up the pieces in one place to assist others in making their own Woodstock Delta Printer!
While the base stucture is exactly like the original Johann Rostock, with 8mm smooth rods placed in pairs 60mm apart, and using 250mm diagonal rods, the frame is a bit shorter. I took the wood panel laser cut design from:
http://www.thingiverse.com/thing:34570
by Docmooney
Even though Docmooney posted his DXF drawings of the wood panels with two thicknesses shown in the names, I used 12mm (1/2" nominal) baltic birch plywood for all of the pieces. They consist of a base panel, a top panel, two sides, and a short front center base support piece, 5 pieces in all. By using laser cut plywood, an extremely precise and square frame can be made, which is crucial in building a successful delta printer.
Besides the frame, 3D printed parts make up the rest of the dimensionally important build. We have three vertical towers, X,Y, and Z each having the two smooth 8mm steel rods held in place by three fixed printed parts. These are the lower stepper motor holder, the upper endstop holder, and the topmost boxed idler bearing block with 608zz skate bearings for the GT2 drive belt.
I used Johann's original design for the stepper motor holder and upper endstop.
My design uses six 30 inch (762mm) hardened steel 8mm rods which extend above the top panel of the wood frame. These extensions are used to hold the boxed idler which performs two functions:

Mounting the idler above the frame allows the belts to be tensioned by loosening the clamp bolts on the rods, and pushing up on the boxed idler.

The idler sitting above the endstop forms a sort of truss for the smooth rods, which stiffens them and dampens vibrations, improving performance of the printer.
The boxed idler comes from:
Chowderhead
Which was remixed from Johann:http://www.thingiverse.com/thing:19903
Now to the fun part where I start really tweaking things.
My moving carriages use Igus polymer bearings for quiet operation.
I used printed u-joints for my original version of this printer, but they are sloppy.
Wanted to go with zero backlash magnetic ball end diagonal arms, so I modified a
SCAD file from this thing:http://www.thingiverse.com/thing:303637
by Kolergy
I really hacked up the original, moving the spacing of the magnets to 60mm, in line with the smooth rods, changed to 12mm magnets, and changed the drive belt grooves to GT2 belts. I also made two sections of grooves with a gap in between to act as your belt coupler, so you can save money and cut your own belts instead of ordering closed loop. I used this to get the GT2 belt profile:
http://www.thingiverse.com/thing:194554
by alj_rprp
I'm pretty hacky with the nice SCAD coding, so my additions aren't too elegant, but they work. I'm including both the SCAD versions as modified by me, and the STL files for printing.
Next, we have to have a moving triangular effector to hold the extruder and hotend.
I modified this thing:
http://www.thingiverse.com/thing:93042
By Aeropic
The mods were to get the magnets to the 60mm spacing, and to open up the center to allow the Titan extruder to fit. Unfortunately, due to the size constraints, the hot end tip is approx. 20mm off center, which isn't ideal, but it prints just fine.
I worked up a design to hold the Titan extruder based upon:
http://www.thingiverse.com/thing:1958993
by bfesser
Again, I hacked it up pretty good, and added an extension for a strain relief 1/4" plastic hose to support and attach the wiring harness from the frame to the effector.
Just add the normal assortment of stepper motors, GT2 belts, GT2-20 tooth drive gears, heated bed (260mm Alu-MK3 bed), the Titan Extruder, E3D hotend, 12V 30A power supply, and off you go!
I'll be adding more photos, and a complete parts list as soon as I can.
Let me know what you think!
Update 3-10-2017:
Just uploaded a new version of the E3D Titan extruder mount.
This one has Holes in the name, and has all necessary mounting holes included.
It has a hex shaped recess in the side for attaching two M3 nuts, one to clamp down
The mount, with the second threaded on higher to hold the tensioning string.