RR-Evo Delta 3D Printer - [E1] plywood version

thingiverse

There was an idea (back to August 2014) to create a delta machine that's very easy to build in home conditions. I didn't like to get a kit with printed or machined parts, but instead, to make it of plywood and then evolve it to something reliable and precise using RepRap features of the technology. So, this is 1st of N series of publications about evolution of my printer. There is nothing to print in this thing. Just laser-cut plane and some notes. Next steps:RR-Evo Delta 3D Printer - [E2] upgraded with Rostock partsRR-Evo Delta 3D Printer - [E3] hot-end mount Description Initially it was designed in Sketchup, but unfortunately I lost sources. So it's reproduced in Onshape and available for public use - RR-Evo Delta 3D printer - E1 plywood version. Note, that laser-cut paths (DXF anf DWG files) were made of Schetchup design, so small differences are possible in Onshape design. There are several old videos showing it's working:RR-Evo Delta 3D Printer: carriages and rods of plywoodRR-Evo Delta 3D Printer: First movesRR-Evo Delta 3D Printer: First print Design Features The mechanics is driven by NEMA 17 stepper motors with GT2 20 teeth pulleys and belts. 8mm diameter 660 mm length linear rods of hardened steel are used with LM8UU linear bearings. 624zz bearings are used as belt idlers. Everything is powered by Arduino Mega 2560 R3 & RAMPS 1.4 with RepRapDiscount Full Graphic Smart Controller and Repetier FW. MK2B Heated Bed. 12V 350W power supply. All the chassis and moving parts are made of 10 mm plywood. Printer geometry Printer radius: ~ 104 mm - 175 (tower radius) - 35 (platform offset) - 35.6 (carriage offset) Diagonal rod length: 215 mm Design issues The main issue - this design is not fully worked in details and assumes some improvisation on some pieces to assembly. One has to follow my solutions (see pictures and assembly notes) or think something up oneself. The pieces are: there are no end-stop switch holders; there is no hot-end mount; carriage belt holders/tensioners are absent; heated bed holders are also not present; Significant problem - long plywood posts started to bend with time, all in the same direction that caused little twisting of the machine from bottom to top. Laser cutting width is not taken into account.. That’s actually minor issue. On the chassis it is not significantly affected. Only can cause problems on moving delta parts, but hand-made plastic washers of an appropriate thickness may help to get rid of possible backlash. To get rid of gaps and securely attach linear rods plumber's PTFE tape is used. The carriages are sliding on two LM8UU linear bearings. The cheap ones I have are not good at all and make carriages skewing. There are couple of things that also could make design better: extruder, made of plywood (I bought one ready to use for bowden setup); a jig, that could help to make lateral holes in moving parts. I made it of materials at hand, the idea to include it into design came too late when all parts were already cut. So, if anybody interested in it just let me know and I'll add it to the thing. Assembly notes General recommendation is to see attached pictures and also assemblies in the Onshape document. And, of course, feel free to ask questions. Delta mechanics is assembled with blind rivets (also known as POP rivets), but without expanding blind end. So, mandrels must be removed before rivets insertion. Everything is held on friction, small amount of glue under rivets heads also an option. Cannot tell exact model, these are ones with body diameter 3.2 mm and length ~10 mm. The "main" screw (to assemble most of parts) I used is ISO 7049 Pan head tapping screws with cross recess 3.5 x 19 mm. End-stop switches are mounted in places with plastic corner fasteners for furniture. They (and end-stop screws on carriages) can be placed at any position you think best. But if you like to follow next steps of the evolution then it's better to set them (screws on carriages) as shown on a picture. The side of the carriage doesn't matter. Conclusions Having all the issues, mentioned above, the construction is working. I was able to print and replace moving parts (this is subject for next post) and then make some more iterations, every time getting better and better device. There is a thing that's the printer somewhere in the middle of its evolution. Starting the project two years ago I had no experience neither in printing nor delta mechanics. I learned a lot since those times. Looking at photos of first printed parts now... I think they are terribly bad :) but they did their job. And now RR-Evo can print things of very good quality. Had I had knowledge I have now I'd improve the machine much faster and in less steps of iterations. So, this could be quite a challenge for beginers, especially in calibration, but nothing is impossible ;)