A8B_Boden_Conversion by allObjects

Last crawled date: 4 years ago

Conversion of Anet A8 to Bowden Drive from out of box Direct Drive with just re-using parts freed up by conversion. The A8B_..._print.stl are the only file you need to print, Screwes come from freed-up direct drive and what came with the printer.
Got inspired by dldesign - https://www.thingiverse.com/thing:2077676 - found via youtube https://www.youtube.com/watch?v=n8nE3fI1zmg
From dldesign I took the hot end carriage - actually only the plate - and added my details to it. The hot end mount and belt fixture I replaced with my design in order to use the parts from the direct drive (no new parts screws, screes, just a few prints). I dimensioned the mount to accommodate the 30mm AND 40mm fan. The 30mm fan came with the hot end and included a snap on air guid that serves at the same time as fan mount. The extra space for the 40mm fan - ex direct drive - I made in case I would need more cooling (so far not happened yet).
For snug fit the hot end, I printed it to measure - which always ends almost always with tighter openings, even with well calibrated printers and prints. To actually seat the hot end, I put its heat sink between the mounting parts, pressed them together while heating it up with a solder iron until it 'forms' itself in. In case it is not tight enough, sand slightly one or both of the facing surfaces of the mounting parts. This way it is not need much pressure to appy by the screws an risk breaking the mounting - of which dldesign talks about - but more the hot molding / fusing that is responsible for an air tight, gap free seat.
Because of the different position of the extruder nozzle relative to the cooling fan, I had to redesign the air duct. I chose resized version of the original, out of the box, simple design, because it fares quite well compared to many much more elaborate ones, so many 'printers' say in their posts. The print has DIY support that is to be broken out and off after print. The duct inserts snug into the fan outlet.
To prevent the cooling air stream blowing at the hot end / hot end block, I made a (blue) 'oversized coat' from a aluminum beer can. It is held in place by the screw that clamps the heating element. First heating up rendered quite interesting, malty smell... ;-) - from coating or from beer residue? ...I prefer to think of the latter... and it was that way.
3Displacement 's - https://www.thingiverse.com/thing:3583021- found via youtube https://www.youtube.com/watch?v=BDBJaQmhlw0 is the closest to what I was envisioning for the extrusion driver stepper motor setup in regard of easing forces inferred by the variable bending of the bowden tube. To reduce them even more with even a shorter tube led me to the very lean setup on the x-axis mount, Where the motor itself is part of the gimbal. Since the motor axle extends only on one side, I complemented it with a printed stub in simple snap on cradle that takes advantage of the motor's socket to stay on.
Currently, the motor-gimbal is held mainly by gravity and secured with a wire or paper clip brace in mounds in the gimbal arms. Where print material bears print material in the back, I used a snip from the same beer can as bearing lining...
The gimbal has a piece that snug fit slides into the opening of the right-side x-axis mount and holds itself with a snap-on gripper. Sand slide in part slightly if it requires force to push in (and may break something). - I had thought of mounting it on the left side next to the x-axis motor, but decided otherwise because it is already crowded there and would need a much more elaborate mount (and most likely additional parts / new screws / bolts / nuts).
To be frank, the design was not necessarily for the sake of being a lean and go with re-use-only of freed up parts: the current lock down and related delayed shippings left me no choice but to be resourceful in order to pull thru in one shot! For the record, I ordered 5x11x4mm ball bearings for the gimbal and will make a re-design of the arms for a more professional setup.
Final comment: Even though marked as remix, there is not much remix left, because I finally modified the carriage plate as well... In a next version I will go for slide in / clamped glide bearings to lighten the extruder carriage even more and achieve greater closeness of extruder nuzzle and x-axis guides and even faster prints (80..100mm/s right now with good results).