Modified Wilson II Printer

thingiverse

NOTE: Please see important update3/27/2020 Originally, I became interested in converting my Flashforge Creator Pro to use a Diamond hotend. After much work toward this end, I decided that it would be more practical to build a completely new printer. So, as a starting point, I chose to use the Wilson II/Prusa design as published by Marty Rice www.thingiverse.com/thing:1086101 . I named my printer WWIII (Weber-Wilson III). My printer is basically the same as the original, but with a 300mm x 300mm bed and many changes or modifications to most of the parts. There are two power supplies, a 24V supply for the heated bed, and a 12V supply for everything else. In order to isolate the two supplies and take the high current bed load off the mainboard, a solid-state relay is utilized. The two supplies fit nicely between the Y-axis rails along with the relay. I modified the original bed mount using bearing holders that eliminate the original wire-tie mounts. All parts were printed in ABS. The mainboard is a Rumba with six TMC 2208 stepper drivers. Firmware is Marlin 2.0. The three extruder steppers are 1.8° 17HS8401 /48mm long. All other steppers are 0.9° 17HM19-2004S 48mm long. One of the major challenges of this design was the wire management. A couple different types of flexible wire chain was used for this purpose. (JD Miles: www.thingiverse.com/thing:1760952) I also used the RepRap Full Graphic Smart Controller and modified it so the encoder has a thumbwheel and separate push button for control. I changed the AC power input module to use a panel mount power socket with fused switch which uses a standard removable power cord. A Y-axis brace (threaded rod) was added to the Y-axis due to the flex of the longer end pieces. A touch probe was added to the hotend cooling tower as was an automotive type 60mm halo 15LED car angel eyes light ring which is controlled by a switch on the Y end panel. The AC power input module houses a Sodial(R) inlet male power socket with fused switch available from ebay, Aliexpress and others. I made a nozzle cover boot using Permatex high temperature red RTV and a mold (www.thingiverse.com/thing:2386473). Paste wax was use as the mold release agent. To insulate the heat-bed I glued (Permatex) a 12” x 12” x 1/4” cork tile to the bottom of the bed. I was concerned that it might not hold with the heat, however, so far, so good. Since the Z-axis has two unlinked stepper motors, it is easy to unlevel the Z-axis, so I made a couple of leveling blocks (20mm) to put on each side so I could periodically manually level the Z-axis. The filament trollies may be a little scary, so I added provision for a safety belt incase the reel slipped off the trolley. The belt consists of a length of standard 2mm x 6mm drive belt looped through the reel center to a slot in each of the trolley stands. I also made a couple nozzle blanks to put into any unused filament holes so I didn’t need filament in every inlet. The blanks consist of #14 wire inside a short length of Bowden tube. During initial testing and trials of the printer, I had problems with extruder skipping while trying to push the filament through the Bowden tubes. I was using standard 4mm PTFE tubing and finally decided to cough up extra money for the premium Capricorn tubing. Much to my surprise, this made a huge difference and made three-filament printing possible. This is not meant to be a complete “How To”, but to possibly provide ideas and help for others doing similar things. The files provided are not a complete set, but those I felt might be of interest to others. Addendums: 2/8/2020 With the extruder motor slipping and struggling to get enough filament pressure on the Diamond nozzle, I decided to try a geared extruder to increase the torque. I combined the Pitan Geared Extruder (thing:2728600) with the Tevo Tarantula Titan Bowden fitting (thing:2677766). This seems to work very well,so I have added the BOM and stl files for this addition. NOTE: Some stl files may be 10X in size. Also, since I like to print with PETG, I am also adding files to add a part cooling fan to the carriage. Since I often print with only one filament at a time, I found that the idle filaments get "cooked up" in the nozzle and cause a clogged nozzle. To prevent this from occuring, I run an extra 50mm of filament from each of the three filaments at the conclusion of every print. I used scripting in the slicer program to do this. I also added a custom command in Marlin to do the same thing whenever I wish. Update: 2/18/2020 I have uploaded my current Marlin 2.x configruation files for those who have expressed an interest. Also, due to the rather large nozzle, I would suggest that in addition to a moulded nozzle cover, a 50W heater be used. A 40 W heater is very weak. Update: 2/23/2020 Just updated the cooling tower with fan nut retainers to hold the fan mounting nuts. Update: 3/27/2020 A major shortcoming of this printer design is with its Z axis lift. The two motor system is not mechanically locked together and can easily be skewed thus requiring frequent adjustments. The single 8mm lead screw nut also has quite a bit of backlash. In an effort to overcome these problems I re-designed the X axis end pieces to incorporate a second adjustable lead screw nut. The adjustable nut is set such that (with the screw in place) there is a slight drag on the screw when moved and thus providing anti-backlash. I highly recommend this upgrade. The two new files provided are: x-idler-endAB.stl, x-motor-endAB.stl