Creality printer mods

thingiverse

The Creality 3D printer is a clone of Deezmaker's excellent Bukito 3D printer (which I also own one of). While the Creality improves upon the Bukito by providing an LCD interface, it is mechanically inferior in several ways The vertical tower in the Creality is held to a horizontal extrusion by a very small corner bracket. There's little to prevent the tower from twisting forward. The Z stepper motor helps to resist twisting backwards. The Bukito firmly secures the vertical tower in two perpendicular planes to the custom bottom plate. The belt paths are not kept in the same plane as the motion of the X and Y carriages. The X and Y idler supports in the Creality are not adequately stiff and introduce additional ringing, albeit negligible at low printing speeds. The Creality's hot end uses a PTFE liner all the way to the hot nozzle. The PTFE will degrade over time and require replacement. Further, this limits the printing temps which can be used to below 240C. It further limits maximum printing speeds as only so much heat can be provided via the reduced melt chamber size. The Creality's pinch gear doesn't have sufficient bite in hard PLA and slips occasionally. While not a mechanical defect, the Creality lacks a print cooling fan. As the Creality is clearly intended for printing PLA (and comes with a sample of PLA filament), lack of a print cooling fan is a significant omission. Particularly since you need one for small prints and the Creality is otherwise best suited to small prints. In this Thing, I provide some modifications which may be used to help address these issues. After you read the amount of modifications and parts changes I made, you may well ask yourself whether this was any less expensive than buying a Bukito kit. Just the electronics alone which I used cost about $240 US not including shipping ($206 for Duet 0.8.5 + Panel Due; another $35 for a larger power supply). I further used at least another $160 in parts and possibly closer to $200 (four stepper motors, heated bed, Neutrik 20A power inlet, E3Dv6 hot end parts, extruder parts, etc.). And that's not counting any shipping costs. So, all in all, it was perhaps a wash when compared to the cost of a Bukito kit. On the other hand, in the end I ended up with a heated bed and a touch screen interface neither of which you get with a Bukito or Creality. As an aside do not believe the Creality claim of "1 hour assembly time". I figure it will take most people more than five hours. A few additional photos at Flickr.Click here for a video of the uncalibrated printer's first print. Instructions 0 Must do The vertical tower must have a more secure mounting mechanism. Below I recommend using an L-plate which you must source (e.g., Adafruit). For printing with PLA, particularly small parts, you need a print cooling fan. While you can just point a fan at the printer, having one mounted on the hot end and controlled via print instructions is far more convenient. You will need a means of mounting a fan as well as sourcing a 12V DC fan (or a 24V fan if you convert your system to that voltage). Inspect your initial prints looking for any signs of the pinch gear slipping (little gaps in the exterior). If you see these signs, then you can try using a stronger spring in the extruder or source a pinch gear with a more aggressive bite or both. Check out the kit's 12V power supply with a volt meter. Mine, even under load, liked to wander between 8.4 to 11.8V. That's not a good sign. And the power supply had NO certifications. (It did, however, have the "China Export" mark which appears designed to look similar to the European CE mark. See this news article.) 1 Hot end I removed the oversized metal hot end enclosure and replaced it with a more compact enclosure, the hot_end_fan_shroud.stl which is a download of this Thing. It accepts a 30x30mm fan. I used my own shroud both to open up the underside of the hot end as well as to provide a mount for a cooling fan. For a cooling fan duct, I used Deezmaker's Bukito PLA cooling fan duct (25 Dec 2016: link is now broken; STL now included with other parts for this Thing): scale it up to fit the size of fan you wish to use. It mounts to the above shroud using two M3 nuts and bolts in the slot on the hot_end_fan_shroud.stl. With the slot, you can adjust the height of the cooling fan. By use of a spacer with the lower mounting bolt, you can also adjust the angle of the fan. To convert the hot end to an "all metal" hot end, I used an E3Dv6 hot block and 0.4mm nozzle. To feed into the hot block I used a maker-bot style M6 threaded thermal barrier tube, available from Carl Raffle, Micro Swiss, or Performance 3-D. All three of those manufacturers make correct thermal barrier tubes with the slight widening of the inside diameter below the thermal break. Note further that you should use an E3Dv6 nozzle with the E3Dv6 hot block: that hot block is a little thicker than most and the E3Dv6 nozzle has a slightly longer threaded neck as well. This prevents having to thread the thermal barrier tube so far down into the hot block that the hot break is partially embedded. 2 Extruder I found that the provided brass pinch gear did not have sufficient bite in hard PLA. Prints were showing occasional gaps from where the pinch gear would slip. I replaced the pinch gear and bearing arm with a more aggressive pinch gear (Deezmaker Tatsu). My change necessitated changing the bearing in the lever arm to a flat-faced bearing. I also had to modify the drive block a bit to accomodate the larger diameter pinch gear. (Owing to the trough machined into the gear, the filament still exited at the correct position to reach the exit hole in the feed block.) I used parts I had on hand. Just be aware of the fact that you too may want to replace the pinch gear with something more aggressive. 3 Idler supports I printed idler supports which would support the idler axles on both ends. This makes the idlers a little stiffer and less prone to bending inward when the X or Y carriages are accelerating away from the idler. That, in turn, reduces vibrations and ringing. The idler support for the X axis is extruder_idler_support.stl. It is thinner on one side so as to allow the extruder carriage to pass over it. Use a low profile M3 bolt as well. The printed parts have interior room for normal extrusion stopper nuts. (I use Misumi's post assembly stopper nuts.) The holes in the parts are intended for a long M3 bolt as the axle. You can change the OpenSCAD sources for a larger bolt. I still used the M8 bearings provided by Creality but inserted some M8 to M3 bushings (e.g., McMaster-Carr aluminum unthreaded spacers). And yes, you can use extruder_idler_support.stl in for both axes and not just the X axis. 4 Vertical tower To better support the vertical tower, I added an L-plate bolted to both the vertical tower and horizontal member. Sinking two M4 bolts through the bottom plate into the bottom of the tower might also be a good idea, but it didn't occur to me until it was too late to do so without a fair amount of effort. Adafruit and others sell L-plates for 20x20 extrusions. I also used a much larger corner bracket than the one provided in the kit. You can get them as well from Adafruit or other suppliers. 5 Drag chain Since I added a heated build plate, I installed a drag chain as well (10x12mm outside dimensions; 7x7mm inside). Use the drag_chain_mount.stl to print a mount which bolts onto the end of the long, horizontal extrusion. 6 Power inlet To handle the 15A+ of a heated bed, I installed a 20A Neutrik jack. This works well with Things 441081 (12V) and 1241088 (24V). 7 Electronics I replaced all the electronics with 64bit ARM electronics using a Duet 0.8.5. That provided nicer electronics, heated bed support, and a very nice web interface. The Duet electronocs and firmware, RepRapFirmware, have an excellent safety record. And they provide a very slick built-in web interface. For an LCD touch screen interface, I added a PanelDue as well. (However, I still need to mount it.) And, frankly, I don't trust the no-name Asian clone electronics. I've seen a few too many go up in smoke. So, I knew from the get go that I would not be using the original Creality electronics. 8 Heated bed I rebuilt the platform into a 120x120 mm sized platform so that I could use a 12V Thing-o-Matic heated bed. See, e.g., Thing 16958. However, I later changed to a 24V system and used a silicone 24V heater from McMaster-Carr. I made the change from 12 to 24V as it's generally my experience that the stepper motors perform better. Having to deal with less current is an added benefit. The pictured build plate is a 120x120 mm Zebra plate from Print in Z 9 Stepper motors First, the Z threaded rod ends up spaced about 1 - 2mm farther away from the vertical tower than the Z stepper motor's shaft. To put them in better alignment, I spaced my Z stepper motor away from the vertical tower by about 1.8mm using two fender washers. The Creality printer kit came with stepper motors which lacked any identification and specifications. I'm not keen on using stepper motors for which I do not have the specifications. As I have plenty of inexpensive, quality, known-to-be-good-for-3D-printing stepper motors, I used them in place of those which came with the kit. (Namely, Kysan 1124090 stepper motors from Ultimachine.)