mendells

Printed a few doorstops with the gear extruder and Olsson block. The 0.8mm nozzle and 0.4mm thick layers makes a sizable dent in the print times. The print time went from over 4 hours to just over 1 hour. The gear extruder could extrude faster but the heater isn't strong enough to keep the nozzle hot. .4mm nozzle, ColorFabb XT 0.12mm layers 70mm/s Print time: 4h 34m .8mm nozzle, ColorFabb XT 0.4mm layers 50mm/s Print time: 1h 4m Nonlethal Door Stop

Updated version of the gear extruder: Moved mounting location. Updated tension screw with thumb screw (no tools needed). Re-Printed housing with XT-CF20 Added SemiFlex cushion to dampen motor vibrations. I have also updated my fan shroud design to accomodate the stock Ultimaker nozzles, improve airflow and include a template for the Kapton tape cutouts. https://www.youmagine.com/designs/um2-olsson-block-fan-mount

This is the kind of thing 3D printer companies should be doing. Good on ya Ultimaker and Anders!

So I'm not crazy hu? There is something about the white pigment that causes inconstant extrusion. I've usually had the best luck with the darker filaments but white seems to be the only one I really have ever any problems with. Even the clear ColorFabb XT prints very well compared to the white XT. From my experience it isn't just ColorFabbs filament either. I've tried white from several different manufactures with similar results. Just don't buy white filament anymore

Thought I would share my fan mount for the Olsson block. I was getting temp errors with the stock fan mount. I printed mine out of ColorFabb XT-CF20 and its been working great. I also changed my "Fan full on at height" to 2.0mm which helped a lot. https://www.youmagine.com/designs/um2-olsson-block-fan-mount

I used a filter/oiler like that on my old Replicator 1 and it made a huge difference. I used a drop or two of olive oil to help lubricate the filament and keep it from jamming inside the hot end. With that said I would NOT recommend using it on the Ultimakers. My oiler was placed right on top of the hot end and the oiled filament didn't have far to travel. With the bowden tube style printers it would likely do more harm than good. It might help keep some dust out of the hot end on the Ultimaker but your probably better off just using the atomic method to clean out the nozzle every once in a while.

Anyone know how to change the maximum retraction speed? I've had to increase the retraction distance to 10-12mm and I want to up the retraction speed to something like 55-60mm/s. I'm guessing its something I would have to change in the firmware but I'm not sure how to change it? Any help would be greatly appreciated.

We have 3 printers. all running 40-50 hours per week. Total print hours per machine: UM2: 2780 UM2: 1975 UME: 687

I try to print without supports whenever possible. If your angles are too steep you could try breaking the model up into multiple pieces or orienting it in such a way you don't need supports. I usually use 60 degrees for my prints. What are your fan speeds? Better cooling usually helps with steep overhangs.

It looks like your getting underextrusion. There are a couple things you can do. You may want to increase your temp a little or slow down your print speed. Also check the tension in your belts to make sure there isn't any slack in the X-Y axis. With hard plastics like PLA when you get to the end of a spool the filament is tightly wound and can cause additional resistance inside the bowden tube. You can try swapping to a new roll and see if that solves the problem. I use "straighteners" on our machines and they make a big difference. https://www.youmagine.com/designs/um2-filament-straightener

I thought it might be nice to have a thread to reference when looking for print settings for different machines and materials. It would be interesting to see how different users print settings compare. Here are my typical print settings for 90% of the parts I print. Machine: UM2/Extended (Stock) Material: ColorFabb PLA/PHA Print Temp: 220C Bed Temp: 60C Fan Speed: 100% Flow Rate: 100% Print Speed: 60mm/s Layer Height: 0.12mm Machine: UM2/Extended (Stock) Material: ColorFabb XT Print Temp: 240C Bed Temp: 70C Fan Speed: 50% Flow Rate: 106% Print Speed: 50mm/s Layer Height: 0.12mm Machine: UM2 (With Gear Extruder + Olsson Block) Material: ColorFabb XT Print Temp: 240C Bed Temp: 70C Fan Speed: 100% Flow Rate: 125% Print Speed: 100mm/s Layer Height: 0.12mm Machine: UM2 (With Gear Extruder + Olsson Block) Material: ColorFabb XT-CF20 Print Temp: 240C Bed Temp: 70C Fan Speed: 100% Flow Rate: 125% Print Speed: 50mm/s Layer Height: 0.12mm What are your typical print speeds and settings?

Try another print with the exact same settings but with a different color and see what you get.

Thanks for the link, I'll see what I can do about getting that test performed. From some of the testing I have already performed the geared stepper motor will skip steps before the gears loose grip on the filament, so from that I believe I can safely say the motor will be the limiting factor not the grip. I haven't had any slipping/grinding so far so there isn't any dust in the gearbox so far.

Your prints look pretty good but we are printing very small parts and I'm really picky . I'd be willing to bet your prints would improve if you switched to a color (the darker colors specifically seems to work well for us). I'll print off a part in white and one in a color and post it here later.

Did a quick speed test. The tower on the left uses the gear extruder the one on the right uses the stock extruder. The gear extruder looks good up to 120mm/s where the stock extruder starts showing signs of underextrusion around 70mm/s. Both printers were printing clear XT at 240C.

I usually print at 50-60mm/s at .1mm. It prints great with every other color but when I switch to white I have layer issues. I've tried printing slower, lower temps, longer/shorter layer times with the same effect. All the other colors print great at the same settings so I just try to avoid white now.

We buy ColorFabb value packs direct from ColorFabb (if you sign up for 3DHubs.com you get a discount code that you can use). Even with shipping the exchange rate is such that each roll ends up costing around $35. We have both PLA and XT in all sorts of colors but we don't buy white anymore. For whatever reason we have never had very good prints using white. The layers don't seem to extrude consistently and we get very visible layer lines. Other than that we are very happy with both the PLA and XT filaments. PLA/PHA Settings: Print Temp: 220-225C Bed Temp: 60C Fan Speed: 100% Flow Rate: 100% XT Settings: Print Temp: 240-245C Bed Temp: 70C Fan Speed: 50% Flow Rate: 106%

This is true but the stock extruder really lacks the torque required to extrude even at normal speeds. With our stock Ultimakers we need to run ColorFabb XT at 240C to print at 40mm/s without underextrusion. With the gear extruder we can at 60-70mm/s. The backlash in the geared extruder seems to have little if any effect. I did have to increase my retraction a bit but I believe that is just due to the increased pressure on the filament. I am running a series of test prints to effectively measure the impact of the gear extruder vs the stock one. I will post it when I have it done.

Higher torque and better resolution. The gears have a larger diameter than the stock knurled feeder, which negatively affects resolution (lowers steps per mm) so to compensate and add more torque (something the original drive motor is a bit lacking) I'm using a geared motor..... and I had one laying around Having a more powerful extruder means you can print at lower temperatures and faster speeds.

I use a 70/30 water/glue mix and it works great. Be warned I have actually damaged my glass build plate printing with XT. The prints stuck so well they pulled off pieces of glass!

I could rig something up to find out, I can guarantee its significantly more than the stock UMO or UM2 feeders. The stepper motor is larger and has a 5:1 planetary gearbox so it should have roughly 5x the pulling force.

Unfortunately the geared stepper motor is too long to mount internally. You could potentially mount it internally if you removed the sheet metal shield that covers the stepper motors but I wouldn't recommend that. I am not 100% happy with the mounting location or method yet so it may still change in the future. I would like to mount it closer to the top of the machine and offset far enough so it doesn't stick out the side. As for the program changes, the only thing that has to be changed is "E-Steps per 1mm filament" in the machine setting. The default is 0 (which I believe the default is something like 86) and the new value is 443.46.

I'm trying to gauge interest in who would be interested in buying a gear extruder? I've been using the design for a little over a week now and it works like a champ. I am still refining the design but will be making another 2 sets at least for our other Ultimakers. If there is enough interest I could see about making enough to sell to those who are interested. Features: More torque No grinding/jamming! Better accuracy (more steps/mm of filament) Easy pressure settings (no more worrying about too much, or too little pressure) What would be included: Drive gears (For standard or flexible filaments) Bearings Hardened Shafts Screws NEMA 17 5:1 Geared Stepper Motor Extension Cable What you would print: Gearbox Shaft coupling Motor Adapter Motor Mount I don't have a price yet but my rough estimate is something in the $100 range with the motor, cable and hardware included. If you are interested please let me know. I will look into making machined aluminum components to replace the printed ones.

I will be doing some more testing/refining first but I've been using it for a little over a week now with no issues what so ever. It has tons of torque and even with retraction set to 20mm it never jams or slips. Here it is printing ColorFabb XT-CF20 with the hardened steel ed3 nozzle at 240C. I need to come up with a better mount than my makeshift openbeam frame but I'm very happy with the function so far. Edit: I may look into selling a kit with the motor, cable extension, gears, bearings and shafts. I will probably end up making an aluminum or stainless steel frame as well instead of the printed one but the printed one seems to be holding up well so far.

All metal hot end for higher temp plastics. Easily changeable nozzles (sizes). Auto Leveling. Stronger extruder/better drive mechanism (geared or otherwise). Single nozzle multi material extrusion. Printing over Wifi would be awesome. Camera to monitor prints (over Wifi). Touch screen controls would be nice.