yyh1002

Hey guys, Just got Mark2 working. Thanks for everyone's effort in this project. Still trying to get it work better but I thought I could share some of the accessories I made for Mark2. Extruder: https://www.thingiverse.com/thing:2289203 Top Spool mount: https://www.youmagine.com/designs/spool-holder-mount-for-ultimaker-2 Bowden Tube Hook: https://www.thingiverse.com/thing:2154124 Filament Guide Roller: https://www.youmagine.com/designs/filament-guide-roller-for-um2 Modified Mark2 Parts: https://www.youmagine.com/designs/mark2-modified-parts

First turn on the hidden setting of support Z distance. THE SOLUTION: The minimum support Z gap is 1 time layer height if you don't want them totally fused together. What you can do is to change the support Z distance to 0.1 for 0.1mm layer height, 0.15 for 0.15 layer, etc. And also turn on the complete support interface. That's going to give you better bottom. THE RANT: The default should be 0.4 for 0.2 layer, and 0.2 for 0.1 layer, which I totally disagree. The double layer height Z gap is guaranteed to produce horrible bottom like what you have. I don't know why Cura has default like these. Imagine there is a 0.4mm gap, plus the 0.2 for the print layer itself, the nozzle would be 0.6mm away from the support surface, even larger than the 0.4mm nozzle diameter itself. How is that ever gonna work? Cura probably don't do over-extrusion to compensate for the gap either. Same thing for the default gap for raft settings. 0.3 gap for 0.1mm layer. I honestly don't know how that could work.

Yeah I found the one causing this issue to be "minimun retraction distance window". The default 6.5mm is preventing retraction for the columns. The filament diameter also affect how the this value affects retraction.

Thanks for trying out. Thats strange. As you can see from the screenshot, it doesn't work for me even if I set it to 0 already. Maybe I need to try erase all the legacy profiles and reinstall.

Hey guys, I'm trying to slice this model in CURA 2.7 (https://www.thingiverse.com/thing:49612). But it won't perform some the retraction needed no matter what settings I change. Is anyone able to successfully slice this model with proper retraction? Thanks.

You could try adding support mesh to the side of your part to stablise it.

Well, problem solved. In G11 definition, I replaced retract_recover_feedrate with retract_feedrate.

With the UM2.1 firmware, the retraction speed setting in LCD menu only controls retract_feedrate. However, retract_recover_feedrate is constantly 25mm/s. Because the retraction noise is very annoying and I sometime need to dial down the retraction speed to reduce the noise. It would be nice if the recover speed can be changed together with the setting. Currently I slice gcode in CURA with reprap flavor to get same 17mm/s for retraction and recover, which result in a very quiet retraction action. But I prefer to slice in UltiGcode flavor if possible. I wonder how to modify the firmware so the retraction recover speed can be changed together with retraction speed in the menu. I tried tweaking it but couldn't get it to work right. Thanks

Then you convert all your machines to 1.75. As I explained earlier, it's easy. No matter what you convert with, 3DSolex, e3d, etc, it's all very simple. If you are concerned by the filament market and don't feel confident about the conversion, then go for the one you feel comfortable with. If you really get a 2.85 printer you might worry about the filament market more. Forget about Ultimaker then. Look for a decent 1.75 printer.

Which high end FDM 3D printers are your referring to as Stratasys and 3D Systems are both using 1.75 filament?

Pull the tube out of the hotend, take it to the front right corner (the furthest corner), see how long you can stick it under the height of linear rod without too much bending. The next thing you need to concern is the fast forward filament run while loading filament. You need to make sure the extruder doesn't outrun your Bowden tube, otherwise the filament is going to shove into the nozzle and be grinded by the extruder. In the 2.1 Marlin firmware, default Bowden length is set to 705mm (set as FILAMANT_BOWDEN_LENGTH in Configuration.h tab). And the fast forward length is FILAMANT_BOWDEN_LENGTH-50mm (set as FILAMENT_FORWARD_LENGTH in UltiLCD2_menu_material.h) If you cut the Bowden tube, better subtract 705 with the length you cut off. With your problem of Bowden tube not being up right, you could also try a Bowden tube hook to restrain the position. I made one before: http://www.thingiverse.com/thing:2154124

The ones in gr5's store is essentially from 3D Solex. Check their website. A credible 1.75 conversion would be e3d. Not the Ultimaker upgrade kit from e3d, but modify the hot end yourself. I would doubt the stock feeder of Ultimaker though. The "pineapple" drive gear profile is not optimised for 1.75 filament. Not only you need to change the hot end, you'll probably need to get a new feeder for fast print speed as well. In 3-5 years, the printer would need a lot of servicing. It's not as durable as conventional electronics at home. You'll probably need to replace parts here and there, swapping extrusion could be one of them. Ultimaker 2 is an open source machine, as long as you know how it works, it's not going to be some trash you have to throw away.

I am not worried about today, I am worried about tomorrow. I can find a decent amount of 2.85 today, but it is harder to come by than 1.75 as less vendors sell it, less manufacturers make it, and even when they do, they offer less selection than their 1.75 filaments. As the number of 1.75 printers grows (seems almost exponential these last few years) and the number of 2.85 printers just kind of stagnates with one or two additions every now and then, the incentive that most manufacturers will have to make and supply 2.85 is diminishing. I do not want to be on the losing side of a standards war. I've done this enough over the last couple decades, from VHS/Beta to BluRay/HDDVD. Dual extrusion is the future. Direct drive doesn't play well with dual extrusion. 2.85 is better than 1.75 for Bowden. Besides, unlike DVD player, you can easily swap the entire extrusion system of printer with little cost.

I am not happy paying $40-$80 per kg for PLA when I can get some really good PLA for $21 from MakerGeeks (or $15 if I don't care about the color). With the amount of filament I go through, the cost difference is non-trivial. What happens when these other places and brands stop supporting the 2.85 standard because it doesn't make business sense to cater to such a small number of printers? With little to no competition, what is stopping the limited number of suppliers from increasing their price even more as the availability of 2.85 decreases? I am worried about a non-forced vendor lock-in created by other vendors moving on to more lucrative pastures. I will look into that, thanks. I just want to know that the option is there when it is eventually needed. The disadvantage of a 1.75 Bowden setup (with a tube as long as Ultimaker) is that you lose the chance to print real flexible filament. Flexible PLA would work, but it's not quite soft. The common TPU based flexible filament is not going to work on a 1.75 version of Ultimaker. I'm not sure about US, but in Europe there are a number of decent brands having 2.85 version of PLA together with 1.75 under 30Euro/kg. Other than Ultimaker, the recently really popular dual extrusion printer BCN SIGMA R17 is also using 2.85. These two dual extrusion playmakers are going to lead the community for a while. I think 2.85 with Bowden will at least have growing source of material if not join 1.75 direct drive as common setup.

Why is the additional nozzle on the right side of the shaft? Wouldn't it have more printable area if the mount is mirrored and have the nozzle on the left?

Warping caused the inconsistent profile of thread. The problem with the bolt in this vise is that the thread seems to have a ISO standard 30 degree angle. It's too steep for most printers. Only printers with strong part cooling fan could handle it. Normally if you create your own bolt, do it with 45 degrees overhang. With average part cooling fan, to improve the overhang print, print with slow wall speed such as 10-15mm/s, in such case the fan can cool the stroke before it warps. As long as the wall speed is slow, it should work fine with 0.1 even 0.2mm layer.

Cool. Can go up to 212x213 now.

Set the brim to 0mm. Cut off corners. I could get it to slice 207x206x200 at max. The bright printable area in Cura is only slightly larger than the 207x206 mass. 208x207 won't slice though.

I don't think there is a fundamental problem with Bowden, only a little drawback. Two of the very commercially successful printers Ultimaker and BCN Sigma both use Bowden drive. The problem with drive gear directly attached to stepper motor, like the one you are using, is that the motor heats up and soften the filament making it likely to grind. Also, if the spring compression is not strong enough, it's more likely for the filament to slip and grind. Geared feeder with decent ratio could eliminate the heat transfer as well as increase the drive force of stepper motor. A Bowden feeder with direct gear is too old fashioned. Dual drive gears increases grip to filament and reduce the chance of grinding, like Bondtech UltiArjan mentioned. You could also check out the one I recently made with dual drive gears and 3:1 ratio: http://www.thingiverse.com/thing:2289203 https://www.youmagine.com/designs/b2d-extruder-strong-and-silent-bowden-extruder