New extruder on UM 2

[albert 2]

Can anyone tell us or show us the new extruder for the UM 2?

As far as I can see it is driven directly from the stepper motor. Is there a way to turn it manually?

I am asking because I believe that many problems with the bowden tube and clogged nozzles come from the fact that people use the automatic "extrude" option and pump too much material into the nozzle when they start the machine.

I have always "primed" the mechanism by hand and never had a jam since I started to work with the Ultimaker in March.

 

[calinb 11]

I have always "primed" the mechanism by hand and never had a jam since I started to work with the Ultimaker in March.

 

I completely agree. Single-handed manual drive capability is essential. (The other hand can simultaneously force the filament too, which is often sufficient to clear jams or partial jams and preclude a hot end teardown).

 

[joergen 2]

There is no way to turn in manually... it is a direct drive (no more gears) which would require many many more turns by hand.

but this was also my first comment on friday, when I saw the machine for the first time.

I am sure we can get the manual filament jog via the menu, or you can print a simple knob that slides over the extruder axle with a slot for the set screw. this will allow you to get the "manual drive" back.

 

[Daid 306]

I'm sure someone will design a printed addon for manual drive. But during testing we did not find a need anymore for manual pushing the filament. With the new hotend design and the direct drive you get a skipping motor instead of overflowing hotends during the priming of the hotend.

(Also, dynamic motor power, you can adjust the motor power on the fly in the firmware :-) )

 

[calinb 11]

It's good to hear that it's possible to add a knob. I'm not worried about the motor as much as the mechanism that applies the motive force directly to the filament. It's always the weak point--not the motor. I predict there will be times, even given improvements in the UM2, that it will be desirable to turn the knob by hand while simultaneously forcing the filament with one's other hand. Manually turning the mechanism will surely continue to be far easier than accessing motor drive control from the UM2 controller menu.

Also, I suspect most pre-release testing of the UM2 was performed with PLA. As with the original Ultimaker, other plastics will probably prove to be more challenging to feed reliably through the hot end.

 

[chopmeister 0]

I really love the simplicity of the new extruder design. I can't wait to see first tests from forum members, especially with nylon, polycarbonate and such. I guess the little slide switches there are for tension adjustment?

 

[Daid 306]

Also, I suspect most pre-release testing of the UM2 was performed with PLA. As with the original Ultimaker, other plastics will probably prove to be more challenging to feed reliably through the hot end.

 

We have a desk full of ABS prints ;-) also to test best platform adhesion (sanded bed glass with glue stick works best. However a sanded bed can grind your nozzle ruining it. Which is why we did not go for a sanded glass plate)

We did not test nylon, PET or other materials. But I do think the UM-Original is a better printer if you want to tinker with stuff. (Buy both! one for printing one for tinkering ;-) )

 

[peter-parnes 0]

What material is the the new plate?

 

[calinb 11]

I've seen sandblasted glass plates, but have not tried it. The potential to ruin a nozzle is a noteworthy downside, Daid!

I'm using Uhu gluestick for nylon, but the best ABS adhesion I've ever achieved is with "ABS-juiced" Kapton or PET tape (and "aged" juiced tape is even better). I've broken a grand total of three of my hot-swapable plates trying to remove large parts from them. Fortunately, I pay only about $3 for a plate at the local glass shop. It's not worth my time to cut them, given my relatively meager skills and poor yield. Borosilicate glass would be an expensive proposition for me, with little or no benefit.

 

We have a desk full of ABS prints :wink: also to test best platform adhesion (sanded bed glass with glue stick works best. However a sanded bed can grind your nozzle ruining it. Which is why we did not go for a sanded glass plate)

We did not test nylon, PET or other materials. But I do think the UM-Original is a better printer if you want to tinker with stuff. (Buy both! one for printing one for tinkering :wink: )

 

[Daid 306]

What material is the the new plate?

 

Some kind of tough glass, not sure what kind, most likely borosilicate, but not 100% sure. It's nice, flat, strong and transparent.

 

[lrodriguez 32]

I would not add anything printed to this beautiful machine. We talked at Maker Faire that all it would take is a manual extrude in the screen like "Prepare | move axis"

 

[calinb 11]

It may be beautiful but I print more than garden gnomes using a variety of plastics for industrial and manufacturing purposes. I'm currently designing and printing nylon solvent-resistant dies that must handle up to 400 psi in a press. On the occasion that I attempt to clear a jam or a chunk of garbage from the hot end or nozzle, it is far easier to manipulate the filament feeder with both hands (one hand pushing hard up on the filament and the other hand rotating the drive mechanism while opposing the 40 or 50 lbs of upwards pressure I can generate with my filament hand (sometimes getting even more pressure with vice grips on the filament). I can use my Ulticontroller to advance the filament (updated my Marlin FW) as with the UM2, but clearing a hot end with the controller is not as effective as the brute force manual approach. One can also manually reverse the filament direction far faster than can be done with a controller. Rapidly "pumping" the filament back and forth (like clearing a toilet with a plunger) can often loosen and clear crud from a hotend. It is very apparent how well the toilet plungering technique works when going from a cruded-up dark material to a lighter one. While the extruded thread might appear clear while extruding normally, some rapid plungering often produces a stream of dark chunks from a fouled hot end! It's best to alternate regular extrusion with plungering until the extrusion runs clear.

I believe that many exasperated user complaints of jams, which I often read about in 3D printer forums (UM forum included), could be solved with my last-ditch, brute force techniques. I will never sacrifice function for beauty in my machines and I will never have an FFF machine without a means to aggressively manually advance and retract the filament.

 

I would not add anything printed to this beautiful machine. We talked at Maker Faire that all it would take is a manual extrude in the screen like "Prepare | move axis"

 

[albert 2]

Second that!