conny_g

What is the improvement of the alu ring, what does it change resp. what’s worse with spring?

Just thinking about converting my 2nd UM2+ to a Mark 2, as I have one „old“ UM2 hotend left from the conversion of UM2 to UM2+ of that. So the question is what are the non-fixable compromises of the UM2 drive train & hotend. What where the differences of the UM2+ upgrade again? Feeder don’t care, will use a Bondtech Print head Olsson block - don’t care, will covert to 3D Solex Matchless V3. Is it possible to mod the UM2 head with that? Stronger heater - already ordered a set of 50W Spring vs. alu ring above the coupler - does that make a difference? Fans and cabling: one was a different hotend Fan and how it’s connected (UM2 always on, UM2+ controlled by firmware?) ? Is it the same fan? The fan shroud is optimized on the 2+. Could print one. And wasn’t there something with the model fans, too? Are they same or different? Cheers, Conny

Check the Cura settings, there are 3 temps to set, initial temperature, print temperature and final temperature, they allow 10 C of tolerance. I set them all the same. And then, which color is the new / 2nd extruder and what kind of extruder is it? Is it a UM2+ extruder or a UM2 extruder? Afaik the UM2 extruder has less power, maybe this is an issue?

I changed my feeders into Bondtech and with these it works much better, I get decent results with Ninjaflex. They have much better grip than the original feeders. Speed must be less than 10mm/s, though, I print first layer, top and outside with 4 and the rest with 8. Still works with more, but with frequent brief periods of underextrusion, smothering object becomes a bit spongy / porose. Attached a photo of rubber feet I printed, diameter about 2cm. And damper feet for the printer.

Much better now, that was it.

Of course I am not printing it always at 270, I ended up increasing to that temp to end the underextrusion and started to worry what would be wrong. Will check that. Was doing a few cold pulls before and disassembled the head to check the coupler. And there was some scratchy edge at the lower inner end that I carefully removed with a scalpell. After that a piece of filament moved much better through the coupler than before. Then started reprinting of the last item and it looked much better even with just 235 C. Let's see what happens as it progresses.

When reading more about the atomic pull I noticed that sometimes also a worn-out Teflon coupler could be the reason for underextrusion. But as the problem is going away with temperature I would rather assume a clogged nozzle as higher temperature does not help for the Teflon coupler issue (the filament gets molten below the coupler), but it does for a partly clogged nozzle.

That makes sense, will try that!

Hi all, I am confused about print temperature. Was using Extrudr Green-Tec for a few things now and it is said to be printed 190-230 C. I was never able to print reasonably below 220 degrees (at speeds of 40mm/s) and now with my latest object with a print speed of 30-50mm/s I even needed 270 degrees to avoid underextrusion. I wonder what the problem might be. Don't think I have a clogged nozzle or a defect extruder heater as other materials behave ok, I can print regular PLA with 210 degrees. Or does the Green-TEC simply need high temperature? Cheers, Conny

Maybe they try to support the supports of the holes. Try to switch to only buildplate, maybe they are gone then.

Surprisingly simple solution! :-) I'd be a bit worried that cutting the bottom and removing the screws from the bottom plate makes the head much less stiff than before. Does that have any effects on the print quality? The prints (dragon egg for example) don't look like it.

Seems to work now to pick from Photo directly! Though the images are ".jpg" suddenly and not ".jpeg" anymore... weird Photo app... however, it works. ;-)

If I pick images directly from the photo app on Mac OS X the images located there are named .jpeg. Unfortunately .jpeg is not allowed as extension to upload, then I need to export the images from Photo (names the image .jpg) and pick it from there. That's unnecessary hassle.

On the bottom side the dock must not be in the way of the axis, see photo, red line. And of course the X / Y slider blocks must not hit the dock, so the outer walls of the dock (facing the frame), must be as far from the frame to allow the slider blocks to pass. See second photo.

Hi all, nice work! I was wondering why I would want a UM2 clone with Alu frame. Is it „because I can“ or is there advantages of doing so?

Where do you read 9 extruders? Without translating it completely, my italian is not good but good enough to scan through it and get the idea. He uses a board with 8 relais to duplicate 2 extruders into 4, each 4 relais switch the 4 wires of driver to one motor of two. Two extension pins of the printer board switch 4 relais at the same time. There is just one hotend with 4 „inputs“ and one temp sensor so that is not solved with this solution to have multiple hotends. In theory heater and temperature could be connected the same way but that would not allow for standby temperature or proactive heat-up. So in my view that’s not a solution for us. Extruders can be multiplexed, maybe even the temperature sensors, but the heater can’t if you need a relevant duty cycle of >= 50%.

What firmware are you using with the duet3d boards?

You mean the 8 diode smoothers, right? I'd expect to have even more influence on the torque as they are taking more voltage off the motors. For me the 8 diode ones worsened the print more than the 4 diode smoothers - I reported my experience that with the the GND on ROSC in place the smoothers made things worse, not better. And with 8 diodes it was more worse than with 4 diodes, so whatever they do gets stronger with the 8 diodes. Btw, I could offer to send some to you for free, ordered too many and have them lying around with no use.

I am not sure that I understand. Would you please elaborate? If I set the print speed to 65 mm/s then Cura sets different speed levels for "sub tasks" like inner wall, outer wall, infill etc. Cura sets infill to 65 and outer wall to 42, that's what I mean with "spread" of speeds, infill is 50% faster. That's a good idea as infill does not need to be as "nice" as outer walls. But it has the effect that physics vary between these two - the 65 require a higher temperature to be able to extrude the corresponding amount of material. And this "gap" or "spread" becomes more challenging the more you increase the speed, up to the point where it's not possible to find a setting that is working for both, either you have too low temp for the infill or too high temperature for the outer walls. For the material I am currently using to print a large object (20 hours at 0.2 layers) - Extrudr Green-Tec - I can't get the infill to work if I have the speed in Cura at 65mm/s, I needed to slow down by 30% to get it work ok. Not sure where the temp limit of Green-Tec would be, didn't want to try with the object in the making, will run a test afterwards. If Green-Tec is still happy at 255 C it might just work. So it seems to also depend on how much the viscosity of a material changes with temperature, I have less issues with other materials. So it seems that this "spread" limits your speed, depending on the material and how urgent you need the infill. If it doesn't work you need to set infill slower vs. outer walls.

The idea is that the horizontal screw and the wedge control the pressure exercised on the dock, the more you tighten the screw, the more the wedge is pulled inside and the more the dock ist lifted upwards.

After some searching, reading I think I got it. It's a matter of the spread of speed between walls and the infill. Cura sets the infill speed like twice as high as the walls, so the infill is hit much faster with any underextrusion issues of the "temperaturs/volume per time" parameter. Then I would need to set the temperature high enough that this still works, but then there is other effects like the extruder can't build the pressure fast enough and part of the infill in small areas is done before the higher line width would help. Or I get stronger stringing etc. So it's a matter of compromises - either I print fast and tolerate weak infill or I print slower (at least the infills) and the spread of speeds is less strong.

Hi all, I am using the 3DSolex Matchless nozzles and can print easily with 60mm/s in general. There is just one issue that I can't seem to resolve: Even though I set the line width parameter to 0.6mm (with 0.4mm nozzle and 0.35 line width otherwise) in Cura to force higher extrusion the infill is very weak. With lower speeds (40mm/s) the infill is ok. Are you having the same issue? How can I resolve it? Is it the right approach to use the infill line width parameter? Thanks, Conny

@musyne, it's not yet "compact" enough to make it easily doable in all details. That would be my long-term plan after I straightened out the software part with Octoprint. Generally the solution consists of: a 150mW 405nm laser diode in a cooling housing, mounted to the UM head using the Mark 2 magnetic plate a laser driver with analog control, i.e. you can switch its power with a voltage of 0-5V from standby-current to 100% (both set via pots on the driver) a low pass filter circuit before the control input of the laser driver to convert 65 kHz PWM to 0-5V a control circuit on basis of a "Pro Micro" (Arduino Leonardo clone) which is connected via its USB port to a Raspberry Pi. The circuit receives the pixels to expose line by line from the Rasperry Pi, gets a "sync" signal from the Ultimaker Mainboard when the line begins. Then it "streams" the pixels out, using PWM to set the power (laser driver control voltage) and switching the PWM off and on for the individual pixels. That in parallel to the move of the UM head. a python script on the Raspberry Pi that sends line by line from a prepared file with pixel data to the Atmega on the control circuit OctoPrint on the Raspberry Pi that send the G-Code to move the head left / right and from one line to the next a python script that converts an input PNG with the circuit to be exposed to the G-code file for the head movements and a file with the pixel data for the "bitstream" script a firmware mod to the Tinker firmware that would send a "sync" signal via an extension port of the UM Mainboard when a certain G-Code parameter is added to a G-Code move a cable plugged into that extension port of the UM board, connecting the control circuit to the sync signal That's all the components in overview. Currently working (more long-term due to time constraints, will take a few months) on creating a Raspberry Pi hat to sit the control circuit on top of the Raspberry Pi and to add the python scripts to Octoprint as a plugin. That would make it much easier to use.

Have Bondtech on my two UM2(+) and very happy with them. Worked with the original UM2+ for 1 year and the Bondtechs are significantly better.