dfrez

The bowden tube I have is the standard UM size, so it's 6.35mm/0.25" OD. Should be able to find pnuematic fittings in that size for imperial. The separately mounted housing is a good idea versus trying to retrofit something to the feeder housing. Like I mentioned I tried searching YouMagine for one, because I figured someone has already thought of this, but I couldn't find anything.

Old thread bump. I've been looking into a similar solution via either a dry box or dehydrator like this. How do we connect the bowden coming from the dehydrator or dry box to the feeder? I have a UM2+ feeder, so there is no provision for a push connect fitting. No luck searching YouMagine either.

Thank you for the clarification. I assumed they were the same thing, but now the different behavior makes more sense.

Interesting. I have used water to remove prints before, either due to the cooling and subsequent contraction of the part or to rinse away the glue.

That seems counter productive, lol. I also thought you weren't supposed to use anything on PEI except isopropyl alcohol between prints. I can give that a try I suppose.

Printed a few parts with Amazon ABS that tends to warp quite a bit with glass and glue stick, but with the PEI sheet there was zero warping and adhesion was very good. Although some of the sheet still tore when pulling the part off. I guess it's because the sheets are so thin. They seem more like single use sheets with how fragile they are.

Yep, I realize that now. I figured the UM PEI would work similarly to the previous PEI I was using. Normally bare glass or very light glue stick is all I use for all my materials.

Old thread bump, but I’m glad I’m not the only one who ran into this issue. I purchased my UM2+ used and it came with an unknown brand of PEI sheet on the buildplate. It worked well with PLA, first layer stuck well and parts popped off easily once cooled down. When it got damaged, I pulled it off and printed on the bare glass or with glue stick for awhile. I then decided to get the UM adhesion sheets to avoid the mess with glue stick. Imagine my surprise when my PLA part had the strongest grip on a buildplate I’ve ever encountered. I tried my scraper, heating it up again, everything. Eventually I was able to manhandle it off and it stuck so well, the sheet tore and pieces were stuck to the part itself... thankfully there are multiple sheets in a box. Lesson learned I guess 😂

Hey @bruman! Since you seem to be printing okay with normal PLA, keep in mind that PLA+ has a slightly higher extrusion temp. I typically do 220°C versus the default 210°C for PLA. Hope you figure it out! I also hate when people don’t post a solution, so I always make sure to update my threads if I do figure it out!

Just to update this, I'm fairly confident that the cause of my issues were the hardened steel nozzle that I had installed for abrasive filaments. You can see it in one of the pics where it is printing a test cube. Not realizing that the lower thermal conductivity of the steel versus the typical brass requires you to increase the temps and/or decrease the print speeds to compensate. Which explains why the prints came out much better at elevated temps. I determined this by doing the filament temp test shown by GR5 and comparing the results between the first extruder and the second extruder that I added as part of the Mark2 upgrade. The second extruder still had a brass nozzle, which is what caused me to wonder why the new print head was able to print at default temps and the original print head couldn't (not realizing that the only difference between them was the nozzle material). I have printed a few tests with the brass nozzle at default temps and speeds and the print quality is much better, like it used to be.

I see, must be the lower mounting puts less of a bend on the bowden when the printhead is in the back corners.

Finally back up and running after installing a new main board. So far I've got the docking position and offsets tuned. But one thing that doesn't make sense to me is that docking/picking up the second head in the printer menu works fine but when running the calibration print, the main head misses the dock when it goes to pick it up (maybe 10-20mm short in Y). This is with the gcode file from github. I still have the default print area set in the firmware. For the second bowden tube, are we supposed to use a standard length or a longer one? Current one has a nice smooth curve to it, it's only a problem when trying to move to the right rear corner of the printer and the second head pops off. Perhaps the magnets I got aren't strong enough. Does anyone know of a good place to buy a single thumbscrew for the second head? I didn't buy the extrusion upgrade from UM so I don't have any extras. I can see the one corner of the mark2 pushed out slightly by the bowden pressing on the teflon coupler.

Bump

No lights come on when powered off and connected to USB (Rx and Tx). Only the “ON” light when switched on.

There is 24V at the headers with the board turned on.

Yep, thank you for all the help, btw. I figured I'd start a thread to possibly help other members in the future. Which lights are we looking for when connected via USB? The LEDs on the board itself or the lights on the UM2? Maybe something shorted when I was handling it. It seems like the board still has some residual power stored even when off and unplugged from PSU for some time. I would imagine due to capacitors etc on the board.

Yep, both safety jumpers are in place. I'll check the 24V connector. In order to check, do all the components need to be connected to the board, or can I just plug in the PSU?

Hi all, Recently purchased a used UM2+ after using one at work for a couple years. It worked well for a few months after catching up on some maintenance. It came with a few extra parts including a partial Mark2 upgrade kit. After getting the rest of the parts, I went ahead and installed the new firmware. I installed the board and printed a few things with a single extruder. Then I removed the board again to finish running wires. Once I put everything back, the steppers no longer operate and am unable to connect to the board through Cura, computer also doesn’t recognize it when plugging in. It also throws a limit switch error since the printhead or bed doesn’t move. Long story short, the board is toast. I’m not sure what I did, maybe I zapped it when I was working with it the last time. But want I help with is determine exactly what’s wrong with it and maybe even being able to fix it instead of just using it as a paperweight. The heaters for the bed and hot end still work. The front display and knob still work. I don’t see any obvious marks on the board that would indicate something burnt out, etc. I do have a spare Chinese board that needs stepper drivers (they are on order) so hopefully I’ll be up and running again soon. I don’t have a lot of experience with board level diagnosis and mediocre electronics knowledge but it just annoys me to have something fail and not know the root cause of the failure.

I got my cable management situated a little better. I was hoping to not have to drill any holes, but drilled one for the printhead and feeder wires to pass through since the UM2+ doesn’t have one. I was hoping to get the calibration finished now that all the hardware is done. But when I tried to check the docking position (first step on the website), I got a X and Y limit switch error... I double checked all my wires everything looked good. Tried lowering and raising the buildplate, got a Z limit switch error. Tried homing all axes, moving the printhead, etc. nothing works and eventually throws a limit switch error of some kind. I figured I would load the factory firmware back on and see if that worked. The printer doesn’t show as being connected via usb in Cura. The buttons to load/update firmware are grayed out. Great. I happen to have a spare board (China clone) and plugged that in, shows up fine in Cura. Is there anyway to check the board or load the original firmware back onto it? Or is it too late for that?

Hi all, recently purchased a used UM2+ with most of the parts for this upgrade including the expansion board. Had to buy some wires and print some missing parts, like the feeder mount. Just finished the wiring. Need to sort out my cable management since there’s no hole under the second feeder like shown in the instructions. Ended up feeding the wires for the head through the hole for the first print head wiring. But now that means the second print head wires are too short to reach the expansion board with it installed in the Mark2 board enclosure. Edit: I was able to get the firmware installed. Turns out I was downloading files from github incorrectly. 🤦‍♂️ I downloaded just the files I needed using right click and “save link as”. Strangely enough the files appeared to save fine in file explorer, etc. but whenever I dropped an STL saved that way into Cura it told me it was an invalid file. Long story short I just downloaded all the files as a zip that way and works just fine.

I also picked up some different filament instead of the eSun and still having issues with underextrusion. But I was able to minimize it by either slowing down my print speed or increasing the temperature. Can you give us some info on your current print speeds and temperature? Those are the two biggest factors that contribute to underextrusion.

I measured the resistance of the temperature sensor at room temp and it was 111 ohms. It should be around 110 at room temp so it looks like the sensor is fine. Maybe the orange PLA just prints a little hotter? *shrug*

I’m wondering if the temp sensor is going bad and creating this issue by reading high. Not sure if this is an accurate way to test, but I took an instant read thermometer between the nozzle and hot end. Measured temperature at a few different points and each were about 20°C lower than reported by the printer. As a a test I printed a cube and a stringing test at 240°C (20° above default PLA profile) and default speeds. The results were much better than before.

Cant figure out how to quote someone on a different thread. So I took GR5’s advice from the following thread regarding underextrusion and printed a test cube and compared to default PLA speeds: 1) Print slower and hotter! Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers): 20mm/sec at 200C 30mm/sec at 210C 40mm/sec at 225C 50mm/sec at 240C The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA. 0.2mm layers at 210C at 30mm/sec versus 0.15mm layers at 230C at 60mm/s. I also printed a temperature tower (starts at 220 and goes up to 195 in 5° increments) and it went a little crazy at 200C... I didn’t catch it in time to stop the print, lol. The slower print cube came out fairly nice. No signs of underextrusion for the most part. So needless to say it can’t print colder than 210... unless something is wrong with the temp sensor. I also swapped out the Bowden tube, cleaned out the feeder, and did a cold pull. I tried running a piece of filament through with the nozzle removed and didn’t notice any excess friction. Although it’s hard because I have nothing to compare to, not sure what acceptable friction should feel like.

I print at whatever the default speed is for PLA. For the above print to come out okay, I turned it down to about 80% in the Tune menu on the printer. edit: according to Cura profiles, the speed is 50 or 60mm/s. I think I printed the above at 0.15mm layers, so it should have been 60mm/s.