gr5

By the way you can tell if a move is a retracting move or not in layer view as there are 2 types of non extruding moves and one is dark blue and one is light blue. One of those are retracting moves (e.g. moves that cross an air gap) - I forget which color is which.

Locate the "combing" setting and set it to "not in skin". That will get rid of those lines. Combing allows non-retracting moves (which is faster as you don't have to retract the extruder) if you aren't bridging an air gap but if you don't like those lines you can just set it to "not in skin" and it will barely change how fast your print is because it only affects top and bottom layers (internal layers that can't be seen will still do combing).

You don't purely split. You have to worry about the extruder position. Say you have printed 3 meters the extruder positions will be something like this: G1 X10 Y20 E3001.71 (3 meters and 1.71mm) As you can see if that was the first gcode then the first thing it would try to do is extrude 3 meters of filament. But you can use the G92 command which says "this is your current position". Like this: G92 E3001.71 That above line tells the extruder that it is now at the 3 meter (plus 1.71mm) position so when it goes to do the G1 it won't extrude 3 meters of filament (and grind it to dust as it extrudes too fast). Also you need to keep in the code that primes the nozzle. You have to keep the home commands (G28). Homing position can not be changed as it's done using a limit switch somewhere. So it matters where the homing limit switch is for Z. If your part is far away from the 0,0 corner of your printer (front left) then maybe it's okay to home there? Or maybe not - maybe the gantry of the printer will hit the part?

The problem is most likely that your car is not manifold. Not solid. Somewhere in that layer there is a tiny hole where two flat planes do not come together. At least that's the most likely issue.

It's a problem with the model. Did you create this model? If so did you use sketchup? If you didn't create the model then just run it through the netfabb free model repair service. You have to create an account but the account and the repair service are free.

Yes, picture please. But everything comes apart easily enough. There is a tiny set screw on the knurled wheel.

I hope some other's answer this but here's a few points. 1) Shutting off a heated bed is a bad idea - for me my parts will pop off the bed if I do that. So you would have to print on 'blue tape'. An older technology that works quite well. You have to clean the blue painters tape with isopropyl alcohol. There are many other technologies that work as well as blue tape but the key is you need the heat off if the whole print or on the whole print. You can't change that part way through. 2) Some printers have the ability to continue a print. For example tinkerMarlin for the UM2 and more notably the newer Prusa firmwares (less than a year or so old) will even let you literally pull the plug, then days later plug it back in and have it continue. It will not continue if the bed cooled too much in the mean time so... see point 1 above. 🙂 3) To continue you absolutely must re-home X Y and most importnat (for this discussion) Z. UM2, UM3, S5, S3 printers all home with the bed farthest from the nozzle. Perfect. But many printers home with the nozzle touching the bed. This might be fine for a tiny chess piece but for a print that takes up much of the print bed you could get a collision with your partly printed print. 4) You can do this gcode splitting by hand. But it is a pain in the neck. The first time I did it, it took me about an hour. The second time 10 minutes. I had to learn about the G92 command for the Extruder axis. Splitting gets easier the more you do it of course. But if you make one small mistake it would really suck.

I call that "stringing". I usually reduce it by printing at slower speeds but thicker layers so it takes the same amount of time. So maybe 0.2mm layers and 35mm/sec for all printing speeds and keep travel speed fast (200 to 300mm/sec).

Not to diminish this bug but you are aware of the "support blocker" feature, right? It's extremely easy to block support on that overhang with this feature - just takes seconds once you've done it a few times.

You are not supposed to have one STL file overlapping the other. Anyway make note of the setting in Cura "Alternate Mesh Removal". Read that description for that feature. Also it matters which order you load the STL file. So remove both and load them in the opposite order - this may help you.

There's a lot to unpack here. If you don't know "ls" well then you probably don't know the vi editor and this might be dangerous. Removing or adding a single quote or semicolon or comma to the json file will make it so the printer doesn't boot fully anymore and the boot process will fail before sshd is started (ssh daemon) which means you can no longer ssh to fix your typo which means your printer is bricked and you need to do a more complicated process to fix it. The "vi" editor is confusing. You have a UM3, right? Note that neotko wrote that post a few years ago and he is less active on this forum now (about one post per month maybe). Do not calibrate x and y and z steps with your calibration cube. You want to calibrate using as much travel as possible so at least 200mm. It's best to set X to 0 and line up a good ruler and move X to 220 and check accuracy that way. However UM made it hard to adjust steps/mm for a very good reason. The printer is already calibrated. The default settings for Cura on the UM3 DO NOT aim for accuracy - they aim for speed and a good looking part. Ultimaker came out with new profiles that aim for accuracy but initially only for the S5. You can so your own accuracy settings just pick your favorite profile and change these settings: Line width: 0.4 Wall thickness: 1.2 Top/Bottom thickness: 1.2 Speeds: 35-40 (all speeds, except travel) Jerks: 20 Horizontal expansion: -0.03 walls: 3 Inital Layer Height = 0.1 Slicing Tolerance = Exclusive Combing Mode = off Outer before Inner Walls = Checked I disagree slightly with these - e.g. I prefer bottom layer 0.3 and I like to set initial layer expansion typically to a negative value (depends on the part) but these settings will greatly increase your dimensional accuracy. But your calibration cube will look like crap as it will have lots of ringing on the letters (e.g. "X"). But if you measure it with a caliper that ringing will be too small to measure anyway. To get the printer to best meet your requirements you have to explain your requirements. You can't have everything all in one profile (e.g. speed, accuracy, visual quality). And everyone's definition of visual quality is different.

Please clarify. What kind of printer do you have? More importantly - did you create 2 STL files? You can assign which STL file goes to which extruder. Did you do that?

@CarloK - I also note that you added a fancy header to your gcode file. Does that make any difference? I was able to get my gcode files to work on the UM3 but not the S5. Maybe I need that header? Do you have an S3 or S5? Or just the UM3?

One more point: The wattage of the print core is also stored on the core and also the PID values for heating the core. These values are different for each wattage. The UM cores are all the same - I think 25W. The 3dsolex cores are mostly 35W. If you use CarloK's programming on a 3dsolex core you will mess up the PID values slightly and you might even trip the power brick by going over it's power budget (the printers are careful to lower the print bed power briefly if both cores are at 100% power depending on stated power in the eeprom on the core). So while CarloK's programming will work for UM cores it will be problematic for 3dsolex cores. Whereas my programming suggestion works for both types of core. But CarloK, please know that I appreciate your contributions and it's nice to get people on here who know this stuff at a more detailed level than most people!

@CarloK - you make some interesting points. 1) Checksum. If you send the wrong checksum on purpose and then read it back you will find it now has the correct checksum. I don't know why. You don't have to set the checksum as somewhere along the process it is fixed anyway. 2) nozzle diameter as a numeric number (not as a strong). For those other than me and CarloK, the nozzle diameter is stored in 2 places, in the name as a string e.g. "AA 0.4" and also a second time as anumber. As far as I can tell, this second value ignored. It doesn't affect the gcode which specify how much to extrude and how far apart lines are. I don't think it's useful. It would be good to fix this but I'm not sure at what cost - there are nearby other values that maybe shouldn't be messed with. 3) Counters. Your code CarloK resets everything back to 0 hours so if someone had used the core for several hours that odometer-like reading will be reset to zero. Mine doesn't do this. It probably doesn't matter as most people hopefully will not print much at all when using a mis-labelled core. 4) XY Calibration. So each core has a serial number and this can not be changed. It's set at the factory where they make the chips that go on each core. The XY Calibration data (and Z data) is stored on the printer (e.g. UM3/S3/S5). Not one the core. No matter what you do that will be saved (which should be fine in this case as we aren't changing X/Y or Z positions in the physical core.

Do you also see the horizontal dark blue line near the bottom of your image? If you click on the circle and drag it then you will see that nozzle moving around. There's also a vertical line off the side of the photo. Drag that and the gray goes away. The gray I think is a minor bug but as soon as you start dragging the thing at the right it is good. Sketchup is not designed to make solids so it's easy to make mistakes in sketchup. i strongly recommend you do a 2 minute quick scan of this document. Particularly the part about "reverse faces": https://i.materialise.com/blog/3d-printing-with-sketchup/

To change core name, instructions are here: http://gr5.org/cores/ Note that original 3dsolex cores were called "Hardcore" in their eeprom but hitting "ignore" all the time got to be too much at some point especially with "cura connect" so now they are also "AA 0.4". Note that I sell 3rd party cores that work with UM3/S3/S5 at thegr5store.com.

So from the image it appears your model isn't sitting flat. One circular area is touching the bed but the rest is not - it is maybe 0.00000000000001mm higher. You could fix it in cad but a faster fix is in cura. Go to menu "preferences" "config cura" and go to "general" tab and uncheck "automatically drop models to the build plate". Then use the move tool and click on the part and set the Z value to a negative value. Try -0.2mm to start then move that value closer to 0mm until it slices "wrong" again and go back. If you are lucky you only have to shave off 0.1mm of the bottom of the part to get it to print "correctly".

Damn. That should have worked. Maybe restart cura? Or is it possible that your part is taller than the gantry height of 25mm? I guess there might be some json file that defines these things (print head settings) and the settings in "machine settings" are ignored? Maybe @burtoogle knows?

Which UM printer do you have? Instructions for recovery vary depending.

Because it doesn't want you to print two things side by side if they are long like that. It's worried that if it prints the part with the right nozzle then the left side of the print head better not hit any part to the left that was already printed. Same thing on right side. But it's basically a bug because that only applies to other parts - not to the edge of the printing surface. You can easily work around this a few ways - I'd go into PREPARE/manage printers/machine settings and change xmin and xmax to zero (but first write them down so you can restore them to the correct values later).

QR is designed for UM2 series (um2go um2ext). DDG is designed for the UM2+ series. I am out of the habit of choosing "change filament" in the UM2 menu. Instead I just slide the filament in and out. You can't do that quickly with the QR. That's one thing I don't like about the QR. Also the QR sticks out a lot in the back of the printer and especially if you move the printer often it can get in the way (hit into doorways for example). But both feeders are excellent. I have the QR on my UM2. But again, the feeder that comes with the UM2+ is quite excellent. It can push very very hard on the filament (about 15-20 pounds). It has a nice lever that you can slide the "wedgebot" (look it up on youmagine) under to insert and remove filament.

UM still supports the UM2 so I think you are safe for a few years. Just don't expect new feature upgrades (although it could happen). Also there are 3rd party sellers of many UM3 parts.

Don't do the QR on the UM2+. It's twice as expensive and not as good. The DDG is much easier to install - it drops right in.

I sell that also - I assume you mean the DDG. The "plus" feeder that comes with the UM2+ is excellent. Really really top notch. However it is not rated for highly abrasive materials (carbon fill, glowfill, glassfill). So I only recommend you upgrade if you plan to print with those or if you already wrecked your feeder with CF filament. I know we drool over shiny things but in this case I think you will be happier with the "plus" feeder. I sell the feeder also (thegr5store.com) but don't want to encourage you to buy it from me as my assistant just flew off to Europe for the holidays and would rather not sell anything until Tuesday. 🙂