gr5

That's... strange. I've never had to adjust flow for PLA. The bottom layer I've done tons of adjusting on in every possible way (thickness, flow, adjusting screws, initial horizontal expansion) but not the subsequent layers. I've been printing for I think about 8 years? I have 5 active printers. I mean I *have* adjusted the flow but I always end up back at nominal, 100% flow.

Please post some pictures. Also know that the gcode is almost useless to us - more useful would be to do a "file" "save" from Cura. This creates a 3mf file that saves all your printer settings, your profile, your stl(s) and any modifications to the STL (such as mirroring, moving, scaling). I guess it would be good to save the 3mf from the left and right version. But most importantly post some pictures. It seems extremely unlikely that the problem is in the model or in cura. More likely something happened with the printer in between. Did you go back to a "left" print and did it recover?

I'm skeptical that it's temperature as with this smaller model it looks like it would have to change temperature very fast. But it's easy to check - watch the temperature on the UM2 while it is printing and make sure it doesn't vary by more than 4 degrees from coldest to hottest. So the other thing that happens when it is only printing the 2 towers is that the printer slows down. A LOT. Probably 1/3 the speed. Because of a feature called "minimum layer time". I bet if you drop the speed by 3X in Cura the quality will go up a lot.

Oh - and another thing - you need the arduino USB driver installed. Maybe you only have that installed on one computer? It gets installed automatically when you install any version of Cura. Oh right - you get the "ba-dum" even if there is no driver. Hmm.

So you get the "ba-dum" when you plug in your keyboard and/or mouse but not the UM2? Check power. Check power cable. I've seen it where the power cable feels like it's in, but it's not. I can't imagine how you broke the PCB but it kind of sounds like that may have happened. I've never heard of anyone breaking it when they connected a USB cable but I suppose it's possible. You can order one from your reseller.

good. So sketchup is great for architectural models that *won't* be printed. It's good for creating walk throughs. But it's not as good for creating real things, like printable models, things that you can hold in real life. Most cad software will not let you create non-solids but sketchup has no problem with it. So if you are still new to sketchup I recommend switching but if you've put in over a few hundred hours then I'd stick with it. Here's a guide on using sketchup for creating manifold models: https://i.materialise.com/blog/3d-printing-with-sketchup/ It took me over a year before I could use sketchup like driving a car - I could do things without thinking about it. My fingers would jump to the right shortcuts and so on and I could do things real fast. When I switched to Design Spark Mechanical it was frustrating for a while but after about a year with DSM I can now make things just as fast. My fingers fly over the mouse and keyboard without me being able to tell you what I just did. Thought turns into action.

This would make sense if your normals are backwards. Did you download this model? Or create it yourself? If so what CAD software? Since it's architectural I'm going to guess sketchup. If sketchup then right click on all gray surfaces in the gaps between the windows and make them white by selecting "reverse faces". Alternatively, Cura has an amazing plugin to test your model to see if something is wrong with it and can repair a very few of the many potential problems: In the upper right corner of Cura click "marketplace" and make sure you are on the "plugins" tab and install "Mesh Tools". Then restart Cura. Now right click on your model, choose "mesh tools" and first choose "check mesh", then "fix model normals" and "fix simple holes" to see if that helps. Cura doesn't fix most issues so...

If cleaning doesn't make any difference then it probably wasn't dirt. There can be many issues with the Z screw, the Z nut, or the 2 Z rods. My guess is the Z nut. Or something completely unrelated to Z such as a temperature issue where there's something wrong and the nozzle temperature varies randomly.

I think it's only 2 screws to remove the cover on the main board. It's a little tricky removing the connector though without seeing what you are doing but I've done it so many times I leave the board mounted and in place. Erin is the expert so you should try it her way. She has assembled and repaired a lot of UM printers.

Please see my 4th post above. Does the COM port show up as described? which com port is it? What baud rate and port did you use in pronterface?

Lowering the print speed will help a bit with those bumps in the photo. Also make all the print speeds the same speed (I think there are 7 printing speeds) but keep the travel speed fast. More important than the printer's Z speed is the Z acceleration. I read a good article about increasing Z accel for my old printer and it really helped a lot. I kept increasing accel until it would skip and then I backed off by about 50%. now Z changes are so fast it's like a "click".

Please attach the log file from Cura.

At first I didn't understand - PLA bridges just fine. But I realize you have a hole in the middle of your layer above the nut. When it goes to print that layer it prints a circle just above the hole in the nut. That circle turns into an ugly mess. So the solution is simple. In CAD model 2 layers above the nut to be a slot that reaches end to end over the nut. That way it won't print a circle of the nut. Then the next 2 layers make it a square hole. Then the remainder can be a round hole above that (if you don't like square holes). Here - pictures are better than words - this is your issue almost exactly: https://shop3d.ca/blogs/blog/3d-printing-tip-1-designing-better-3d-printed-holes

Maybe the STL file is too big? Not sure but this is one possibility. How big is the STL file? I would try exporting a smaller STL file with fewer triangles. Try to keep it below 1 million triangles (about 50MB). I usually aim for 100K triangles in my STL file. You can change the settings in fusion 360 on the export step or you can decimate (reduce) using this wonderful method: http://www.shapeways.com/tutorials/polygon_reduction_with_meshlab The nice thing about meshlab is that it also tells you how many triangles the STL has when you load it and also again at the bottom of the screen. Meshlab is quite fast.

What Carla said. Also note that you can right click and drag to orbit around your print and mouse wheel will zoom in and out. Also shift-right click drag will pan so you can recenter what you are trying to zoom in on.

This looks like alternating underextrusion and overextrusion. The lines that stick out - do they go all the way around? Or are they only on one side - does the same exact line continue all around? If not then it's probably a issue with play just X or just Y axis. But this looks much more like a Z issue. If the Z axis (up and down) doesn't move far enough then there isn't enough space for the molten filament and it sticks out like this. This may happen for one or 2 layers and then suddenly it moves farther (catches up) and you get a layer of underextrusion. One test for this is to put a brick or other heavy weight on the bed. It should get better. Try cleaning the Z screw. Just do a quick cleaning to see if it's better. On the UM2 it's pretty easy to unplug the Z stepper and remove 4 screws and the entire stepper/z-screw assembly all slides out the bottom of the printer. Then you can clean it much better over newspaper using WD40 and rags. Then when it's clean and dry, add just one drop of grease.

When I ordered my 2 part silicone I also ordered some mold release. If you don't know what mold release is, look it up.

It sounds like your bed isn't as flat as you need and the raft takes care of this. What kind of printer do you have? Does it have multipoint leveling? It might be worth it for you to make your print bed super flat using shims or something and a good straight edge to test flatness of the bed.

Note that raft is an old technology - not used much these last 7 years or so. It was used back in the day before PLA became popular and before heated beds when we just had ABS filament only. It was the only way to get parts to stick to a cold bed. Now with heated beds, and ABS glue stick and PVA glues and so on, it's just not the preferred method. It gives an ugly bottom to the print when you remove it. And I suspect the makers of Cura have never used it for it's original intention so probably didn't make it very flexible (which is what you need so the part can shrink without separating from blue tape or whatever type of bed you have.

there's a parameter called "build plate adhesion type". Set that to "raft" and then all the raft settings will be accessible.

Once a bowden has slipped out once or twice you really need to cut a few mm off the end so it has a fresh spot of bowden to grip with the blades.

Oops. Somehow I missed this part. Can you take the collet out and send a photograph of the blades in the collet? There are 4 blades - like razor blades. Curved to the shape of the bowden. So when reinstalling a collet it is good to push down on the tube and the collet. Then while still pushing down on the bowden tube with one hand, lift the collet with the other. Then lift the tube and it should hold the collet up. While the collet is up, slide the clip under. I have to tell you that I've never had this problem (bowden slipping out a lot). Well I had it a few times on my UMO but not the later machines that I own (UM2, UM3, S5).

Oh! I see you have an UM3. How old is it?

What kind of printer do you have? I saw something recently... I'll go look it up. I think it applied to certain Ultimaker printers?

It took me a while to figure out what a backing tray was. The ice cube tray mention actually somehow helped. I fixed your spelling above. 2) I've never tried this but I'd consider something more flexible like TPLA (tough PLA) or anything to the left of PLA and ABS in this diagram. Maybe even TPU or "ninjatech cheetah" (which I think is TPU): http://gr5.org/mat/ I'm not sure how brittle ABS, PLA, etc get at freezing temperatures. Maybe someone else knows. 1) Pretty much there aren't any materials like this. I mean PEEK can do baking trays but it's very expensive and no Ultimaker printer can print it without pretty much replacing or relocating most of the parts (servos need to be outside the printer, enclosed printer, heated bed needs to have another 200W heater added, print head needs to be higher temp, firmware needs changing). HOWEVER, I recommend making a mold out of PLA and pouring silicone into the mold. Silicone comes in 2 part mixtures - look on amazon, ebay or other places. Check how hot the silicone can withstand. For example they talk about "tin" silicone which is designed for molten tin (450F - hotter than most baking). Look around for temperature limits for various silicone mixtures. Many baking products are made out of soft silicone. Like muffin trays. Silicone mold making is a very rewarding experience I have found! Also once you make a single mold you can make many baking sheets and sell them on etsy if you want. They can be custom shapes like if you want to make minion baking trays to create minion shaped cup cakes! Yay for minions! For first try it's not a big deal but if you wan't professional quality molds with no air bubble defects, you need to buy a vacuum chamber and put the silicone mixture in that to remove all the gasses before pouring into your PLA mold. There are TONS of videos about working with 2 part silicone. Check out these 2 videos: