lars86

Thanks for testing Titus. What material are you printing with? Are you printing directly on glass? For my tests, I am using PLA, and printing on a thin layer of glue, with only a little warmth on the bed. Everything stuck nicely. I really avoid going to full bed heating on PLA prints, as it makes it impossible to get the same level of print cooling, and you lose a lot of crispness and overhang ability in the print. It looks like, from your photos, that there were still adhesion issues. This makes it hard to compare results objectively. Especially, the 4th print. The .4mm overlap looks very similar in the photos, but the blue color makes it hard to see. Your eyes will probably be able to see better than the camera.

The point you are describing, is the seam. I can see it very clearly in your lizard print. That is what I am trying to improve.

UM2 files have been updated for proper footer code.

Thanks! I wouldn't worry much about the inside of the part, as it isn't actually representative of a hollow part. This was a solid model, and I sliced with 0% infill, so the exposed inside face would always be hidden by infill. If the model was actually hollow, Cura would treat the inside perimeter much like the outer surface.

Awesome, thanks for the results! I'll check into the end of print retract and try to fix those files. It looks like your results are very similar to mine. I know it can be very hard to photograph the seam in a way that fits with how they look in real life. It's easy to over or under-exaggerate certain features. In your opinion, which print gave you the best overall seam?

I reprinted all tests last night to include the .6mm and .8mm overlap tests in my results. For me, I would say a 0.6mm overlap gives the best result.

Did you try my settings for accel and travel velocity?

Okay, all files converted for UM2: https://dl.dropboxusercontent.com/u/60958586/Seam_Overlap_UM2.rar

Hi ! This prints great without a problem, nice work ! It doesn't override the machine's settings anymore. I see the flow is automatically set to 638%. I have a flow rate between 2 and 3 mm^3/s. It doesn't scratch the build platform anymore. Thanks ! By the way, what would be the best color to print your models, to have the best vision possible of the seams ? Awesome to hear, and thanks for testing it! (sorry the other one dragged the nozzle!) I will modify the rest for UM2 and post them. For color, I would say dark. Black is best in my eyes for showing imperfections (just like in car paint jobs).

Try this file I modified and see if it works: https://www.dropbox.com/s/lel2i7a9hirxgib/UM2_Control.gcode?dl=0

You are correct, it should just be a straight multiplier. I calculated at one point, and it was 6.__x, so your calc is probably right. If you download the files that use the flow multiplier to correct for 1.75mm filament, you could just edit the flow multiplier M code in the header for the 638 value, and let us know if it works.

The issue is, which you already found out, the UM2 expects the extrusion values in mm^3, and the older machines use just mm. The relative distances are way off, so you got massive under-extrusion.

Sorry about that! I just added the note to the original post, that these files are Reprap style gcode, for Ultimaker Original (and + I think), but don't work on the Ultimaker 2. I can work on another set for the UM2, but you are the first who has expressed interest.

Mind sharing a macro photo of one of your seamless prints? I'd say that the more likely case, is that you have random seam placement in your slicer settings. This just distributes them all over. They will look like tiny holes in the surface if your seam is dimpled, or pimples on the surface in the other case. I can see what needs to change to move from UM to UM2 code, but it's a bunch of work. If only one person with a UM2 wants to try, and they already feel like their seams are perfect, I'm not sure I'd invest the time.

Good point Titus, I forgot that the UM2 uses different gcode flavor. In looking at that more, the differences seem to be: no real header code, retracts with G10, and extrusion amounts in mm^3, not mm. I'm not sure there is a clean way to quickly port all my modded code for UM2. I think the best bet would be to regen the code for UM2, then alter to add overlap. I really wish the seam location was exact, but it wobbles a little, and that makes it harder to automate the changes. I would be far more inclined to jump on this and do it, if the interest level wasn't so dismal. It's really sad, because before the new forum software rolled out (wayyy before it was ready), the community was pretty awesome. Now it seems all the doers were pushed away by a clunky interface, and were replaced with browsers. When you say that you don't have "trouble" with seams, what do you mean exactly? Seams are never really trouble, in my eyes, but if they are visible, they are ugly. That probably bothers some people more than others. My goal is to be able to challenge someone to find the seam on my prints, which is a fairly high bar. Would you really say that an aligned seam is hard to find on your prints?

Here it is! I finally was able to write a regex search and replace to change the 116 overlap positions. Cura had shifted the start/end points, very slightly throughout the print, which made it hard. You will probably need to add the XY shift code in for your smaller bed, and push through your script. If you want to send back your processed versions of the 0.6 and 0.8 overlap code, I'll add them to the original post. https://www.dropbox.com/s/76ngzpusmzcwjlt/Overlap_0.8.gcode?dl=0

556 views... 1 participant. Killing it!

I have never owned or used one. It would be interesting to see if Tom would re-review it with the newer software version. Do you have any references about what has improved?

You are correct. In order to have an aligned seam (especially important in this test), you need to do a quick reversal after the overlap segment. Once we can make an aligned seam almost disappear, I really think that you can switch to a random seam placement, and lose it all together. I run fairly aggressive travel speeds, and think in these test files I have that set to 190 mm/s. What I would suggest, is for you to turn your XY Jerk, and/or XY Max Accel settings down. I don't know where the defaults are set on your printer, but I feel that the UM's come set too aggressively. My machine is quite rigid, and low friction, so I can get away with more aggressive settings in general. I currently run at XY Jerk = 14, and XY Accel = 2700. If you want to be a little more conservative, setting them to 12 and 2000 will net nice motion too. You may also want to put a hard limit on XY travel speed. You could set that around 160 to calm down the fast travel moves.

Hahahaha! I know I'm a picky pain in the butt on the Cura Github, but it is really out of love! I know you guys have cumulatively put in an absurd amount of time and energy on this piece of software. We seriously appreciate it, and plain and simple, it makes great prints.

Okay, I went ahead and cleaned up the original post for clarity. I also took out the code which had no coasting. Since it appears to have no appreciable difference on the seam, it was a redundant print.

Good luck with the print! I just printed the 0.6mm overlap and saw even better results. It is now hard to tell the actual seam from the slight ripple from the print head settling in after the travel move. I guess I need to make a 0.8mm version now.

That is welcome feedback. Like I said initially, I would like to hear people's experiences with perimeter seams. Confirmation of my theory is nice, but I want to see what the majority experience. Would you mind posting a close up of a print from S3D, with an aligned seam for reference? This thread is about whether overlap will improve prints in the new Cura, so it isn't directly applicable. But I'm interested to see.

One week since posting. 300 views. One person has responded. This forum has devolved into a sad lurker majority.

Okay, I modded one for a 0.6mm overlap, and added to the original archive. Here is a direct link as well: https://dl.dropboxusercontent.com/u/60958586/Coast_Overlap_0.6.gcode