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lars86

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Posts posted by lars86

  1. Had a lot of trouble with bed adhesion, the skirt was great, but the print was not sticking. So I upped the bed temperature to 60 degrees.

    Left(control) to right. I'd say normal is the best though

     

    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.

  2. @lars86, I decided to do some testing too.

    Printed on a UMO with heated bed+dual fan setup and Ruby .4 Nozzle. UM Blue.

    Normally I use Cura 15.04.4. and can't really say I have Z scars, other than these where you see the place the z step goes down in the same spot:

    Your gcodes are coming up!

     

    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.

  3. For me, over 0.4mm overlap, the seam is barely noticeable. 0.6mm overlap seems to be the best to reduce it.  However, with 0.6mm overlap and higher we can see a bump in the inside of the object. That's not a problem for a solid object, but for an hollow cylinder, that can be annoying.

    Finally, (on my prints), the seam seems to be picking inward on the control print and on the one with 0.2mm overlap. However, with the prints with 0.4mm, 0.6mm and 0.8mm overlam the seam is bumping outward.

     

    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.

  4. I've finally printed all the test models. It was a bit weird because there was too much retraction at the end of each gcodes, so the filament just went out and I had to insert it again at each print. Whatever. Here are the results, I used a macro lens and I tried to make an high resolution picture. Tell me if you need more pictures. Unfortunately, I won't be able to do more tests for a month, I'm going on vacation.

     

    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?

  5.  

    Try this file I modified and see if it works:

    https://www.dropbox.com/s/lel2i7a9hirxgib/UM2_Control.gcode?dl=0

     

    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).

  6. 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.

  7. Hi, I've tried your Control gcode on my Ultimaker 2 upgraded to an Ultimaker 2+... it seems to have done nothing but scratching my buildtak... A bit of fillament is coming out but the nozzle is too close from the bed (other models sliced with cura work fine). Does the gcode overwrite the Z level set in the printer before printing ? Is there a way I could generate these gcodes ?  That would be easier I think.

     

    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.

  8. 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.

  9. Just read the topic, I can imagine your irritation with the amount of response. Though it is holiday season :)Some other probable causes:

    Can you specify for which printer the gcode is? UMO/UMO+/UM2 are quite different from each other in terms of gcode input etc.

    Also, I don't really have trouble with seams, so the need is less for me, and possibly others to test

     

    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?

  10. lars86, got a Coast + .8mm you'd like me to try?

    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

  11. Latest Test Results:

    5a331edf92bef_Test_6265.thumb.JPG.275051a081a886b6cffa17ef2553091d.JPG

    The Coast .6 is showing the least zipper, but I have some concerns on the head jerking.

    I think what is happening is that at the end of the layer, after the coast, you're moving the head back .2 to .6mm from whence it came.  There is an audible 'snap' on my printer when this jerk occurs. It's kinda disconcerting. But more than that, I think it's not helping the finish.

    What if you instead continued to move the head .2 - .6mm forward (just following the beginning of the path) instead of going backward. I think this might result in even more seam inprovement as there wouldn't be an abrupt stop and retrace.

    Of course, this opens the issue of what if then end of the layer is not where it started and there is nowhere to go forward - which it probably why you do a retrace backward...

    Hmm.....

     

    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.

  12. 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.

  13. I'm in the midst of printing a rocket ship (with smoke) that takes all day. Will test you .6mm overlap first thing in (my) morning :)

     

    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. :)

  14. Me for example I haven't posted because I disagree on the approach. I think a wipe + retract like s3d does its more than enough to not even need coasting. It needs test and adjustments, but I don't get z blops or marks because it can retract on that wipe + retract when changing z. So I rarely get that on the outside.

     

    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.

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