txesc

I've been chasing down seam problems on the latest versions of cura. I print mainly curved objects without any corners to hide the layer start/stop. I was wondering if it was possible to configure cura to place the layer seam on a specific object? I've tried the seam alignment and layer start/stop but I can't quite get it right. Context - I'm trying to print multiple curved objects at once, so a small waste object is worth it if it will help the surface quality and improve the print time. Retractions are dialed in and not leaving any surface aberrations but I have a recurring problem, not with a bump but a dent where the layer starts and stops. It can be improved by slowing down the print but it's always present. Generally quality is nice, no under-extrusion etc. Thanks!

Tweaking 2.4/5 settings so far has only been able to minimise it. It looks like it's underextruding the last part of the path to compensate for potential build up, perhaps? This is even with coasting/combing/retract on layer change off. Perimeters first or infill first has relatively no effect. The seam is generally embossed rather than building up as I've experienced in the past. Strangely enough, the same models sliced with Cura 15.4.6 don't have a seam at all... So short term it's sorted I guess, although the prints are losing out on the quality and feature gains of the newer versions of the slicer.

Thanks for tips! As for layer start vs seam, why would you want to separate them?

thanks XYZ. I'll give the wipe distance a go. Moving the scar is useful but unfortunately I don't have any corners on these models. Coasting's handy but I find it creates discolouring which draws the eye, although it is a time saver on prints that are finished properly. Do you know if there's any advantage to separating where the layer starts and seam alignment? They are two options now.

I'm having trouble with the newer Curas and reducing the seam, I'm getting major scarring on round models - tubes, curves etc. I used to print similar models without this problem. I've been trying the usual solutions - slowing down, adjusting the acceleration, temperature, adjusting retraction, even different materials... I've not been printing much lately so have found it challenging to keep up with the changes in the latest versions of Cura (not complaining! I really like a lot of the new features that I've touched so far). So my question is what else effects the seam when slicing and how have the calculations changed from older versions, if they have? It's definitely seems to be happening at the slicing stage and not a printer problem; I've tried on two kinds of printer (ultimaker 2 and i3) and both have the same issue. Cheers!

Do you have combing switched off?

pm_dude mine looks like that too. but I've been fighting a number of extrusion issues for the past couple of days, so I don't believe my machine is a shining example yet.

Does reducing that overlap setting affect bridging or top-layer in a noticeable way?

So do the Bowden tube and the Teflon piece on the hotend need to touch but not exert force?

100mm/s travel? Is it in the same places each time or doesn't it matter? Are you using any skirting loops?

pm_dude were you thinking along the lines of something like this - https://www.youmagine.com/designs/printhead-bowdenfix-um2#!design-information or this https://www.youmagine.com/designs/bowdentube-holder-vor-um2#!design-documents ? Personally I'm hoping one of these will do the trick - https://www.youmagine.com/designs/bowden-locking-clamp-clip#!design-documents I haven't touched the the travel speed yet, but was tempted to take it to 200 or 250mm/s. I use 150 on my mendel style printers, but as to whether the actual speeds ever touch the speeds in the gcode is another question...

Thanks pm_dude. There's a few possibilities on there. All with slightly different wording making them fun to track down. Lot's of great ideas. What's the aim of the clip - ideally, does it restrict all movement or does there need to be a bit of give?

Thanks gr5. Good shout on the bowden seal. Mine is currently moving, but all i can do is just push it down a little more, the blue shoe doesn't seem to be doing much, each time i push it down it just pops back up again. How did you seat it better? The Z axis acceleration - is that 'Max speed Z' in the maintenance menu on the machine? It's currently set to 40mm/s, which seems fast enough. How fast does the UM go?

tl;dr - my retraction settings are a lot higher than recommended. Is that going to cause problems down the line? ------------------------------------------------- New Ultimaker 2 user here. Really impressed with how quickly the machine was up and running, the speed and the quality of prints. However, I'm quite picky and have never used a bowden set-up before. I've been trying to eradicate as much as possible the seam created by the pauses in a retraction move repeated on every layer (does Cura have a 'randomise start points' option like slic3r?). The material is the roll of PLA that comes with the machine, printing between 40 and 60mm/s. So far, I've got the seam down to be fairly imperceptible and I'm pretty happy with it. I've gone to 6.00mm @ 45mm/sec and added a 0.1mm Z-lift (hop), which is fine for a simple model with only two regular retractions per layer but I'm a little worried that with anything more complex that this will cause jamming. What's everyone's experiences with more extreme retraction settings? Do you need them? Are they more trouble than they're worth? Have you found you needed to change the settings a lot per model or does one setting generally sort them all?