LHawes
Posts: 30
Joined: Tue Jul 18, 2017 9:52 am

Re: Perimeter Layers Not Adhering

Tue May 22, 2018 8:06 pm

airscapes wrote:
Tue May 22, 2018 6:13 pm
So each time I print something I create a factory file with a V1 and name the gcode similar. Then If I change something I create another factory file and increment the V#.
This way you can make tweaks to the process and if it goes bad, just open the factory file and you are back to where you started. Always use save as otherwise it may overwrite your good one.. I know this does not help you now but it is a good habbit to get into.. If you have a process that works well with and you are doing a new model that is similar, you can open the factory file of your previous model , delete the model, import the new one and save the file with the new name V1 and go from there.. I don't do much in the way with profile, just the process.. if you know what i mean.

Can you save your factory file now and upload it? This way we all can take a look at the model and the settings.
Great advice and thank you very much for replying. I'm afraid I am not that disciplined though I do save factory files and multiple versions. This one got away from me. Didn't notice the problem on a couple test prints, made some changes, did not increment the factory file, and ended up lost as you describe. No one to blame.

If this print fails in the same way I'll upload the factory file for review. Again thanks for your help.

LHawes
Posts: 30
Joined: Tue Jul 18, 2017 9:52 am

Re: Perimeter Layers Not Adhering

Tue May 22, 2018 8:22 pm

dkightley wrote:
Tue May 22, 2018 7:50 pm
Rather than messing around with multiple process that get you nowhere, stick to one process and cure the problem!

Is the separation happening on all layers? If not, as I suspect is the answer, then what is the bottom of the first layer like? Is it smooth...or is it ridged, showing the individual extrusions.

If not smooth, then adjust the GlobalZ setting (on GCode tab) by a negative amount by minus 0.1mm and reprint. Check the finish again. If not smooth, repeat until the finish is smooth.


If the finish is smooth and you still get separation, try increasing the Outline overlap, slowing the perimeter print speed down, or even raising the temperature a tad. One or more of these has an effect on bonding around the perimeter. But NEVER adjust two settings at the same time unless you're 100% sure what you're doing! If one change had the desired effect, how will you know which one it was?
Thank you Doug. The separation doesn't seem to effect the first or top or bottom layers, only the far outside perimeter outlines over support. Every layer prints very nicely except for the last outline perimeters as the photo shows.

Sadly I do tend to change more than one setting which causes problems you describe. This current test I slowed the outline print speed from 80% to 50% of the default 60 mm/sec. And that's the only change. Testing now.

LHawes
Posts: 30
Joined: Tue Jul 18, 2017 9:52 am

Re: Perimeter Layers Not Adhering

Tue May 22, 2018 9:54 pm

Thanks so much for all your help.

Last print came out fine. No separation but did change quite a few parameters to get here. I think slowing the outline speed to 50% and increasing the outline overlap to 65% were the main factors. I'm printing again, and saving the factory file, to ensure I can reproduce the results.

Thanks again

GBuchwitz
Posts: 10
Joined: Mon Oct 23, 2017 3:18 pm

Re: Perimeter Layers Not Adhering

Sat Jun 02, 2018 8:57 pm

I was experiencing similar delamination of shell layers in some stuff I was printing in PETG - especially when thinner sections were subject to bending or twisting stresses. I'd had better luck in cases where I could have thinner parts printed directly on the heated bed (I've read that material bond strength generally increases with temperature), but this usually isn't an option. Drove me nuts! I'll describe what helped me with the hope that it conveys something useful. The basic idea is to get the side surfaces of those shell layers right up against each other to promote good thermal bonding - in part by tweaking the Extrusion Multiplier and Extrusion Width parameters.

BACKGROUND: S3D uses three parameters to estimate the extrusion speed required to achieve your specified layer width per length traveled. These are Filament Diameter, Nozzle Diameter (fixed), and Extrusion Multiplier. I measured and entered my filament diameter. I then printed a 20x20x2 mm cube with one shell layer and no top or bottom layers and then measured/averaged the four wall thicknesses (i.e. Extrusion Width). This along with the current settings in S3D for Extrusion Width and Extrusion Multiplier gave me the information I needed to calibrate the Extrusion Multiplier parameter.

Extrusion Multiplier (calibrated) = Extrusion Multiplier (setting) x [Extrusion Width (setting)/Extrusion Width (measured)]. This calibration estimated the speed with which S3D should tell my printer to extrude filament - per mm traveled - to achieve the specified Extrusion Width at the specified Layer Height.

BACKGROUND (Cont'd): Based upon what I've read, S3D uses only one parameter, Extrusion Width, to calculate the horizontal distance between the center lines of adjacent layers. So... the extrusion rate AND the horizontal layer spacing BOTH have to be set correctly (compatibly?) to optimize bond strength. In other words, the layer width, and the distance between layer centers must be set to promote inter-layer contact.

After entering the measured Extrusion Width and the calibrated Extrusion Multiplier into S3D (Extruder tab), I prepared to print. Zooming close in from a top view in Preview Mode I could see that there were small gaps between my perimeter shell layers... especially where I was observing delamination on previous prints! I went back and forth between editing my process and checking Preview Mode - increasing S3D's Extrusion Width setting - until the spaces between shell layers had disappeared.

I printed another trial, and found that while the shell layer bonds had improved, they still delaminated when flexed significantly.

I increased my Extrusion Multiplier from 0.91 (calibrated) to 0.95, and the resulting print exhibited no further delamination when flexed.

LHawes
Posts: 30
Joined: Tue Jul 18, 2017 9:52 am

Re: Perimeter Layers Not Adhering

Sat Jun 02, 2018 9:03 pm

VERY helpful information. I seem to have solved my adhesion problem but without the detailed analysis you've provided. If/when I experience it again I will take the steps you outlined.

Thank you very much for the follow up post - much appreciated.

GBuchwitz
Posts: 10
Joined: Mon Oct 23, 2017 3:18 pm

Re: Perimeter Layers Not Adhering

Sun Jun 03, 2018 1:06 pm

You’re very welcome. This forum has been very helpful to me, and it feels good to give something back. Much of the information in my post was relayed from prior posts from other members.

I wanted to correct an error I made in my post yesterday.

I incorrectly stated, “This calibration estimated the speed with which S3D should tell my printer to extrude filament...” What I should have said is that a calibrated Extrusion Multiplier value allows S3D to more accurately estimate extrusion speed. Extrusion Multiplier is a coefficient. It has no units (e.g. mm/second).

Nico
Posts: 1
Joined: Fri Oct 30, 2020 4:47 pm

Re: Perimeter Layers Not Adhering

Fri Oct 30, 2020 4:49 pm

LHawes wrote:
Sat Jun 02, 2018 9:03 pm
VERY helpful information. I seem to have solved my adhesion problem but without the detailed analysis you've provided. If/when I experience it again I will take the steps you outlined.

Thank you very much for the follow up post - much appreciated.
Hey there just found this post, I have the same problem, how did you rectify?

Many thanks,
Nico

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