Outline Shells Not Bonding

[mrbanana101]

Hi all, running into an issue here I just can't seem to solve.

I'm printing a hollow model in PLA using 3 perimeters/outline shells, no infill at all. No matter what I seem to do, the outline shells just won't bond to each other, such that you can easily take an xacto knife (or maybe even by hand) and pull the outline shells apart. This completely decreases the durability to the point that even applying slightly pressure to most parts of the print cause it to bend as if it were just a single wall thick. I've searched for awhile on the forums with no luck (either they never solved the issue, or their solutions don't seem to work for me).

Some background info and what I've tried: I'm printing at 120 mm/s with an FLSun Delta QQ-S. Thinking it was an underextrusion issue at such a high speed with the shells not bonding to each other, I raised the temperature from 190 C to 200 and 210 C without any success. I upped the extrusion multiplier from 0.9 to 1 and then 1.1. It certainly extruded more, because the print was covered with tons of blons and zits, yet the outline shells still didn't bond together. I wanted to continue printing at high speeds, but afraid that it just wasn't going to work, I lowered the print speed to 80 mm/s and lowered the outline shell speed to 48 mm/s. Absolutely no improvement whatsoever. I changed the outline overlap percentage from 15% up to 50% and higher, but I assumed it wouldn't make a difference since it seems to be only for infill (and the print confirmed that). I even tried manually adjusting the extrusion width just to see.

So between making a dozen test prints or so adjusting temperature, speeds, extrusion multiplier, and extrusion width with varying results on surface quality but 100% the same no-adhesion between just the perimeter shells, I'm at a complete loss.

I was able to get a pretty beautiful print, nice surface detail, very, very few deformities, etc., with the only significant issue still being the outline shells not bonding to each other. No matter what settings I tinker with, nothing seems to help. I tried slicing and printing in Cura instead just to see, trying to use the same exact settings from S3D (temp, speeds, flowrate, layer height, etc.), and the shells bonded wonderfully and I ended up with a solid, durable print through and through. So what could I possibly be doing wrong in Simplify3D?

Any suggestions are greatly appreciated, thanks!!

[mrbanana101]

Just wanted to update on this issue. It seems to be mostly fixed now - the outline shells are bonding together tightly enough in most areas for me to no longer consider it a significant issue. I had tried upping the extrusion multiplier from 0.9 to 1, then 1 to 1.1, and I there was no noticeable improvement with the shell bonding. I decided to give it one more shot and bump the extrusion multiplier up to 1.2 with much better results. Because I increased the extrusion multiplier, I also increased the temp a bit (for PLA, from 190 up to 210) to avoid any potential under extrusion. Wanted to share incase anyone else tried increasing the extrusion multiplier but, like me, just needed to go one notch further for success.

[Trigger82]

Well your not the only one.
Had Simplify3d for 2 days now and can't get the same print quality I can on Cura ???

But heres a pic of my delamination

[Ayres3D]

The normal reason for this is that the thickness of the wall that's being printed is not a multiple of the extrusion width. eg extrusion width is 0.4 and the wall is 1.0. That leaves a 0.2mm gap between two 0.4mm extrusions. If this is what's happening then the best option is to play with the wall options in the Advanced menu. Typically, set single-extrusion fill which will create a narrow single extrusion between the two "full" ones. You could also "force" it by upping the extrusion width, but this is a less elegant option.

[Trigger82]

That was one of my first print with S3D, I ended up using that single extrusion infill. Didn't quite help. I also noticed I was getting a little under extrusion in other places. Then I noticed the default extrusion multiplier was set at 0.9, with a bit of fiddling its happy at 105% and no delamination, infill gaps etc. Just nice happy walls.
Its just taking a bit of tinkering as I had previously spent 3 weeks on Cura learning and now trying to work out what does what with S3D

[Extrudor]

Hi,

I had the same Problem here after i went from PLA to PETG. Everything seems to be great but the outer perimeter wont stick.
Tried all the sugestions but none helped.I calibrated my extrusion stepper 2 months ago but i always had to pick a extrusion Multiplier below 1 , i my case 0.9 or 0.88 for a clean print. Didnt know why but it worked for me.

Then i tried something completely different.

Imagine your nozzle (because its a cheap replacement part) isnt exactly 0.4 mm ? What if its 0.35 ? The Slicer software calculates a bigger space berwen the Perimeters for a 0.4 mm nozzle and the real extrusion is printet with 0.35 so the Perimeters are slightly to far from each other and wont stick propperly.

My Solution was simply to select a nozzle size of 0.35 instead of 0.4mm in s3d and set the Extrusion multipilier from 0.9 to 1.0 . The result was the same perfect print as usual including the outer perimeters bond together like hell.

Greets and happy printing