PETG Infill Rot

[pyronaught]

Ok you need to download the latest s3d release. Its 3.1. 3.0 had lits if bugs. S3d never over writes the old version so you can always go back. As for your speed, your probably better off with an e3d volcano. It will exctrude way faster. You can only push filament through a hot end so fast before the back pressure takes over and you strip it out. All depends on your layer height though and extrusion width setting. 6000 would be no sweat at .15 mm for instance but not at 0.3. Its just too much material. Fast honeycomb is as fast or a touch faster than rectilinear.

It's not the print speed of honeycomb that was the problem, it's that infill pattern causes s3d to take forever to prepare the g-code and then my computer runs out of memory in the process. I'm guessing it just requires a lot more g-code to generate that pattern than it does straight lines. There's a "grid" pattern that is fast to generate though so that's what I'm using. I tried it at 6000 speed and was still getting a rough surface indicating some of the infill lines were breaking. I've dropped it down to 3600 now and it appears to be working. So I'm testing all suggestions on this print to see how far it gets: 245 temp, 3600 mm/min, non rectilinear infill and minimal tension on the filament drive screw, plus I replaced the nut with a nylon lock nut to insure the screw does not stray from its tension setting. Nozzle has also been blow torched and feed tube drilled out with 2mm bit. S3D is estimating 48 hours to print, which based on how far off S3D print times usually are means 72 hours. The amount of plastic exceeds a 1Kg spool so I'll have to feed in a new one if it gets that far.

[jimc]

Thats why i said get the latest version. Honeycomb should take no longer than anything else. It should slice your model in seconds. At 6000 its probably severly underextruding because the hit end just cant melt plastic that fast.

[pyronaught]

This is the first print I've ever done in PETG that didn't have blobbing on the nozzle. I just thought nozzle blobs was a fact of life with PETG, but with the above settings they are gone now. Sweet!

[jimc]

Blobs are from over extrusion or when your infill looks all crappy like in your pic.

[pyronaught]

Blobs are from over extrusion or when your infill looks all crappy like in your pic.

I think blobs also come from stringing, where the nozzle runs into strings and they accumulate. I'm not getting any stringing now either, so the lower temp got rid of that too.

[jimc]

Absolutely. Any plastic sticking up above the nozzle level. Petg is just so sticky that the nozzle will just collect all that stuff. Abs and pla the nozzle just sorta pushes it around or rides over it. Good luck with the print. Let us know how it goes

[pyronaught]

I actually aborted the print after it became apparent that the problem was solved. I didn't want to go through a whole spool of PETG printing a duplicate part of something I've already finished in ABS. Also after sanding down the ABS part and then sanding on a partial PETG part, the ABS part was a lot easier to sand than the PETG. The ABS just knocks down a whole lot faster and since there is a ton of sanding to do on these things in preparation for using them as mold halves,that is a big plus in favor of ABS. Combine that with the much faster print rate of ABS and it just becomes the obvious choice. If ABS+ reduces the warping problem by 50% as claimed then that should be enough to keep the corners from flipping up.

I feel more confident using PETG for other projects now though, so I'm glad the cause of PETG infill rot was identified and solved. Thanks!

[pyronaught]

I think you can use the ABS slurry directly on the MIC6,( right insta)? It's just flatter than glass, and it carries the heat all the way out to the edges. (Which you need for something that large.)

Talk to insta. He prints ABS on his MIC6.

I print eSUN's ABS+ on MIC6+Kapton+nojuice.

ABS+ is the secret sauce though.

Picture below is eSun ABS+ on kapton with juice. I did not notice any difference in warp compared with regular ABS. This was straight out of the sealed bag too, no chance to absorb any moisture. Disappointed.

[jimc]

abs+ still warps for sure. normal esun abs has a shrink factor of 0.8%. its been awhile since i tested it but if i remember right the abs+ was 0.65% so yes it warps less but marginal.

[insta]

I think you can use the ABS slurry directly on the MIC6,( right insta)? It's just flatter than glass, and it carries the heat all the way out to the edges. (Which you need for something that large.)

Talk to insta. He prints ABS on his MIC6.

I print eSUN's ABS+ on MIC6+Kapton+nojuice.

ABS+ is the secret sauce though.

Picture below is eSun ABS+ on kapton with juice. I did not notice any difference in warp compared with regular ABS. This was straight out of the sealed bag too, no chance to absorb any moisture. Disappointed.

abs_warp.jpg

Man, I was printing largeish (5x5") boxes straight on Kapton with no juice, with a 5-line brim and zero warp at all. I also had more of a first-layer smash than you do.