Translucent PETG

[sTaLa]

I just began using PETG. So far I used:
- Orange opaque from filaments.ca
- Red opaque from MG Chemicals.

Juicer Opaque PETG (1)

Juicer Opaque PETG (2)

I had really good results with both. Just look at that Orange Juicer: No clean up at all on what you see.

But, I just began to use translucent PETG: I just designed that robot arm and sold this idea of seeing all the air channels through the arm... I should have just stick to opaque.

Anyway, this translucent PETG oozes like crazy. I began printing at 247C, and would not go passed three layers.
Bed fan is On from second layer until the end.
So I just decreased the temperature to 225C. I almost finished the print, but a blob formed and it just stopped printing as you can see on the picture below.

Translucent PETG at 225C

The specs of the filaments.ca PETG I am using is 200-240C. Which is far from the 247C Jules was advising (thanks a million times for that write up on PETG Jules btw!).
My next step will to lower the temperature some more since it seems to make improvements.

Is there something I am missing?
Should I focus on another parameter?

Thanks again guys!

[jimc]

be sure to measure your filament accurately and make the change in your slicer. a very small amount of material collecting on the nozzle during a long print is normal with petg but if its excessive then that is a sign of too much material....over-extrusion. also not uncommon to see a difference between colors, especially from opaque to translucent.

[sTaLa]

Checked!
I adjusted the filament diameter to 1.70 mm in SD3, which is what I measured on the filament. It seemed pretty low to me, but that was the measurement.
I just went over and it still between 1.70-1.71 mm. Some points at 1.72mm, but mostly 1.70-1.71 mm. It could have increased in the middle of the roll...

[sTaLa]

Just did another run at 210C.
I turned the fan off at about the 6th layer. It seemed to me at that time that the air blowing was flipping over some of the filament layed down.
It did not prevent that filament from cutting those corners though... All those strings/cut corners are far beyond the 6th layer...

[sthone]

How fast are you printing?

Try the settings from Black PETG settings thread. I just did a 16 Hour print with them and it came out mint. Even though its for the black I use pretty much the same settings for the trans red and it also works great.

[jimc]

210 is too low. Extrusions are not sticking to one anither. 240 and it actually looks like your slightly underextruding because those pulled perimeters arent stuck to the perimeter next to it but that could just be temp related.bump up the temp first, test and then make extrusion adjustments. Fan should be off for petg. You dont need it unless you are printing a small part or have layers that print very quick and get heat soaked.

[Jules]

Agreed. 210° is too low, because your filament is too cool to bond to itself on that last one.

The 225° print looks good....might be a little bit too warm still - (you could try 220°).

The big glob that you got on the back of the nozzle is caused from strings that your nozzle picks up as it travels. PETG is a super sticky filament - you can increase the retraction by about 0.4 mm to suck it back up farther, and make sure you have a jump on retraction enabled.

But sometimes, I have to reach in with the tweezers once in a while and carefully scrape it off while it's running, so it doesn't char and land in the print. Just depends on the filament.

Very important to clean the buildup off the nozzle after a print finishes too, while it's cooling, so you don't have trouble with the next print.

[sTaLa]

I think I just nailed it!

Listening to you guys and reading got me conviced there should not be much difference between opaque and translucide PETG. So I went back to the parameters that got me good results with the orange PETG, and got what you can see below. I did not change a single thing from the Orange Opaque to the Blue Translucide.

The first time I tried printing with the blue, I went upfront and measured my filament diameter. I had 1.70-1.71 mm, with some peaks at 1.72 mm. So I dialed in 1.71 mm in SD3.
Then I tried printing and you can see the results above and the posts from Sept. 13th.


Now for my successful print I changed two variables: SD3's filament diameter and cleanleness of the nozzle.
1. In SD3, the initial value from my Orange PETG was 1.72 mm instead of 1.71 mm. So I did my successful print at 1.72 mm even though the diameter was slightly less. In a way this makes sense: my understanding is that a lower value in SD3 will make the printer extrude more plastic to compensate for the smaller diameter. And was feeling I was extruding too much plastic, thus creating the ooze and the blobs. I have a hard time believing that really is the root cause though even if it theoritically makes sense: .01mm variation is much less than the +/- 0.05 mm guaranteed by the manufacturer.
2. Also, I cleaned my nozzle in a better fashion. I used to only clean it with my tweezer after every print, but this time I used a brass brush.

I have been printing at 50 mm/s the whole time to answer Sthone.

Jimc,
You mention underextrusion on one of my prints. Could you point me towards this? Because if that is the case, my understanding is all backward .

Here's a pdf of all my settings (based on Jules' Black Esun):
http://www.filedropper.com/2016-09-14-p ... ilamentsca

Thanks guys I love this forum!!!
I now will be preparing for a 60 hours print with that filament...

[jimc]

well the extrusion volume is calculated by the filament dia as you already know and it is also fine tuned with the extrusion multiplier. i said you were under-edtruding BUT if your temp was too low, that can cause too little material to be extruded as well even if your settings are right because the printer simply cant push out the amount of filament required due to the temp being too cold. the melted plastic is basically too stiff. now if you under-extruding then the extrusion width in real life is smaller then what the slicer thinks it is so 2 perimeters side by side wont touch and be bonded to each other. when it comes to extrusion think of a 3d printer as a computer controlled caulking gun.

[zemlin]

I just updated the Calibration Cross, btw. Glad to see someone using it. Hope you find it helpful.
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