Posts: 1
Joined: Mon May 06, 2019 11:18 am

Re: Extrusion blobs with S3D

Mon May 06, 2019 11:34 am

The blobs happen after the line. For some reason the nozzle pauses too long after and when it goes to the next line. Coasting doesnt do anything. I use more retraction 7-9mm but that was before I calibrated my extrusion settings. I havent used simplify3d lately. Or should I say S3D is better if you want to print something quickly and the supports are spectacular. If I want to get a perfect print I have to use Cura. I have been able to get s3d to make the blobs much smaller but I was printing .1 layer height.

To the guys point about a lot of people using it and not complaining. Most people don't expect the level of perfection that I want. Even some of the bloggers prints look horrible in comparison.

I will attach a couple of pictures. With cura I was able to print a gear bearing with PETG. If anyone has printed with petg you know how much of a B1tch that is. It took a while to get the settings right but it pops loose with very little force and is smooth as butter. It was impossible to do with S3D. I havent tried the upgraded version.

I am running a cr-10 upgraded to cr-10s (Board and LCD). Upgraded to TH3D firmware (Marlin), EZABL, Bondtech direct drive extruder (The direct drive is recent I didn't have it when I printed the gear bearing or much else. Still getting the settings down), frame Stiffeners, Hard ABS mounts, I need to put a new fan mod on using stock right now because of Direct drive extruder.

Here are some test prints. That is a hard drive under them for size reference. (The dragon and the girl are old/test prints.)

Posts: 2
Joined: Sun May 19, 2019 7:52 pm

Re: Extrusion blobs with S3D

Sun May 19, 2019 9:32 pm

I've had this "pausing" and blobbing problem as well. Made some great progress today.

I manually compared the gcode from S3D & Cura for a hollow, 2 perimeter cube. S3D was retracting between every layer...which what was the biggest cause of the blobs.

Changed the following settings under "advanced" and it helped a great deal (though not perfect...yet..Cura still has ZERO blobs with default values). My retraction is 6.5 mm for both Cura & S3D and with a 5mm/s max extrusion speed, it sits there for about 1 sec retracting.

Check the box: "Only retract when crossing open spaces"
Uncheck: "Force retraction when crossing open spaces"

ALSO: under layer tab, "line width" defaulted to 0.48 mm. When I selected "manual" and set this value to "0.4" (for a 0.4 nozzle), I got my best results with "No coast" & "no wipe." This Gcode looked the most similar to the Cura output. Random start for perimeters has some stringing problems with this setup.

Still have a blob at the bottom to hollow layers transition (must be retracting there even though it doesn't need to.)

It is also worth noting that Cura uses a couple of "small" (0.4mm) extrusions at the end of each side. So it looks like Cura keeps a continuous flow going by smoothly transitioning between ??? (maybe the first perimeter and the 2nd?) without stopping the flow of plastic rather than stopping and moving like S3D does. Bigger file but the results are obvious to those of us with this problem.

Note: Was printing with PETG and my printer has a very long bowden--so oozing has always been an issue. But none of this explains why Cura is slicing better than a paid product (fortunately, my 2 week trial is not over yet....)

Please post any improvements you folks find.

My OpenScad code for the cube I used to debug is as follows:

difference () {
translate( [.8,.8,.8] ) cube( [18.4,18.4,20]);

Good luck!

Posts: 2
Joined: Sat Jan 12, 2019 8:45 pm

Re: Extrusion blobs with S3D

Sun Jul 14, 2019 9:41 am

So has anyone actually figured this out yet?

Posts: 1
Joined: Tue Nov 05, 2019 9:41 pm

Re: Extrusion blobs with S3D

Tue Nov 05, 2019 9:52 pm

I'm having the same issue with TPU, changing the extra retraction to a negative value worked great for the cube but then lead to a new problem. I was printing something else that had lots of retractions which eventually ran into under extrustion (the negative value adds up pretty quick).

From what I can tell it is overextruding at the start after a retraction. Maybe theres a way to avoid resuming from retractions on perimeters?

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