Corners Bigger Than Body

[parallyze]

Your extruder is over extruding every time it slows down or stops due to the built up pressure. That's why every corner is bulging slightly. There is no setting in S3D that can help that.

That's very specific to the machine used... acceleration/jerk/JKN Advance, whatever you call it. But he's definitely having problems on the retracts, it might be more obvious if you had a look at the other thread from fatboy1271 linked somewhere in this thread.

I wouldn't suggest fiddling around with those settings before retracts are working as they should.

[parallyze]

If I print just a single cube it is much less pronounced, but it still doesn't measure evenly.

Some additional "material", maybe it can help somewhat. Remember, using the slicer you can control almost every aspect and
decide what should happen.

When looking for problems with retracts I'd use something like this:

3 simple boxes (20mm x 10mm x 20mm). Each one rotated at 22.5° to make sure the travel paths later on will go across
perimeters not only at the points where retracts happen (start and end of a layer/island):
www.aunix.de/tmp/s3d/s3d_retracts_1.jpg


I chose 3 perimeters and no infill / top layers. Don't really need them to check retracts, we can save some material and time here:
www.aunix.de/tmp/s3d/s3d_retracts_2.jpg


After setting up a single process I created three additional ones. The only difference between them:
1. Each process starts and ends at another height (0-5mm, 5-10mm, 10-15mm, 15-20mm).
2. Retract Distance (0.3mm, 0.6mm, 0.9mm, 1.2mm)
www.aunix.de/tmp/s3d/s3d_retracts_3.jpg

No coasting and/or wiping, no extra restart distance. Layer start points are aligned to the side of the bed where I
put the camera.


This is what it looks like with all the travel paths shown.
www.aunix.de/tmp/s3d/s3d_retracts_4.jpg


Now select "Preview by Line" inside the preview and check how the toolhead moves:
www.aunix.de/tmp/s3d/S3D_Retracts_Preview_1.mp4


As you can see it will do the same moves all over again. Start at the inner perimeter, print 3 perimeters, retract and move on to the next one.


This is the center one (already in the 0.9mm process):
www.aunix.de/tmp/s3d/S3D_Retracts_Closeup_1.mp4

Looking closer at the print you can see the first process using 0.3mm oozes some material which gets stuck to the outside walls
when travelling between the boxes. Also the skirts aren't really good, there's material missing/stuck in places where it doesn't belong:
www.aunix.de/tmp/s3d/IMG_1369.jpg

Process 2/0.6mm is starting to look better, but still there's some spots of material left on the outside walls. With 0.9mm they're gone.

And while it doesn't change on the outside any longer there's a difference at the start point/inner wall:
www.aunix.de/tmp/s3d/IMG_1409.jpg
(If you have a look at the lower right corner in this picture you can see an aspect of what jshell mentioned. Depending on settings
these corners might overshoot a bit or get bevelled/foreshortened. But I wouldn't start diving into this before everything else is
working.)

There's clearly some material missing - this is at 1.2mm retract distance, a bit too much for this direct drive/e3d v6 one.

This doesn't really give you values you can use because of all the differences, but maybe it can give you an idea of how to
pinpoint problems when printing. Like said in the other thread: If you're only having troubles at the start points, maybe
using a small negative value for "Extra restart distance" may help you there.

Another thing to check might be how hard your extruder grips the filament. There's often a spring which can be adjusted. If that's
a bit too loose the extruder might slip a bit instead of pulling back the filament completely but forward it the full amount after the
retract. Too tight and your extruder might have problems feeding filament at higher feed rates because of the resistance.

Oh, and yet another thing: Temperatures. Too high and the material will tend to ooze more. But as far as I can remember your
temperatures were in the ~200ish range which (to me) doesn't look to high for PLA at 0.2mm layer height (the PLA I'm using is
rated at 215°C +/- 10°C, I use it at ~210-220).

What are your retract distances right now, did I miss them or didn't you mention them here for all the cubes?

Notes:
1. All the images didn't show up when using the img/url tags. All links had "forum.simplify3d.com" in front of them, don't know why
that's not working as expected right now...
2. I know there's quite a lot wrong with that printer - it's my "tinker bot" where I change things all the time, so don't care too much
about elephant foot or vibrations or anything like that....

[fatboy1271]

Wow, thanks for everyone trying to help me out here; your time is greatly appreciated! parallyze, that's a lot of info, so it will take me some time to go through it. Busy week so it may take me some time to get to these suggestions.

[fatboy1271]

Once again, a huge thanks!

3 simple boxes (20mm x 10mm x 20mm). Each one rotated at 22.5°...

After setting up a single process I created three additional ones. The only difference between them:
1. Each process starts and ends at another height (0-5mm, 5-10mm, 10-15mm, 15-20mm).
2. Retract Distance (0.3mm, 0.6mm, 0.9mm, 1.2mm)

I knew from previous tests that these retract distances wouldn't be good, but I ran them anyway: 0.3mm, 0.6mm, 0.9mm, 1.2mm. My next set was 1.5mm, 1.8mm, 2.1mm, 2.4mm.

1.8mm showed just a little bit of extra material where the cross travels for the interior layers are. 2.1mm eliminated the extra material:

Like said in the other thread: If you're only having troubles at the start points, maybe
using a small negative value for "Extra restart distance" may help you there.

Using 2.1mm Retraction Distance and a -0.2mm Extra Restart Distance didn't seem to make much difference. I'm running another set at -0.5mm.

Another thing to check might be how hard your extruder grips the filament.

I can grab the filament and push/pull it at the extruder and it does have some play. Should there be zero play? I'll take a video and upload that later.

Oh, and yet another thing: Temperatures.

I'm currently running MatterHackers Build PLA between 195 and 205. The Black I'm using right now prints best at 205 and for some reason the White roll I have prints best at 195.

What are your retract distances right now, did I miss them or didn't you mention them here for all the cubes?

It had been 5mm. That must be the default when I first started up S3D, because prior to all of this I hadn't touched that setting.

Sorry for using Black filament, as it's hard to see some details...

Here's a video I took; is it helpful? https://youtu.be/Z1rW5HKu7oU

[parallyze]

I knew from previous tests that these retract distances wouldn't be good, but I ran them anyway: 0.3mm, 0.6mm, 0.9mm, 1.2mm. My next set was 1.5mm, 1.8mm, 2.1mm, 2.4mm.

Oh, sorry. Didn't mean you'd have to use those values, they were in a good range to go from "needs more" to "too much" on my direct drive one.

1.8mm showed just a little bit of extra material where the cross travels for the interior layers are. 2.1mm eliminated the extra material:

Using 2.1mm Retraction Distance and a -0.2mm Extra Restart Distance didn't seem to make much difference. I'm running another set at -0.5mm.

Hmm... -0.5mm is already pretty much, would've thought there'd be a difference... hmm... ^^

I can grab the filament and push/pull it at the extruder and it does have some play. Should there be zero play? I'll take a video and upload that later.

When the stepper/extruder is enabled you should not be able to move the filament.... could it be the grub screw(s) came loose somehow? If it's a bit loose and sitting where the flat part of the motor shaft is, there might be a bit of play each time the extruder changes direction. Could explain this behavior.

Preheat the machine and use the menu to extrude a few mm. Can you push/pull the filament when the stepper should be having a tight grip on it?

I'm currently running MatterHackers Build PLA between 195 and 205. The Black I'm using right now prints best at 205 and for some reason the White roll I have prints best at 195.

PLA around ~195-220°C depending on speed/volume sounds very much what I'm using PLA at most of the time. Shouldn't be the cause, PLA is usually not oozing that much below ~230°C.

Sorry for using Black filament, as it's hard to see some details...
Here's a video I took; is it helpful? https://youtu.be/Z1rW5HKu7oU

Hmm... still a "blob" when starting the layer. If you watch closely you can see that the additional material at the start is missing the first few cm on the inner perimeter. It takes a while until it "thickens" up again to the proper width and it's not bonded to the middle perimeter there. So the total amount of material doesn't seem to be off by much, there must be something else...

[dkightley]

Look at the video...and stop it at 6 seconds.

Look at that whopping great blob at the start of the extrusion. What you can't see is a similar blob at the start of extrusion of the second perimeter....and again at the start of the third perimeter - which is what you have an issue with!

So, now knowing which end, you now need to adjust the right settings to reduce the plastic flow Are you retracting? If so, are you then using Extra-restart? Are you using coasting as well, as that may have an effect on over extrusion at the start.

My first change would be to remove any extra restart. If that has no effect, dial in some negative extra restart.

Read again the section I referred you to and you shoukd be able to visualise what is happening...and you 'll then be able to work out what changes are needed to stop the over-extrusion ( or blob).

[fatboy1271]

I knew from previous tests that these retract distances wouldn't be good, but I ran them anyway: 0.3mm, 0.6mm, 0.9mm, 1.2mm. My next set was 1.5mm, 1.8mm, 2.1mm, 2.4mm.

Oh, sorry. Didn't mean you'd have to use those values, they were in a good range to go from "needs more" to "too much" on my direct drive one.

No worries! I figured why not, what do I have to lose...

1.8mm showed just a little bit of extra material where the cross travels for the interior layers are. 2.1mm eliminated the extra material:

Using 2.1mm Retraction Distance and a -0.2mm Extra Restart Distance didn't seem to make much difference. I'm running another set at -0.5mm.

Hmm... -0.5mm is already pretty much, would've thought there'd be a difference... hmm... ^^

I'll set it back to 0 and then look at what Doug was saying about the video.

I can grab the filament and push/pull it at the extruder and it does have some play. Should there be zero play? I'll take a video and upload that later.

When the stepper/extruder is enabled you should not be able to move the filament.... could it be the grub screw(s) came loose somehow? If it's a bit loose and sitting where the flat part of the motor shaft is, there might be a bit of play each time the extruder changes direction. Could explain this behavior.

Preheat the machine and use the menu to extrude a few mm. Can you push/pull the filament when the stepper should be having a tight grip on it?

When engaged there is no play!

[fatboy1271]

Look at the video...and stop it at 6 seconds.

Look at that whopping great blob at the start of the extrusion. What you can't see is a similar blob at the start of extrusion of the second perimeter....and again at the start of the third perimeter - which is what you have an issue with!

This guy?

So, now knowing which end, you now need to adjust the right settings to reduce the plastic flow Are you retracting? If so, are you then using Extra-restart? Are you using coasting as well, as that may have an effect on over extrusion at the start.

My first change would be to remove any extra restart. If that has no effect, dial in some negative extra restart.

Read again the section I referred you to and you shoukd be able to visualise what is happening...and you 'll then be able to work out what changes are needed to stop the over-extrusion ( or blob).

Here are the last settings I used in Extruder. Retraction Distance = 2.10mm and Extra Restart Distance = -0.50mm, I also tried -0.20mm and didn't see anything noticeable. No Retraction Vertical Lift, Coast, or Wipe. I still have the Tips page open in a Tab, so I'll go back and look through that again.

Should "Force retraction between layers" be checked or not?