gruvin
Posts: 8
Joined: Thu Aug 18, 2016 7:50 pm

Double over printing ruining prints

Thu Aug 18, 2016 8:39 pm

Hi

I've been using Slic3r for years. Recently tried Cura but was disappointed with the way it (doesn't) handle thin walls. More recently, I took the plunge and purchased Simplify3D. Of course, that was working well until the day after the trial period expired! LOL

I often print Thingiverse thing #26237. The upper half contains a, "thin wall".

Using Slic3r, that wall has simply never been a problem, whether I use a 0.4mm or 0.6mm nozzle. Simplyfy3D on the other hand doesn't handle it well at all. Instead, Simplify3D double prints each layer of the wall.

For example, with a 0.6mm nozzle -- my heavily preferred for just about everything -- at 0.1mm layer height, the extruder is told to lay down a nice 0.1mm layer along the length of the wall -- OK so far -- and then track back along the line doing it all over again, apparently on the [i/exact same track[/i] or at least very close to it. This blocks the nozzle (because there's already cooled plastic at that height) or spills out over the wall, creating an ugly mess.

I'm guessing that Simplify3D is seeing a wall of something over 0.6mm x 120% wide but less than that x 2 and instead of adjusting the extrusion width, "automatically" it just pumps out the usual 120% (so called, "Auto") width. This creates a giant, ugly overlap and destroys the print.

As a super ugly hack, I have manually reduced the flow rate (Marlin) to 50% during these wall prints and all appears to go well -- though I doubt a microscope or physical stress test would produce agreeable evidence.

This doesn't seem to be a difficult thing to get right, to me. Slic3r has done it for aeons. I've never known any different, in fact. To be fair, Cura (if memory serves) does a similar stupid thing, while MatterControl simply makes the wall thicker to get around the, err, problem?

I have considered going to manual extrusion width. But then the onus is on me to know the exact wall thickness in the design -- as if there is only ever one thickness. I've never looked, but I think it's 1mm and set a 0.6mm nozzle to 0.5mm output width? Well, I think not. That would ruin the bottom half of the print. Slic3r appears to simply extrude 1mm width plastic strip, from my 0.6mm nozzle -- which of course has the flat area around the exit hole, to cope with such things. Anything up to about 2mm width should work fine with what I consider to be any half decent 0.6mm nozzle design ... though only 0.9mm should ever be required. That's only 50% over width. Not a problem, in my view.

I have to say that I'm surprised -- if not annoyed, since I paid money and thus have a right to be :-P -- that a slicer that does most other stuff so[/] well, cannot get something this simple and indeed critical, right.

So what to do? I am not prepared to reduce nozzle size. Do I have to use free software to print some things and Simplify3D for others? That would be less than ideal, to be polite..

Is this a feature request? Not unless, "get the simple stuff right, please" is. Is this a bug report? Not unless, "Hey! Seems you never even tried in the first place!" is a bug report. Somewhere in the middle, then? Hence my post here.

My primary reason for liking Simplify3D is its decent, snappy (quick) user interface, plus a couple features that don't come to mind right now. Obviously, the best UI in the world is a waste if simple thin wall handling isn't even present.

MOOD DISCLAIMER: Yes, it's true. The tone of the message is one of dismay and frustration. But I've decided not to edit it away. *shrug* Thanks for understanding.

Kind regards,

Bryan
New Zealand

JohnOCFII
Posts: 34
Joined: Tue Jul 19, 2016 1:26 pm
Location: Minnesota, USA

Re: Double over printing ruining prints

Sat Aug 27, 2016 12:33 pm

I got a chuckle out of your note. Sadly, I don't have the solution for you.

As someone else who has recently moved from Slic3r to Simplify3D, I have often hit those, "How the heck do I do that <one simple thing> in Simplify3D???"

I do wish there were a "Moving from Slic3r to Simplify3D" document describing the differences. There are some wonderful features with Simplify3D, and the UI is great, and it works natively on the Mac, but there are still things that give me troubles.

John

Heutinck
Posts: 77
Joined: Thu Mar 03, 2016 2:14 am

Re: Double over printing ruining prints

Sun Aug 28, 2016 10:31 am

I personally have never used this mode, but maybe vase mode may help in printing a single perimeter object. alternatively you could change the number of perimeters to 1 instead of the default 2.

dorsai3d
Posts: 237
Joined: Mon Jan 11, 2016 9:01 am

Re: Double over printing ruining prints

Mon Aug 29, 2016 10:57 am

This is part of the larger general problem with thin walls that's been annoying just about everyone for a long time now. Please go add your voice to this thread so the S3D devs can ignore it too: viewtopic.php?f=23&t=3471

gruvin
Posts: 8
Joined: Thu Aug 18, 2016 7:50 pm

Re: Double over printing ruining prints

Sat Sep 03, 2016 5:47 pm

dorsai3d wrote:This is part of the larger general problem with thin walls that's been annoying just about everyone for a long time now. Please go add your voice to this thread so the S3D devs can ignore it too: viewtopic.php?f=23&t=3471
Thank you. I will.

Thank you for the kind support (pun?) folks.

I've been joking lately with my friends that I, "hate" Simply3D because ... hear me out ...

a) it doesn't handle thin walls well at all and
b) it's otherwise the best damned slicer available, hands down!

Oh and, it's closed source ... so I can't fix the thin wall thing myself. What's not to hate?! LOL :-P

Seriously though, it really does do an impressive job. The print quality -- mostly the lack of "funny business" is quite something.

Bryan.

gruvin
Posts: 8
Joined: Thu Aug 18, 2016 7:50 pm

Re: Double over printing ruining prints

Sat Sep 03, 2016 6:04 pm

Heutinck wrote:I personally have never used this mode, but maybe vase mode may help in printing a single perimeter object. alternatively you could change the number of perimeters to 1 instead of the default 2.
Thanks. Done all that -- except vase mode, which would ruin the rest of the print.

The problem is that a 3D model's solid walls of any thickness always have two sides. Simplify3D (and other slicers, to be fair) insist that both sides need to be printed -- usually one side in one direction and the other on the way back, on the "other side" of the wall.

Combining this with a fixed extrusion width of 120% nozzle diameter throughout the entire print, the likes of a 0.8mm wall and a 0.6mm nozzle are never going to work -- 0.6 x 2 x 120% if on auto-width = 1.78mm. That's a whole bunch more than 0.8mm!

I don't know exactly how Slic3r does it. But there's an option in there, "Detect thin walls". With that feature turned on, Slic3r figures out a way to run down the thin wall only once, increasing extrusion width (within reasonable bounds) to make up the thickness beyond the nozzle diameter, if required.

MatterSlicer seems to recognise the proximity of the two lines and adds distance to avoid nozzle blockage. this just results in a thicker than want wall. It may try to reduce extrusion volume as well. I'm not sure.

Reducing my nozzle size from 06 to 0.4 would fix this specific issue for me, on this particular print. But that would also mean dropping from 100mm/s (0.1mm layers) to 66mm/s, as well as reducing overall extrusion volume by 33% (0.4 / 0.6 * 100) thus doubling overall printing time -- for no other gain whatsoever. No one wants to change nozzles for just one print.

Well, I'm sure this has all been said before. But there it is again, just to get it off my chest.

gruvin
Posts: 8
Joined: Thu Aug 18, 2016 7:50 pm

Re: Double over printing ruining prints

Sat Sep 03, 2016 6:25 pm

subscribing to notifications, again.

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