thin-wall feature strange behavior

[phil.t]

Sure, try this factory file for the tray STL I posted earlier. The settings are the defaults for the Printrbot Simple Metal with the only change being setting the extrusion width to .50.

The issue shows up from layers 45 to 59, which are the layers where the tray's handle is printed. I'm running this on a Mac.

Thanks for looking into it.

[jimc]

you know whats strange. i downloaded your file and tried it on my mac. i can see that its doing it but if i remove your process and set this back up for my makergear and use any one of my profiles then it doesnt do it. i kept the ext width the same, single perimeter and tried many different infill densities. i just couldnt make it happen on my machine. only thing that is different really is the print and infill speeds on my profiles are slower. i dont think that would make a difference.

[3Drasle]

I believe the new thin-wall feature in version 2.2.0 is doing something strange with one of my prints. I wonder if anyone else can reproduce this.

I have a small box with a wall thickness of 1.852 mm (see attached STL). I set my process to the defaults for the Printrbot Simple Metal, except I set the extrusion width to 0.50 mm. When I slice it, most of the wall of the box looks like the following:

normal-fill.png

Which is correct, but some of the wall (specifically in the layers with the handle holes), look like this:

over-filled.png

Notice that it has somewhat double-infilled the wall (I'm showing a single layer in the above screenshots). When I print it, that part of the wall is bumped out and rough, due to the extra infill (I have a picture I can provide, but I've reached the max attachments for this message). There seems to be a range of extrusion width values that result in this issue, while others do not. Turning off the thin-wall infill makes it just use perimeters which does work like the previous version.

Any thoughts on what might be going on?

Thanks,
Phil

I have the same problem, and it is not only in ver. 2.2.0.
it only happens when you choose 1 perimeter shell.
I was hoping they had fixed it in ver.2.2.0 but ran into the same problem again today.
The only way I have found to fix it is to set perimeter shell higher than 1.

[masnart39]

I'm having the same issue with my MakerGear M2. I've attached the factory file, which has this problem on layers 6-11, 45-49, and 51-52.

Edit: I checked the same STL in a factory file from an earlier version, and it's still there. So this isn't new to v2.2. I've been trying to improve this print for some time, but just noticed what was actually happening while watching the print in the machine.

[KeyboardWarrior]

Thanks for giving it a try - I'm glad to hear I'm not the only person seeing this. It has since happened on a couple of my other models.

By the way, here's what that tray looks like printed:

printed-tray-s.jpg

That area of double-infill stands out as a bumpy band in the print, so I'm pretty sure it must be abnormal to be filled like that.

For now, on another model at least, I've turned up the "Allowed Perimeter Overlap" percent under the Thin Wall settings until it stops using infill on the walls and uses additional perimeters (essentially making the wall solid). Note that this seems to be different than picking "Only use Perimeters for thin walls" setting, which for my model created a single perimeter and a empty inside wall space.

Thanks,
Phil

In Phil's picture, you can see that the ribbing only occurs for the layers that have the handle cut-outs. This means that there is less material being printed for these layers, and the speed-overrides are adjusting the speed slowing down these layers. I've found a great way to reduce this, is to either adjust the Speed Overrides so it can only slow my print down to 45% instead of 20% speed, or by disabling that option all-together and lowering my default printing speed under the advanced tab to get rid of the ridging.


-My experience has been that speed is the primary factor for these ridging's.