Corner Curling on boxes, thin perimeter only walls or something else going on?
I'm fairly new to 3D printing, and this is my first post on the forum, so please let me know if there's somewhere better for it. I have a mk4 I recently finished assembling and overall things have been going well. One of the reasons I got it was to make box inserts for my board games. I've recently been working on a box insert for my Fallout board game and although most of it has gone okay, there are a couple of parts I'm struggling with to get to print right.
The current project is for the Fallout board game and I'm working from this model here. It's worth noting that those models need to be scaled to 1000% when you add them in the slicer. The pieces I'm having trouble with are F_Inlay_21.stl and F_Inlay_40.stl, however I've been trying to customise them for some tweaks, so have created my own versions of the models. I will try to attach all the custom files to the post, along with my slices.
The main problem I'm having is with each of them (others too, but these ones are more significant) I'm having trouble having them not lift at the corners. I have given my print surface a good wash with detergent which might have helped slightly, but didn't fix it. The filament I'm using (PLA+ from 3dFillies) seems to get stringy at higher temperatures so I had dropped down its temperature, however I tried with other filaments too at the original temperature and I have tried reprinting the larger card tray with the higher first layer temperature to see if that would help with adhesion. The smaller part that acts as a skirt that sits on top of a smaller tray I have tried printing with a brim and on a raft, which again helps but it's still lifting at the corners.
Other things I'm looking at trying are adding large circles to the corners, however I don't think this will help as even with a brim the corner starts to lift partially.
What's bugging me about this is that I have done other games box inserts and haven't suffered this problem. It's had me thinking that maybe it's the thickness of the walls, these being thinner than other box inserts I've done. I'm wondering if maybe the fact that with 2 perimeters there's no infill so it's just 4 long lines along each side, if that's causing extra pull as they are extruded. I'm wondering if dropping down to 1 perimeter might cause less pull along the length of each wall. Alternatively I could make the walls thicker so there is infill between, but you still have 4 long extrusions down each side at each layer so I don't see how that would be different.
By the time you get to the top it's flat again, it seems to squish at some point up the wall to make up for the height difference. They are usable, but I would love to figure out what's causing this so I can avoid it or adjust for it in the future.
Photos of the most recent prints can be found at https://photos.app.goo.gl/3HFdnpjMCv1z9NA2A
I've included photos of the sides showing the curve and lined up with the grid on the cutting board below
My model files and slicer project files:
The large card box (F_Inlay_40) Model and most recent Slicer 3mf
Small card tray skirt (F_Inlay_21) Model and most recent Slicer 3mf
RE: Corner Curling on boxes, thin perimeter only walls or something else going on?
I don't think there's anything particularly wrong with your model or your settings (even though I for one wouldn't use IS for this) it's just the Curse of Large Rectangular Models. You've tried a few standard remedies– washing the sheet with detergent and a brim. I'd try the mickey mouse ears but more importantly, for a model like this I wouldn't hesitate for a second to put Layerneer or Magigoo on the sheet.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
A classic design issue with long extrusion runs - how to handle thermal contraction and prevent warping:
When making boxes a couple of extra bottom perimeters add stiffness. Anyhing that breaks the long extrusion runs reduces the tension of contraction - so piercing with a few holes is easest, or consider an expansion 'jink' __/\__ where tension can be relieved by flexion.
When 'solid' bodies are warping choose a fill and direction that will redirect and perhaps absorb the stresses. Prusa always suggest gyroid which absorbs stress but reduces stiffness, very often cuboid at at 45° will be better, or honeycomb where non-directional stiffness is required.
Cheerio,
RE:
When you say IS I assume you mean input shaping? It's not something I've turned off/disabled for anything yet. There's a setting on the printer for it, but do I need to adjust the settings in the slicer too? Is it just a matter of using a slower profile?
Nevermind, I realised you can add a second printer profile for the MK4 without the input shaping
RE:
Which printing plate are you using... smooth, satin, textured ?. On models where extra adhesion is welcome, for PLA a smooth plate is preferable. Also, as fuchsr suggests, products like Laverneer, 3Dlac or hairspray (basically the same thing) do help a lot.
Last, but not least, in spite of Prusa claiming always a perfect first layer for the Mk4, we’ve learned that this isn’t often the case and Z offset needs to be adjusted manually a bit. Maybe lowering the first layer by 20 microns or so, would give you the amount of extra adhesion required to fix corner warping. It’s worth trying anyway.
Finally, as personal experience, if you want a PLA with VERY strong adhesion to the plate. Overture PLA matte is your friend. Be careful though, this filament sticks so strongly to the smooth plate that the problem isn’t warping but to remove the model without damaging the PEI layer. Guess how I know that.. 🙄