Roctopuses rock, but sponges sock

I am printing out Roctopuses fairly easily but my attempts at box like shapes are failing. At nozzle/bed temps of 230/~110 degrees, my ABS prints are warping at the corners. I have been using Simplify 3D with a fair amount of success, rockotopus wise, but needless to say I need to be able to print more than that to get my money’s worth :wink:

Below is an example of the warping I am seeing.

I have tried numerous attempts with and without a raft and always after about 20 minutes, the print starts to peel up at the corners. One shot-in-the-dark guess is that as the plastic builds, layer by layer, there is a temperature differential between the print’s middle and it’s corners…and I really have no idea if that has anything to do with it. Any suggestions appreciated.

Below is an image of what I’m trying to end up with.

Can I assume you have a PEI sheet on there that is clipped down instead of using adhesive?

Yes, I chose to clip for the time being, because of earlier leveling issues with a warped 1/16" PEI sheet which could not be leveled in this life or the next. I am currently using 1/32" thick PEI that levels consistently. Another reason for clipping is because of my previous experience with 468MP. It may or may not have contributed to my previous bed leveling issues. But now you have me thinking…

I haven’t tried my PEI yet, but from what I’ve read you should be using the rough side and need to have your first layer dialed in properly (print a single layer print and measure it with calipers). If you print on the smooth side of the PEI, ABS is supposed to have some trouble sticking. If both sides are smooth, they talk about roughing it up with a super fine grit sand paper and cleaning with isopropyl alcohol.


Like you I believe the rough side offers a tooth to the plastic that should allow it more surface area to stick to than the smooth side. But the web has numerous botters out there evangelizing both smooth and matte. At any rate I like your idea about adhering the PEI to the borosilicate. There may be some play, albeit slight, that is causing this. I have numerous 12x12 sheets of 468MP. I do not like working with sheets of 468MP. It makes fly paper look like WD-40.

You can try and set the skirt to print as high as your part to block the layer to layer temp changes that tend to cause lifting on the corners by cool air. It is something like skirt line counts 999 in Cura expert settings.

I’m not clear on what a skirt line is. I think it’s that first line printed around the object you are printing. Is that correct?

Yes, that is the line/s printed around the part, you make it become an enclosure that helps protect your printed part. It does not always work, but you might try and see if it does.

You need to enclose your printer inside a box-like structure to trap in heat and keep out “colder” drafts.

ABS shrinks when it cools. You need to slow that shrinking process way down. Build a box around your printer with cardboard and try to get the ambient temp around your entire printer to be closer to 90 degrees F before printing.

Use a “brim” feature too. More surface area beyond the part.

Can you share the STL for the print?

I’ve been experimenting with varying the temps on prints (variations in parentheses beginning to end): ABS (245-240C) on the stock PEI (105-80C). Its produced fairly decent results on my projects with large flat bottoms. The variation is from reports that high bed temps actually degrade the adhesion of the ABS.

My strategy has been bed temps of 100C+ for the first layers, at about 2-3mm decrease below 100C. Dial down extrusion temps as the the initial layers become rigid enough to keep from warping. Keep the extrusion temps high enough to ensure a good bond and no delamination. Cooling from the fan is non-existent for the first few layers, then introduced at 20%-30% at about 2mm… with one more change 10-20mm to promote cooling of upper layers. Again, I’m getting good results, but YMMV.

Eventually expect to build an enclosure, which should negate all this experimentation… but with the current good results, I’m in no particular hurry.

Also - if possible, print the infill first, then the perimeters.
I know this is an option in Slic3r and it’s been working well for me.

Forgot to add… try adjusting initial Z-height for better adhesion. Rather than the Z-stop knob, try the Z-offset setting in the slicing software. Adjust by -.05 or -.1 increments… careful not increase too much that the nozzle digs into the bed.

Are you using Lulzjuice?

Thanks for all the good info guys. I am sure it will come in handy.

As an FYI, my warping problem went away when I glued the PEI to the glass. I like it when the simple solution works :wink: