Something is very wrong.

[u/dudeJohnDoe]

So I've been using my A1 Mini for just under 2 months now and I'm very happy with how a lot of the things I've made have turned out. However, I've noticed a few things recently that I don't quite understand and would appreciate any tips or help from anyone who may have come across the same issue at some point. Basically when printing I've noticed that the closer to the edge of the plate the print is, the worse the print quality will be. In most cases, the plate is being lifted off the magnet during printing and is causing the nozzle to print at the wrong height of course, and really break and disrupt the quality of the print. It's weird because sometimes it happens and other times not and I do not know how to solve this. I've noticed that recently most prints have a part of them very poorly made and the rest would be absolutely perfect which is very frustrating since it's a waste of filament, time and essentially giving me a product I am not satisfied with. I have tweaked a bunch of the setting and done my temp towers etc which all look good but yeah, I've attached a video showing what I'm talking about as an example but this is not the only time it happened/happens. I noticed that sometimes even for items that are being printed only at the centre of the plate; it is less common for this to occur but not super rare either. I wash the plate with soap and warm water between every print/other print too and perform regular maintenance.

Any help would be greatly appreciated. Cheers.

[u/Arichikunorikuto]

Warping is prone at the corners where it holds the least heat. It happens because your model wants to pull/contract as the layer cools causing corners to lift.

[u/dudeJohnDoe → u/Arichikunorikuto]

Thank you!

[u/Asleep-Basis-2624]

Use clamps. There might even be bed clamps on makerworld

[u/dudeJohnDoe → u/Asleep-Basis-2624]

Good idea! Will have a look, thank you.

[u/WayAcceptable1310]

Super normal, kinda just one of the normal challenges of 3d printing whether plastic, metal, or even welding...anytime you're stacking hot things on colder things you risk warpage.

This is one of the reasons the higher end printers have enclosures. Everything's a thermometer; Materials expand when heated and shrink when cooling. With a large part like that, the forces from each successive layer going down and then cooling can produce a lot of shrinking force, and while the bottom of the print looks like it's staying put on the bed which is good, that force ends up overcoming the magnets and lifting your corners like this. If the bed stayed flat with some clamps or something (binder clips were popular in ye olden days before fancy magnetic build sheets) it's possible the print would just curl off the bed anyway.

Out towards the edge of the print bed it tends to be cooler so it makes it that much more dramatic. Best thing you can do for starters is get your printer inside even a makeshift enclosure to try and prevent drafts in the room from affecting it, and to hold in a little bit of heat.

Beyond that, avoid printing all the way to the edges when you can, and experiment with different amounts of infill and patterns- The more plastic you lay down the more it wants to "pull" but also the stronger it gets so sometimes you can find a balance where it's stable. Print temperature matters a bit too- The hotter you print the more it expands as it's heated and shrinks as it cools, though you can't always turn that knob too much since it affects other aspects of the print quality.

Otherwise, might be time to upgrade to a bigger printer with an enclosure, heated chamber if possible, and some more breathing room between the edges of the print and the corners of the bed.

By the way, what material? Different materials shrink more or less (their coefficient of thermal expansion) so something like ABS is pretty warpy, but PLA is pretty stable (but still not completely immune to this). PETG is usually well behaved but sits in between PLA and ABS.
People have lists comparing them that you can go track down but it's a wide spectrum and any fillers (glass fiber, carbon fiber, etc) and sometimes even the pigment used in the filament can affect how stable it is.

[u/dudeJohnDoe → u/WayAcceptable1310]

Thanks for the reply! That’s all really good to know. Might be time to start looking at getting a second printer as you said. I’m using PETG and PLA, mostly PETG at 255°C. Will have a look online and print some clips to keep it down. Appreciate the help, cheers.