ABS Warping.

[Nolin]

I am having a peculiar issue which others might have faced and wanted to know if there is a solution. When I am doing ABS prints, normally at 0.15 layer height, and the part requires supports, the first layer Vive the support starts to warm maximum. This happens because there is always a gap between the support and the part body and although the layer cannot droop down, it has all the freedom (on account of its thinness) to curl upwards. So while rest of the part gets printed OK because of adhesion to layers below it, the segment over a support is always curled up. What is the solution? Is it reducing the gap between the support and the part to achieve adhesion and then sanding the support off?

[TypeR]

If you have a free-hanging overhang and need supports, the best thing to do is NOT use any gap between the support and the model. It is in my experience the only way to avoid the warping of the object.
However, even with no gap, there is a chance that the object will still warp, pulling itself loose from the underlying supportmaterial is there is only a little bit of support specified.

[wirlybird]

You could try using the fan just a bit to help it cool slightly. This is tricky since too much and it will warp.

Also, see if you may be able to lower the bed temp some after the first few layers.

You can also see about orientating the model so these areas are facing the coolest part of the printer chamber.

[cobnut]

Hi @Nolin it may well be that there’s no perfect solution for this problem. FDM 3D printing has limitations, especially when combining some models and materials. I don’t use ABS any more, there are other materials that can match it for strength and/or temperature resistance, so the simple answer might be simply not to use ABS.

[wirlybird]

Cob, what are you using in place of ABS other than PETG? I get a lot of orders for parts in ABS that really are not so suited to ABS. On a fair number PETG may not be the best choice either since it can be a bit flexible in areas where ABS will get too hot and we know how that goes.

[cobnut]

Hi Chris, at the moment it’s mostly PETG, though I’m always looking for something else. I’ve got some Fillamentum CPE arriving today/tomorrow that looks like an interesting candidate (I really like their PLA).

Hardly any of my customer orders for ABS have been about the temperature resistance, it’s just about strength and personally I blame a lot of that on how the materials (ABS, PLA, PETG) are described by 3DHubs in the ordering process. They make PLA sound like it’s going to shatter if you drop it and PETG is just described as “having improved mechanical properties”, which really doesn’t mean much.

In my opinion, if someone knows the part is going to be exposed to high temperatures, above the GTT of PLA or PETG, then even ABS isn’t safe. If something is going to get properly hot, then it needs to be printed in proper high-temperature material, like Formlabs’ Hi-Temp resin, where we’re talking about 290C.