Poor layer adhesion with multimaterial printing

[KW12]

Well, I tried printing a bell upside down as you suggested, and I have to say that in many respects, it worked out very well. The layer adhesion is excellent. The part is very strong. The surface quality of the bell interior is good. The overhang was too much for ASA and the other issue was that the bead (wire round the rim of the bell) becomes a floating region. If it were the only way to print it then I'd do the two parts separately and glue them together, but I'd prefer to aim to print it in 1 piece with a minimum of post-processing.

[CrazyIvan]

I'm currently fighting with a project in PETG, and using PLA as support is not a panacea. Obviously we don't want the support to stick, but that also means the underside of a "roof" tries to print onto a support platform that is worse for adhesion than the build plate. In the absence of dissolvable support, I'm having to go back to break-off support in the same material.

I'm thinking dissolvable support might be your answer too.

the other issue was that the bead (wire round the rim of the bell) becomes a floating region.

Can't you adapt the design to avoid that? 3D printing relies at least as much (probably more) on design for printability as it does on tuning the slicing.

[CrazyIvan]

@KW12 You messaged me and I replied, but the reply doesn't seem to have been picked up. Let me know whether there's a problem.

[KW12]

Just didn't check the forum until now. I've passed on my message to the address you suggested.

I've experimented with two soluble supports. One is HIPS and the other is PVA. I've also tried various material combinations e.g. PLA/PCTG.

I've had the most luck with HIPS - but not because it's soluble. It sticks reasonably well to the ASA / ABS but also peels off nicely which is all that I need for a bell. I think the PLA burned too easily and I got nozzle clogs, but if I get a dedicated multi-material extruder I will experiment with it again.

I hadn't realised quite how expensive Limonene was when I bought the HIPS, but I like it much more than the SunLu PVA which seems to go mushy rather than dissolve and wash away. PVA would be easy enough to remove from any place you can reach with a toothbrush and I found it easier to print than I expected, but it doesn't work for the internals of musical instruments which are reasonably inaccessible. Even if you pipe a stream of hot water through to flush it out. But that's not an issue for a bell. But I've had the same issue as you've been having with the PLA - the PVA doesn't adhere all that well to the main filaments that I've been using.

[KW12]

bell00.png (97.98 KiB) Viewed 17 times

Here's the model, for interest.

[CrazyIvan]

Thanks for that. Yes, tricky.

[KW12]

Well, I clicked 'buy' on a Ratrig 400 IDEX. Wish me luck!

[CrazyIvan]

Luck!!