I’ve been getting really bad prints when printing phone cases that needed support. Even without support, the vertical walls of the case printed with a lot of bobs or blobs, not smooth at all. (Picture Side1 & Side2).
In addition, when printing with support for the back of the case due to embossed wording (see picture Word), the surfaces came out really rough and lots of single lines finished when i pulled away the support material. It happens every time i printed something that needs support. It won’t give me a smooth surface.
Your wall are too thin to print without cooling. Super thin layers like that require fan to print even with abs. The support side is just a bad idea. You will never get that to print clean as is. Print the other piece flat, print that piece flat side down, lettering up and then glue the two parts together.
Thanks piercet. If requiring fan for ABS, should I increase the temp a 5 degrees C to compensate for the cooling factor? How do I glue ABS to ABS parts?
You only ever need fan for very thin walls, small parts, or bridging. And it only needs to be operational for those problem areas. Using it elsewhere will ruin the part. Temperature compensation will depend on the material.
You can glue abs using plastruct plastic weld, acetone, model cement, epoxy or CA glue.
ok it seems to work now, i turn on fan for all levels, no problem so far. First time using ABS with fan on lol. I’m beginning to suspect if this is material issue. Anyway, so is it safe to assume that any flat surfaces printed with support will come out rough and there’s no workaround for smooth flat overhang with support?
Ok too soon to celebrate. After the passing trial with your suggestion(I tested it with benchy previously), I decided to print a new phone case. Now this time is unlike anything I’ve seen before, halfway through the print, the filament curls upward towards the nozzle instead of sticking to the bed! I don’t see any warping at the corners, so i dont think is temperature issue. There’s no fan on at lower levels. However, it laid and print the other parts before this pretty well. It even extrude nicely during the skirt priming! I’m clueless now. Here are the settings:
ABS:
Nozzle temp. : 220 degree C, tried 210 to 215 too
Bed temp.: 100 degree C, tried 95 too
The rest remains unchanged.
I’ll upload a picture if you don’t know what I mean. I googled but can’t find anyone with similar problem. All their problems are regarding warping.
Now you are hitting the other end of the ABS temperature spectrum. ABS doesn’t adhere well compared to other plastics like PLA. But, with very thin walls it needs cooling to prevent blobbing. That very act of cooling however reduces the bad adhesion still further. The fix is to generally print ABS much hotter than 220 for better layer adhesion, while simultaneously cooling thin layers. You are looking for a very hot bond at the melt point, while still cooling the outside surface. Usually I print dark color ABS up around 240. In this case I would keep the same level of fan cooling, but bump the nozzle temperature to 230 or even 235 to start. I suspect 235 will adhere much better, but may start reintroducing the blobby section. It’s going to take some trial and error, and it will vary by filament manufacturer and color (different pigments react differently to temperature)
Yes ABS is a pain in the ass. I understood what you mean about the cooling part, which is why in my new setting i set fan on only after 3mm, so the layers in question does not have any cooling whatsoever, and I see no warping, all edges sticking well. It starts curling when the nozzle move to a new “empty” side of the bed to lay the filament based on my design. No idea why it happens, as it is in the middle of the bed, heat is higher there, should be able to stick well. I did try 230C too.
I don’t think this is a heat related issue anymore, because i tested it again using PLA this time. Pictures might help, as you can see, all of them failed to print the middle section, totally clueless why. I have attached the stl file too, maybe you can try to print at your end. I can’t figure out what’s wrong (NEW) iphone 6s plus hinged 1.stl (195 KB)
Well, that one will never print without support. The hinged flappy section is up 0.5mm or so above the heat bed. So it trys to start printing the flap section in open, unsupported space. This is equivelent to you trying to set a glass jar of pickles on a shelf, but instead of placing it on the shelf, you let go of it a foot above the shelf and hope for the best.
You would either need to make the flap thicker so it was in contact with the bed when printing, or use support. You could just make the edge thicker and use a fillet to try and provide support, but the general rule of thumb is that anything over a 45% angle overhang is going to be difficult to print
