Print fails at height
Hi,
I have had this a few times now and drives me nuts. My MK3+ MMU2 prints ok, not great, not to happy with the MMU. But when I print larger pieces the print fails when it gets higher. The Nozzle digs into the print en rips it from the plate. Not always, the print on the picture I printed 2 times before with no problem, this one failed after 12 hours.
Does any one know what makes this happen and how I can prevent it?
RE: Print fails at height
The layers just below the top edge of a circular hole, where the two sides are starting to come together but haven't met yet, form an extreme overhang. This can often be tolerated in a very small hole like a screw hole, but at a large size like this it's almost certain to fail — the filament will not have enough material below it to stick to, so it won't stay put properly. You need to redesign your part. Here are some common techniques:
- Print the large circle in the horizontal plane instead of vertical (so there is no overhang). In your case this also means you would have to print two parts for later assembly.
- Change the shape of the hole, if it does not need to be circular:
- Teardrop💧 — usually designed with 45° overhang but you can choose any slope you like
- Hexagon with flat top and bottom ⬢ — max 60° overhang
- Hexagon with flat sides ⬣ — max 30° overhang, very easy, but the top is a horizontal bridge
- Split the print at a line bisecting the hole and flip one half of the print upside down, so all of the circle interior is facing upward.
RE: Print fails at height
I looked at your photo and i assumed you were using support material (either soluble or the same material as the object). If this is the case, you need to add removable bracing for your drawing so their is no "sway" of the object during printing (minor warpage). If you're not using support material for all overhangs greater than 45 deg, you'll never get that thing to print; it needs to be supported by some removeable material. Try the support material first if you're not already.
RE: Print fails at height
Hey,
Thanks for the answers. I did print it once without support, guess I have been very lucky there. I understand what you say about the support. I cannot change the circle into a teardrop because it is a Bottle holder for the Soda Stream bottles. I will print it again with support.
Thanks again for the answers. I add a picture of the one I printed before.
RE: Print fails at height
Printed it gain. Supported the larger holes, the smaller one on the basis not. Worked like a chrtm. Thanks for your input and help.