Printing issue - shifting...sort of?? What is this from??
Hi All!
So for the most part, this printer has worked wonderfully and issues have been basically non-existent. However, there are a couple of prints that I've done recently where it looks almost like a shift, but not exactly, and I'm completely puzzled as to how/why it's happening.
The first print was of a coaster - 3.5" in diameter, with a rim approximately .10" wide by .10" tall. The base 'looks' solid, but I printed at 20% infill. Starting from the plate up, it comes out perfectly until it gets to the Z-height where the rim starts. At this point, the outside diameter increases for a few layers by roughly .010". After that "bump" the rest of the rim prints straight up, but it is about .005" larger than the pre-bump diameter.
The second part is a basket that has a shelf near the top. The basket is hollow inside until it gets to the shelf, which is about .200" thick. Once again, the print comes out beautifully until it gets to the Z-height where the shelf inside starts. At that point, once again there develops a "bump" around the entire perimeter of the part, coincident with both faces of the shelf.
My first thought is some kind of thermal issue based on the mass of the material at the more solid areas (the shelf and the coaster base) which then transitions to thin walls (coaster rim and basket outer wall). My obvious problem is that I don't know how to combat it. Has anyone encountered this, or a similar, issue before?
Re: Printing issue - shifting...sort of?? What is this from??
It's my understanding the printer averages filament flow rate based on moves and extrusions it is making. When it gets a "step function" the flow rate doesn't instantly change, hence thicker (or thinner) extrusions at discontinuities like your inner layer.
100% guesswork here, but that's my story and I'm sticking with it.
Re: Printing issue - shifting...sort of?? What is this from??
Hi there,
I'm not allowed yet to send PM. Did you find a solution?
I think I'm having the same problem:
https://shop.prusa3d.com/forum/how-do-i-print-this-printing-help--f63/buldge-when-print-reaches-solid-layers-t27983.html#p130480
Re: Printing issue - shifting...sort of?? What is this from??
I'm not 100% certain on the cause, but two factors come to mind. One if the internal printer flow characteristics, the other is the nozzle temperature recovery.
To remove nozzle heat recovery from the suspect list - and I know this is painful - try setting the print speed down to 50% and see if the bulge it still there.