Scratch / Quality issue in the middle of the print
Good morning print gurus,
I am having some troubles with a print and cannot explain why. This is on a Prusa mk3s+ with Nyloc Mod. PLA, 60º / 215 First then 200ºC. Speed reduced to 80% on the Prusa with the knob.
At some point in the print, I got this on 1/4 of the circomference:
The print goes well before and after, and goes well also in the rest of the circumference. It piece was well attached to the bed with a 12mm brim. Did not move a bit. I do not jump around the printer and it's on a solid wood furniture that does not move at all.
I was expecting some troubles with the top because I was game to print it without any support but it went pretty well. The reason I printed it on this side is to have more stability. If I print with the small home on the bed, I would need support for the beginning with the risk on marks on the outside.
It's not so easy to see because it's IR during the night, but here is the area with the problem:
I've checked again and the bed is really flat. I never have problem with first layer adhesion nor having large pieces really flat. So I do not suspect something wrong on the bed. I use 7x7 and 3 reads for the superPinda. The part was really well attached on the bed and the first layer is perfect.
So, unless the Christmas leprechauns are having fun with my printer at night, what do you think I did wrong ?
Thank you for any help or idea or suggestion!
RE: Scratch / Quality issue in the middle of the print
I suspect the Arachne mode vs Classic. I see one little bump in this zone when I zoom a lot on this area. It's a very little bump (compared to the catastrophe I have) but still it is one.
Also I precise that I am not using Stealth mode and I de-activated Crash Detection that I know can cause those problems.
Let's see with Classic mode, after that I am out of ideas.
If you rotate the part on the bed does the flaw rotate too or does it stay in the same position wrt the printer?
That structure is bound to cause eddies and deadspots in the air flow from the print fan, I supect a cooling issue which *might* be reduced with a gentle airflow from a second fan directed to the rear.
Cheerio,
RE: Scratch / Quality issue in the middle of the print
I started a new print and will report on the position if there is still problems. So far on the IR camera I cannot see any defeat with Classic instead of Arachne.
Another reason might be the wall thickness, I have 1.6mm for the structure and it might be too little when there is an angle.
Is there any smart way to improve the air flow? Or even a mod that is proven to work for this kind of structure? Or should I forget this type of structure with FDM and go to resin?
RE: Scratch / Quality issue in the middle of the print
2nd try: with Classic and support, the area with supports is a complete disaster. OK I could print it with 180º like initially. But still there are lines everywhere in the other areas that I cannot explain at all. Is is something with the printer or this kind of organic thing cannot be printed at all? Outside we see a "hole" and inside we have some floating filament in those areas.
Do you have any idea what is wrong in the STL or my 3mf settings? LampShade
Or is this only achievable with SLS printers?
RE: Scratch / Quality issue in the middle of the print
Aside from the shifting problems, I see a very strange change in the slicer. And this is where I see a "line" in the printed object. It shifts this whole area inside so it's a bump inside and a hollow on the outside. Why is the direction changing here?
RE: Scratch / Quality issue in the middle of the print
I did a test with Cura (this is the first time I use it, so I should really learn all parameters before sending to the printer) and this area is really handed differently. I would say it's better handled to me. How to achieve that with PrusaSlicer?
Your print does compromise several thin, flexible, barely supported sections that are bound to try to evade pressure as they're printed. It might be worth creating a sacrificial internal support structure to hold them in place as they build; perhaps a column with spokes.
That way we can eliminate some of the flaws due to the demanding structure and see what's left to fix.
Cheerio,
RE: Scratch / Quality issue in the middle of the print
OK, I give you that the model was thin and flexible, so vibrations in long sections are challenging. I have bumped to 2.49mm the walls and changed the design.
So close to a success. Unfortunately, something bad happened. I guess the head got into the model and then the spaghetti happened because all was shifted. It was still stuck on the plate (inside brim 12mm). Let say that was an isolated problem.
What worries me more is the quality (see red circles on the picture below). Any Idea what can cause that ?
