Issues at printing the large part

[Kruno3D 2]

Hello all

recently I have 3D printed a large prototype and run on strange phenomena.

The prototype was rather industrial plastic part, with thin walls (2,6 mm).

What happen is that all corners were bent upside, but surface are above corners is still flat, as it should be.

What is causing this phenomena?

I know it has to do with cooling, but does it heated bed caused, or because the part is so big, so the corners cools to fast or something else?

Any tips what to do to prevent this from happening again?

There were also another anomaly that happen on the same print.

Roughly 12 mm from top of the part, few layers didn't melted together, and its looks like someone has cut the part with horizontal line.

Material: PLA

Edited November 13, 2016 by Guest

[Shiren1981 0]

try reasing your bed temp and flow for what i can see you have under extrusion but thats what i thingk

ps did you check if your bed is lvled thats mostly my problem that my first layer is 2 high so doenst sick well

[IRobertI 521]

Which print settings are you using? What type of material are you using? How many hours have you printed on this machine, roughly? Have you had problems with underextrusion before?

[Kruno3D 2]

Material was PLA

Print speed 60 m/s

Layer height 0,16 mm

Material temp 210 C

Bed temp 60 C

Hours printed on this machine is roughly over 1000h

I did bed leveling and testing before I started this long print, bed was leveled good.

Didn't noticed problem with under extrusion so far, but looking back on some of my prints, every one and then there is visible line, that could refer to underextrusion.

Edited November 13, 2016 by Guest

[neotko 1,417]

1000H with the PTFE coupler not the TFM coupler? (since you use a Spring I thing you still have the old ones right?)

Your PTFE coupler is dead and you need a new one to fix that underextrusion.

To get a better fix on the bed use a Brim, a Raft if is a very complex material (like Nylon) or just do

a) Take bed glass

b) Clean it with soap and semihotwater

c) Dry the glass

d) Put the glass back on the printer

e) Put some glue on the glass (glue, hairspray applied with a towel (don't ever directly, elmers glue diluted in water with a brush, etcetcetc)

[Kruno3D 2]

1000H with the PTFE coupler not the TFM coupler? (since you use a Spring I thing you still have the old ones right?)

Your PTFE coupler is dead and you need a new one to fix that underextrusion.

To get a better fix on the bed use a Brim, a Raft if is a very complex material (like Nylon) or just do

a) Take bed glass

b) Clean it with soap and semihotwater

c) Dry the glass

d) Put the glass back on the printer

e) Put some glue on the glass (glue, hairspray applied with a towel (don't ever directly, elmers glue diluted in water with a brush, etcetcetc)

 

Thanks for the tip.

Is there some type of test, to check with coupler is it dead, or is it something else?

Because from outside coupler looks fine (it was changed before some time, I need to check when).

As for bed adhesion, I did all of what you have listed except using glue. But parts looks very deformed, so I assume that there were pretty much forces from thermal dilatation at work.

Just wandering if there is some tip on printing large "boxed" part, to prevent thermal dilatation.

Here's the image of how part should look like.

[neotko 1,417]

Well the test it to take the coupler out and check how it looks, the part that gets dmg over time/use is the tip so there's no other way to check it than taking out to look at it.

Here's a guide (new TFM couplers last longer and they use a fixed size spacer instead of the spring)

https://ultimaker.com/en/resources/19619-ulti-evening-maintenance

If the bed doesn't stick well it might be also related to bed level, and maybe the first layer needs to be closer to the nozzle (rotate the bed thumb screws to the left a tiny bit but the same on all 3 points).

If is a very hard material to get adhesion you could design some mouse ears on every corner to get a better adhesion.

http://3.bp.blogspot.com/-UBOxCCBA3F0/TtE1heFo2qI/AAAAAAAAHTQ/DCdYoWHrOz4/s1600/DSC_0959.JPG

[Kruno3D 2]

You are all right, the problem was in PTFE Coupler!

I have found benchmark test to check coupler condition.

Here you can download it here

Here are models printed after, and before I changed coupler.