"Caved in" sides in PLA prints

[Multitube 0]

Hi!

 

When printing with Ultimaker PLA on my S5 Pro Bundle and an AA 0.8 print core, the sides of the prints are 'caved in', see attached image.

The middle is around 1,5mm under sized, top and bottom are ok.

 

I've used the default Ultimaker profile, with the only difference being the layer height (0,4mm)

See attached 3mf and ufp files.

 

I've never really experienced any shrinkage using PLA and the problem doesn't occur when printing with Ultimaker Nylon (which is my go-to material).

 

Any idea's?

Thanks!

 

Tim

UMS5_X21-0000079-Rev_-.3mf UMS5_X21-0000079-Rev_-.ufp

[geert_2 542]

I would guess it is because of the heat? PLA print want to be cooled fast to below 50°C, otherwise they sag or deform. If you print 0.8mm wide and 0.4mm high sausages, that is a lot of heat. So I could imagine that they do not cool down and do not solidify quickly enough? So the walls stay somewhat soft, and are pulled inwards? Especially if the bed-temperature would also be quite warm. Molten plastic tends to be pulled into a thick blob. This is a guess, but it is the only thing I can immediately think of.

 

[Multitube 0]

Hi Geert,

 

Thanks for the reply. Temperature would be my first guess as well, but since we have no problems at all with all other profiles I figured there would be something else going on.