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gdgd

Possible Overhang Issue ? - Any help greatly appreciated!

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Hey Guys,

I'm new to the forum but have been a lurker for a while and hoping to get a bit more involved with the forum. :)

I'm looking for some advice on my print which has a rough texture - from my research on here I believe the is an overhang issue, but maybe someone can confirm.

I'm using a UMO with colorfabb 2.85mm white filament.

Cura settings where:

0.9mm layer

0.8 shell thickness

0.6 bottom/top

100% fill (part must be solid)

75mm/s speed

210 C

Touching buildplate support

Brim enabled

fan at 100%

17hr print

No adjustments to advanced/expert settings.

the part has a 2.5mm wall which must be solid - this is what you see in the pictures. Also - it is printed in this orientation to avoid any support being added to the internal which must remain as designed.

IMG_1093_zpswmcf9stp.jpg

IMG_1082_zpsrfbycetr.jpg

Thanks in advance,

Grant

 

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May I suggest you try the same but change the layer height to 0.1 and lower the speed to 30-40. Mind that in order to control the speed you need to go to the "Advanced" tab of Cura and set the individual speeds for the various part of the print. I would set inner shell-outer shell-infill to 30-40 max and leave the other speeds as they are.

Overhangs get better by lowering the speed and possibly the temperature of the print. So if you go down to a speed of 30, it should be safe enough to lower the temp to 205 or slightly less.

 

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If it still fails after personal drone's suggestions then change the wall to 0.6 and check the layer view in Cura. Are you getting a single wall or a double wall? If a double wall then take the wall down to 0.4. Something I did last week suggests that on overhangs a single wall may work better than multiple walls. I was using a 0.8 nozzle with a wall of 1.2 (and got a single wall). Personally I would go to 20-30mm/s with 20 being the preference. But if it took 17 hours at 70mm/s I can see that will not be a popular suggestion :-P

 

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Thank you very much guys! I'll incorporate all these changes.

Would there be benefit here in either printing 2 items at a time to allow extras cooling or even increasing the minimum layer sec (cooling) in cura?

Also - this was printed in quite a cold environment - could this actually help or hinder the print? What is the optimal surrounding set up? just room temp?

Many thanks!

Grant

 

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Sorry I disagree, you live in Scotland not the Mediterranean! I would go with ambient temp. which is probably circa 18- 20 unless of course you eat porridge and wear a kilt in which case that would probably be 5 :) I do not think it materially affects the print during printing if your printer is enclosed but the bigger the temp. range on completion then the more shrinkage you are likely to get without managing it.

The first thing you need is to specify minimum layer time; there are some different views on what the minimum time should be, personally I go for 10secs. Even that though will not help you at the bottom and at the top of the sphere as the printer will probably only go as low as 10mm/s. So yes a 2nd copy on the bed, placed far enough away to get you 10 secs might be mandatory - difficult to judge the size of the sphere.

An alternative is to use z-lift; this though has the disadvantage of leaking filament which will get dragged over the top of your model - but if you supervise with a screwdriver, with a bit of practice you can wipe the leaked filament away just before it moves back to the print the next layer. A PIA but it can be done

 

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