Z dimensions tolerance on overhanging surfaces
 
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mrdaniele86
(@mrdaniele86)
Active Member
Z dimensions tolerance on overhanging surfaces

Hi to everyone,

I have i question for you If you can help me to understand an issue that I have, for example when I print this object below.

On the side where you see the two holes I have an overhanging surface, therefore I have use supports ss you can see in the second picture.

I tried few settings to obtain a better surface under the overhanging surface. After printed I remove the supports and I obtain a good printed object.

My issue is that the distance between the two surfaces are lower of 0.5mm of the dimension that should be. The overall dimensions of the object are perfect and also the lower part (where is the lower hole) is perfect. The upper overhanging part instead is more thicker of 0.5mm.

I tried to adjust the problem by the modifying the drawing, but I still have the problem.

Do you maybe know what could I do to prevent this problem coming out?

Thank you

Best Answer by JoanTabb:

I suspect this is due to the gap between the supports and the lower face of the supported area, the lower face tends to sag towards the support and doesn't squish as it normally would if it were building upon normal lower layers, the net result is that the top part becomes thicker, 
Could you make the top part thinner be the 0.5mm on the bottom face to allow for the droop.    or use soluble supports, or use 'Scaffold' break away supports with a zero mm gap? 

regards Joan

This topic was modified 4 years ago by mrdaniele86
Posted : 04/10/2019 8:47 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Z dimensions tolerance on overhanging surfaces

I suspect this is due to the gap between the supports and the lower face of the supported area, the lower face tends to sag towards the support and doesn't squish as it normally would if it were building upon normal lower layers, the net result is that the top part becomes thicker, 
Could you make the top part thinner be the 0.5mm on the bottom face to allow for the droop.    or use soluble supports, or use 'Scaffold' break away supports with a zero mm gap? 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 05/10/2019 1:40 am
mrdaniele86
(@mrdaniele86)
Active Member
Topic starter answered:
RE: Z dimensions tolerance on overhanging surfaces

@joantabb

Thank you very much Joan, I did it. Sorry for my late reply 🙂

Do you thing with the MMU, printing PETG or NYLON, is possible to print the support with a soluble filament and will I obtain a good result?

Thank you

Have a great weekend.

Daniele

Posted : 11/10/2019 7:13 pm
Chocki
(@chocki)
Prominent Member
RE: Z dimensions tolerance on overhanging surfaces

Without seeing the whole part, cant you place the furthest end away from the view in the picture, flat on the print bed and print it that way, looking at the shape there doesn't look to be anything over 60 Deg overhang so it should print just fine.

Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.

Posted : 11/10/2019 7:21 pm
mrdaniele86
(@mrdaniele86)
Active Member
Topic starter answered:
RE: Z dimensions tolerance on overhanging surfaces

@chocki

Here another view of the object (the green one), you mean I could print the object in this way? (the grey one)

Thank you

 

Posted : 11/10/2019 8:31 pm
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(@)
Illustrious Member
RE: Z dimensions tolerance on overhanging surfaces

Grey is how I'd print it.

Posted : 12/10/2019 12:03 am
mrdaniele86
(@mrdaniele86)
Active Member
Topic starter answered:
RE: Z dimensions tolerance on overhanging surfaces

@tim-m30

Thank you!

Posted : 12/10/2019 7:07 am
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