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Suggestions for sand casting patterns.  

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kmccon
(@kmccon)
New Member
Suggestions for sand casting patterns.

I am working on several patterns for sand castings.  The first set of patterns were destroyed by the pattern maker when they were removing them from the mold.  At that time, I used normal perimeters and 30-50% infill.  After that, I have been using 100% infill and haven’t had any destroyed.   However 100% infill takes a very long time.   

Does anyone have suggestions on what would be a good balance between strength and time?

Thanks

Best Answer by Neophyl:

The video in qestion is by Stefan, from CNC Kitchen.  He also has a website https://www.cnckitchen.com/

He makes some very good video content.

Summary though is that more perimeters gives you greater strength than infill for the same weight of plastic.  If I want strong parts then I usually use 3-4 perimeters and only around 15-20% infill (cubic).  Depending on how exactly the foundry guys are handling them then increasing that to 6-7 perimeters while keeping the infill around 20% should make a very strong part.

Also as factors of course are your printing temps (interlayer adhesion) and also your layer height.  Basically you want to print as hot as you can get away with while still keeping the detail you want to make the layers bond better.

Go watch Stefans videos.

Posted : 30/01/2021 2:50 pm
towlerg
(@towlerg)
Noble Member
RE: Suggestions for sand casting patterns.

There is a vid on youtube where the guy does comparison to determine max strength, extrude thickness vs infill (pattern and percentage) vs number of walls vs etc etc. IIRC GNC kitchen or something. Don't you have problems with uneven shrinkage using 100%?

Posted : 31/01/2021 10:45 am
kmccon
(@kmccon)
New Member
Topic starter answered:
RE: Suggestions for sand casting patterns.

@towlerg

Shrink seems ok, but depending on the part, I get some lifting off the plate.   Will look for the video.  

Thank you 

Posted : 31/01/2021 3:22 pm
Neophyl
(@neophyl)
Famed Member
RE: Suggestions for sand casting patterns.

The video in qestion is by Stefan, from CNC Kitchen.  He also has a website https://www.cnckitchen.com/

He makes some very good video content.

Summary though is that more perimeters gives you greater strength than infill for the same weight of plastic.  If I want strong parts then I usually use 3-4 perimeters and only around 15-20% infill (cubic).  Depending on how exactly the foundry guys are handling them then increasing that to 6-7 perimeters while keeping the infill around 20% should make a very strong part.

Also as factors of course are your printing temps (interlayer adhesion) and also your layer height.  Basically you want to print as hot as you can get away with while still keeping the detail you want to make the layers bond better.

Go watch Stefans videos.

Posted : 31/01/2021 4:34 pm
kmccon liked
kmccon
(@kmccon)
New Member
Topic starter answered:
RE: Suggestions for sand casting patterns.

@neophyl

Thank you!

Posted : 31/01/2021 5:39 pm
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