Part Defects

Under-Supported Overhang

10min

Under-supported Overhang
Overhangs are not fully supported, resulting in malformed or missing features.
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How to Identify
Under-supported overhang can be diagnosed as follows:
Part geometry did not resolve properly
Unsupported overhangs will appear thinner than they should, tapering down in thickness over the length of the overhang.
When supports are too far apart, what should be a straight edge will instead appear curved.
When lattices have struts that are spanning too far, the struts may not connect properly during printing. This most often occurs with a "palm tree formation", where a vertical strut (the trunk) supports horizontal struts (the branches) that have longer than recommended bridges.
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Cause - No supports at overhang﻿
Solution - Print Preparation or Part Design
Cause - No supports at overhang﻿
Solution - Print Preparation or Part Design
Cause - Not enough supports﻿
Solution - Print Preparation or Part Design
Cause - Overhang too long﻿
Solution - Print Preparation or Part Design
Troubleshooting
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Print Preparation or Part Design Adjustments
The following solutions will address print or part-related causes of the defects. Choose among the suggested actions below and select the best approach for your application. Usually only one type of adjustment is needed.
Change orientation to maximize self-supporting structure. Reference Recommended Feature Sizes﻿ for unsupported angles per resin.
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Add supports to overhangs and bridges
Reference Recommended Feature Sizes﻿ for overhangs per resin.
Add supports to islands
Tall supports should be trussed together for extra strength.
Carbon printer software will automatically truss together supports that are generated at the same time.
L1 printers can fit taller parts in their build volume, so be especially aware.
Reference the Orientation & Supports - Print Success Factors﻿ for tips on supporting overhangs/bridges and islands.
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Non-Lattices
Add gussets to stabilize overhangs that are too long to support themselves
Reference Recommended Feature Sizes﻿ for overhangs per resin.

Tilt horizontal overhangs 40 degrees +/- so that they are self-supporting
Reference Recommended Feature Sizes﻿ for unsupported angles per resin.
Lattices
When lattices have struts that are spanning too far, add a strut.
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Print Plan Adjustments are not applicable for this defect.
If problems persist, please reach out to Carbon Support.
Explanation & Causes
Explanation
Overhangs, bridges or islands are either not supported or under-supported.
Overhangs should be less than the recommended length, oriented at a self-supporting angle, or redesigned to meet these conditions.
Reference Recommended Feature Sizes﻿ for overhangs and unsupported angles per resin.
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Causes
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Root Issue
Problem
Why Defect Presents
Orientation
Overhang is oriented at less than the recommended angle to be self-supporting.
Each slice can only handle a small amount of cantilevered curing material.
Supports
Overhang not supported
Each slice can only handle a small amount of cantilevered curing material.
Supports
Island is not supported
Curing material must either connect to a previous slice or to the platform via supports.
Supports
Supports are structurally weak
Tall supports must be trussed together to be structurally strong enough to support an overhang.
Design


Overhangs are too long or are oriented at less than the recommended angle to be self-supporting.
Each slice can only handle a small amount of cantilevered curing material.
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Root Issue	Problem	Why Defect Presents
Orientation	Overhang is oriented at less than the recommended angle to be self-supporting.	Each slice can only handle a small amount of cantilevered curing material.
Supports	Overhang not supported	Each slice can only handle a small amount of cantilevered curing material.
Supports	Island is not supported	Curing material must either connect to a previous slice or to the platform via supports.
Supports	Supports are structurally weak	Tall supports must be trussed together to be structurally strong enough to support an overhang.
Design	Overhangs are too long or are oriented at less than the recommended angle to be self-supporting.	Each slice can only handle a small amount of cantilevered curing material.

Under-Adhesion

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