Part Defects

Pillowing

12min

Pillowing
Unsupported portion of a horizontal surface is stretched out of position during printing.


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How to Identify
Pillowing can be diagnosed as follows:
Pillowing occurs on surfaces that are horizontal, or parallel to the platform, during printing.
The defect appears at the center of the surface's span, between supports
Pillowing appears as a pillow, or convex surface, between supports.
﻿Looping﻿ and Fanging﻿ are defects that arise from the same issue but appear at different locations or features: at horizontal struts or nodes, respectively.
Cause - Inconclusive
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.
Reorient the part to minimize horizontal surfaces.
Supports may be needed with a new orientation.
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Add supports to the affected overhangs.
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Add gussets to stabilize overhangs that are pillowing.
Tilt horizontal overhangs 40 degrees +/- so that they are self-supporting.
Reference Recommended Feature Sizes﻿ for unsupported angles per resin.
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Reference Print Plan Adjustments﻿ for guidance on the following parameters:
﻿1 Pump Up Parameters﻿ 
Pump Height Parameters
Minimum Pump Height
Minimum Distance from Peak
Distance from Peak Multiplier
Platform Speed Parameters
Motor Up Speed
﻿3 Pump Down Parameters﻿ 
Platform Speed Parameters
Motor Down Speed
If problems persist, please reach out to Carbon Support.
Explanation & Causes
Explanation
Pillowing occurs when a portion of a horizontal surface is stretched out of position during printing. Because of how the slicing plays out over the geometry, only a thin portion of this surface is cured before the next slice captures more of the geometry.
Part sliced to capture a portion of a horizontal surface
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This makes the affected partial surface, between supports, a thin, unsupported overhang which is weak during the pump up stage. While the platform moves up, the weak partial surface is temporarily held in place by the surface tension of the dead zone, pulling it out of shape before the tension is broken. When the platform moves back down, the surface is even weaker in its stretched out shape, leaving it susceptible to be pushed in the other direction under the pump down forces. This is the position the malformed part stays in when the next slice cures, leaving it to appear as a pillow between supports.
Pillowing on a printing slice
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Reference DLS Printer Dynamics﻿ for more information on the stages of printing a slice.
Z dimensions for pump height and slice thickness are exaggerated in the diagrams above for visibility.
Causes
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Root Issue
Problem
Why Defect Presents
Orientation
Part is oriented to have surfaces printing horizontally (relative to platform).
Surfaces may be sliced to be thin and susceptible to pillowing.
Supports
Part requires more supports at pillowing overhangs.
Surfaces may be sliced to be thin and susceptible to pillowing.
Design
Part is designed to have flat surfaces.
Surfaces may be sliced to be thin and susceptible to pillowing.
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Printing Stage
Parameter Type
Type of Adjustment
Why Defect Presents
1 Pump Up
Pump Height
﻿Increase﻿
Increased pump height provides more space for the weak surface to be stretched out of shape.
1 Pump Up
Platform Speed
﻿Increase﻿
Increased Motor Up Speed provides less time for the weak surface to break from the dead zone surface tension while also increasing suction forces.
3 Pump Down
Platform Speed
﻿Increase﻿
Increased Motor Down Speed increases the pump down forces that push the weak, stretched surface out of position.
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Root Issue	Problem	Why Defect Presents
Orientation	Part is oriented to have surfaces printing horizontally (relative to platform).	Surfaces may be sliced to be thin and susceptible to pillowing.
Supports	Part requires more supports at pillowing overhangs.	Surfaces may be sliced to be thin and susceptible to pillowing.
Design	Part is designed to have flat surfaces.	Surfaces may be sliced to be thin and susceptible to pillowing.

Printing Stage	Parameter Type	Type of Adjustment	Why Defect Presents
1 Pump Up	Pump Height	Increase	Increased pump height provides more space for the weak surface to be stretched out of shape.
1 Pump Up	Platform Speed	Increase	Increased Motor Up Speed provides less time for the weak surface to break from the dead zone surface tension while also increasing suction forces.
3 Pump Down	Platform Speed	Increase	Increased Motor Down Speed increases the pump down forces that push the weak, stretched surface out of position.

Overcure

Projection Error