Part Defects

Fanging

10min

Fanging
Portion of a lattice node is stretched out of position during printing.


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How to Identify
Fanging can be diagnosed as follows:
Fanging occurs at lattice nodes, where struts intersect.
The defect appears on the struts just before they connect together.
Fanging appears like vampire fangs pointing towards the platform.
﻿Looping﻿ and Pillowing﻿ are defects that arise from the same issue but appear at different locations or features: at horizontal struts or surfaces, respectively.
Cause - Inconclusive
Cause - Inconclusive
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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.
Add struts to provide more structure at the problematic struts before they reach their connecting node.
The performance of the lattice will change.
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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
Fanging occurs in a lattice when struts are stretched out of position during printing. Struts that are building towards a connection node are structurally at their weakest just before connecting together.
This makes the affected struts dangling and weak during the pump up stage. While the platform moves up, the weak struts are 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 strut 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 struts stay in when the next slice cures, leaving it to appear misshapen as "fangs" just before the struts connect together.
This defect usually occurs with elastomeric resins that are soft and pliable during printing.
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 below for visibility.
Struts are more susceptible to movement just before they connect together
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Fanging on a printing slice
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Causes
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Root Issue
Problem
Why Defect Presents
Designed
Lattice contains struts that are longer and weaker before connecting at nodes.
Short struts are less likely to be weak before connecting at their nodes.
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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 struts to be stretched out of shape.
1 Pump Up
Platform Speed
﻿Increase﻿
Increased Motor Up Speed provides less time for the weak struts 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 struts out of position.
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Root Issue	Problem	Why Defect Presents
Designed	Lattice contains struts that are longer and weaker before connecting at nodes.	Short struts are less likely to be weak before connecting at their nodes.

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 struts to be stretched out of shape.
1 Pump Up	Platform Speed	Increase	Increased Motor Up Speed provides less time for the weak struts 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 struts out of position.

Excess Resin

Filled Holes on Skin