Looping
Looping
Portion of a horizontal strut is stretched out of position during printing.
Looping can be diagnosed as follows:
- Looping occurs on struts that are running horizontal, or parallel to the platform, during printing.
- The defect appears at the center of the strut's span.
- Looping appears as though part of the strut has been pulled away from the rest of the strut, leaving a gap.
- Minor cases of looping may appear as a bump on the strut.
Cause - Inconclusive
Cause - Inconclusive
Cause - Inconclusive Minor Looping
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.
If problems persist, please reach out to Carbon Support.
Looping occurs in a lattice when a portion of a horizontal strut is stretched out of position during printing. Because of how the slicing plays out over the lattice geometry, only a thin portion of this horizontal strut is cured before the next slice captures more of the strut.
This makes the affected partial strut a thin, unsupported overhang which is therefore weak during the pump up stage. While the platform moves up, the weak partial strut 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 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 partial strut stays in when the next slice cures, leaving it to appear disconnected from the rest of the strut.
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.
Root Issue | Problem | Why Defect Presents |
|---|---|---|
Oriented | Part is oriented to have longer struts printing horizontally (relative to platform). | Horizontal struts may be sliced to have thin partial struts that are susceptible to looping. |
Designed | Lattice is designed to have longer struts. | Short struts are less likely to be weak even when sliced to have partial horizontal struts. |
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 partial strut to be stretched out of shape. |
1 Pump Up | Platform Speed | Increase | Increased Motor Up Speed provides less time for the weak partial strut 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 strut out of position. |