---
title: Shrink Line
slug: troubleshooting/shrink-line
description: Discover effective solutions for addressing the "Shrink Line" part defect from Carbon DLS printing. This comprehensive document explains how to identify, troubleshoot, and understand the root causes.
docTags:
createdAt: 2024-06-14T00:57:59.485Z
---
::::VerticalSplit{layout="left"}
:::VerticalSplitItem
**Shrink Line**
Lines on the part surface corresponding to changes in geometry.
:::
:::VerticalSplitItem
::Image[]{src="https://api.archbee.com/api/optimize/3CesIL2dYMCHPZvRjp8S0/ph8jeoaiRcpVyOlu8ssrX_image.png" size="80" width="1680" height="1680" position="flex-start" caption="Lines on the outside of the part correspond to ribs on the inside" alt="Lines on the outside of the part correspond to ribs on the inside" showCaption="true"}
:::
::::
# How to Identify
Shrink lines can be diagnosed as follows:
- Lines correspond to a feature change in the geometry.
- Lines can appear in any direction relative to the build platform.
- Lines do **not** have a sharp edge.
- Lines can often be seen but not felt.
Cosmetic only
::::LinkArray
:::LinkArrayItem{headerType="IMAGE" headerImage="https://api.archbee.com/api/optimize/Nvx7WdIjE2XFpMaBlbCES-vLV2fTNCAqWDF6KetSckA-20240812-182422.jpg"}
**Cause -** **Cross Section**
**Solution** - Print Preparation or Part Design
:::
:::LinkArrayItem{headerType="IMAGE" headerImage="https://api.archbee.com/api/optimize/Nvx7WdIjE2XFpMaBlbCES-ILGjjergeTsbjfR40dxcn-20240812-182430.png"}
**Cause -** **Cross Section**
**Solution** - Print Preparation or Part Design
:::
::::
# Troubleshooting
:::hint{type="info"}
It is recommended that you review all the possible solutions before taking action to ensure you are pursuing the best course of action.
:::
If the best course of action is not apparent, try the troubleshooting options in the order listed. Refer [here](docId\:pPm8gmeGCY_0fkFwgTCyj) for more tips.
## 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.
::::ExpandableHeading
### Orientation
- **Cross Section**
- Reorient part so the **hero surface**** does not intersect** the offending feature's cross section that is presenting the shrink lines.
- Reorient part so the change in cross section occurs **very gradually**.
:::hint{type="warning"}
Supports may be needed with a new orientation.
:::
::Image[]{src="https://api.archbee.com/api/optimize/3CesIL2dYMCHPZvRjp8S0/xI5JVoqBi7fQM9D7sSzQq_shrink-line-orientation.png" size="70" width="1006" height="1000" position="flex-start" showCaption="false"}
::::
:::ExpandableHeading
### Design
- **Cross Section**
- Redesign the part to add **generous bevels or fillets** to transition between cross sections gradually.
::Image[]{src="https://api.archbee.com/api/optimize/3CesIL2dYMCHPZvRjp8S0/nkkk0DUnoYaihx7iYSeuU_shrink-line-design-sml.png" size="70" width="1154" height="1000" position="flex-start" showCaption="false"}
:::
:::hint{type="info"}
If problems persist, please reach out to [Carbon Support](mailto\:support@carbon3d.com).
:::
# Explanation & Causes
## Explanation
- The process of polymerization produces heat as each slice cures.
- Slices cool after initial cure.
- Cooling rate is determined by cross section.
- When cross section changes due to a feature change in the geometry, cooling will occur at different rates where the geometry changes.
- Smaller cross sections cool more quickly than larger cross sections.
::Image[]{src="https://res.cloudinary.com/carbon3d/image/upload/v1740677411/Education/Process/DLS-printer-dynamics/DLS-Dynamics/Shrinkage-cooling.gif" size="70" width="1080" height="1080" position="flex-start" showCaption="false"}
## Causes
### Print Preparation or Part Design
::::VerticalSplit{layout="middle"}
:::VerticalSplitItem
How the part is **oriented**, **supported**, or **designed **is causing the defect.
:::
:::VerticalSplitItem
:::
::::
| **Root Issue** | **Problem** | **Why Defect Presents** |
| -------------- | ------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Cross Section | Cross section changes suddenly | Smaller cross sections cool more quickly than larger cross sections. When a sudden change in cross section occurs between slices, the change in cooling can manifest in a surface finish difference. |