--- title: Cracking - Bulk slug: troubleshooting/cracking-bulk description: Discover effective solutions for addressing the "Bulk Cracking" part defect from Carbon DLS printing. This comprehensive document explains how to identify, troubleshoot, and understand the root causes. docTags: createdAt: 2025-02-28T02:04:18.458Z --- ::::VerticalSplit{layout="left"} :::VerticalSplitItem **Bulk Cracking** Cracks/fissures form during the thermal curing process at high stress points. ::: :::VerticalSplitItem ::Image[]{src="https://res.cloudinary.com/carbon3d/image/upload/Education/Troubleshooting/Part-Defects/Cracking_Bulk/Bulk-cracking-example.png" size="70" width="1080" height="1080" position="center" alt="Bulk Cracking" showCaption="false"} ::: :::: # How to Identify Bulk cracking can be diagnosed as follows: - Cracks appear as thin, dark lines in the part, **occurring at stress points such as a corner** - Lines appear after baking. Parts look fine off of the printer and after washing. :::hint{type="info"} Bulk cracking is differentiated by other types of cracking by where it occurs on the part. This is a geometry-based form of cracking that occurs solely at stress points. Reference [Cracking - Medial Axis](docId:5HA-yH1HU5CPMnaPFurPa) and [Cracking - Excessive Solvent](docId\:WYB5x-5127PoKNOm_LJjW) for other types of cracking. ::: ::::LinkArray :::LinkArrayItem{headerType="IMAGE" headerImage="https://api.archbee.com/api/optimize/dptYqcTHPbVZhe3zuNg4v-aw4nxrGv9w6TcA-PK64FT-20250102-003405.png"} **Cause** - Inconclusive ::: :::LinkArrayItem{headerType="IMAGE" headerImage="https://api.archbee.com/api/optimize/dptYqcTHPbVZhe3zuNg4v-s4OKvxYJgXNK9tThjyOD3-20250228-025521.png"} **Cause** - Inconclusive ::: :::: # 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. ## Process, Material, and Hardware Checks If any of these conditions apply to your print, take the corrective action and reprint to see if the problem is resolved. :::ExpandableHeading ### Washing Follow solvent exposure times closely in the resin post-processing protocol. - **Do not exceed maximum solvent exposure times** and reduce exposure time when possible if parts are fully clean. - Use swabs in corners, or other stress points that trap solvent. - After washing, dry parts on a blue towel or raised mesh (with air flow around the whole part) until all solvent is evaporated prior to baking. ![Solvent exposure](https://res.cloudinary.com/carbon3d/image/upload/Education/Troubleshooting/Part-Defects/_Common-troubleshooting-for-all/Solvent-exposure.png) ::: :::::ExpandableHeading ### Baking ::::VerticalSplit{layout="middle"} :::VerticalSplitItem Check that the correct bake schedule was used per resin protocols. Resins most susceptible to cracking use a bake schedule that ramps up temperature gradually. ::: :::VerticalSplitItem ![Ramped baking](https://res.cloudinary.com/carbon3d/image/upload/v1740710072/Education/Troubleshooting/Part-Defects/Cracking_Bulk/Ramped-baking-gif.gif) ::: :::: ::::: ## 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 ### Design ::::VerticalSplit{layout="middle"} :::VerticalSplitItem Add fillets or chamfers to corners, or similar stress points, to mitigate bulk cracking. ::: :::VerticalSplitItem ![Fillets](https://res.cloudinary.com/carbon3d/image/upload/Education/Troubleshooting/Part-Defects/_Common-troubleshooting-for-all/Fillets.png) ::: :::: ::::: :::hint{type="info"} If problems persist, please reach out to [Carbon Support](mailto\:support@carbon3d.com). ::: # Explanation & Causes ## Explanation Bulk cracking occurs when stresses build up during the print and are then released in the bake. The most susceptible conditions of bulk cracking are: - Sharp inside corners - Excessive solvent exposure - Brittle resins: EPX ## Causes ### Post-Processing ::::VerticalSplit{layout="middle"} :::VerticalSplitItem How the part is **handled** in post-processing is causing the defect. ::: :::VerticalSplitItem ![Post-Processing](https://api.archbee.com/api/optimize/3CesIL2dYMCHPZvRjp8S0/L8qIt6vOxrll63alqGpyY_image.png) ::: :::: | **Root Issue** | **Problem** | **Why Defect Presents** | | -------------- | ------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- | | Washing | Solvent exposure | Too much solvent exposure weakens the material, making stress points weaker. | | Baking | Wrong bake schedule | The most common resins for bulk cracking are the brittle resins (EPX) that use a ramping program to raise the temperature slowly and prevent thermal shock. | ### Print Preparation or Part Design ::::VerticalSplit{layout="middle"} :::VerticalSplitItem How the part is **oriented**, **supported**, or **designed **is causing the defect. ::: :::VerticalSplitItem ![Print Preparation or Part Design Cause](https://api.archbee.com/api/optimize/3CesIL2dYMCHPZvRjp8S0/LhaBjVT_Yxhp03FPtHLyF_orient-and-support-quick-view-v0101-xxs.gif) ::: :::: | **Root Issue** | **Problem** | **Why Defect Presents** | | -------------- | -------------------- | -------------------------------------------------------------------------- | | Design | Sharp inside corners | Stress points such as sharp inside corners are weaker under thermal shock. |