Cracking - Bulk

bulk cracking cracks/fissures form during the thermal curing process at high stress points 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 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 cause inconclusive cause inconclusive troubleshooting 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 part defects 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 washing follow solvent exposure times closely in the resin post processing protocol do not exceed maximum solvent exposure times 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 baking 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 ramped baking 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 design add fillets or chamfers to corners, or similar stress points, to mitigate bulk cracking fillets if problems persist, please reach out to carbon support 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 how the part is handled in post processing is causing the defect post processing 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 how the part is oriented , supported , or designed is causing the defect print preparation or part design cause root issue problem why defect presents design sharp inside corners stress points such as sharp inside corners are weaker under thermal shock