Thermal shock cracks caused by opening the furnace too quickly after sintering is completed

Rushing to open the furnace door to take out parts after high-temperature sintering is completed causes thermal shock cracking of the product. Cracks may appear on the surface or inside of the product, and in severe cases penetrate the entire wall thickness, mostly exposed during demolding or post-processing.

(1) Stress distribution aspect: The product is rapidly cooled from high temperature, generating huge thermal stress; internal stress concentration causes the product to crack or deform in subsequent use. (2) Material aspect: Insufficient material toughness or excessively high crosslinking density leads to increased brittleness. (3) Process aspect: Excessively fast cooling rate generates thermal stress that exceeds the strength limit of the material. (4) Design aspect: Stress concentration at sharp corners or abrupt wall thickness changes.

(1) Implementation measure: The furnace must not be opened until the furnace temperature has naturally dropped to a safe temperature (PTFE recommended ≤200℃), formulate specific operation plans in combination with actual production conditions, and verify the implementation effect. (2) Implementation measure: Opening the door at high temperature is prohibited., formulate specific operation plans in combination with actual production conditions, and verify the implementation effect. (3) Design improvement: Avoid sharp corners and abrupt wall thickness changes, and increase the fillet radius to reduce stress concentration. (4) Material modification: Add toughening agents or adopt flexible segment resin systems to improve material toughness. (5) Preventive measure: Establish a sound process control standard and quality inspection system, and regularly review process data for continuous optimization.

The essence of cracking is that the internal stress exceeds the strength limit of the material, and it is necessary to proceed from two aspects: reducing stress concentration and improving material toughness.