Part Deformation After Post-Treatment? Causes & Solutions Here

1. Three Core Causes of Deformation: Locate Problems at the Source

1. Unreleased Internal Stress: Raw materials contain stress before processing (e.g., rolling stress of cold-rolled steel plates, cooling shrinkage stress of injection-molded parts). Temperature changes during post-treatment (e.g., welding, heat treatment) trigger stress release, leading to part bending. For example, if stainless steel plates are not stress-relieved annealed after laser cutting, they are prone to 1-2mm warping during subsequent electroplating.
2. Mismatched Process Parameters: Improper control of temperature, time, and cooling rate in post-treatment. For instance, if the bath temperature exceeds 25℃ and cooling is uneven during aluminum alloy anodizing, the deformation rate of thin-walled parts (thickness <1mm) increases by 30%; failure to temper steel parts promptly after quenching and excessively fast cooling easily cause crack-like deformation.
3. Structural Design Flaws: Excessive wall thickness differences (e.g., a housing part with 1mm and 5mm wall thickness) and unevenly distributed ribs lead to inconsistent shrinkage/expansion in different areas during post-treatment, inevitably causing deformation.

2. Four Targeted Solutions: Effective When Implemented

1. Stress Relief Pre-Treatment: Conduct "stress-relief annealing" (steel parts heated to 600-650℃ for 2-4 hours) or "aging treatment" (aluminum alloys heated to 120-180℃ for 6-8 hours) before processing to release internal stress in materials in advance, reducing the basis for deformation from the source.
2. Optimize Post-Treatment Processes: Match parameters to material properties—control the bath temperature at 20-22℃ for aluminum anodizing and use staged cooling (first air-cooled to 50℃ then water-cooled); replace rapid cooling with "isothermal quenching" for steel heat treatment to reduce deformation caused by temperature gradients.
3. Improve Structural Design: Through DFM optimization, control the wall thickness difference within 1:1.5, add process holes in thick-walled areas, and arrange ribs evenly (rib height not exceeding 3 times the wall thickness) to balance the shrinkage rate during post-treatment.
4. Auxiliary Fixing and Correction: Use special fixtures to fix deformation-prone parts (e.g., long sheet metal parts) during post-treatment (e.g., magnetic positioning tools for welding); restore dimensions after deformation via "cold straightening" (fine adjustment with a press) or "hot straightening" (local heating to recrystallization temperature for correction).