Product deformation/warpage

After sintering, the product shows bending, twisting, or irregular dimensional changes. Deformation usually gradually intensifies after demolding of the product, and is more significant especially in parts with asymmetric structures or large wall thickness differences. This problem causes the product dimensions to exceed the tolerance range, affecting assembly accuracy and product function.

(1) Density distribution aspect: The density of the cold-pressed preform blank is uneven, and density differences reflect uneven densification degrees in various parts of the product. (2) Temperature parameter aspect: Uneven temperature in the sintering furnace causes shrinkage differences among various parts, and temperature deviations directly affect the physical and chemical state of the material and the reaction process. (3) Stress distribution aspect: Uneven cooling produces thermal stress, and internal stress concentration causes the product to crack or deform in subsequent use.

(1) Implementation measure: Ensure the density uniformity of the preform material, formulate specific operation plans in combination with actual production conditions, and verify the implementation effect. (2) Implementation measure: When sintering, place the products so that all surfaces are heated evenly, formulate specific operation plans in combination with actual production conditions, and verify the implementation effect. (3) Process control: Adopt program-controlled uniform temperature reduction in the cooling stage., establish an online monitoring mechanism, set upper and lower parameter limits and implement alarm management. (4) Preventive measure: Conduct shrinkage and warpage simulation analysis in the product design stage, and optimize the structure and process plan in advance.

Deformation problems originate from internal stress generated by uneven shrinkage or heating of various parts of the product, and need to be systematically solved from three aspects: structural design, process parameters, and post-processing.