Blank delamination during cold-press preforming

The preform blank shows horizontal layer cracking during demolding or transfer. The interlayer separation phenomenon gradually expands after the product is stressed or acted upon by the environment, seriously affecting structural integrity.

(1) Gas removal aspect: Insufficient venting after pressurization produces elastic recovery delamination; gas retention forms internal defects affecting the compactness of the product. (2) Pressure parameter aspect: Pressure is released too quickly during demolding; improper pressure control directly affects the compactness and molding quality of the product. (3) Raw material characteristic aspect: Excessive internal lubricant in the powder weakens interlayer bonding; the physical characteristics of the powder directly affect the preforming and sintering quality.

(1) Implementation measure: Fully hold pressure and slowly release the pressure, formulate specific operation plans in combination with actual production conditions, and verify the implementation effect. (2) Material selection: Use molds with demolding chamfers, establish material selection evaluation standards, and determine the optimal plan through comparative tests. (3) Process control: Control the amount of internal lubricant., establish an online monitoring mechanism, set upper and lower parameter limits and implement alarm management. (4) Preventive measure: Establish interlayer bonding strength testing standards, regularly sample and test interlayer shear strength, and monitor the stability of process parameters.

The essence of the interlayer separation problem is insufficient interfacial bonding force, which needs to be systematically improved from three aspects: impregnation quality, interlayer cleanliness, and process parameters.