Stress cracking occurs in the product after long-term use

In the '2079851475616104458 (vacuum forming) production process, the product exhibits the quality defect of "Stress cracking occurs in the product after long-term use".The specific manifestation is Cracks appear on the product surface after use.This defect is more common when processing materials such as PP, PS, PET, PVC and ABS sheets, and its occurrence is usually related to unreasonable settings of sheet heating temperature, forming pressure/vacuum, mold temperature and cooling time.When the Stress cracking occurs in the product after long-term use situation is severe, it will cause a series of chain quality defects in the product's appearance, dimensional accuracy, mechanical properties and other aspects, which not only reduces the product's functionality and safety in use, but also directly increases the scrap rate and production cost.Therefore, this problem requires systematic diagnosis and optimization from multiple dimensions such as material selection, the status of the '2079851475616104458 machine, heating oven, mold and vacuum/air pressure system, and sheet heating temperature, forming pressure/vacuum, mold temperature and cooling time.

1. Long-term action of residual stress.This factor causing the problem reflects that certain process conditions or material properties in '2079851475616104458 (vacuum forming) do not meet the optimal forming requirements.Such problems are often cumulative and concealed, and should be investigated and verified as key focus items during process debugging and finalization to ensure hidden dangers are eliminated at the source. 2. Acceleration by environmental factors.This factor causing the problem reflects that certain process conditions or material properties in '2079851475616104458 (vacuum forming) do not meet the optimal forming requirements.Such problems are often cumulative and concealed, and should be investigated and verified as key focus items during process debugging and finalization to ensure hidden dangers are eliminated at the source. In addition, the insufficient overall coordination of sheet heating uniformity and stretch ratio control is also a factor that cannot be ignored; there are complex interactions and coupling relationships among the process parameters, and the deviation of any parameter may aggravate the degree of Stress cracking occurs in the product after long-term use through chain effects. In terms of equipment maintenance, the regular overhaul and accuracy confirmation of the '2079851475616104458 machine, heating oven, mold and vacuum/air pressure system are not in place, causing the actual operating parameters of the equipment to deviate from process requirements, which will also become a potential inducement of the Stress cracking occurs in the product after long-term use problem.

1. Optimize the process to reduce residual stress.Adjustments should follow the principle of gradual progress; each adjustment should not be too large, and a decrement of 5%~15% of the current value is recommended.After each adjustment, stably observe the product quality changes for at least 5~10 mold cycles, and continue adjusting only after confirming the improvement direction is correct; never make excessive one-step adjustments. 2. Add stabilizers.Formula and ratio adjustments should be determined on the basis of laboratory small-scale tests, and then verified by on-line pilot tests.Any change to the formula should be recorded and its impact on all aspects of product performance evaluated.Automatic metering and batching devices can effectively reduce manual batching errors and batch-to-batch fluctuations. It is recommended to formulate a preventive checklist for the Stress cracking occurs in the product after long-term use problem, incorporate sheet heating uniformity and stretch ratio control into the daily inspection scope, and conduct online monitoring of key parameters through the SPC statistical process control method to achieve early warning and rapid response to problems. In terms of material management, incoming inspection of raw materials and in-process testing of work-in-progress should be strengthened, and key performance indicators of PP, PS, PET, PVC and ABS sheets should be strictly controlled to ensure the stability of forming quality from the source.

In summary, the causes of the "Stress cracking occurs in the product after long-term use" problem can be attributed to the combined action of multiple factors such as Long-term action of residual stress, Acceleration by environmental factors.To solve this problem, it is necessary to start from aspects such as Optimize the process to reduce residual stress, Add stabilizers and take systematic governance measures.In actual production, it is recommended to establish a prevention and rapid response mechanism for this problem, achieving stable production and continuous improvement through sheet heating uniformity and stretch ratio control.