Item: Name of the assembly/sub-assembly/part being analyzed

Function: the function of the product being analyzed, that is, the design intent

Process function: analyzed operation/process name

Process requirements: the purpose of the process/process

Symptoms of loss of function and structure (the same function and structure can have multiple manifestations)

Performance that fails to achieve the purpose of the process (the same process can have multiple performances)

Customers include internal customers, OEM customers, and final customers

The extent to which potential failure modes impact safety or regulatory compliance must be identified

Consequences to end users include: noisy noise, abnormal operation, odor, leakage, customer dissatisfaction, endangerment to users, etc.

The consequences for downstream processes include: inability to process, inability to install, damage to equipment, endangerment to operators, etc.

Classification of levels: 1 to 10. The larger the S, the more serious the consequences.

Classification of special characteristics of the object being analyzed (critical, major, etc.)

Including special characteristics at each level of assembly/sub-assembly/parts

Incorrect design structure

Incorrect design parameters

Incorrect material selection

Incorrect process methods

Incorrect process parameters

Inadequate control methods

Material not considered: premature yielding, premature fatigue, instability, etc.

Not considering the product itself: premature wear, oxidation, corrosion, etc.

Use failure chain

Even asked why

Find the root cause

Design review: 1. Preventive control methods can prevent the cause of failure or reduce the probability of occurrence.

Design verification (DV): ② Detection control method can find the cause of failure

Design confirmation: detection control method to find failure modes

Application of error-proofing: preventive control methods to prevent failures from occurring

Monitoring and inspection: preventive control methods, which can find the cause of failure (the cause of deviation from process requirements) and take preventive measures

Inspection: detection control method to find failure modes and take corrective measures

Classification of levels: 1 to 10. The larger the O, the more likely the failure mode is to occur. To analyze:

Three degrees (S, O, D) quantify the severity of failure modes from different perspectives

The RPN alarm or line should be determined empirically based on product characteristics. The general recommendation is: when RPN<27, it is safe; when 27≤RPN<64, the risk is greater; when RPN>125, the risk is serious. (RPN also needs its own file to set its own value)

When RPN is high or S is high, measures should be taken to reduce it. (Severity when S>8)

Numerical reductions in severity can only be achieved through design changes.

Reduce severity S: change the design mechanism and change the process method

Reduce frequency O: change the design structure, change the design parameters, change the materials used, change the process methods, change the process parameters, change the preventive control methods

Reduce detection D: If the control method is sufficient, increase the degree of control. If control methods are insufficient, add/change control methods

If the RPN value or S value is high, reanalysis is required.

If the RPN value or S value is not high, the analysis ends