Comprehensive Analysis of PFMEA: From Purpose to Implementation, Ensuring Production Quality and Customer Satisfaction

I. Purpose

　　In the complex process of production and manufacturing, Process Potential Failure Mode and Effects Analysis (PFMEA) plays a crucial role. It is like a rigorous "detective", committed to searching for clues in every aspect of the process to achieve several important goals.

　　First of all, PFMEA can identify and evaluate potential failures and their consequences in the process. The production process is like a complex web, and every link may harbor the risk of failure. These failures may be minor defects or major problems that can affect the entire production chain. Through PFMEA, we can conduct an in - depth analysis of each link like a "detective" investigating clues, find those potential and hard - to - detect failure points, and predict their possible consequences.

　　Secondly, another important mission of PFMEA is to find measures that can avoid or reduce the occurrence of these potential failures. Once potential failure risks are discovered, we cannot just sit back and do nothing. Instead, we should take active actions. Based on the analysis of failure modes and consequences, PFMEA will propose a series of targeted measures. These measures are like a series of solid defense lines, keeping potential failure risks out and ensuring the stability and reliability of the production process.

　　Finally, PFMEA will conduct a written summary of the above process. This is not just a simple record, but a refinement and elevation of the entire analysis process. Through the written summary, we can improve the design process and integrate the valuable experience and lessons learned from the analysis into subsequent design and production. The ultimate goal of doing this is to ensure customer satisfaction, because only by producing high-quality and defect-free products can we win the trust and recognition of customers.

II. Scope of Application

　　The scope of application of PFMEA is extensive, covering multiple aspects of the production process.

　　1. New assemblies/parts/processes: For all newly designed, newly developed assemblies, parts, or processes, PFMEA is essential. New things are often accompanied by more uncertainties and potential risks. By introducing PFMEA in the early stage, possible problems can be identified at the design stage, and timely adjustments and optimizations can be made to avoid serious consequences in subsequent production and use.

　　2. Changed assemblies/components/processes: When changes occur to assemblies, components, or processes, even minor alterations may trigger a series of chain reactions and bring new potential failure risks. Therefore, it is very necessary to conduct a PFMEA analysis on the situation after the change. This can ensure that the change does not introduce new problems and also verify whether the change has achieved the expected effect.

　　3. Existing assemblies/components/processes with changes in the application environment: Changes in the application environment may have an impact on existing assemblies, components, or processes. For example, changes in environmental factors such as temperature, humidity, and pressure may cause changes in the performance of the product, thereby increasing the possibility of potential failures. In this case, conducting a PFMEA analysis can help us evaluate the impact of environmental changes and take corresponding measures to ensure the normal operation of the product in the new environment.

III. Responsibilities

　　The PFMEA team assumes core responsibilities throughout the PFMEA implementation process. This team is like a well-trained "special forces" responsible for carrying out various tasks of PFMEA. Team members usually come from multiple departments such as design, production, quality, procurement, and sales. They each have different professional knowledge and skills and can conduct a comprehensive analysis and evaluation of the process from multiple perspectives. The main tasks of the PFMEA team include collecting relevant information, conducting failure mode and effects analysis, and formulating preventive and improvement measures. Through the collaborative cooperation of the team, the scientificity, effectiveness, and comprehensiveness of PFMEA implementation can be ensured.

IV. Definitions

　　1. Customer: The definition of a customer is relatively broad. Generally speaking, it refers to the "end - user", that is, the consumer who purchases and uses our products. However, in the production process, the concept of a customer can be further extended. It can also be the subsequent or the next manufacturing or assembly process, because the product quality of the previous process will directly affect the smooth progress of the subsequent processes. In addition, the object of service work and government regulations can also be regarded as customers. For example, products need to meet the relevant government regulatory requirements, which means that government regulations put forward requirements for the design and production of products to a certain extent, so they can also be regarded as a kind of "customer" demand.

　　2. Failure: Failure refers to the situation where a product fails to perform its intended functions under specified conditions. These specified conditions cover multiple aspects such as the environment, operation, and time. Specifically, failure may manifest as the product's parameter values being unable to stay within the specified upper and lower limits. This is like an athlete's performance going beyond the normal range, indicating that there is a problem with their state. In addition, phenomena such as cracking, breaking, jamming, and damage of the product within the specified range also fall into the category of failure. These failure situations not only affect the normal use of the product but may also bring potential safety hazards and economic losses.

V. Work Procedures

(I) Establish a PFMEA team

　　In response to different situations, the Technology Department will adopt different methods to form the PFMEA team.

　　1. For all new assemblies/parts/processes, the Technical Department will actively contact relevant personnel from relevant departments such as design, production, quality, procurement, and sales. This is like a "gathering of heroes", where professional talents from various departments come together to contribute ideas for new projects. After the establishment of the group, it needs to be reported to the general manager for approval to ensure that the establishment of the group complies with the company's overall strategy and requirements.

　　2. For all changed assemblies/parts/processes and the original assemblies/parts/processes with changes in the application environment, the Technology Department is responsible for convening the PFMEA team. This is because the Technology Department has the best understanding of these changes and can accurately organize relevant personnel for analysis and evaluation.

(II) Risk analysis and assessment

　　The PFMEA team is responsible for analyzing or re - confirming the risk levels of each process in the process flow chart. The process flow chart is like a "map" of the production process. Through careful study of this "map", the team identifies the areas where risks may exist. Then, the analysis results are formed into a written process flow chart/risk assessment form. This form is like a "risk report", clearly showing the risk status of each process and providing an important basis for subsequent decision - making.

(III) Process Potential Failure Mode and Effects Analysis

　　1. FMEA Number: Enter the number of the FMEA document. This number is like the ID number of the document, which facilitates tracking and usage. The number of the Process FMEA form follows specific rules, including the project number (used in a cycle from 01 - 09), the month, and the last two digits of the Gregorian calendar year. Through this numbering method, the source and time information of the document can be clearly identified.

　　2. Part name: Fill in the name and number of the process system, subsystem or part to be analyzed. An accurate part name and number helps to clarify the object of analysis and avoid confusion.

　　3. Process responsibility: Fill in the original equipment manufacturer (OEM), department, and team. If known, also include the supplier's name. Defining process responsibility can ensure that relevant responsible persons can be promptly identified when problems occur, facilitating problem-solving and improvement.

　　4. Compilation: Fill in the name, phone number of the engineer responsible for preparing the FMEA work and the name of the company they belong to. This facilitates communication with the compiler when necessary.

　　5. Model Year/Vehicle Type: Enter the expected model year and vehicle type that will be used and/or affected by the analysis process (if known). This helps to combine the analysis results with specific product and market requirements, enhancing the pertinence and practicality of the analysis.

　　6. Critical date: Enter the scheduled completion date for the initial FMEA, which should not exceed the planned start date of production. A reasonable setting of the critical date can ensure the timely completion of the PFMEA analysis work and provide a guarantee for the smooth progress of production.

　　7. FMEA Compilation Date: Fill in the date when the original FMEA draft was compiled. Recording the compilation date can reflect the chronological order of the analysis work, facilitating the traceability and evaluation of the analysis process.

　　8. FMEA Revision Date: Enter the date of the latest revision of the FMEA. As the production process continuously changes and develops, the FMEA form also needs to be continuously updated and improved. Recording the revision date can promptly reflect the latest status of the form.

　　9. Core group: List the responsible individuals and units with the authority to participate in or execute this work. It is recommended to list the names, units, phone numbers, addresses, etc. of all group members separately, which can facilitate communication and collaboration among group members.

　　10. Process function/requirement: Briefly describe the process or operation being analyzed and explain the purpose of the process or operation as simply as possible. If the process includes many operations with different failure modes (e.g., assembly), these operations can be listed as independent processes. A clear description of the process function and requirements helps to accurately identify potential failure modes.

　　11. Potential failure modes: Based on the characteristics of parts, subsystems, systems or processes, list each potential failure mode corresponding to a specific process or operation. The premise here is to assume that such failures may occur, but they don't necessarily have to occur. By comprehensively listing potential failure modes, more sufficient basis can be provided for subsequent analysis and prevention.

　　12. Potential failure consequences: Potential failure consequences refer to the impacts of failure modes on customers. Customers can be the next process, the next project or location, dealers, or vehicle owners. When evaluating potential failure consequences, these different types of customers need to be considered. For end - users, the consequences of failure should always be described in terms of the performance of the product or system, such as noise and abnormal operation. If the customer is the next process or subsequent processes/workstations, the failure consequences may manifest as being unable to fasten or drill. Describing the failure consequences in detail can help us more intuitively understand the impact degree of potential failures.

　　13. Severity: Severity is the score corresponding to the most serious consequence of the given failure mode. Severity is a relative score for each FMEA. If the customer's assembly plant or product user is affected by the failure mode, the evaluation of severity may be beyond the experience or knowledge scope of the process engineer/group. In this case, consultations and discussions should be held with the design FMEA, design engineer and/or the process engineer of the subsequent manufacturing or assembly plant. The recommended scoring criteria specify the severity scores corresponding to different consequences. For example, a hazard without warning is scored 10 points, and a hazard with warning is scored 9 points. There is no need to conduct further analysis for a failure mode with a severity score of 1 point.

　　14. Grading: Grade some special characteristics of parts, subsystems or systems that require additional process control (such as critical, major, important, key, etc.). Through grading, different control measures can be taken for different characteristics to improve the effectiveness of process control.

　　15. Causes/Mechanisms of Potential Failures: For each potential failure mode, list every conceivable cause of failure within the broadest possible scope. When making the list, specific errors or misoperation situations should be clearly recorded, rather than using vague words. Accurately identifying the causes and mechanisms of failures can provide a basis for formulating targeted preventive measures.

　　16. Occurrence rating: List the specific occurrence ratings of failure causes according to the occurrence rating criteria. The rating criteria determine different occurrence ratings based on similar failure rates and PpK values. For example, a failure that occurs continuously is rated 10 points, and a failure that is unlikely to occur is rated 1 point. Understanding the occurrence frequency of failures helps us allocate resources reasonably and prioritize the failure modes with a higher occurrence frequency.

　　17. Current preventive process control: List the preventive process control methods used in the current process control. These methods are like "firewalls" that can prevent failures before they occur and reduce the probability of failure.

　　18. Current detective process control: List the detective process control methods used in the current process control (divided into two types: detecting the cause and detecting the failure mode). Detective process control is like a "monitor", which can promptly detect the failures that have occurred so that corresponding measures can be taken for handling.

5.4.19 Detectability

5.4.19.1 Determination of detection degrees

　　In the entire quality control system, detectability is a key element. We need to determine the specific detectability score according to the detectability scoring criteria stipulated in 5.4.19.2. This process is like setting a precise ruler for product quality inspection, which can help us accurately measure the ability of inspection methods to detect problems. Only by accurately determining the detectability score can we provide a reliable basis for subsequent risk assessment and measure formulation.

5.4.19.2 Detection check criteria

　　The inspection of detectability involves multiple aspects. We will conduct a detailed analysis from several dimensions, including inspection standards, inspection types, the scope of recommended inspection methods, and the corresponding scores.

　　Inspection criteriaInspection types (A: Manual inspection; B: Measuring tools; C: Error-proofing method)Scope of recommended inspection methodsScore

　　Almost impossible - Cannot be detected or inspected10

　　When the inspection is in an "almost impossible" state, it means that the current detection conditions are simply unable to detect potential problems. It could be due to the limitations of detection technology or the fact that the product characteristics themselves are too concealed. For example, for some tiny internal defects, due to the lack of suitable detection equipment, it is absolutely certain that these problems cannot be found. In this case, a detection rating of 10 points is given.