Military Standard Review: What is the difference between special processes and key processes?

Based on practical issues encountered in the certification audit of quality management systems for equipment design development and production processes, further explore the audit characteristics of key and special processes and the details that should be grasped, aiming to improve the effectiveness of the audit work.

01 Adequate preparation before the audit is essential

The audit of key and special processes is an important part of the auditor's work in the certification audit of quality management systems for equipment design development and production processes. The depth of the audit and its findings directly affect the evaluation results of the auditee. Therefore, sufficient preparation should be made before the audit.

1. Familiarize with several important terms and definitions

a. Key process. A process that plays a decisive role in forming product quality. Generally includes processes that form key important characteristics; processes with high processing difficulty, unstable quality, or that may cause significant economic losses.

b. Key operation. The operation where key characteristics are formed. That is, in the product manufacturing process, the operation that plays a decisive role in product quality and requires strict control. Generally includes operations composed of key and important characteristics; operations with high processing difficulty, unstable quality, expensive raw materials, or that cause significant economic losses if defective products occur; key incoming inspection operations for purchased materials, etc.

c. Process. A set of interrelated or interacting activities that transform inputs into outputs.

d. Special process. A process for which it is difficult or uneconomical to verify whether the formed product is qualified, commonly referred to as a "special process."

e. Process requiring confirmation. When the output of production and service provision processes cannot be verified by subsequent monitoring or measurement, causing problems to appear only after product use or service delivery, the organization should implement confirmation for any such process.

f. Process capability. Also called process capability; the ability of a process to meet specified requirements under stable conditions and normal variation.

2. Familiarize with several important technical documents

For equipment or products, key process technical documents include design documents, process documents, inspection documents, and the "key operation" directory (details) compiled by the process department, such as precision turning of main spindle profiles, precision boring of nozzle inner holes, etc.; special process technical procedures, such as welding, forging, steel heat treatment, surface nickel plating processes, inspection procedures, and confirmation criteria for special processes. Auditors should understand and thoroughly grasp these technical documents according to their professional characteristics.

3. Correctly identify special processes and processes requiring confirmation

(1) Whether the process forms intrinsic quality characteristics required by the customer; processes unrelated to intrinsic product quality characteristics are not special processes.

(2) Although the process forms intrinsic product quality characteristics, if these characteristics can be continuously and periodically verified by the organization in subsequent inspections, the process is not a special process.

(3) Identification of special processes should be based on the actual situation of the organization and product; it cannot be simply determined whether a process is or is not a special process.

02 The audit process should focus on key points and grasp the essentials

Check the completeness of documents (1 drawing, 4 tables, 2 specifications)

1 drawing: product drawing (including parts).

4 tables: key operation detail table, key operation "three fixed" table, process capability survey table, and statistical technical tables.

2 specifications: product inspection specification, test specification.

03 Check the traceability of on-site identification

a. Key processes must be marked with "key process" or "G" on process procedures and route cards; there are also key part (characteristic) markings.

b. For any quality characteristics or factors under key control, process control management points should be established according to product characteristics. Auditors review whether control management points clearly specify control items, control methods, control categories, control requirements, inspection frequency, measurement methods, control charts, tables, and measuring personnel according to product characteristics.

c. First article inspection. Review whether the first article has undergone self-inspection and special inspection, and whether actual measurement records are maintained.

d. Inspection of key and important characteristics is usually conducted with 100% inspection and actual measurement records are maintained.

e. All original quality records, drawings, tables, etc. must be complete, data accurate, properly stored, and traceable.

f. Key processes must implement the "three fixed" system, i.e., fixed operation, fixed personnel, fixed equipment, fill in the three fixed table, and whether it is approved by labor, process, and quality departments.

g. Personnel requirements for key processes. Personnel engaged in processing, assembly, and inspection of key processes must remain relatively stable and be regularly assessed. When personnel change, the three fixed table should be refilled.

h. Placement of products with key characteristics. Products (parts) involving key and important characteristics in key processes should be placed in storage and transportation tools or areas with distinctive markings.

i. Process capability verification. The process department should regularly conduct verification and analysis of process capability during production and issue verification analysis reports.

04 Check the sufficiency of special process confirmation

Special processes are also called special operations. The audit process for special processes is basically the same as that for key processes (operations), divided into document audit and on-site audit, focusing on confirmed elements: man, machine, material, method, environment, measurement (5M1E).

Man: Operators of special process operations should have skill training and hold qualification certificates, such as welder certificates, flaw detector certificates, chemical analyst certificates, inspector certificates, etc., ensuring they are qualified for the process.

Machine: The infrastructure, equipment, tooling, and various monitoring and measuring instruments for the process should be equipped according to their functions, with accuracy meeting process requirements; multi-use of one instrument is strictly prohibited. Instruments critical to product quality should be doubly equipped and have safety alarm devices.

Material: Various raw and auxiliary materials should have qualified incoming certificates and quality assurance documents. Raw and auxiliary materials with significant impact on product quality should be re-inspected upon entry according to relevant requirements.

Method: Specifically refers to process procedures. Special process technical documents should clearly specify process parameters and also have specific provisions on control methods and environmental conditions to ensure document sufficiency. Changes to special process parameters must undergo sufficient testing and verification; conclusions must be approved and incorporated into relevant technical documents before implementation.

Environment: The identification of environmental conditions for special processes must be confirmed by relevant authorized departments.

Test: Refers to the identification or confirmation of special processes. Various quality inspection records, laboratory and analysis reports, control charts, tables, etc., must be organized and kept according to the archiving system and be available for inspection at any time. During product processing, identification and inspection personnel should frequently be present at the production site to supervise and check the implementation of process procedures and the recording of original records, and maintain supervision and inspection records.

Auditors should pay attention to the completeness and applicability of confirmation criteria, the conditions for reconfirmation, and the traceability of special process confirmation (reconfirmation) records. Special attention should be given to the fact that the confirmation process must be synchronized with the applicable product; confirmation not combined with the product is merely a process review.