4.9. Process Control

Process control refers to the entire process of producing a product and the method by which you control and ensure that your processes are followed - it is not limited to some form of statistical process control. The standard frequently uses the term "procedures" when referring to process control.

You must provide a controlled work environment that ensures that the quality of the product is adequate and in conformance with the documentation and record requirements of ISO 9000. This requires you to provide adequate and controlled written instructions (procedures) or representative samples that ensure proper assembly and workmanship standards. These standards should define the criteria for acceptable workmanship.

The process should define the equipment, environment, reference standards, and quality plans, and must include regular monitoring during production. The equipment used by the employees must have appropriate operating instructions and maintenance plans.

Work instructions must reviewed by authorized personnel. These instructions are required whenever their absence could adversely affect the quality of the output. The instructions should be reviewed periodically to ensure adequacy and proper alignment with other procedures. The work instructions must clearly define the acceptance criteria so the operator can differentiate the good from the bad.

A "special process" is any process that cannot be fully confirmed through immediate testing or inspection so a defect may only surface when the product is being used by the customer. Typical examples are welding, paint applications (Zyglow inspection), and heat treatment of materials. These processes require identification as special processes, clearly defined process parameters, operation by appropriately trained personnel using qualified equipment, and/or continuous monitoring with supporting records. Special processes must also meet the full requirements of this section.

To meet the requirements of this section:

• You will have a documented and controlled system of procedures and instructions in place that ensures all processes affecting customer requirements are carried out in a controlled manner.
• Documented procedures are required where the lack thereof could adversely affect the quality of the product or service being provided.
• A controlled process will include the approval of suitable production, installation, and servicing equipment by an authorized individual.
• A monitoring of appropriate process and product requirements shall occur during the processing of the customer's requirements.
• A suitable working environment and maintenance of equipment shall be provided for.
• Clear accept/reject decision criteria shall be documented and made available, as related to workmanship or material conformance.
• When you cannot immediately verify acceptability of the material/workmanship (termed special processes, such as painting, welding, and heat treating) you must identify prequalified process parameters, provide fully trained personnel and authorized equipment. The documentation will also include a full identification of the special processes, and will ensure continual process parameter monitoring of those processes.