Mastering Process Quality Control in Heat Treatment

Successful thermal processing ensures that the final product meets the purchaser's specifications. Effective process quality control is essential for producing conforming products and maintaining overall conformance. This article explores key aspects of achieving repeatable results through specific inputs, enabling validation and control of outputs in thermal processing.

Understanding Customer Requirements

The first step in quality control is product realization, which involves thoroughly understanding customer requirements. For instance, a heat treater receiving a batch of widgets with a purchase order stating "heat treat AMS2770" needs additional information, such as material type and desired final condition. Ensuring the contract review process includes steps to gather necessary information from customers is crucial. For Nadcap-approved organizations, the AC7102 checklist specifies contract review requirements that must be included in the applicable procedure.

Documenting Established Processes

Once the process is developed, documenting it is essential to conform to customer requirements. This documentation typically takes three forms: procedures, work instructions, and travelers (or routers).

1. Procedures: These document default requirements that apply to all hardware processed in the equipment. For example, maintaining a vacuum level below 1 micron before applying heat in a vacuum furnace or using a specific minimum number of load thermocouples each cycle.
2. Work Instructions: These provide detailed steps for specific tasks, such as braze joint preparation, including joint gap requirements, alloy used, and loading requirements.
3. Travelers/Routers: These reference work instructions and outline the sequence of operations to ensure requirements are met. They may also document post-thermal process test results and equipment limitations.

Implementing and Flowing Down Processes

Implementing the documented process and flowing down specific requirements to the relevant personnel is the next critical step. This ensures that everyone involved in the process understands and adheres to the established standards, maintaining consistency and quality throughout the thermal processing operation.

Maintaining Quality Through Internal Audits

Internal auditing serves as a check and balance to ensure quality control. This is a requirement of ISO/AS standards and Nadcap. Establishing a procedure that captures the critical variables from contract review to final inspection is essential. For Nadcap-approved processes, the procedure should include all elements of the Nadcap scope of approvals, which can be achieved by incorporating applicable Nadcap checklists during internal audits. This practice helps prevent the omission of specific requirements.

Using Consultants

Quality control in thermal processing is vital to ensure the final product meets the purchaser's specifications. Utilizing outside subject matter experts can aid in this process by providing training for staff and enhancing overall quality control practices.

If you're interested in learning more about how Conrad Kacsik can help with your quality control processes, reach out and contact us today! With over 40 years of experience and dozens of Nadcap-certified customers, we have the expertise you need to keep your facilities operating at their best.