VI.12.1. Purpose
This procedure describes the requirement and methods for using statistical techniques for the control of processes.
VI.12.2. Application
Applies to all processes in the manufacture.
VI.12.3. Procedure
12.3.1. All personnel in the company are given regular training in statistical techniques.
12.3.2. Statistics are used in a wide range of areas as a continuous improvement tools, the following are commonly used;
PARETO / ISHIKAWA DIAGRAMS / MIL-STD 105D SAMPLING PLANS / SPC CHARTS / SCATTER DIAGRAMS / PROCESS CAPABILITY INDEX, Ca , Cp, Cpk, Cmk / DESIGN OF EXPERIMENTS
12.3.3. Quality Assurance or Process Engineering shall determine the control methods, control charts and the control items to control the manufacturing process as deemed necessary.
12.3.4. The control items in process capability analysis shall be determined by Quality Assurance engineer or Process engineer, the following will be the general guideline for the element selection:
CUSTOMER ASSIGNMENT / CHARACTERISTICS WITH HIGH DEFECT RATE IN THE PROCESS / CRITICAL CHARACTERISTICS / CRITICAL PROCESS PARAMENTERS
12.3.5. Adequate SQC or SPC charts shall be applied for critical manufacturing process, the variations or changes shall be immediately investigated and corrected to assure that the process is kept at the state of statistical control.
12.3.6. Quality Assurance shall periodically review the process capability, the control limit and the specifications. A summary report shall be prepared and distributed to related department for continuous quality improvement planning. The control charts, data, Quality Assurance Department shall retain reports.
12.3.7. The sampling plans used shall be coordinated with Customer Representatives when required by contract.
12.3.8. The SQC or SPC charts shall be displayed on the production ling as close as possible to the work place or equipment.
12.3.9. The line supervision is responsible for implementing SPC, corrective action taken and process improvement.
