Control chart for half normal and half exponential power distributed process.

Area of Science:

• Industrial Engineering
• Statistical Quality Control
• Reliability Engineering

Background:

• Attribute control charts (ACC) are crucial for monitoring manufacturing processes.
• Traditional methods may not adequately address defective items under time-truncated life tests (TTLT).
• Lifetime data often follows non-standard distributions like the half-normal distribution (HND) and half-exponential power distribution (HEPD).

Purpose of the Study:

• To develop and evaluate ACCs for defective items using TTLT.
• To investigate the performance of charts based on HND and HEPD.
• To compare the proposed charts with existing methods using average run length (ARL).

Main Methods:

• Construction of ACCs for HND and HEPD under TTLT.
• Derivation of in-control and out-of-control average run length (ARL) values.
• Performance evaluation through simulation for various parameters and process shifts.

Main Results:

• The proposed HEPD-based ACC demonstrates superior performance compared to HND and Exponential Distribution (ED) based charts.
• The HND-based ACC also shows advantages over ED-based ACCs, indicated by smaller ARL values.
• Performance is sensitive to sample size, control coefficients, and truncated constants.

Conclusions:

• The developed ACCs using HND and HEPD are effective for monitoring defective items under TTLT.
• The HEPD-based chart offers enhanced defect detection capabilities.
• The study provides a foundation for practical implementation and further research in quality control.