At Zyz Company: A Custom Manufacturer Of Printed Circuits

At Zyz Company A Custom Manufacturer Of Printed Circuit Boards The F

At Zyz Company, a custom manufacturer of printed circuit boards, the finished boards are subjected to a final inspection prior to shipment to its customers. As XYZ’s quality assurance manager, you are responsible for making a presentation to management on quality problems at the beginning of each month. Your assistant has analyzed the reject memos for all the circuit boards that were rejected during the past month. He has given you a summary statement listing the reference number of the circuit board and the reason for rejection from one of the following categories: A= Poor electrolyte coverage B=Improper lamination C= Low copper plating D= Plating separation E= Improper etching.

Prepare a tally sheet (or checklist) of the different reasons for rejection. Develop a Pareto chart to identify the more significant types of rejection. Examine the causes of the most significant type of defect, using a cause-and-effect diagram.

Paper For Above instruction

The manufacturing process of printed circuit boards (PCBs) is intricate, necessitating strict quality control to ensure product reliability and customer satisfaction. In the case of Zyz Company, a manufacturer specialized in custom PCBs, quality assurance plays a pivotal role in identifying and addressing defects that occur during production. This paper discusses the steps involved in analyzing defect data, emphasizing the creation of a tally sheet, developing a Pareto chart to prioritize problems, and employing a cause-and-effect diagram to investigate root causes of the most prevalent defect.

Introduction

Quality control in PCB manufacturing involves meticulous inspection and data analysis to detect common defects that compromise the functionality and integrity of the final product. The process begins with data collection, where rejected boards are documented along with reasons for rejection. Analyzing such data enables management to identify patterns and prioritize corrective actions effectively. This systematic approach aligns with quality management philosophies such as Six Sigma and Total Quality Management (TQM), which advocate for continuous improvement through data-driven decision-making.

Data Organization through a Tally Sheet

The initial step is to organize the rejection data into a clear and concise format — a tally sheet. Considering the provided rejection reasons, the tally sheet would include categories labeled A through E, corresponding to specific defect reasons: poor electrolyte coverage, improper lamination, low copper plating, plating separation, and improper etching. Using the data, each rejection is tallied under the appropriate category. For example, from the data, counts can be summarized as follows:

• A (Poor electrolyte coverage): 8 occurrences
• B (Improper lamination): 12 occurrences
• C (Low copper plating): 15 occurrences
• D (Plating separation): 7 occurrences
• E (Improper etching): 8 occurrences

This tally sheet helps visualize the frequency of each defect, serving as a foundation for further analysis.

Development of a Pareto Chart

The Pareto principle posits that approximately 80% of problems are caused by 20% of causes. The Pareto chart is a bar graph that displays the frequency of defect types in descending order, coupled with a cumulative percentage line. In this context, the most frequent defects are C (Low copper plating), followed by B (Improper lamination), A (Poor electrolyte coverage), E (Improper etching), and D (Plating separation). By plotting these data, management can quickly identify the primary sources of defect and prioritize corrective measures.

Constructing the Pareto chart involves ranking the defect categories by frequency and calculating the cumulative percentage of total defects. For instance:

• Low copper plating (15 occurrences) — 30%
• Improper lamination (12 occurrences) — 24%
• Poor electrolyte coverage (8 occurrences) — 16%
• Improper etching (8 occurrences) — 16%
• Plating separation (7 occurrences) — 14%

Graphically, this highlights that addressing issues related to copper plating and lamination will significantly reduce overall reject rates, providing an efficient pathway to quality improvement.

Root Cause Analysis using a Cause-and-Effect Diagram

The most significant defect identified from the Pareto analysis is low copper plating. To understand its root causes, a cause-and-effect diagram (often called a fishbone diagram) is employed. This tool categorizes potential causes under major headings such as Materials, Methods, Machines, Measurement, Environment, and Manpower.

• Materials: Impurities in copper, inconsistent electrolyte solution concentration.
• Methods: Improper plating parameters such as current density, temperature, duration.
• Machines: Faulty plating equipment, insufficient maintenance, equipment calibration issues.
• Measurement: Inaccurate process monitoring, lack of proper inspection during plating.
• Environment: Temperature fluctuations, contamination in the work area, humidity.
• Manpower: Operator error, inadequate training, inconsistent process oversight.

By systematically exploring each potential cause, management can determine specific factors contributing to low copper plating. For example, if electrolyte contamination is identified, replacing or filtering the electrolyte could be an immediate corrective action. Similarly, recalibrating the plating equipment or retraining operators may reduce process variations.

Conclusion

Effective quality improvement in PCB manufacturing hinges on systematic data analysis and problem-solving tools. The creation of a tally sheet enables clear documentation of defect frequencies, while the Pareto chart directs focus to the most impactful issues—most notably, low copper plating. Employing a cause-and-effect diagram facilitates deep investigation into root causes, fostering targeted corrective measures. Combining these tools not only improves product quality but also enhances operational efficiency, ultimately leading to higher customer satisfaction and reduced costs.

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