The Power of 7 QC Tools and PDCA: A Case Study on Quality Problem Solving

I am Muhammad Umar Ibrahim, an advocate for Operational Excellence. I'm excited to co-author this article with Sanam Ijaz , a notable Supply Planning Specialist at a beverage manufacturing company. Sanam's expertise in data analytics and SAP, combined with her hands-on experience in energy audits and renewable energy systems, offers a unique perspective. Together, we aim to provide insights into optimizing operational processes and the importance of data-driven strategies in today's fast-paced industry. Join us on this enlightening journey!

Introduction:

The world of quality control and continuous improvement is vast and ever-evolving. Organizations worldwide strive to ensure that their products and services are of the highest standards. To elucidate the effectiveness of quality control methods, we embarked on a case study using the 7 QC tools and PDCA cycle on a data base of a sample bottle manufacturing unit. The results were enlightening, underscoring the importance of systematic quality measures. Our analysis focuses on identifying the common bottle defects in a manufacturing unit, understanding their root causes, and suggesting ways to mitigate these issues.

The Challenge:

Upon reviewing a data base available for analysis from the Bottle Inspection Check Sheet, we observed recurrent defects. These defects ranged from cap issues, improper labeling, gate out, high/low fill levels to base cracks. The data highlighted patterns that needed to be addressed immediately.

Overview of Bottle Defects

The data collected shows the following main types of bottle defects:

• Improper label
• High/low fill levels
• Cap issues
• Base cracks
• Gate out The Approach:

1. Fishbone Diagram & 5 Whys Analysis: Through the fishbone diagram, we identified five categories contributing to the problem: Mother Nature (storage environment conditions), Man (training of operators), Machine (labeling machine calibration), Material (label quality), and Method (measurement tools accuracy). The subsequent "5 Whys" analysis pinpointed specific reasons within each category, such as a malfunctioning climate control system or outdated training programs.
2. PDCA Cycle: With a structured Plan-Do-Check-Act approach, we charted a clear roadmap to address each identified problem:Plan: Establish objectives based on the 5 Whys results. Do : Implement corrective actions, like repairing climate control systems or updating training programs. Check: Monitor outcomes, gather feedback, and assess the success of implemented measures Act: Refine and adjust, standardizing effective strategies and reconsidering ineffective ones.

Application of the 7 QC Tools:

1. Pareto Chart: Through the Pareto charts presented, we identified the most significant defects. The 'Improper label' defect was the most frequent, demanding immediate attention.
2. Histogram: It gave us a snapshot of the frequency of each defect, reinforcing what the Pareto chart revealed.
3. Fishbone (Ishikawa) Diagram: By analyzing potential causes for the defects, we identified several factors spanning Mother Nature, Man, Machine, Method, and Material.
4. Flowchart (not shown in the data): Creating a flowchart would help map out the entire process of bottle production to identify bottlenecks or areas of improvement.
5. Check Sheet: The initial data set, which served as our primary reference, helped in categorizing defects and was instrumental in data collection.
6. Control Chart (not shown in the data): By plotting a control chart, we could track defects over time and identify if the processes were stable.
7. Scatter Diagram (not shown in the data): This could help in understanding relationships between two variables, such as the relationship between the time of day and defect frequency. Check Sheet

Data is collected from following sample check sheets

Data Base

Data Insights

1. Defects vs. Defect Count: The most prevalent defect is the 'Improper label' with 1618 instances, followed by 'High/low fill' and 'Cap issue'.
2. Pack Size vs. Defect Count: The 500ml bottles seem to be the most problematic, leading in defect counts.
3. Brand vs. Defect Count: Brand C bottles have the highest defect count, closely followed by Brand A and D. Pareto Analysis

Potential Causes of Defects

By employing a Fishbone (Ishikawa) diagram, we've been able to break down potential reasons for these defects across several categories:

1. Mother Nature Temperature & Humidity variations in the storage area Dust & Foreign Particles
2. Man Inadequate training of operators Inattention to Quality Incorrect label handling
3. Machine Age & Maintenance of the label machine Calibration errors Wear and tear
4. Material Inconsistent material quality Static charge issues Supplier variabilities
5. Method Inaccurate measurement tools Faulty gauges 5 Whys Analysis This method can be used to drill down into each root cause. For example, if we consider the 'Improper label' defect: 1. MOTHER NATURE: Issue: Temperature & Humidity Variations in the storage area. Why 1: Why are there temperature and humidity variations in the storage area? Answer: The climate control system is malfunctioning. Why 2: Why is the climate control system malfunctioning? Answer: It hasn't been serviced or maintained in over a year. Why 3: Why hasn't it been serviced? Answer: Maintenance schedules were not set up for the system. Why 4: Why weren't maintenance schedules set up? Answer: Oversight by the facilities management team; it wasn't prioritized. Why 5: Why wasn't it prioritized? Answer: Lack of training and awareness about the importance of climate control in label adherence. 2. MAN: Issue: Inadequate training of operators leading to incorrect label handling. Why 1: Why was the training of operators inadequate? Answer: Training programs were outdated. Why 2: Why were the training programs outdated? Answer: No regular reviews and updates to the training curriculum. Why 3: Why weren't there regular reviews? Answer: No dedicated team or individual responsible for continuous training improvements. Why 4: Why wasn't someone responsible for it? Answer: Management did not see the immediate value of continuous training. Why 5: Why didn't management see the value? Answer: Lack of feedback mechanisms to report issues stemming from training gaps. 3. MACHINE: Issue: Label Machine Age & Maintenance leading to calibration errors. Why 1: Why are there calibration errors in the labeling machine? Answer: The machine hasn't been calibrated recently. Why 2: Why hasn't the machine been calibrated? Answer: Maintenance schedules are inconsistent. Why 3: Why are maintenance schedules inconsistent? Answer: The plant has been running at maximum capacity, and there hasn't been downtime to service machines. Why 4: Why hasn't there been downtime? Answer: High demand and production targets set by the management. Why 5: Why are targets prioritized over machine maintenance? Answer: Short-term revenue goals overshadowed the importance of long-term machine health and quality. 4 Material: Issue :Inconsistent Material Quality High Slip Why 1: Why is the label placement improper? The label material has an inconsistent quality with high slip. Why 2: Why does the label material have an inconsistent quality with high slip? The supplier's production process has variations leading to variable quality in the label materials. Why 3 : Why does the supplier's production process have variations? The supplier doesn't have a stringent quality control process in place. Why 4: Why doesn't the supplier have a stringent quality control process? The supplier is trying to cut costs and speed up production. Why 5: Why is the supplier trying to cut costs and speed up production? The supplier is facing financial pressures and is trying to remain competitive in the market. 5 Method: Issue: Inaccurate Measurement Tools Why 1: Why is the label placement improper? The measurement tools used during the labeling process are inaccurate. Why 2: Why are the measurement tools inaccurate? The gauges used to calibrate the measurement tools are faulty. Why 3: Why are the gauges faulty? Regular maintenance and checks of the gauges were not scheduled or overlooked. Why 4: Why were regular checks of the gauges overlooked? The plant lacks a consistent preventive maintenance program for its tools. Why 5: Why doesn't the plant have a consistent preventive maintenance program? Management hasn't prioritized it, believing it to be a cost rather than an investment in long-term quality.

Implementing the PDCA Cycle:

PLAN: Objective: To reduce the improper label placements on Brand A - 500ml bottles.

Analysis of the Current Situation: Based on the fishbone diagram and 5 Whys analysis, there are problems with material quality, inadequate training, malfunctioning climate control, machine calibration, and measurement tool accuracy. Actions to be taken: Review the label material suppliers and consider alternatives. Update training programs for operators and ensure regular updates. Service and maintain the storage area's climate control system. Establish consistent calibration and maintenance schedules for labeling machines. Introduce a preventive maintenance program for measurement tools.

DO: Implementation: Change the label material supplier or collaborate with them to enhance quality. Roll out new training sessions for operators. Repair or replace malfunctioning parts of the climate control system. Perform calibration on all labeling machines. Initiate the preventive maintenance program for tools.

CHECK: Measurement & Evaluation: Monitor the frequency of improper label placements over the next month. Take feedback from operators on the effectiveness of the new training programs. Check the consistency of the storage area's temperature and humidity. Verify the calibration accuracy of the labeling machines. Review the implementation and adherence to the preventive maintenance program.

ACT: Review and Continual Improvement: Based on the feedback and monitoring, if improper label placements have decreased, standardize the changes across all production lines. If issues persist, re-evaluate the root causes and solutions. Make adjustments as necessary. Continuously monitor and use the feedback loop to keep refining the process.

Conclusion:

The 7 QC tools, when combined with the systematic approach of the PDCA cycle, can yield impressive results, as demonstrated in our case study. Addressing quality issues requires a methodical, data-driven strategy. By focusing on the most pressing defects and systematically addressing root causes