Understanding how to calculate and improve process yield is essential for optimizing production and maintaining high-quality standards. Read on to learn the step-by-step methods for calculating yield and implementing effective improvements to enhance your manufacturing processes.
Process Yield and Its Importance in Manufacturing
Process yield is a measure of the quality of a manufacturing process, calculated as the ratio of good units to total units produced. It’s a key metric for lean manufacturing, helping manufacturers measure performance by determining the percentage of products that pass through compliance checks and are defect-free, and identify areas for improvement to optimize their processes for better quality and efficiency.
Types of Process Yield Metrics
First-Time Yield (FTY) vs. Rolled Throughput Yield (RTY)
First-Time Yield (FTY): This metric measures the quality of a process by calculating the percentage of units produced without defects on the first attempt. It provides a snapshot of a process’s efficiency during its initial run.
Understanding the final yield relative to the first process is crucial for accurate performance and cost analysis in multi-step processes.
Rolled Throughput Yield (RTY): This metric, on the other hand, measures the quality of a process by calculating the percentage of units produced without defects over multiple attempts. RTY offers a more comprehensive view of a process’s overall performance across different stages.
Understanding both FTY and RTY can help manufacturers pinpoint areas for improvement and optimize their processes for better quality and efficiency. By focusing on these metrics, businesses can reduce waste, enhance productivity, and ensure higher customer satisfaction.
Calculating Process Yield
Calculating First-Time Yield (FTY):
To calculate FTY, identify the number of defect-free units produced at each process step and divide it by the total number of units produced at that step.
Calculating Rolled Throughput Yield (RTY):
To calculate RTY, multiply the FTY values of each process step together. This gives you the cumulative effect of the entire process.
For instance, if a manufacturing process has three steps with FTY values of 0.90, 0.85, and 0.95 respectively, the RTY would be calculated as follows:
RTY = 0.90*0.85*0.95 = 0.72675
This means the overall yield for the entire process is approximately 72.7%.
RTY is especially useful because it reflects the cumulative effects of all process steps, providing a clearer picture of where improvements are needed.
Download Process Yield Calculator Template
You can simplify calculating process yield by using the Process Yield Calculator Template from Shoplogix. Visit our website, click on the pop-up window on the bottom right that says “Download 1 of 10 Continuous Improvement Templates,” fill in your information, and select the “Process Yield Calculator Template.”
Strategies for Improving Process Yield
Identify Poor Performing Process Steps:
Start by pinpointing the process steps that have the lowest yield. These are your biggest opportunities for improvement. For instance, if a certain step consistently produces a high number of defects, it should be your first target for corrective actions.
Implement Process Improvements:
Once you’ve identified the critical problem areas, implement targeted process improvements. This could include:
- Reducing rework rates by refining the process or improving operator training.
- Enhancing defect detection methods to catch issues earlier in the production cycle.
- Optimizing individual process steps to streamline operations and eliminate inefficiencies.
Continuously Monitor and Evaluate
After making initial improvements, it’s crucial to continuously monitor and evaluate the performance of your processes. Use real-time data and regular assessments to ensure that the changes have the desired effect and that performance remains at an optimal level. This ongoing vigilance helps sustain improvements and prevent regression.
By systematically addressing yield-limiting factors and implementing these strategies, you can significantly enhance overall process yield, leading to better quality products and increased operational efficiency.
Implementing and Monitoring Process Improvements
We’ve researched for you real-world examples of companies that have successfully implemented and monitored process improvements to increase process yield, resulting in cost savings and revenue growth:
Toyota Motor Corporation
Toyota is renowned for its Toyota Production System (TPS), which emphasizes continuous process improvement and waste elimination. One notable example is Toyota’s efforts to reduce setup times for machinery changeovers using the Single Minute Exchange of Die (SMED) technique. By implementing SMED, Toyota reduced changeover times from hours to mere minutes, leading to increased productivity and higher process yields.
To sustain these improvements, Toyota employs regular gemba walks (on-site observations) and monitors key performance indicators (KPIs) such as cycle times, defect rates, and overall equipment effectiveness (OEE). This continuous monitoring allows Toyota to identify new opportunities for improvement and ensure that gains in process yield are maintained over time.
Motorola
Motorola pioneered the Six Sigma methodology, which focuses on reducing defects and improving process yield. In the 1980s, Motorola implemented Six Sigma across its operations, resulting in significant improvements in product quality and customer satisfaction.
To monitor the success of its Six Sigma initiatives, Motorola tracked metrics such as defects per million opportunities (DPMO) and process capability indices (Cp and Cpk). By continuously monitoring these metrics, Motorola could identify processes with suboptimal yields and implement targeted improvements, leading to substantial cost savings and increased profitability.
Intel Corporation
Intel, a leading semiconductor manufacturer, has long recognized the importance of process yield improvement. The company has implemented various initiatives, such as advanced process control (APC) systems and statistical process control (SPC) techniques, to monitor and optimize its manufacturing processes.
Intel closely tracks metrics like overall equipment effectiveness (OEE), cycle times, and defect rates to identify opportunities for process improvement. By continuously monitoring these metrics and implementing targeted improvements, Intel has been able to achieve industry-leading process yields, resulting in significant cost savings and increased profitability.
These companies demonstrate the importance of not only implementing process improvements but also continuously monitoring process performance to sustain gains in process yield. By regularly tracking key metrics and making data-driven decisions, organizations can identify new opportunities for optimization, ensuring that their processes remain efficient, cost-effective, and aligned with customer needs.
What You Should Do Next
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