First Pass Yield and First Time Yield

Understanding First Pass Yield (FPY) and First Time Yield (FTY) in Process Efficiency

In the world of process efficiency, two critical metrics stand out: First Pass Yield (FPY) and First Time Yield (FTY). Both are vital indicators that help businesses assess how effectively their processes are performing by measuring the quality and efficiency of production. In this blog, we’ll explore the definitions, differences, and importance of these metrics, as well as provide practical examples of how to calculate them.

What is First Time Yield (FTY)?

First Time Yield (FTY) is a measure of how many products or services pass through a process without defects, rework, or rejection the first time around. It calculates the percentage of items that meet quality standards without requiring any additional work.

In simpler terms, FTY shows how well a process produces good products right from the start. A high FTY means fewer defective items and a more efficient process, while a low FTY indicates problems with quality control that need attention.

FTY Formula:

FTY= Good Units Produced / Total Units Entering the Process × 100

For example, if a factory produces 100 items, and 90 of those items are defect-free on the first attempt, the FTY would be:

FTY = 90 / 100 × 100 = 90%

In this case, the factory has a 90% First Time Yield, meaning that 90% of the products were made correctly the first time, with no need for rework or repair.

What is First Pass Yield (FPY)?

While FTY gives us an initial look at how well a process is performing, First Pass Yield (FPY) goes a step further by considering rework and scrap. FPY measures the percentage of products that pass through the process without requiring rework or being scrapped and replaced. It provides a more detailed view of process efficiency by accounting for units that may have been fixed or corrected after the first pass through production.

FPY Formula:

FPY = Units Completed to Specification with No Rework / Total Units Entering the Process ×100

For example, imagine a factory produces 100 units. 90 of those units are defect-free, but 10 units needed to be reworked to meet the quality specifications. The FPY would be calculated as follows:

FPY = 90 / 100 × 100 = 90 %

Now, let’s add another layer: if, during the production of 100 units, 90 products were completed to specification, but 10 required rework (out of which 5 were fixed and 5 had to be scrapped), the FPY calculation would change to:

FPY =(90−10) / 100 × 100 = 80 %

In this scenario, only 80% of the units made it through the process without rework or scrap, making FPY a more comprehensive measure of efficiency than FTY.

Key Differences Between FTY and FPY

Although FTY and FPY are both important measures of process efficiency, they focus on slightly different aspects of the production process:

• FTY only considers how many products are produced correctly the first time, without factoring in rework or scrap.
• FPY, on the other hand, takes into account the products that required rework or were scrapped, giving a more complete picture of process performance.

In essence, FTY looks at the first attempt to get things right, while FPY measures how many products pass through the process successfully without needing additional fixes.

Importance of FPY and FTY in Process Efficiency

Both FTY and FPY are crucial metrics for understanding process performance and identifying opportunities for improvement. By monitoring these metrics, businesses can:

1. Reduce Waste: Low FTY and FPY rates indicate that there is significant waste in the process, whether through scrap, rework, or defects. Improving these metrics helps minimize waste, leading to cost savings.
2. Improve Quality: High FTY and FPY rates demonstrate that the process is producing high-quality products consistently. This can lead to greater customer satisfaction, fewer returns, and better brand reputation.
3. Increase Efficiency: When fewer items need rework or repairs, the production process becomes more efficient. This allows businesses to produce more units in less time, ultimately boosting productivity.
4. Identify Bottlenecks: Tracking these metrics over time can help identify where bottlenecks or inefficiencies exist in the production line. This enables businesses to focus their improvement efforts where they will have the greatest impact.

Example: Calculating FPY and FTY

Let’s walk through a real-world example to illustrate how FPY and FTY work.

Imagine a company that manufactures smartphones. Over the course of one week, they produce 1,000 smartphones. Here’s the breakdown:

• 900 smartphones are defect-free on the first pass through production.
• 50 smartphones need rework to meet specifications.
• 30 smartphones are scrapped because they cannot be fixed.

FTY Calculation:

FTY=900 / 1000 × 100 =90%

FPY Calculation:

FPY=(900−50) / 1000 × 100 = 85%

In this case, the FTY is 90%, meaning 90% of the smartphones were produced correctly on the first attempt. However, the FPY is only 85%, indicating that after accounting for rework and scrap, the process is less efficient than the initial FTY might suggest.

Rolled Throughput Yield (RTY)

In addition to FTY and FPY, businesses often use another metric called Rolled Throughput Yield (RTY) to measure overall process efficiency. RTY is the probability that a product will make it through all steps of a multi-stage process without defects or rework. It’s calculated by multiplying the FTY for each stage of the process.

For example, if a product goes through three stages with FTY rates of 90%, 85%, and 95%, the RTY would be:

RTY = 0.90 × 0.85 × 0.95 = 0.7267 =72.67%

This means that only 72.67% of the products are expected to make it through all three stages without defects.

Conclusion

First Pass Yield (FPY) and First Time Yield (FTY) are essential metrics for measuring process efficiency, quality, and performance. By regularly monitoring these metrics, businesses can identify areas for improvement, reduce waste, and boost overall productivity. Whether you are manufacturing products or delivering services, improving FTY and FPY can lead to better outcomes, satisfied customers, and a more efficient process.

Keep these metrics in mind as you strive to enhance your operations and achieve operational excellence.