First pass yield (FPY) is an important quality metric that measures the percentage of units produced correctly in a single pass By tracking FPY, manufacturers can identify production inefficiencies, reduce scrap and rework, and improve overall equipment effectiveness This article provides a step-by-step guide to calculating first pass yield, analyzing the results, and using FPY data to drive quality improvements.
What is First Pass Yield?
First pass yield is defined as the number of good units produced divided by the total number of units going into the process. It indicates the percentage of products that successfully pass through a process without requiring rework or scrap.
For example, if 100 units go into a process and 90 good units come out, the first pass yield is:
FPY = Good Units / Total Units Input = 90/100 = 90%
A higher first pass yield translates to less waste, lower costs, and better productivity. World-class FPY is considered to be 99% or greater.
Why Track First Pass Yield?
There are several benefits to monitoring FPY:
- Identifies quality issues and improvement opportunities
- Reduces scrap, rework, and material waste
- Lowers manufacturing costs
- Improves productivity and equipment utilization
- Provides data to set quality goals and benchmark progress
- Allows comparison between processes, shifts, and machines
- Drives a quality-focused culture
Regularly calculating and analyzing FPY keeps quality top of mind and helps sustain a culture of continuous improvement.
How to Calculate First Pass Yield
Follow these steps to calculate first pass yield:
1. Define the Process
Clearly identify the manufacturing process you want to measure. This might be a production line, work cell, or individual machine.
2. Record Input Units
Count the total units fed into the process over a defined period of time. This is the denominator of the FPY equation.
3. Record Passed Units
Count the total units that successfully completed the process without requiring rework or scrap. These are the good units.
4. Calculate FPY
Divide the good units by the total units entered into the process.
For example:
- Total units input: 1,000
- Good units produced: 950
- FPY = 950/1000 = 95%
5. Analyze FPY Results
Compare your calculated FPY to goals and benchmarks. Look for trends and patterns. Identify processes, shifts, or machines with low FPY.
6. Identify Root Causes
Dig deeper into low FPY areas to determine reasons quality issues are occurring. Look for common failure modes or defects.
7. Implement Improvements
Based on your findings, implement process, training, or equipment changes to address root causes and improve FPY.
8. Continually Monitor
Re-calculate FPY at defined intervals to track improvements over time. Celebrate wins and find new opportunities.
Tips for Accurate FPY Calculation
Follow these tips for reliable first pass yield metrics:
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Automate data collection: Manual counting of units invites human error. Use automated systems like machine monitoring software.
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Define period of measure: Calculate FPY over consistent intervals – shift, daily, weekly, etc.
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Remove subjectivity: Establish clear criteria for what defines a good unit vs. scrap.
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Include all units: Capture all units put into production, including scrapped or reworked ones.
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Validate data: Perform regular audits to confirm output and input unit counts.
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Document formulas: Note calculations and assumptions to ensure consistency over time.
Using FPY to Drive Quality Improvement
Once you have accurate FPY metrics, put the data to work:
- Set FPY goals based on benchmarks
- Add FPY metrics to dashboards
- Identify FPY trends and areas of underperformance
- Conduct root cause analysis on low FPY processes
- Address common failure modes impacting FPY
- Standardize processes to reduce variability
- Optimize preventive maintenance plans
- Improve training programs based on defect patterns
- Automate and error-proof processes
- Celebrate and promote FPY wins
Proactively monitoring and acting on FPY drives waste reduction and quality gains over the long-term.
Examples of Using FPY Analysis
Here are two examples of how companies can use FPY data for improvement:
Example 1
A manufacturer finds Line 1 has an FPY of 85%, well below their 95% goal. Pareto analysis identifies the top defect as tool wear. Historically, tools were replaced based on lifespan estimates.
By implementing a predictive tool wear monitoring system, tools can be changed proactively before they produce bad parts. This reduces tool wear defects and improves FPY to 92%.
Example 2
An automotive plant sees 95% FPY for Shift 1 but only 90% for Shift 2. Investigation finds operators on Shift 2 are not adhering to the standardized work instructions.
Updating training programs and increasing oversight during Shift 2 results in more consistent execution and an improved 93% FPY within two months.
Key Takeaways
- First pass yield is the percentage of good units out of total units into a process
- Calculating FPY requires accurate input and output unit counts
- Higher FPY indicates lower waste and higher quality
- Monitoring FPY identifies problem areas and improvement opportunities
- FPY analysis should drive root cause investigation and corrective actions
- Consistently measuring FPY ensures quality remains a priority
Start leveraging first pass yield in your operations to reduce waste and drive a culture of quality. Consistent FPY analysis and improvement will lower manufacturing costs while delighting your customers with defect-free products.
How to Calculate First Pass Yield
What is first pass yield (FPY)?
First Pass Yield (FPY), also known as throughput yield, measures quality units produced as a percentage of the total units that began the process. There’s a very straightforward reason for manufacturers to track and improve FPY: Reducing waste. When scrap parts are created, or units that require re-work, there is waste generated in several forms:
How to calculate first pass yield?
Calculating First Pass Yield (FPY) helps in understanding the efficiency of a manufacturing process. To correctly calculate first-pass yield, one must focus on the proportion of products that meet quality standards without rework against the total products in a batch. Follow this step-by-step guide to compute your FPY accurately:
What is a good first pass yield?
Generally speaking, a good FPY goal for most companies is at least 90%. So, if a company is producing 250 units a day, ideally at least 225 of those units should be sellable to attain a good FPY. The plant in our example may want to evaluate their process to reduce the number of defects and improve their output. Why measure First Pass Yield?
How do you calculate first time yield?
Be sure to recognize that the total number of products is different than the total number of tests run, since a single product may be tested multiple times if rework is involved. First Time Yield = [Number of product without error / Total number of products] For example, the planning department creates 20 quote request documents.
