First Pass Yield (FPY)

What is First Pass Yield (FPY)?

First-pass yield (FPY) is a key performance indicator that provides manufacturers with a ratio of quality units produced to the number of total units. This number is most often expressed as a percentage.

A good FPY signals that your process has been well-designed and that your workforce is well-trained, enabling you to create products that meet quality standards the first time. On the other hand, a bad FPY signals production problems like defects and rework, producing more inefficiencies and further work.

The FPY equation is used to determine two key manufacturing parameters.

• Efficiency
• Effectiveness

Production lines that create defective units or numerous units that need rework are inherently inefficient due to wasted time and materials. Plus the operation as a whole is ineffective since it’s not producing the required amount of quality units.

How to Calculate First Pass Yield

While the First Pass Yield equation is quite simple, it is a powerful snapshot of efficiency and effectiveness.

To calculate FPY, simply count the number of units produced that were not considered rework or scrap and divide that number by the total amount of units going through the process. The equation looks something like this:

FPY = (number of good units produced / total number of units produced) x 100

First-Pass Yield Calculation Example

Imagine you are a supervisor at a knife manufacturer and you’re team is about to launch into fabricating and assembling a new line of all-purpose blades.

The process begins and out of 200 units, 10 blades are scrap and 17 blades need rework.

Suspecting a problem and knowing that your company has set an FPY goal of at least 90%, you quickly perform the following equations.

10 scrap + 17 rework = 27 defective units
200 - 28 = 173 good units
(173 / 200) x 100 = 86.5% FPY

Now, knowing that the process is underperforming within your intended goal, you can begin to figure out the cause of your low First Pass Yield.

Common Causes of a Bad First Pass Yield

If you find your FPY low, there is a high likelihood it is due to the following usual suspects.

1. Unreliable processes
2. Inadequate training
3. Faulty equipment
4. Material defects

While each operation will have different root causes that lead to the low FPY, it's a good idea to address these issues by asking yourself 4 key questions.

• Is my process consistent?: If an operation has unclear or nonstandardized processes, the chances of rework are much higher. Everything from machine setup and activation to manual actions and data acquisition needs to be dependable and repeatable. Consistent actions achieve consistent results.
• Is my workforce adequately trained?: Workers who are unfamiliar with a given process need training and guidance. Step-by-step visual instructions can be used to train workers and guide them through each procedure and operation.
• Are my tools and equipment properly maintained?: Defects can often be caused by improper machine calibration or equipment malfunctions. Check when the machines were last serviced and look at calibration records.
• Are there defects in my materials?: If sourcing subpar materials, there is a higher likelihood that defects will occur. If you’re stuck with subpar materials, it is useful to have a clear inspection process that guarantees no faulty units enter the production line.

Each of the above questions is not a solution on its own, but they are major factors when optimizing your operation and seeking to achieve a higher First Pass Yield.

How to Improve First Pass Yield: 3 Key Methods

Thankfully, there are several ways manufacturers can improve their FPY.

1. Perform Root Cause Analysis

First, you’ll need to determine the cause of the low FPY, otherwise, you’ll be shooting in the dark. In this case, you can use root cause analysis tools like the 5 Whys, Ishikawa (Fishbone) Diagram, and more to pinpoint where the problem is occurring.

Also, machine monitoring methods like digital checklists, IoT sensors, and SPC (Statistical Process Control) enable organizations to receive greater insight across their equipment and operations. These tools help employees identify problems quickly and preemptively.

2. Increase Standardization

Once you’ve determined the cause of the issues, you can create consistent processes to standardize the solution and incorporate it into your training methods. Variability is the number one cause of defects across the manufacturing industry so any method that teaches and guides the workforce with consistent standards is a huge step forward.

If faulty materials are the issue, then implementing a standardized inspection procedure will be quite beneficial. If workers are unclear about how to accomplish their tasks, then a step-by-step visual standardization tool like work instruction software is extremely effective. Pictures, videos, annotations, and other tools help to convey complex information easily and reliably.

Additionally, consistent and standardized procedures enable manufacturers to find issues quickly. While variations from the normal process are readily apparent, standardized data acquisition and validations enable organizations to quickly flag any discrepancies.

3. Integrate Quality Control into the Process

While digital standardization tools enable users to receive the right instructions at the right time, there are built-in quality control tools that make the process foolproof.

Using real-time monitoring, smart forms, checklists, and auto-validations, workers have a digitally automated team member helping them ensure that all actions are followed properly and all appropriate data is captured accurately.

Take this a step further and companies can implement connected worker technologies, such as smart tools and digital workflows, to automatically verify all actions and prevent issues before they happen.