What is Rolled Throughput Yield (RTY)?
Rolled Throughput Yield (RTY) is a critical Six Sigma metric used to evaluate the true quality and efficiency of a multi-stage manufacturing or business process. Unlike traditional yield metrics that may only look at the final output versus the initial input, RTY accounts for rework and scrap at every single step of the chain.
In simple terms, RTY measures the probability that a single unit will pass through the entire process without defects, without requiring any rework, and without being scrapped. This provides a more "honest" view of process health than the First Pass Yield (FPY) of just the final stage.
How to Calculate RTY
The calculation for Rolled Throughput Yield is the product of the individual yields of each sub-process or stage. The formula is expressed as:
RTY = Y1 × Y2 × Y3 × ... × Yn
Where "Y" represents the yield of a specific stage (expressed as a decimal). For example, if you have a three-stage process with yields of 98%, 95%, and 99%, you convert them to decimals (0.98, 0.95, 0.99) and multiply them together.
Why Use an RTY Calculator?
Many businesses fall into the trap of looking at "Final Yield," which ignores the hidden costs of rework. If your final stage has a 99% yield, but the previous three stages had to rework half the items to get them there, your process is actually very inefficient. Using an RTY calculator helps you identify which specific stages are dragging down the overall quality, allowing for targeted Lean Six Sigma improvements.
Frequently Asked Questions
What is a good RTY score?
A "good" score depends on the industry. In high-precision manufacturing or Six Sigma environments, companies strive for 99% or higher. However, any improvement in RTY directly translates to lower operational costs and higher customer satisfaction.
What is the difference between FPY and RTY?
First Pass Yield (FPY) usually refers to the yield of a single process step. Rolled Throughput Yield (RTY) is the cumulative yield of the entire end-to-end sequence.