Yield

Running Yield as a Daily Management System

Yield decides how much of what you start actually earns revenue. Measure first pass yield honestly, roll it through the routing, and manage it every day.

Yield is the fraction of what you start that you get paid for, and every point of it is money. A line starting 10,000 units a week at 94 percent yield delivers 9,400 sellable units; the missing 600, at $18 of accumulated cost, burn $10,800 a week, about $560,000 a year. Yield also sets capacity: at 94 percent you must start 6.4 percent more material and machine time than you ship, so a yield point recovered is capacity gained without buying anything. Plants that treat yield as a quality department statistic instead of an operations number leave both piles of money on the table.

Measure first pass yield, not final yield, or rework will hide the truth. FPY equals units passing on the first attempt divided by units entering the step. A station taking in 1,000 units, passing 940 first time, reworking 45 into eventual passes, and scrapping 15 shows a comforting 98.5 percent final yield but a 94 percent FPY. That 4.5 point gap is the hidden factory: paid labor, machine time, and queue space producing nothing. The Yield calculator handles the input, good output, scrap, and rework arithmetic; the discipline is counting rework as a first pass failure every time.

Roll yield through the routing, because steps multiply. Rolled throughput yield is the product of every step's FPY: three operations at 98, 95, and 97 percent give 0.98 times 0.95 times 0.97, or 90.3 percent RTY. Ten steps at a seemingly fine 98 percent each deliver only 81.7 percent. This multiplication is why long routings need step yields above 99 percent to be economic, and why the RTY number, not any single station's, tells you how much material to launch: shipping 9,000 units at 90.3 percent RTY means starting 9,967.

Benchmark by process type, not wishful thinking. Mature machining and stamping should run 98 to 99.5 percent FPY per operation. Assembly runs 95 to 99 depending on complexity. Painting, plating, and other surface processes run 90 to 97 and are usually the RTY bottleneck. New product launches commonly start 15 to 30 points below mature yield and should close half the gap every quarter; a launch still 20 points down after two quarters is a design problem, not an operator problem. Whatever the process, an FPY chart that is flat for a year means nobody is working it.

The levers rank in a consistent order. Process stability first: most yield loss traces to variation in a few inputs, and locking the top 3 to 5 process parameters with control limits typically recovers 30 to 50 percent of the loss. Error-proofing second: a $2,000 fixture that makes wrong assembly impossible beats a $60,000 vision system that finds it afterward. First-part verification at changeover third, since the first 20 to 50 pieces after setup carry 3 to 10 times the base defect rate. Training and standard work carry the rest, especially where FPY differs by more than 2 points between shifts running the same product.

The failure modes are cultural more than technical. Blending yield across products hides the one part number running 85 percent inside a 96 percent average. Reporting final yield lets rework absorb failures invisibly until labor variance blows up. Chasing yesterday's blip instead of the 30 day Pareto wastes engineers on noise; a single day at 91 percent on a 95 percent line is probably nothing, while a month drifting from 96 to 94 is a $250,000 problem forming. And celebrating 100 percent days on a line with loose data collection usually means defects are being counted somewhere else, or not at all.

Deploy it as a cadence. Daily: FPY by line on the tier board next to scrap dollars, with any line more than 2 points under its 30 day baseline getting a named cause before the meeting ends. Weekly: Pareto of first pass failures by defect mode and station, with owners and due dates on the top five. Monthly: recompute RTY per routing, reset material launch quantities, and review yield against the cost of quality ledger. World-class means FPY above 99 percent at mature operations, RTY known and posted per product family, rework hours under 1 percent of direct labor, and yield discussed in dollars at the same table where output and safety are, every single morning.

Published 2026-07-02.