EOL Calculations

How to Calculate End-of-Line Packaging Throughput, Cycle Time, and ROI

The core end-of-line math worked in full: cycle time, throughput, line balance, and payback with real inputs and units.

Start with palletizing cycle time, because it gates everything downstream. A single robot picks one layer, indexes, and places it: cycle time per case = (pick time + travel time + place time + index time) divided by cases per pick. If a robotic arm handles 4 cases per pick with a 1.8 second pick, 1.2 second travel, 1.0 second place, and 0.6 second index, that is 4.6 seconds for 4 cases, or 1.15 seconds per case. Rate = 3600 divided by 1.15, which is 3,130 cases per hour theoretical. The Palletizing Cycle Time calculator uses exactly these four sub-times, so time each motion segment separately rather than one gross stopwatch number.

Convert theoretical rate to real output using availability and a full-pallet penalty. Effective cases per hour = theoretical rate times availability times pattern efficiency. Take the 3,130 figure, apply 0.90 availability and a 0.96 pattern efficiency for slip sheets and pallet changes, and you get 2,704 cases per hour. If a pallet holds 60 cases, that is 45 pallets per hour, or one pallet every 80 seconds. Robotic Palletizing Utilization takes the same availability input and reports the gap between busy time and calendar time, which is where you find hidden idle seconds during pallet discharge and infeed starvation.

Case packer and case erector rates set the ceiling the palletizer feeds from. Case Erector Capacity is blanks per minute times uptime: an erector rated at 30 blanks per minute at 0.92 uptime yields 27.6 good cases per minute, or 1,656 per hour. Match that against Case Packer ROI throughput, which multiplies pack rate by shift hours minus changeover minutes. A packer at 25 cases per minute over a 7.5 hour net shift with 40 minutes of changeover runs (450 minus 40) times 25, which is 10,250 cases per shift. If the palletizer clears only 2,704 per hour, the packer is oversized and will accumulate.

Labeler throughput is products per minute, but the input that trips people up is web index and no-read rejects. Labeler Throughput = line speed in products per minute times (1 minus reject rate). A labeler tracking 120 products per minute with a 2 percent no-read reject applies (120 times 0.98), which is 117.6 good labels per minute, or 7,056 per hour. Carton Sealer Throughput follows the same shape: belt speed divided by carton length plus gap. A sealer belt at 30 meters per minute sealing 0.4 meter cartons with 0.1 meter gaps handles 30 divided by 0.5, which is 60 cartons per minute.

Line balance is the calculation that ties the stations together. Line efficiency = sum of station times divided by (number of stations times the bottleneck time). Suppose five stations run at 2.0, 2.4, 3.1, 2.2, and 1.9 seconds per unit. The sum is 11.6 seconds and the bottleneck is 3.1 seconds, so efficiency = 11.6 divided by (5 times 3.1), which is 11.6 divided by 15.5, or 74.8 percent. The Packaging Line Balance calculator flags station three as the constraint. Balance delay is 1 minus efficiency, here 25.2 percent, meaning a quarter of station capacity is idle waiting on the slowest step.

Automation payback ties throughput gains to labor removed. Simple payback in years = installed cost divided by annual savings. Annual savings = (operators removed times fully loaded rate times annual hours) plus scrap and rework reduction. Removing 3 operators at 32 dollars per hour across 4,000 annual production hours saves 384,000 dollars. On a 620,000 dollar installed palletizer, payback = 620,000 divided by 384,000, which is 1.61 years. Palletizer Payback and End-of-Line Labor Savings both drive off headcount times loaded rate times hours, so pull the loaded rate from finance, not the base wage.

Shrink wrapper capacity depends on film cut length and dwell, not just conveyor speed. Bundles per minute = 60 divided by (index time plus seal dwell plus shrink tunnel residence per bundle). A wrapper indexing 1.1 seconds, sealing in 0.8 seconds, with a 1.6 second effective tunnel contribution per bundle runs 60 divided by 3.5, which is 17.1 bundles per minute. Shrink Wrapper Cost pairs that rate with film consumption: film per bundle in meters times film cost per meter gives the variable rate you multiply by throughput. Always compute the tunnel as the likely constraint, since it rarely matches the sealer's rated speed.

Close the loop by reconciling every station back to the slowest machine in units per hour, not per minute or per shift, so the numbers are directly comparable. Convert erector 1,656, packer 1,500 effective, labeler 7,056, sealer 3,600, and palletizer 2,704 to the same basis and the true line rate equals the minimum, 1,500 cases per hour from the packer once its changeover is amortized. Every calculator in this category should be run at that common basis; a rate that looks huge in products per minute can still be the constraint once you annualize it against a 4,000 hour production year.

Published 2026-07-01.