Depalletizer OEE: Layer Sweeps, Tier Sheets and Starving the Filler

Key takeaways

• Most depalletizer losses are short stops at the layer sweep and the tier sheet pick, plus waits for full pallets.
• Waiting for pallets from the warehouse is a supply loss, not a machine fault; code it apart.
• The depalletizer is built faster than the filler, so a Performance figure below its rated speed is often design, not a loss.
• Its stops only cost line output when they outlast the conveyor buffer in front of the filler.
• Broken or fallen containers are its Quality loss.

Depalletizer OEE measures the machine that feeds empty bottles or cans to the line: how long it runs, how close to its rated speed, and how many containers it loses on the way. Its typical losses are tier sheet faults, layer sweep jams, fallen or broken containers and waits for full pallets, and only the stops that outlast the buffer starve the filler.

Fabrico, an OEE and light MES platform, logs each depalletizer stop with its reason and keeps own stops apart from waiting and starved time. This guide is for line managers on glass, PET and can lines. It covers where the depalletizer's time goes, how to measure each OEE factor, format changes, and a worked shift.

Where does the depalletizer's time go?

A depalletizer takes a pallet of empty containers, removes the top frame and tier sheets, sweeps or lifts each layer onto a conveyor, and stacks the empty pallets. Each step has its own stops.

Damaged pallets and poorly placed tier sheets look like machine faults but trace back to the container supplier or the warehouse. Give them their own codes, as our palletizer OEE guide does for the other end of the line.

How do you measure Availability, Performance and Quality on a depalletizer?

• Availability = run time / planned production time. Own faults reduce it; in the full view, so do waits for pallets and blocked time.
• Performance = containers out / (run time x rated containers a minute). Set the rated speed per container format.
• Quality = good containers out / containers handled. Broken, fallen and damaged containers that are thrown away count against it.

Like most machines around the filler, the depalletizer is built with spare speed, usually about 10% faster than the filler in the V-curve design, so it can refill the conveyor after a stop. Measured against its own rated speed it will rarely reach full Performance on a line fed at the filler's pace, and that is not a loss to chase.

How do you separate the depalletizer's own stops from line effects?

At any moment the depalletizer is running, down on its own fault, waiting for pallets, or blocked because the rinser or filler is not taking containers. Only the own faults are its crew's to fix.

1. Code waiting for full pallets apart from machine faults, with the time from empty to the next pallet in place.
2. Read the outfeed sensor when the machine stops: containers backed up means blocked, charged to the machine downstream.
3. Report Availability twice: all causes, and own causes only.
4. Rank own causes by count and by minutes: tier sheet faults are often frequent and short, broken glass rare and long.

Then check which stops reached the filler. A stop that ends before the conveyor runs dry costs nothing; a longer one starves the filler. Our guide to starvation and blocking explains the logic, and filler OEE on a bottling line shows the same stops from the filler's side.

What happens at a format changeover on a depalletizer?

A new container size can mean new layer patterns, sweep or gripper heights, tier sheet settings, guide rails on the single filer and different pallet dimensions. Measure from the last good container of the old format to a steady flow of the new one at rated speed.

Split the steps into internal (machine stopped) and external (prepared while it runs). Settings recorded per format, change parts on a trolley and the first pallets of the new format staged before the change are the usual first wins.

A worked shift on a depalletizer

Sample line (illustrative numbers, not a customer): a glass bottle line where the filler runs 600 bottles a minute and the depalletizer is rated at 660. The conveyor between them holds 4 minutes of bottles. The shift has 450 minutes of planned production time, and the contribution margin is $0.10 a bottle, or €0.10 in a euro plant.

• Availability, all causes = 395 / 450 = 87.8%.
• Availability, own causes only = (450 minus 21) / 450 = 429 / 450 = 95.3%. So 21 of the 55 lost minutes belong to pallet supply.
• Performance against its own rated speed = 600 / 660 = 90.9%. That gap is the designed spare speed, not a loss.
• Quality: 237,000 bottles handled, 900 broken, fallen or damaged and thrown away: 236,100 / 237,000 = 99.6%.
• Which stops reached the filler: each 7 minute pallet wait starves it for 7 minus 4 = 3 minutes, so 9 minutes, and the broken glass for another 3. The short faults end inside the buffer.
• 12 filler minutes x 600 = 7,200 bottles, at $0.10 = $720 this shift, or €720.

The tier sheet faults carry the most own minutes, but they never reached the filler. The pallet waits and one long glass cleanup did. Ranked by money, pallet supply goes first.

Which mistakes do plants make with depalletizer OEE?

• Booking waits for full pallets as depalletizer faults, so the warehouse never sees them.
• Chasing Performance against the rated speed when the machine runs at the filler's pace by design.
• No code for pallet or tier sheet quality, so supplier problems land on the crew.
• Filtering out short stops, so tipped bottles at the layer transfer never reach the ranking. Our guide to micro stops covers thresholds.
• Ranking losses by minutes instead of by what reached the filler.

Where Fabrico fits

Fabrico is a computer vision enabled Manufacturing Performance Platform. OEE and light MES come first: automatic downtime logging that keeps own stops, waits and starved or blocked time apart, and OEE live by line and shift.

• The operator confirms the reason in one tap, so a tier sheet fault and a pallet wait get different codes.
• A camera clip as evidence for a stop, where a camera watches the layer transfer or the single filer.
• Losses priced in money and ranked, so the stops that starve the filler rise to the top.
• One view across plants for depalletizers on different sites.

You start with a pilot on one line, with a baseline and a decision date agreed in advance. There is no free plan and there are no tiers: each plant gets a quote. See how stops are captured on camera on our computer vision OEE page.

Frequently asked questions

How do you calculate depalletizer OEE?

Availability is run time over planned production time, Performance is containers out over what it could deliver at its rated speed for that format, and Quality is good containers over containers handled. Multiply the three.

What causes depalletizer stops?

Tier sheets that are not picked or picked double, layers that do not transfer cleanly, tipped or broken containers, damaged pallets and waits for the next full pallet.

Should waiting for pallets count against the depalletizer?

Show it in the full view, but code it as a supply wait, not a machine fault, so the warehouse or logistics team sees it.

Why is depalletizer Performance below its rated speed?

Because it is usually built faster than the filler and runs at the filler's pace most of the time. The spare speed is there to refill the conveyor after stops.

When does a depalletizer stop the filler?

When it lasts longer than the conveyor buffer between them. Shorter stops are absorbed if the buffer has time to refill.

See your depalletizer's losses in a demo

Bring one line and its current downtime log. We will show the depalletizer's own stops, its waits and what reached the filler.

Request a demo · Contact us