Which Scrap Handling System Pays Off on a Coil Line?
A 400-tonne cell running 1.2 mm SPCC at 42 strokes a minute produced 118 kg of skeleton scrap an hour.
Two operators spent 40 minutes of every shift dragging bins to the dock, and the press stopped twice a week because a bin filled mid-run.
The plant had budgeted for automation of the line and nothing at all for the material leaving it.
Scrap handling is the last purchase in a coil line project and the first one to be cut. It is also the one that decides whether the line runs unattended.
Three systems cover almost every stamping plant. They differ less in what they lift than in who walks to the dock.
What the Press Cell Pushes Out in a Week
Scrap leaves a coil line in four streams, and they behave differently. Skeleton web comes off in one continuous ribbon. Edge trim comes off in two narrow strips.
Cut-off slugs arrive in bursts timed to the die. Misfeed scrap arrives without warning and usually tangles.
On a 320 mm strip with a 4-up layout, the skeleton can be 180 mm wide and travel at strip speed. A 42 SPM press moves it 25 metres a minute.
Edge trim is thinner and faster. Two 12 mm strips at 25 metres a minute will ball up in a bin within minutes unless something pulls them.
That difference matters, because a system sized for skeleton usually handles trim badly and a system sized for trim cannot carry a 180 mm web.
Measure the four streams separately before choosing anything. Total scrap weight tells you almost nothing about the handling problem.
Three Systems That Move Scrap Out
Bins and a forklift. The default, and still the right answer for low-volume cells. Scrap falls into a bin under the die, and someone swaps it.
A belt conveyor to a central bin. A 600 mm cleated belt runs under the die and lifts scrap to a container outside the cell. It removes the manual swap entirely.
A press-side baler or briquette press. Scrap is compacted into 20 to 40 kg blocks, which cuts volume by 60 to 75 percent and turns handling into a weekly task.
Each one changes three things: how often a person touches scrap, how much floor the cell loses, and what happens when the system stops.
The third item is the one buyers forget. A conveyor that jams takes the press down with it unless the die has a scrap chute that can be pulled.
- Drop point. Where the skeleton leaves the die decides the chute angle, and anything steeper than 45 degrees bridges on wide web.
- Jam recovery. A reverse jog on the drive turns a 25-minute stop into a 2-minute one. Ask for it before delivery.
- Container position. A 6 m³ container holds about 1.1 tonnes of loose skeleton, so two a day on a 42 SPM cell.
- Power drop. A 4 kW conveyor needs a 16 A three-phase supply at the press, not a trailing lead across the aisle.
Compare on Labour, Floor Space and Downtime
Price the three systems on the same four rows and the choice usually settles itself. The figures below come from a 42 SPM cell on 1.2 mm cold-rolled strip.
| System | Labour per shift | Floor lost | Where it costs you |
|---|---|---|---|
| Bins and forklift | 35 to 45 minutes, two people | None | Press stops when a bin fills; scrap on the floor |
| Belt conveyor | 10 minutes, one person | 1.8 m behind the press | Jam stops the press; belt wear on hot or oily scrap |
| Baler | 15 minutes a week | 3.2 m beside the press | $38,000 capital; needs 7.5 kW and a clear service side |
At $28 an hour fully loaded, 40 minutes a shift with two people is $37 a shift, or about $18,600 across 500 shifts a year.
The conveyor costs $12,000 to $18,000 installed and removes roughly 25 of those 40 minutes. Payback lands inside nine months on labour alone.
The baler pays back on freight and floor space rather than labour. Compacted scrap ships at three to four times the density of loose skeleton.
If your scrap dealer charges by the load rather than by weight, that density change is worth more than the labour saving.
What Each System Costs Per Tonne of Scrap
Per-tonne cost is the number that survives a budget review. Take the annual cost of the system and divide by the scrap tonnage it moves.
On this cell, 118 kg an hour across 3,600 productive hours is 425 tonnes of scrap a year.
Bins and forklift cost $18,600 in labour plus $2,400 in bin repair and forklift time, which is $49 a tonne.
The conveyor costs $15,000 installed over five years, $1,800 in belts and $3,700 in labour, which is about $11 a tonne.
The baler costs $7,600 a year in capital, $2,100 in power and wear, and $1,400 in labour, which is $26 a tonne before freight savings.
Add the freight difference and the baler drops to roughly $14 a tonne on a 300 km haul. On a 40 km haul it stays near $24.
That single line explains why balers sell well in dense industrial regions and poorly in clusters next to a scrapyard.
Where a Conveyor Stops Making Sense
A conveyor is the wrong purchase below about 60 kg of scrap an hour. The belt runs mostly empty, and the maintenance cost is unchanged.
It is also wrong when the die produces long tangled slugs. A 300 mm cut-off slug will bridge a 600 mm belt and stall the drive within a shift.
Plants running stainless or aluminium should think twice about a steel-belt conveyor. Soft scrap wraps around rollers and cuts through cleats.
And a conveyor assumes the press runs long enough to justify it. A cell with four changeovers a day spends more time being cleaned than conveying.
None of this appears on a quotation. It appears in the third month, when the maintenance log starts filling with belt splices.
Where any of these conditions holds, bins with a scheduled swap and a level sensor cost $1,800 and solve 80 percent of the problem.
Layout Constraints That Decide Before Price Does
Scrap handling is a floor plan problem disguised as an equipment problem. The conveyor needs a straight run from the die to the container.
On a 400-tonne press with a 3.5 m bed, the run is 5 to 7 metres and usually crosses a walkway or a forklift route.
Crossing a walkway means either a tunnel, a lift section or a guard. Each one adds $2,000 to $6,000 and a maintenance point.
A baler needs a service side of at least 1.5 m and a power drop of 7.5 kW that most plants have not routed to that corner.
Put the container position on the layout before the foundation drawing is issued. Moving it afterwards means cutting the slab or accepting a longer belt.
Sizing to the Die, Not to the Tonnage
Suppliers size conveyors by tonnage because tonnage is easy to quote. The die decides whether the system works.
A 4-up layout with a 180 mm skeleton needs a 600 mm belt and a 4 kW drive. A 1-up layout on 120 mm strip needs 400 mm and 2.2 kW for the same tonnage.
Cut-off slug size decides the chute, not the belt. Slugs over 150 mm need a separate chute or a crusher ahead of the belt.
Scrap rate per hour is the number to quote, and it comes from stroke rate, strip width and layout, not from annual tonnage.
Belt widths, drive power and container sizes for the coil line equipment range are listed per model, which is where to check a quoted 4 kW drive against a 118 kg an hour duty.
| Scrap rate | System that fits | Where it breaks |
|---|---|---|
| Under 40 kg/h | Bin with level sensor | Manual swap still needed once a shift |
| 40 to 120 kg/h | 600 mm cleated belt, 4 kW | Long slugs bridge; soft scrap wraps rollers |
| 120 to 300 kg/h | Belt plus baler | Two service points, 3.2 m of floor, 7.5 kW |
| Over 300 kg/h | Belt, crusher and baler | Capital above $90,000; needs a dedicated operator |
FANTY builds lines into plants across more than 60 countries, and the scrap question arrives late in almost every one of them.
Bringing the die layout to the machine specification meeting is the cheapest fix available. It costs a drawing and saves a retrofit.
The wider question of how much scrap a line should generate at all is covered in our coil line knowledge base, because most avoidable scrap is a feed accuracy problem rather than a handling problem.
At what scrap rate does a conveyor pay for itself in under 12 months?
About 45 kg an hour on a two-shift pattern at $28 an hour labour. Below that the labour saved does not cover the $12,000 to $18,000 installed cost within a year.
Does a baler really cut scrap volume by 60 percent?
Yes, typically 60 to 75 percent on skeleton web, and 40 percent on loose slugs. Density goes from about 180 kg/m³ loose to 700 kg/m³ baled.
Can a 600 mm belt carry edge trim from a 1.2 mm strip?
It will carry it and it will not keep it. Two 12 mm strips at 25 metres a minute need guide plates and a 15-degree incline maximum, or they ball and stall the belt.
How much floor does a press-side baler take on a 400-tonne cell?
About 3.2 m by 2.4 m including the service side, plus a container position. Plants that budget 2 m end up with the baler outside the cell and a longer conveyor.
Is scrap handling covered by the line supplier's scope?
Rarely. Most coil line contracts stop at the die area, and the conveyor or baler is a separate purchase. Ask for it in writing before the purchase order is signed.
Where to go next
This article sits in the stamping solutions cluster, where line layout, scrap and feed accuracy are treated as one system.
If your scrap problem starts before the die, the error budget shows where the avoidable kilos come from.
Read the feed accuracy error budget
