Which Coil Loading Method Pays Off Below 8 Coils a Day?
A 5-tonne coil car costs about USD 24,000. An overhead crane big enough to lift the same coil costs USD 35,000 before the building steel is reinforced to carry it.
Most plants already own the crane, which makes the comparison look settled. It is not, because the crane's cost was paid years ago and the coil car's cost is paid per coil, every shift, in minutes.
Below eight coils a day the arithmetic usually refuses to close. Above it, the answer flips, and the number that decides it is not the capital figure.
The Handling Cost Nobody Puts in the Quote
Loading a coil onto a decoiler looks like a two-minute job on a factory tour. Timed with a stopwatch it is rarely under eight.
With a crane, the sequence runs: find the slinger, hook the C-hook, lift and travel, lower onto the mandrel, check alignment, release, return the hook.
Two people are involved for most of it, and the crane is unavailable to the rest of the plant throughout.
With a coil car, one operator drives the cradle under the coil, lifts it 200 mm, travels to the mandrel, and raises to centre height. The mandrel expands and the car withdraws.
The difference is not the machine. It is that the crane is a shared resource and the car is not.
Shared resources also fail differently. A crane that is down for an inspection stops every bay at once, while a car that is down leaves the crane as a fallback.
That redundancy has a price and it belongs in the case. Plants that keep the crane after buying a car are paying for insurance, not for handling.
Three Routes With Three Cost Structures
Every decoiler is loaded one of three ways, and each one moves the cost to a different place.
| Route | Capital outlay | Where the cost lands afterwards |
|---|---|---|
| Overhead crane with C-hook | USD 30,000 to 60,000 installed, plus structural work if the bay was not built for it | Two operators, 8 to 10 minutes per coil, and a crane that cannot serve anyone else meanwhile |
| Coil car with V-cradle | USD 18,000 to 45,000 depending on capacity and travel | One operator, 3 to 5 minutes per coil, plus 1.2 m of clear travel and a floor that takes the wheel loads |
| Loading ramp with winch | USD 4,000 to 9,000, plus a pit or 4 m of approach | Two operators, 8 to 12 minutes, and a real risk of edge damage on every roll |
The ramp is the route buyers underestimate in both directions. It is cheap to buy and expensive to live with, because the coil slides on its own edge for part of the travel.
A 5-tonne coil on a 12-degree ramp presents about 850 N of sliding force, and the winch cable takes it through the bore rather than the body. The edge carries the rest.
On 1.2 mm hot-rolled that is survivable. On 0.7 mm galvanised it is not, and the damaged wrap is discovered at the press rather than at the ramp.
Working Out the Break-Even Honestly
Take a plant running 6 coils a day on a 250-day year, with a loaded labour rate of USD 32 an hour.
A crane load takes 9 minutes of two people, so 18 person-minutes, or USD 9.60 per coil. A coil car takes 4 minutes of one person, so USD 2.13. The saving is USD 7.47 per coil.
Six coils a day over 250 days is 1,500 coils, so the annual saving is about USD 11,200. Against a USD 24,000 car, payback is 2.1 years.
At 12 coils a day the same arithmetic gives USD 22,400 a year and payback just over a year. At 3 coils a day it stretches past four years, and the maintenance on the car starts to eat the difference.
Those figures assume the crane is free. If the crane is also serving the blanking area and the shipping bay, the waiting time it imposes is not in the calculation and is usually larger than the labour saving.
Sensitivity is worth running before the order. Doubling the loaded rate to USD 64 halves the payback; halving the coil count to 3 a day doubles it.
The figure that moves the answer most is not the labour rate but the crane queue. One extra 15-minute wait per coil adds more cost than the entire labour saving.
Coil weight matters too, and in the opposite direction to intuition. Heavier coils mean fewer loads for the same tonnage, so a plant running 8-tonne coils gets the car's benefit at half the cycle count.
At how many coils a day does a coil car pay back inside 2 years?
Around 7 coils a day at a USD 32 loaded rate and a USD 24,000 car. Below 5 coils a day the payback moves past three years unless the crane is shared with other departments, which changes the number substantially.
What floor loading does a 5-tonne coil car impose?
Typically 0.35 to 0.5 N/mm² under the wheels with a full coil, which is within a standard 150 mm reinforced slab. A 20-tonne car with a wide cradle is a different question and usually needs a designed pad.
Can one car serve two decoilers?
Only if they sit on the same travel line within about 12 m. Beyond that the car spends its time travelling, and a second car or a transfer track costs less than the lost cycle time.
Damage and Downtime Sit Outside the Spreadsheet
The labour comparison is the easy part. Three other costs decide whether the route is actually cheaper.
| Cost | How it appears | What it does to the case |
|---|---|---|
| Coil edge damage | A crushed wrap on a 0.8 mm galvanised coil loses 30 to 60 m of usable strip | Two damaged coils a month on a 1,200 mm wide coil wipes out a year of labour savings |
| Mandrel damage | A C-hook that contacts the mandrel segments scores the bore contact faces | Segment replacement runs USD 1,500 to 4,000 a set, and the wear accelerates afterwards |
| Crane waiting | The decoiler waits while the crane finishes a die change two bays away | Adds 5 to 20 minutes of idle machine time per coil change, which the labour rate never captures |
Edge damage deserves the closest look. A coil car with a V-cradle supports the coil on its outside diameter. A C-hook supports it from the bore. Neither touches the edge, which is why both beat a ramp.
The mandrel point is less obvious. Every crane lift puts the coil's full weight on the bore as it slides onto the mandrel, and a 5-tonne coil lowered slightly off-centre will mark the segments.
Owning a car adds a maintenance line the crane never had. Hydraulic seals, wheel bearings and the lift cylinder are consumables on a 250-day year.
Budget 3 to 5 percent of the purchase price annually. On a USD 24,000 car that is USD 720 to 1,200, which is small against the labour saving and fatal against a 3-coil-a-day case.
The inspection routine is short: check the cradle for coil damage, the wheels for flat spots, and the lift for drift under load. Ten minutes a week covers it.
When the Cheapest Route Is the Correct One
Three situations make the crane or the ramp the right answer, and a supplier who will not say so is selling rather than specifying.
- Under 3 coils a day. The labour saving never repays the capital, and the car becomes another asset to maintain and inspect.
- A crane with spare capacity and a short hook path. If the crane is idle and the decoiler sits under the runway, the load takes six minutes and nothing is queued behind it.
- A building that cannot take the wheel loads. A 20-tonne car on a mezzanine slab is a structural project, not a handling upgrade.
The car also cannot fix a bad layout. If the decoiler sits 4 m from a wall and the coil storage is in another bay, the car will travel further than the crane did and the cycle time advantage disappears.
Travel distance is the hidden specification. A car quoted at USD 24,000 usually covers 6 to 8 m of travel; beyond that the cable chain, rail and drive change and so does the price.
Measure the route before requesting a quote, including the turning radius at the storage end. A car that cannot turn inside the bay is a car that reverses, and reversing doubles the cycle.
What the car does buy, beyond labour, is repeatability. The same operator loads to the same height every time, the mandrel sees a centred coil, and the bore contact stays even.
On a decoiler that runs 4,000 hours a year, that shows up as longer segment life rather than a line in a business case.
For the sizing rules behind that claim, including bore, capacity and mandrel type, the specification chain is set out in our coil line knowledge base.
For the wider equipment range this loading decision sits inside, the machine specification pages list each decoiler and uncoiler frame size against its rated coil weight.
Where to go next
Loading is one decision in a longer chain that starts with coil weight and ends with brake control.
The next step in that chain, sizing a decoiler against the coils you actually buy, is covered in the specification walkthrough.
Read the decoiler specification guide
