1600 Ton Scrap Metal Shear: Downtime Accounting

Ask a three-shift mill operator what their shear costs them and they will not name the purchase price. They will name the day it stopped. Downtime at 200 to 240 tons a day is the dominant economic fact of the Q91-1600, and it is the fact least visible in any quotation. This article is the accounting method: how to price an hour of downtime honestly, which failure modes actually stop the line, and what the quotation and the spares plan should contain to keep those hours rare — for the Q91-1600 and the classes around it.

For the wider operating economics of the class, the three-shift economics guide covers energy, wear and staffing.

Pricing an Hour Honestly

Most downtime accounting is wrong in the same direction: it counts the repair and stops. The honest price of an hour has four components, and only the first shows up on an invoice.

Lost production. The tons the machine did not cut. At this class that is the largest number, and it is the one buyers can compute before they own the machine — daily tonnage divided by running hours, times the margin per ton.

Downstream idling. The stages behind the shear — baler, shredder, furnace preparation — do not stop when the shear stops; they wait. Every hour of shear downtime is an hour of paid idle time behind it, and in a staged line that multiplier is real money.

Material handling. Material arrives regardless. An hour of downtime is an hour of intake that has to be stockpiled, diverted or turned away, and stockpiled material gets handled twice more before it reaches the box.

The repair itself. Parts, labour, and the crane time the repair needs. The smallest of the four numbers, and the only one most budgets track.

Buyers who compute all four before the order make different specification choices than buyers who only count the fourth — and the choices show up as seal specifications, spares depth and maintenance windows rather than as price.

The Failure Modes That Actually Stop the Line

Not all failures are equal, and the ones that stop a three-shift line share a profile: they are wear-related, they are predictable, and they are preventable by a schedule.

Blade failure. A chipped or cracked edge found mid-shift stops the line until the set is changed. The prevention is rotation on a tonnage schedule rather than on failure, and the log that tells you the interval has arrived. The shelf set is what turns the stop into a planned change.

Hydraulic seal failure. Pressure loss mid-cycle stops the line and often takes the longest to restore, because the repair is inside the power unit. The prevention is oil cleanliness and temperature discipline — filters on schedule, oil condition checked weekly — plus the seal specification conversation at quotation.

Discharge blockage. Cut pieces banking up until the box cannot clear. Not a machine failure at all, but it stops production just as effectively. The prevention is the flow plan — buffer, handling and destination confirmed against your layout before installation.

Feeding jam on over-class material. A piece beyond the band, charged anyway, stalling the cycle. The prevention is the sorting gate and the boundary posted at the control station — the cheapest prevention on this list and the most commonly skipped.

What the Quotation Should Contain

At this class the quotation is a downtime document as much as a specification. Four things belong in it:

• The duty declaration — three shifts on the material mix you actually run, written down, because the build follows it.
• The wear-part schedule — expected life per item at your declared duty, the rotation interval for blades, and the replacement procedure for each wear part.
• The spares plan — what ships with the machine, what sits on your shelf before commissioning, and the resupply channel. Spare blades ship within 48 hours by DHL or FedEx; the shelf set exists for the shift you cannot wait on.
• The commissioning plan — test runs on your material, training across shift teams, and the first-month schedule around your production plan, with the maintenance window inside the production plan rather than against it.

The Maintenance Window as Production Planning

The operations that keep downtime rare treat the maintenance window as a production-planning item, not a maintenance-department item. The blade rotation, the weekly gap check, the monthly rail and electrical checks and the oil schedule all sit inside a planned window that the production schedule is built around — which is only possible if the window was specified before the machine arrived.

That is the whole argument of this article in one sentence: downtime at this class is priced before the order or paid after it, and the buyers who price it first get machines whose maintenance logs stay boring. Send your material profile, shift pattern, power details and downstream stages, and the written quotation comes back within two business days with the specification your electrician and foundation contractor can work from.

Building the Downtime Number

The four-component price of an hour is computable before the order, and computing it changes the specification choices. Lost production is daily tonnage divided by running hours, times the margin per ton. Downstream idling is the paid time behind the gap — baler, shredder preparation, furnace crew — which in a staged line is a multiplier rather than an addend. Material handling is the intake that arrives regardless and gets stockpiled, diverted or turned away. And the repair is parts, labour and crane time — the smallest of the four and the only one most budgets track.

Buyers who compute all four before the order make different choices than buyers who count only the last: the choices show up as seal specifications, spares depth and maintenance windows rather than as price. That is the whole argument for pricing downtime at quotation — the specification follows the total, not the invoice.

The First-Month Schedule

Commissioning at this class is a production-planning exercise rather than an installation one. The first month should be scheduled around your production plan: test runs on your actual material, operator training across shift teams, and the maintenance window placed inside the production schedule rather than against it. The wear-part replacement procedure for each item gets walked through with the crew that will perform it — not demonstrated, performed — because at three-shift duty the procedure is what converts a stop into a planned change.

The first month is also when the blade log starts and the handover becomes formal. The habits that hold downtime rare for a decade are all formed in the first month, and all of them are cheaper to form with our engineer on site than to retrofit from a maintenance manual.

The Blockage That Is Not a Failure

The most common production stop at this class is not a machine failure at all — it is discharge blockage, cut pieces banking up until the box cannot clear. The machine is fine; the flow behind it has become the constraint. The prevention is entirely in the flow plan: buffer, handling and destination confirmed against your layout at quotation, sized against the box’s delivery rate rather than against a rule of thumb. The diagnostic is worth teaching the crew: when the cycle stalls with no alarm and no hydraulic symptom, look at the pile before you look at the machine. The most expensive version of this stop is the one where the crew spends an hour diagnosing a machine that was never the problem.

The Repair, Priced Before It Happens

The last discipline in downtime accounting is pricing the repair before it happens — for each wear part, at the declared duty, in hours and crane time. The blade change, the seal kit, the filter stock, the wear liners: each has a procedure, and each procedure has a duration the crew can rehearse during commissioning rather than discover during a stop. The factory that publishes those durations in the quotation is describing a maintenance program; the factory that quotes only parts prices is describing a catalog. At 200 to 240 tons a day the difference between the two is measured in furnace terms, and it is priced before the order or paid after it.

Buyer FAQ

How do I calculate my downtime cost?

Four components: lost production at your margin per ton, downstream idling, material handling for intake that arrives anyway, and the repair itself. Compute all four before the order — the specification choices follow the total, not the last line.

Which failure stops the line longest?

Usually hydraulic seals, because the repair is inside the power unit. Oil cleanliness and temperature discipline on schedule is the prevention, and the seal specification conversation at quotation is the insurance.

What spares should be on the shelf?

One blade set, the seal kit and the filter stock, sized to three-shift running on the shelf. The resupply channel covers the rest, with spare blades shipped within 48 hours by DHL or FedEx.

Is discharge blockage a machine problem?

Almost never — it is a flow problem. Buffer, handling and destination confirmed against your layout at quotation is the fix, and it is cheaper before installation than after.

What is the class’s capacity?

200 to 240 tons per day across three shifts, with the position inside the band set by plate proportion, bale proportion and where the maintenance window sits in the schedule. Budget the four components annually rather than per incident — the annual figure is what the specification conversation should be priced against, and it is the number that turns downtime from an anxiety into a managed line.