Machine-shop quotes: price the minutes your busiest machine gives up

A machining order can show an attractive margin per part and still displace more valuable work from the only machine capable of finishing it. Before approving a quote during a full production week, calculate how much contribution the order produces for each minute of the constrained machine. Include the setup and inspection time that occupies that machine, then compare the order with work the shop would actually postpone or decline.

This is a scheduling and commercial decision model. It does not replace the shop's inventory-costing policy, financial statements or normal price list. Its purpose is to answer a narrower question: does this particular order justify using capacity that another confirmed order needs? The answer changes when the machine has spare capacity, when a different machine becomes constrained, or when an order carries an unavoidable contractual commitment.

NIST MEP describes setup reduction and continuous flow as ways to improve production. For the quote review, measure the shop's own production route and setup interval. A supplier's advertised cycle time cannot establish the capacity available on your floor.

List the material purchased for the order, outside processing, order-specific tooling, incremental freight, and any additional paid hours that accepting it causes. Deduct recoveries only when they are supportable. A reusable fixture may serve several future jobs, but an expected future order is a weak basis for removing its entire cost from today's decision. Show the initial cash payment and the proposed allocation separately.

Use the same cost definition for every competing order. If regular operator payroll will be paid regardless of the selected work, treating it as an incremental cost for one quote and a standing cost for the other distorts the comparison. When overtime is required, include its additional payroll cost and the realistic output of that shift. Finance should retain a separate view showing whether total contribution covers the shop's standing costs over the planning period.

A quote should also identify operations outside the constrained machine. These operations can create a second capacity problem. An order that moves quickly through machining may wait in a long finishing or quality queue, so a high contribution per machining hour does not establish that the promised delivery date is achievable.

Consider an illustrative shop with 600 available minutes on a specialist machine this week. Order A would bring in $4,800, requires $2,400 of incremental costs and occupies 300 machine minutes, including setup. It therefore contributes $2,400, or $8 per constrained minute. Order B would bring in $3,900, costs $1,200 incrementally and uses 450 minutes. It contributes $2,700, or $6 per minute.

Order B contributes more dollars by itself, while Order A uses the scarce machine more efficiently. That difference does not automatically make A the winning schedule. The shop needs a feasible use for the 300 minutes left after A. If another confirmed order produces $1,500 in those minutes, the combined contribution is $3,900. If the remaining time cannot be sold or used, choosing B could produce the larger weekly contribution.

The calculation should therefore compare feasible schedules. Keep indivisible lot sizes, tool changes, due dates and customer commitments in the schedule. Dividing contribution by machine time is a useful ranking signal; it is not permission to split orders into quantities that customers will not accept.

A rush fee should reflect the actual disruption. Ask the planner which confirmed job moves, whether that job can run later without penalty, whether an extra setup appears, and whether subcontracting provides an acceptable alternative. Include expedited freight only once. If the customer pays that freight directly, it does not also belong in the shop's cash cost unless the agreement says otherwise.

Suppose a rush job produces $1,100 before disruption costs but requires an additional setup costing $180 and displaces $1,200 of contribution that cannot be recovered later. Under those illustrative assumptions, the rush job reduces the week's contribution by $280. A $280 price increase only reaches economic parity; it provides no allowance for estimating error or commercial risk. The sales team can instead negotiate a different delivery date or a smaller first shipment.

Document the displaced order by identifier. A vague opportunity-cost percentage can survive long after the backlog has disappeared. If the delayed work can be completed next week with unchanged economics, show the timing effect and any extra cost instead of treating all of its contribution as permanently lost.

Review setup time, first-piece approval, expected good output and rework on the constrained equipment. Use actual results from comparable jobs where possible, with a note on differences in material, geometry, tooling or tolerance. A quote based on a perfect uninterrupted run needs an explicit explanation if the shop's normal route includes inspection pauses or operator intervention.

Run a small sensitivity table around the assumptions that change the decision. For Order A, increasing constrained time from 300 to 400 minutes reduces contribution per minute from $8 to $6. At that point its original ranking advantage disappears. If expected material cost rises by $300 while time stays at 300 minutes, its contribution becomes $2,100, or $7 per minute. These calculations help the estimator focus on the measurements worth confirming.

Capacity improvements need their own evidence. A proposed setup reduction may be worth pursuing, but count the freed minutes in a committed delivery promise only after operations can reproduce the new method. NIST's supply-chain guidance also supports examining the critical production path; solving a nonconstrained step may leave the delivery limit untouched.

Save the approved quote, route version, constrained minutes, incremental-cost assumptions, alternative schedule and reason for the decision. Record any strategic exception, such as a customer qualification run, as an approved commercial choice. Calling that work profitable through a revised cost definition prevents the team from learning what the exception actually cost.

After production, compare estimated and actual good units, machine occupation, outside processing and incremental spending. Explain differences by cause: an optimistic setup estimate, a revised drawing, a new inspection requirement or an unplanned breakdown. Update the relevant estimating input rather than applying a blanket surcharge to every customer.

The next quote review should start with the current backlog and machine availability. A minimum price appropriate during a fully committed week may be unsuitable during an idle week, while a temporary low-price order can become expensive when it blocks an established customer's delivery. Put an expiry date on the capacity assumptions so the approved calculation is not reused after its operating conditions have changed.