The Variances That Matter in a Forge Shop
Three variances usually dominate forging margin. Material yield: pounds of bar consumed per good forging compared with the quote. Rate and time: press hours, heater hours and labor against estimate, including slow starts after die changes.
Die cost: pieces per die set actual against quoted life. Add scrap and rework, which at a forge can be expensive because scrap occurs after material, heat and press time are already spent, and outside processing variance when processor prices or lot minimums change. A report that shows these separately tells you which assumption failed; a single total tells you only that something did.
- Material yield variance in pounds and dollars
- Press and heater hours versus estimate
- Die life versus quoted pieces per set
- Scrap, rework and outside processing variance
Allocating Furnace, Energy and Overhead Fairly
Energy is a real cost in forging, especially for gas-fired furnaces and induction heaters, and it does not scale with piece count alone. Idle furnace time, heat-up and cooldown cycles add cost that belongs to the jobs that caused them. A flat overhead rate per press hour hides these differences.
Where practical, separate rates for hammers, presses, heaters and heat treat, and allocate fuel or electricity by measured use or by cycle hours. The goal is not accounting precision but making sure a small job with long furnace holds does not look as profitable as a high-volume run.
Standard, Actual and Job-Level Costing
Standard costing gives stable numbers but can mask forging variability, since yield and die life differ by job. Actual job costing shows the truth for each work order but needs accurate time, scrap and material capture at the point of work. Many shops use standards for quoting and actual job costs for review, comparing them by part family after each job closes.
Whichever method your ERP uses, close the loop: update standards from measured actuals, rather than leaving the original estimate in place for years.
- Quote against standards built from recent actuals
- Review actual job cost when each work order closes
- Roll up by part family and customer
Try it here, free
Bar Stock Yield and Material Cost per Part Calculator
Work out how many parts come from each bar after cutoff and end loss, how many bars to buy, and the true material cost per part.
Reading Margin by Part Family and Customer
Group closed jobs by material, size range and die complexity and compare quoted to actual margin. Patterns appear: perhaps stainless parts lose margin to scrap, or one customer's small lots lose to heat treat minimums, or a long-running part has dies past their expected life. Those findings drive pricing changes, minimum order quantities or process fixes.
Be careful with small samples; one bad job is an anecdote, five is a pattern. An assistant that queries the ERP in plain language can produce these cuts quickly, but the numbers are only as good as the shop-floor data entered.
- Margin by alloy and size range
- Margin by customer and order size
- Jobs where actual cost exceeded quote by more than a set threshold
When Costing Detail Is Not Worth It
If you run a small number of repeat parts with stable results, extensive variance analysis is overkill; a simple quarterly check of price versus cost per pound may be enough. Deep job costing makes sense when part variety is high, when you quote often, and when a few percentage points of yield or scrap decide whether a job is profitable. Do not build reporting on top of operator time entries that no one trusts.
Frequently asked questions
How do you calculate job cost in forging?
Add material at actual input weight, press and heater time at their rates, labor, heat treat, testing, outside processing, scrap, and die cost per piece. Compare each element to the quote and group results by part family to see patterns.
Why do forge shops lose money on jobs that look profitable?
Often from yield, scrap or die life that differs from the quote, or from small-lot minimums at heat treat. Averaged overhead rates can also hide energy and idle time that belong to specific jobs.
Is standard or actual costing better for a forge shop?
Use standards for quoting stability and actual job costs for review, and update standards from measured results. Pure standard costing hides variability; pure actual costing needs very reliable data capture.
Netray can query your ERP for quoted-versus-actual cost by part family, read-only, so margin leaks are visible without a reporting project.