Finishing Cost

Mass Finishing Cost Per Part: How to Build a Deburring and Polishing Quote

What actually drives cost per part in mass finishing, how to assemble a defensible per-batch quote, and the four places estimates quietly lose money.

Mass finishing cost per part is a batch number divided by yielded parts, not a per-hour rate. Build the batch cost from five buckets: machine time, media consumption, compound, labor to load and unload, and scrap or rework. For a typical vibratory run finishing 220 good parts over a 10 hour cycle, machine time at a $12 to $25 per hour burdened rate contributes $120 to $250. Divided across 220 parts that is only $0.55 to $1.14 each, which surprises estimators who assume machine time dominates. Labor and media usually cost more per part than the machine itself.

Media is the sleeper cost. Ceramic media runs $2 to $6 per pound and wears 0.5 to 1.5 percent per hour; plastic runs $3 to $8 per pound and wears faster. A 576 lb ceramic charge losing 1.0 percent per hour over 10 hours sheds about 57 lb, so at $3.50/lb that is $200 of media per cycle, or $0.90 per part on 220 parts. Estimators who forget wear and only amortize the initial charge underquote by exactly this amount. Use Media Wear Rate to project makeup pounds, then price them into every batch rather than treating media as a one-time capital buy.

Compound and water are smaller but real. At 1:60 dosing and 1 gal/ft3/hr on a 7 ft3 load, a 10 hour cycle uses roughly 147 oz, about 1.15 gallons of compound. At $15 to $30 per gallon that is $17 to $35 per batch, or $0.08 to $0.16 per part, plus water, effluent treatment, and sludge disposal that can add $0.05 to $0.20 per part where discharge is regulated. Run Compound Usage to get ounces per cycle, then attach your local chemical and disposal prices. Skipping effluent and sludge is a frequent reason shop quotes look cheap on paper and lose money in practice.

Labor is often the largest single bucket and the easiest to underestimate. Load, screen, unload, hand-pick, and inspect can run 0.3 to 1.5 minutes per part depending on size, weight, and separation difficulty. At a $22 per hour loaded labor rate, 0.8 minutes per part is $0.29 each, and on 220 parts that is $64 of labor, exceeding compound and rivaling media. Use Unload Labor Time to size the handling minutes from part count and separation yield, because low Part Separation Yield forces hand picking that quietly doubles labor. Automated separation decks cut this bucket by 40 to 70 percent.

Scrap and rework are the swing that turns a good quote bad. If 2 percent of parts come out over-radiused, impinged, or with lodged media that damages edges, you either scrap them or re-run. A 2 percent scrap on a $9 machined part adds $0.18 of loss per good part before you count the re-finish labor. Impingement scrap climbs fast when media-to-part ratio drops below 3:1. Quote a realistic first-pass yield of 95 to 99 percent and carry the scrap as an explicit line, not a hope. The Deburr Cost Per Batch calculator rolls machine, media, compound, labor, and scrap into one per-part figure.

Overhead and setup get spread wrong on short runs. Fixed setup, media changeover between part families, and QA sampling might total $40 to $120 per batch regardless of quantity. On a 220 part batch that is $0.18 to $0.55 per part; on a 40 part batch it is $1.00 to $3.00 per part. Estimators who quote one blended per-part price across all volumes lose money on small lots and overprice large ones. Break setup out as a per-batch charge and let it amortize honestly with quantity, then quote parts on the variable buckets above.

Assemble the quote as batch cost divided by yielded parts, then add margin. Example: $150 machine, $200 media, $30 compound and disposal, $64 labor, $40 setup, and $36 scrap equals $520 for 216 good parts, or $2.41 per part before margin. At a 35 percent gross margin you quote about $3.71 per part. The two errors that sink this: pricing media as a sunk asset instead of a per-cycle consumable, and using an optimistic separation yield that hides hand-pick labor. Use Rework Reduction Savings to show a customer how a better ratio or media choice lowers scrap and defends a higher first-pass price.

Sanity-check every quote against a benchmark band before sending it. Small precision parts commonly finish at $0.50 to $3.00 each all-in; larger castings and forgings at $1.50 to $8.00; delicate bright-polish work higher. If your number lands far outside the band, a bucket is wrong, usually media wear omitted or labor understated. Re-run Deburr Cost Per Batch with corrected media makeup pounds and real unload minutes, and confirm the machine-time share sits near 20 to 35 percent of total cost. When machine time dominates your estimate, you have almost certainly undercounted media and labor.

Published 2026-07-01.