TAHA Engineering Toolsby TAHA Knowledge Lab

Machining & Workshop

Machining Cost & Tool Cost per Part Calculator

Cost per part from machine rate, cutting and handling time, tool life and tool cost per edge.

Inputs

Calculate from

Cost of running the machine with its operator for one hour, including overheads if you want a full cost.

Loading, unloading, rapid moves, measuring — everything except cutting and tool changes.

Minutes of cutting before the edge is changed (from experience, the supplier, or the Taylor tool life calculator).

Result

Total cost per part
375
Cutting-tool cost per part
80
Machine cost of cutting
200
Machine cost of non-cutting time
75
Machine cost of tool changes
20
Parts per cutting edge
5parts
Total time per part
5.9
Parts per hour
10.1695parts/h
Working
Edge share per part = 4 ÷ 20 = 0.2 Cost = rate × (tc + tn + tt × share) + edge cost × share = 3,000/60 × (4 + 1.5 + 2 × 0.2) + 400 × 0.2 = 375 PKR

Each part costs about 375, of which 80 is cutting-tool cost. The machine makes about 10.1695 parts/h.

Educational estimate — check the assumptions below.

About this calculator

The cost of a machined part is mostly machine time plus a share of the cutting tool. Each part uses up a fraction of a cutting edge (cutting time ÷ tool life), so it also carries that fraction of the edge’s price and of the time spent changing it. This calculator adds these up into a cost per part and shows the separate cutting-tool cost per part, which is often what you compare when trying a new insert grade or cutting speed.

Formula

Cost per part = R × (tc + tn + tt × tc ÷ T) + Ce × tc ÷ T

Cost per edge Ce = insert price ÷ edges + holder price ÷ edges per holder

R = machine + operator rate per unit time, tc = cutting time per part, tn = non-cutting time per part, tt = time to change an edge, T = tool life per edge (cutting minutes), Ce = tool cost per edge. Parts per edge = T ÷ tc.

Worked example

Rate 3000 per hour (50 per minute), cutting 4 min, non-cutting 1.5 min, tool life 20 min, edge change 2 min, insert 1600 with 4 edges (400 per edge):

  • Edge share per part = 4 ÷ 20 = 0.2 (5 parts per edge)
  • Machine cost = 50 × (4 + 1.5 + 2 × 0.2) = 50 × 5.9 = 295
  • Tool cost = 400 × 0.2 = 80 per part
  • Total = 375 per part; 5.9 min per part ≈ 10.2 parts per hour

Assumptions and limitations

  • One tool (or one edge type) is costed. For several tools, add the tool-related terms for each.
  • Material, set-up, programming, inspection and scrap costs are not included unless built into the hourly rate.
  • Tool life is an average; actual life varies. The currency label is for display only — no conversion is done.

References

  • Classical machining-economics cost model (e.g. Gilbert’s analysis; Kalpakjian & Schmid, Manufacturing Engineering and Technology).