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Rough Estimating Cost Machined Parts Equations and Calculator

Rough Estimating the Cost of Machined Parts Equations and Calculator

Machining costs are determined by understand the cost of the engineering material specified, the initial volume of material, machining time, mechanical tolerances and geometry requirements.

This calculator does all three of the following:

  • Rough Estimating Machined Parts Cost with Known Rough Stock Volume
  • Rough Estimating Machined Parts Cost with Known Round Rough Stock
  • Rough Estimating Machined Parts Cost with Known X, Y, Z Known Rough Stock

Note: This method is used as an A vs B design tool and does not consider material costs in the calculations. Actual manufacturing costs must be obtained by live quotes from manufacturing job shops, etc..

Preview: Rough Estimating the Cost of Machined Parts Calculator (Membership Required: Premium).

Multiple Parts per Lot

Part Lot Cost =  N x [ ( Vr – Vm ) x Tm x Rt x (1hr/60min) ] + Ohm + Sc 

Where:

Vr = Volume of Rough Stock (in3, mm3 )
Vm = Volume of Final Machined Part (in3 , mm3 )
Tm = Material Removal minutes per unit volume (min/in3 , min/mm3 )
Rt = Machine shop rate ($/ hr )
Ohm = Machine shop overhead ($)
Sc = Lot manufacturing setup costs ($)
N = Lot built quantity

Metal removal rates vary as follows:

Milling operations: 0.5 in3 / min ( 2 min/in3 ) to 500 in3 / min ( 0.002 min/in3 )
Small dia. end mill – Shell insert cutter

Lathe turning: from 0.5 ( 2 min/in3 ) to 50 in3 / min ( 0.02 min/in3 )

Drilling: from 0.3 ( 3.33 min/in3 ) to 36 in3 / min ( 0.028 min/in3 )

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