This document summarizes a project to simulate and optimize the machining process for an optical mount. It includes: - Building a toolpath for machining the mount using specified tooling and simulating the process to evaluate cycle time. - Estimating tool life using Taylor's model and calculating the number of parts each tool can machine. - Estimating total original machining cost of $8.84 including material, labor, tools, equipment, and overhead costs. - Generating a cost model and optimizing speeds and feeds to minimize cost, resulting in an optimized cost of $8.30.

1. Machining process simulation and cost optimization of an optical mount
AUE 867 – Automotive Manufacturing Processes
Varun Kumar1
1Clemson University
Varun Kumar
Clemson University
Email: kumar3@g.clemson.edu
Phone: 864-986-5405
Contact
1. Oberg, E., 2012, “Machining operations-feeds and speeds,” Machinery’s Handbook 29th Edition, Industrial Press, p. 1043.
References
Objective:
 To build a tool path for machining the optical mount using the
specified set of tooling
 To evaluate tool life for each tool using Taylor’s model
 To evaluate the total cost of machining the part
 To optimize the process parameters to minimize machining cost
Project overview
 Build tool path using NX tool path generator
 Simulate the complete machining process to evaluate cycle time
 Estimate total cost of machining by including material, labor, tool,
equipment, energy, salvage cost of chips and overhead costs
 Generate a cost model with process parameters (speed and
feed) and optimize them for minimum machining cost
Abstract
Machining time with given tooling: 1.38 minutes
Total cycle time with given tooling: 3.45 minutes
Tool life estimates
Original machining cost for part: $8.84
Optimized machining cost: $8.30
Optimization results
Tool path planning:
 12 machining steps used
 CNC code generated using NX manufacturing for each step
 Cutting speed and feed values selected from Machinery
Handbook for given material and tool [1]
 Engagement time for each tool during machining evaluated
 Complete process simulated to estimate cycle time
Tool life estimation:
 Taylor’s tool life equation VTn = C used
 n and C values for Carbide tools used for calculation
 Number of parts from each tool was estimated using
No. of parts = Tool life / engagement time with work piece.
Machining cost estimation:
 Ctotal= 𝐶 𝑚+ 𝐶𝑙 + 𝐶𝑐 + 𝐶𝑒 + 𝐶𝑡 + 𝐶𝑖
Cost optimization:
 Parametric cost model in terms of tool feed and speed generated
 𝐶𝑦𝑐𝑙𝑒 𝑡𝑖𝑚𝑒( 𝑡 𝑐𝑦𝑐) = 𝑓(𝑡𝑜𝑜𝑙 𝑓𝑒𝑒𝑑)
 𝐿𝑎𝑏𝑜𝑢𝑟 𝑐𝑜𝑠𝑡( 𝐶𝑙), 𝐸𝑞𝑢𝑖𝑝𝑚𝑒𝑛𝑡 𝑐𝑜𝑠𝑡( 𝐶𝑐), = 𝑓( 𝑡 𝑐𝑦𝑐)
 𝑇𝑜𝑜𝑙𝑖𝑛𝑔 𝑐𝑜𝑠𝑡( 𝐶𝑡) = 𝑓 𝑐𝑢𝑡𝑡𝑖𝑛𝑔 𝑠𝑝𝑒𝑒𝑑
 𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑠𝑡( 𝐶𝑡𝑜𝑡𝑎𝑙) = 𝑓 𝑐𝑢𝑡𝑡𝑖𝑛𝑔 𝑠𝑝𝑒𝑒𝑑, 𝑡𝑜𝑜𝑙 𝑓𝑒𝑒𝑑
 Objective function: min (Total cost, Ctotal)
 Constraints: (feed × cutting speed)≤ 2.(feed × cutting speed)recommended
 Optimization algorithm: MOGA 2
 DOE generator: Latin Hypercube
Method
The cost of machining can be minimized by using following tool
speeds and feeds
Design changes to some features can help improve machining
Conclusions and recommendations
Tool number Life (min)
100 mm face mill 16.97
25 mm end mill 26.29
10 mm end mill 26.29
3 mm end mill 1516.40
Chamfer tool 1516.40
Introduction
A new optimal mount is to be machined for Tier-1 automotive supplier
Customer requirements
 A high quality and cost competitive part
 Detail analysis report for machining process, tool life and tool
paths
 Cost estimation and cost optimization routine
 Identification of possible areas of concern for machining
Details of part
 Material: Aluminum 6061-T6
 Number of holes to be machined: 07
 Number of slots: 01
 Stock present in raw part: 25.4 mm all around
Results
Figure 1. Rendered view of optical mount. Figure 2. CAD view of optical mount.
Figure 3. Tool path for machining side pocket Figure 4. Tool path for machining holes
Table 1. Tool life estimates for given tooling set
Figure 5. Optimised cost results from MOGA optimisation algorithm
Tool number Feed (mm/tooth) Speed (ft/min)
100 mm face mill 1.270 500.15
25 mm end mill 0.635 500.50
10 mm end mill 0.635 300.24
3 mm end mill 0.635 64.00
Chamfer tool - 50.00
Table 2. Optimized feed and speed for minimum machining cost
Figure 6. Elliptical feature needs more
tool moves
Figure 7. Generous corner radius can save
cycle time