1. Optimization of Cutter Life DSES 6070 HV5 Professor Gutierrez-Miravete By: Frank Gibilisco

2. Problem Statement Determine optimal cutter life for 2.000 diameter RNC end mill exposed to a variety of cutting conditions

3. Assumptions Feed & Speed held constant  Torque controlled machining Operator held constant  Reduce risk of measurement error Each operation will have a failure point  cutter application requires multiple cutters to complete one operation.  Run time is such that replacement is mandatory to reduce risk of damage to part or machine. Cutter Failure Modes 1)Cutter broken 2)Cutter chipped 3)Cutter excessive wear

4. Methodology Data Collection  30 part sample Minitab / Excel  Best-fit distributions Maple  Verify reliability statistics

5. Discussion Best Fit Distribution  Weibull vs. Lognormal  Lognormal is used as a repair distribution  Weibull – general distribution with many applications Reliability Statistics  MTTF: 82.711 min  Shape: 4.41186  Scale: 90.739

6. Results Maple Calculations  Verified Minitab data using shape/scale parameters from Minitab  MRL (@t=60 min) = 28.7 min Interpretation  MTTF: 82.711 min  Consider increasing cutter time limit on machine  Potential savings ($30000 per year) with process improvements Baseline - 500 cutters ordered per year $220 per cutter Plot of Survival Function (R)

7. Conclusions Reliability  MTTF > time limits set by experience  Torque value – limited effect Next steps  Determine effects of changing torque values to utilize available horsepower on machine  Determine effect of new vs. regrind cutters on optimal cutter life / business strategy