Design and Analysis of a Turbine Blade Manufacturing Cell MEAE-6960H01 Professor Ernesto Gutierrez-Miravete Presenter: Ray Surace Term Project Presentation:

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 2 Project Overview : Created a hybrid coding scheme for three turbine blade part numbers (P/N) to be produced in a group technology environment Reviewed the performance of an initial turbine blade cell design with 12 workstations Developed an improved cell design with 10 workstations Created a facility layout using the Column-Sum Insertion Heuristic Used a modified Approximate Three-Stage Markov Chain Model to determine the optimum size of buffers placed before and after an airfoil overlay coater Performed a Mean Value Analysis to validate the final design of a turbine blade manufacturing cell

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 3 Three (3) P/Ns with common features were grouped to form a composite part family: An alphanumeric hybrid coding scheme was derived from the machining sequence: The code makes use of the chain property; each character place in the code has a specific meaning: Example: P/N 100b1 Code:1b1y3 first digit part stage cooling hole of engine model i.e. 1=STG1 code part type coating? b=blade y=yes, n=no Cooling hole code: 0=no cooling holes, 1=laser cooling holes, 2=EDM cooling holes, 3=laser and EDM cooling holes Part Coding:

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 4 Initial cell design incorporated 12 workstations into a ‘U-shaped” cell layout to complete machining and finishing operations on P/N 100b1, 200b1, and 100b2 turbine blade castings isle Performance of 12 Workstation Cell Design :

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 5 Performance of 12 Workstation Cell Design : Customer demand rates for all 3 P/Ns dictate that 9.12 parts must be produced per hour Thus, cycle time C, must be 0.11 hrs. for each workstation Processing time of the precipitation heat treat furnace is 24 hours; the retort can hold 150 blades. Thus, C = This is unacceptable. To meet customer demand rates the furnace retort must have a capacity of Checking utilization we find that the heat treat furnace is a bottleneck operation: Thus, U m, furnace = 1.46 If a furnace with a capacity of 219 blades is purchased, WIP would increase by 69 pcs: 219 blades blades = 69 blades By removing the heat treat furnace from the cell, the overall WIP (WIP=PxT) of the cell can be reduced by 150 pcs. : New cell design to include 10 workstations; precipitation heat treat and shot peen machines moved to a separate department

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 6 Final turbine blade manufacturing cell design incorporates 10 workstations into a ‘U-shaped” cell layout: coater input buffer coater output buffer isle Layout of 10 Workstation Cell Design :

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 7 Column Sum-Insertion heuristic used to create a block plan of a turbine airfoil manufacturing facility with the following departments: –Receiving –Vendor Inspection (incoming casting inspection) –Blade Cell –Vane Cell –Heat Treat / Sot Peen Department –Shipping Receiving A Receiving Vendor Inspect I A I Shipping Blade Cell Vendor Insp. Blade Cell E X U U E Vane Cell A O A O Heat Treat/Peen O Heat Treat / Peen Vane Cell A Shipping Turbine Airfoil Manufacturing Facility Layout :

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 8 Analysis of Coater Buffer Capacity : Buffers are required before and after the coater in order to maintain a cycle time of 0.11 hrs. An Approximate Three-Stage Markov Chain Model was modified to determine the optimum buffer size The following modeling assumptions were made: –Cell modeled as a paced transfer line with M=10 stages –Coater capacity of 19 blades –Assumed the average mean time to failure, α -1 of workstations 1-5 and 7-10 approaches 0. Therefore α 1-5,7-10 = 1e-6 –Assumed α coater =1. Once the coater starts a cycle, any incoming parts go into the incoming buffers –The avg. mean “repair” time (coater cycle time) for the coater b -1 =18.18cycles, or b=0.05 The results of the Three-Stage model analysis are as follows : –The effectiveness of the cell without buffers, E 00 = –The maximum cell effectiveness is E 21 = –Therefore, the optimum buffer size before and after coating is Z=21

4/19/01Design & Analysis of a Turbine Blade Manufacturing Cell Ray Surace 9 Performance of 10 Workstation Cell Design: A Mean Value Analysis (MVA) was performed to validate the 10 workstation blade cell design The cell was modeled as a closed network with single servers It was assumed that each P/N (p) may visit each workstation (j) in that part’s processing sequence once A visit count (V jp ) table was constructed: To initialize the algorithm, a queue length (L jp ) of 1 was assumed in front of each workstation The algorithm was calculated using the following formulas: (eqn A&S), (eqn A&S), (eqn A&S) After three (3) iterations the algorithm converged *The total production rate of the cell, X total =9.92 parts per hour. This exceeds the demand, 9.12 parts per hour by 8%. Thus, the 10 workstation cell design is acceptable.