【正文】 169。 1994 General Motors Corporation. All rights reserved. Y 169。 1994 General Motors Corporation. All rights reserved. BOTTLENECK An Operation Which Limits the Overall Output of a Series of Operations 1,000 900 800 700 600 500 400 300 200 100 0 1 2 3 4 5 6 7 8 Bottleneck Demand C A P A C I T Y OPERATION CAPACITY DEMAND 169。 1994 General Motors Corporation. All rights reserved. 169。 1994 General Motors Corporation. All rights reserved. THE TYPICAL PLANT ENVIRONMENT ? ? ? ? ? ? Plant Operates at a Productivity Plateau, With High Throughput Variability . Plant Throughput Is Often 10% to 50% Below Designed Rate . Lost Production Is Made up With Overtime. Production Blames Maintenance, Maintenance Blames Production, General Assembly Blames Paint, Paint Blames Body, Etc. In Many of Our Plants, We39。 1994 General Motors Corporation. All rights reserved. 169。 1994 General Motors Corporation. All rights reserved. Step 1: Identify the Constraint/Bottleneck ? ? If shifts/ week required shifts available, then a constraint exists ? Note: This will be shown by a “ ” on the Capacity Spreadsheet If no constraint exists: – examine the operations for the greatest number of shifts required, and the lowest capability per day. – The operation with the greatest number of shifts closest to the requirement is the bottleneck. – Note that constraints may not be immediately visible on the capacity spreadsheet due to interactions between operations (buffers) Shifts available = 15 Requirement/day=450 169。 1994 General Motors Corporation. All rights reserved. Starving/Blocking ? ? Never Starve a Constraint – Utilize Buffer Management – Place buffer inventory ahead to assure it always has parts to run – Load parts ahead to ensure constraint runs Never Block the Constraint – Decouple the Operations – Assure parts are pulled away so operation doesn’ t stop (enough racks,containers, space) – Unload after the constraint if the system downstream is down STARVED System (No Jobs to Work On) BLOCKED System (Choked) (No Place to put Job) DESIRED System L uu ZZZZZZ L Blocked Station Full Buffe r uu ZZZZZZ Failed Station Failed Station Empt y Buffer Starved Station J Workin g Station J Constraint Working Station 169。 1994 General Motors Corporation. All rights reserved. 5 Step Improvement Process Step 0: Establish Baseline Step 1: Identify Constraint/Bottleneck Step 2: Exploit Constraint Step 3: Subordinate nonconstraints Step 4: Elevate a: Run All of the Time b: Add Capacity Step 5: Restudy 169。 1994 General Motors Corporation. All rights reserved. 5 Step Improvement Process Step 0: Establish Baseline Step 1: Identify Constraint/Bottleneck Step 2: Exploit Constraint Step 3: Subordinate nonconstraints Step 4: Elevate a: Run All of the Time b: Add Capacity Step 5: Restudy 169