Outline. Manufacture. What is mfg systems? How Man, Machine, and Material Spend Time in the Factory Manufacturing Systems

Transcription

1 2.008 Manufacturing Systems Outline 1. Manufacturing Systems 2. Types of Plant Layouts 3. Production Rates 4. esign and Operations 2 Manufacture What is mfg systems? Market Research onceptual esign esign for Manufacture actory, Systems & Enterprise ssembly ssembly and and Joining Joining Welding olting onding Soldering Unit Unit Manufacturing Manufacturing Processes Processes Machining Injection molding asting Stamping hemical Vapor eposition 4 Time spectrum of Typical ctivities in a Manufacturing Organization Seconds Period ctivity 10 8 ecade Plant design, Machine Selection, 10 7 Year System Simulation 10 6 Month Process design: atalogs Week Select manufacturing methods 10 5 ay actory Operation 10 4 Ship Receive Hour Transport Inventory Minute Part handling 10 1 Load/ Unload ssembly 1 Second.1 Machine control N N.01 daptive control Intelligent machines.001 Millisecond Process control 5 How Man, Machine, and Material Spend Time in the actory Waste People Materials Machines Waste : waiting for materials, watching machine running, produci ng defects, looking for tools, fixing machine breakdowns, producing unnecessary items, etc. u e - Val Value - adde d adde d Waste Waste : transportation, storage, inspection and rework Value - adde d Waste : unnecessary movement of machine, setup time, machine breakdown, unproductive maintenance, producing defective products, producing products when not needed, etc. 6 Waste 1

2 isruptions/variation (Random Events) Machine failure Set-up change Operator absence Starvation/lockage emand change Types of Plant Layout Job Shop Project Shop low Line Transfer Line ellular System 7 8 Job Shop Project Shop Machines/Resources are grouped according to the process they perform Raw Material Machines/Resoues are brought to and removed from stationary part as required Raw material/ 9 10 low Line and Transfer Line ellular System Machines/Resources are grouped in lines according to the processes sequence of part(s) Raw Material G Machines/Resources are grouped according to the processes required for part families Raw Material E E G

3 i 13 Production Quantity and Plant Layout Project Shop Production Rates ase I: One machine Everything works Job Shop ellular System M low Line ,000 10, ,000 Quantity 1 Production rate = Operation time Spr ng ase II: One machine Machine breaks down (disruption) Everything else works ase III: Many machines No machine breaks down No buffers M MTT MTT Efficiency = = (utilizati on) MTT + MTTR MTTR Efficiency Production rate = Operation time M 1 M 2 M i M k ase IV: Many machines (same operation time) No machine breaks down No buffers ase V: Many machines (same operation time) Machine breaks down No buffers M 1 M 2 M i M k M 1 M 2 M i M k

4 i 19 ase VI: Many machines and buffers in between Machine breaks down M 1 1 M 2 2 M k-1 M k M 3 k-1 Production rate increases if: Increase the rate of the slowest machine Reduce the disruptions Introduce buffers Introduce in-process control Spr ng isruptions (Random Events) Machine failure Set-up change Operator absence Starvation/lockage Waiting Underutilization Idleness Inventory Inventory/Work-in-Process (WIP) It costs money It gets damaged It becomes obsolete It shrinks It increases lead time ycle Time and Lead Time Supplier Takt time = Plant aily available time aily average demand ustomer

5 ycle Time ycle Time The time a part spends in the system ycle Time (cont d) Example: Operation time = 1, One-piece operation Little s Law: L = λw i L: average inventory ycle time = 5 λ: average production rate Inventory = 5 w: average cycle time M 1 M 2 M 3 M 4 M 5 Product on rate = ycle Time atch Production ycle Time One-Piece Production 1. Op1 Op2 Op3 2. Op1 Op2 Op3 Operation time: 3 minutes atch (Lot) size: 1000 ycle time = 1,000*3 + 1,000*3 + 1,000*3 = 9,000min Operation time = 3 minutes ycle time = 1,000*3 + 2*3 = 3,006 minutes ycle Time and Lead Time Supplier Takt time = Plant aily available time aily average demand ustomer Systems esign and Operation ycle time < Lead time Lumpiness Information contents

6 Lumpy emand Typical esign Guidelines Wrench Wrench Wrench Wrench P 5 5 P P P orging X orging Y P P Steel Z Leveling alancing Single-piece flow Low materials handling Low setup time Smaller lot size Low WIP aster feedback Plant Operations Push (MRP, ERP, etc.) vs. Pull (JIT) atch vs. One-piece 33 6