Manufacturing Systems III Chris Hicks MMM Engineering Email: Chris.Hicks@ncl.ac.uk
Assessment • End of year examination • 2.5 hours duration • Answer 4 questions from 6
Manufacturing Systems III • Manufacturing Strategy • JIT Manufacturing • Manufacturing Planning and control • Company classification • Modelling & Simulation • Queuing theory (CFE)
Reference • Hill, T (1986),”Manufacturing Strategy”, MacMillan Education Ltd., London. ISBN 0-333-39477-1
Manufacturing Strategy • Long term planning • Alignment of manufacturing to satisfy market requirements
Significance of Manufacturing • Manufacturing often responsible for majority of capital and recurrent expenditure • Long term nature of many manufacturing decisions makes them of strategic importance • Manufacturing can have a large impact on competitiveness
Manufacturing Strategy • Make / buy • Process choice • Technology • Infrastructure, systems, structures & organisation • Focus • Integration with other functions
Strategy Development • Define corporate objectives • Determine marketing strategies to meet these objectives • Assess order qualifying and order winning criteria for products • Establish appropriate processes • Provide infrastructure
Identifying Market Requirements • Order Qualifying criteria • Order winning criteria • Order losing criteria
Manufacturing Influences • Costs • Delivery • Quality • Demand flexibility • Product range • Standardisation / customisation
Profile Analysis • Assess match between market requirements and current performance • Identify changes required to manufacturing system
Market Requirements Unimportant V Imp. Price Quality Delivery CofOwn Customisation Other factors
Current Performance Unimportant V Imp. Price Quality Delivery CofOwn Customisation Other factors
Market requirement Achieved performance V Imp. Unimportant Price Quality Delivery CofOwn Customisation Other factors
Process Choice • Type of process: project, jobbing, batch,line • Flexibility • Efficiency • Robustness wrt product mix / volume • Unique / generic technology? • Capital employed • How do processes help competitiveness?
Manufacturing Structure • Layout: functional or cellular? • MTS / MTO • Flexibility of workforce • Organisation, team working etc. • Breakdown of costs • HRM issues
Products • Relative importance, present and future • Mix • Complexity • Product structure • Concurrency • Standardisation / customisation • Contribution
Measures of performance • What are they? • Frequency of measurement • Comparison with plan. • Orientation: product / process / inventory • Integration with other functions
Infrastructure • Manufacturing planning & control • Sharing information / knowledge • CAD / CAM • Accounting systems • Quality systems • Performance measurement
Case studies • Heavy engineering • PIP teams, simplification, value engineering, cellular manufacturing • Automotive supplier • “world class” but still relatively low productivity compared with Japanese sister company. Why?
“Manufacturing is a business function rather than a technical function. The emphasis should be on supporting the market” Terry Hill (1996)
References • APICS (1987),”APICS Dictionary”, American Production and Inventory Control Society, ISBN 0-935406-90-S • Vollmann T.E., Berry W.L. & Whybark D.C. (1992),”Manufacturing Planning and Control Systems (3rd Edition)”, Irwin, USA. ISBN 0-256-08808-X • Browne J., Harhen J, & Shivnan J. (1988),“Production Management Systems: A CIM Perspective”,Addison-Wesley, UK, ISBN 0-201-17820-6
Just-in-Time Manufacturing “In the broad sense, an approach to achieving excellence in a manufacturing company based upon the continuing elimination of waste (waste being considered as those things which do not add value to the product). In the narrow sense, JIT refers to the movement of material at the necessary time. The implication is that each operation is closely synchronised with subsequent ones to make that possible” APICS Dictionary 1987
Just-in-Time • Arose in Toyota, Japan in 1960s • Replacing complexity with simplicity • A philosophy, a way of thinking • A process of continuous improvement • Emphasis on minimising inventory • Focuses on eliminating waste, that is anything that adds cost without adding value • Often a pragmatic choice of techniques is used
Just-in-Time Goals • “Zero” inventories • “Zero” defects • Traditional Western manufacturers considered Lot Tolerance Per Cent Defective (LTPD) or Acceptable Quality Levels (AQLs) • “Zero” disturbances • “Zero” set-up time • “Zero” lead time
Just-in-Time Goals • “Zero” transactions • Logistical transactions: ordering, execution and confirmation of material movement • Balancing transactions: associated with planning that generates logistical transactions - production control, purchasing, scheduling .. • Quality transactions: specification, certification etc. • Change transactions: engineering changes etc. • Routine execution of schedule day in -day out
Benefits of JIT • Reduced costs • Waste elimination • Inventory reduction • Increased flexibility • Raw materials / parts reduction • Increased quality • Increased productivity • Reduced space requirements • Lower overheads
Just-in-Time JIT links four fundamental areas • Product design • Process design • Human / organisational issues • Manufacturing planning and control
Product Design • Design for manufacture • Design for assembly • Design for automation • Design to have flat product structure • Design to suit cellular manufacturing • Achievable and appropriate quality • Standard parts • Modular design
Process Design • Set-up / lot size reduction • Include “surge” capacity to deal with variations in product mix and demand • Cellular manufacturing • Concentrate on low throughput times • Quality is part of the process, autonomation, machines with built in capacity to check parts • Continuous quality improvement • No stock rooms - delivery to line/cell • Flexible equipment • Standard operations
Human / Organisational Elements • Whole person concept, hiring people, not just their current skills / abilities • Continual training / study • Continual learning and improvement • Workers capabilities and knowledge are as important as equipment and facilities • Workers cross trained to take on many tasks: process operation, maintenance, scheduling, problem solving etc. • Job rotation / flexibility • Life time employment / commitment?
Organisational Elements • Little distinction between direct / indirect labour • Activity Based Cost (ABC) accounting • Visible team performance measurement • Communication / information sharing • Joint commitment
JIT Techniques • Manufacturing techniques • Production and material control • Inter-company JIT • Organisation for change
Manufacturing Techniques • Cellular manufacturing • Set-up time reduction • Pull scheduling • Smallest machine concept • Fool proofing (Pokayoke) • Line stopping (Jikoda) • I,U,W shaped material flow • Housekeeping
Group Technology / Cellular Manufacturing • Improved material flow • Reduced queuing time • Reduced inventory • Improved use of space • Improved team work • Reduced waste • Increased flexibility
Set-up Time Reduction • Single minute exchange of dies (SMED) - all changeovers < 10 mins. 1. Separate internal set-up from external set-up. Internal set-up must have machine turned off. 2. Convert as many tasks as possible from being internal to external 3. Eliminate adjustment processes within set-up 4. Abolish set-up where feasible Shingo, S. (1985),”A Revolution in Manufacturing: the SMED System”, The Productivity Press, USA.
Basic Steps in a Traditional Set-up Operation 1. Preparation, after process adjustments, checking of materials and tools (30%). 2. Mounting and removing blades, tools and parts (5%) Generally internal. 3. Measurements, settings and calibration (15%) includes activities such as centring, dimensioning, measuring temperature or pressure etc. 4. Trial runs and adjustments (50%) - SMED Typical proportion of set-up time given in parenthesis.
Set-up Analysis • Video whole set-up operation. Use camera’s time and date functions • Ask operators to describe tasks. As group to share opinions about the operation.
Three Stages of SMED 1. Separating internal and external set-up doing obvious things like preparation and transport while the machine is running can save 30-50%. 2.Converting internal set-up to external set-up 3. Streamlining all aspects of the set-up operation
ANDON A board which shows if any operator on the line has difficulties • Red - machine trouble • White - end of a production run • Blue - defective unit • Yellow - set-up required • Line-stop - all operators can stop the line to ensure compliance with standards • Flexible workers help each other when problems arise
JIT Material Control • Pull scheduling • Line balancing • Schedule balance and smoothing (Heijunka) • Under capacity scheduling • Visible control • Material Requirements Planning • Small lot & batch sizes
“Pull” Systems • Work centres only authorised to produce when it has been signalled that there is a need from a user / downstream department • No resources kept busy just to increase utlilisation Requires: • Small lot-sizes • Low inventory • Fast throughput • Guaranteed quality
Pull Systems Implementations vary • Visual / audio signal • “Chalk” square • One / two card Kanban
Material Requirements Planning / JIT • Stable Master Production Schedule • Flat bills of materials • Backflushing • Weekly MRP quantities with “call off” , a common approach
JIT Purchasing • JIT purchasing requires predictable (usually synchronised) demand • Single sourcing • Supplier quality certification • Point of use delivery • Family of parts sourcing • Frequent deliveries of small quantities • Propagate JIT down supply chain, suppliers need flexibility • Suppliers part of the process vs. adversarial relationships