CLASS 1, PRODUCTION BOTTLENECKS
Breaking bottlenecks (or avoiding them
altogether) is a primary focus for effective production/operations management.
DEFINED:
BLOCKADES TO INCREASED OUTPUT RESULTING IN A BUILDUP OF WIP AT A CERTAIN
POINT OR POINTS ALONG THE PRODUCTION LINE.
TWO
TYPES:
STATIONARY-
·
EASY TO SPOT
·
WORK BUILDS-UP BEHIND IT
· CAUSE USUALLY RELATED TO CAPACITY INTERFERENCE DUE TO -
o
BROKEN OR OVERTAXED MACHINES OR
o
INSUFFICIENT WORKERS
SHIFTING-
·
FROM ONE PART OF PROCESS TO ANOTHER
·
NO CLEAR CAUSE (Perhaps product or process
changes)
·
MAY SHOW UP AS QUALITY DEFECTS IN PRODUCT
·
LOCUS DIFFICULT TO PINPOINT
ANALYSIS
OF BOTTLENECKS - Largely based on common sense and
observation
PROCESS
FLOW DIAGRAM IS USEFUL TO TRACE FLOW AND DO WHAT-IF GAMING
LOOK
FOR CAPACITY INTERFERENCE
INFORMATION
FLOW DIAGRAM USEFUL TO ANALYZE FLOW OF INFORMATION WITHIN ORGANIZATION: (See Androscoggin example in Tour A)
CAUSES
OF BOTTLENECKS (*
MATERIALS RELATED)
EPISODIC
(FIRES/ALLEGATORS, DISCRETE IN NATURE- THREE TYPES)
1. MACHINE BREAKDOWNS- CAUSED BY ACCIDENT, POOR PM, MISSING PARTS*
2.
*MATERIAL SHORTAGES- TRACEABLE TO VENDOR OR PURCHASING, CONSISTS OF WRONG PART
RECEIPT OR DELAYED ARRIVAL OF NEEDED REPAIR PART
3.
LABOR SHORTAGES-
·
UNION PROBLEMS
·
ILLNESS
·
UNEXPECTED VACANCIES DUE TO BUMPING, ETC.
·
HIRING/TRAINING DIFFICULTIES
CHRONIC/RECURRING
BOTTLENECKS- (Systemic Causes)
1.
MATERIALS PROBLEMS- (SUGGESTS POOR PRODUCTION PLANNING OR PURCHASING SYSTEM) -
ORDERING
WRONG PART REPEATEDLY
INSUFFICIENT
MATERIALS RESULTING FROM:
·
UNTIMELY ORDERING
·
POOR INVENTORY MANAGEMENT
·
INADEQUATE FORCASTING
·
MYOPIC OR POOR PRODUCTION PLANNING
·
UNRELIABLE FUNDING
UNSTABLE
PRODUCT MIX CAUSED BY-
IRREGULAR DEMANDS ON CAPACITY
ERRATIC
CAPACITY UTILIZATION DUE TO CONSTANTLY CHANGING PRODUCT MIX
POOR
MARKET FORECASTS
INAPPROPRIATE
CAPACITY OF PROCESSES WHICH ARE CRITICAL TO CURRENT PRODUCT MIX
2.
PROCESS PROBLEMS-
§
INSUFFICIENT CAPACITY
§
QUALITY PROBLEMS
§
POOR PLANT LAYOUT
§
INFLEXIBLE PROCESS WITH NO ALTERNATIVES WHEN
CONDITIONS CHANGE
LAYOUTS:
BOTTLENECKS
AND LAYOUT OF PHYSICAL PLANT ARE RELATED -
POOR
LAYOUTS-
·
INTERRUPT FLOW OF MATERIAL
·
INCREASE OVERHEAD OF LABOR/MACHINERY
·
INHIBIT INFO FLOW
·
INCREASE MATERIAL HANDLING TIME
(IN SUMMARY, CAUSE OPERATING INEFFICIENCIES)
POOR LAYOUTS CAN OCCUR OVER TIME DUE TO REPEATED, PIECEMEAL EXPANSION OR PRODUCTION LINE CHANGES
POOR
SITE PREPARATION TO ACCOMODATE NEW EQUIPMENT OR PROCESSES CAN CREATE
BOTTLENECKS (ILL PLANNED INSTALLATION)
THREE
TYPES OF LAYOUTS –
1. JOB SHOP- (OR PROCESS LAYOUT) - PRODUCT
CHARACTERIZED BY MANY SMALL, DISSIMILAR ITEMS (MOST FLEXIBLE LAYOUT TYPE)
·
NO DOMINANT FLOW WITHIN PROCESS
·
SIMILAR MACHINES ARE GROUPED TO FACILITATE-
o
MAINTENENCE
o
PRODUCTION CONTROL
o
MATERIALS FLOW
o
STORAGE OF PARTS/TOOLS
2.
LINE FLOW- (PRODUCT SPECIFIC LAYOUT) - PRODUCT LINES ARE FEW AND CONSISTENT IN
DESIGN (LEAST FLEXIBLE LAYOUT TYPE)
·
IF DOMINANT FLOW CAN BE DISCERNED (IE.
CONTINUOUS FLOW PROCESS)
·
CHARACTERIZED BY ORDERLY FLOW OF WIP THRU SEQUENTIAL
OPERATIONS
TWO TYPES-
1. WORKER PACED (IE BURGER KING WHERE THE WORKER IS THE MACHINE
2.
MACHINE PACED - SUCH AS AN AUTO PLANT OR CARRIER
FLEXIBILITY
OF THESE TWO VARIANTS OF LINE FLOW IS LEAST IN THE CONTINUOUS FLOW PROCESS AND GREATEST
IN THE WORKER PACED LAYOUT.
THE
MACHINE PACED LINES SUCH AS THE CARRIER PLANT OR AN AUTOMOBILE PLANT ARE
SOMEWHERE IN-BETWEEN
3.
FIXED POSITION LAYOUT- (WHEN PRODUCT IS LARGE/COMPLEX)
·
PRODUCT IS STATIONARY (HOME AND SHIP BUILDING
ARE EXAMPLES)
·
WORKERS AND MATERIALS MOVE TO PRODUCT (AN
EXAMPLE OF THIS "STALL BUILD" CONCEPT WHICH HAS CHALLENGES DUE TO THE
INHERENT INEFFICIENCIES OF LAYOUT, MATERIALS HANDLING,WORKER ACCESS, ETC.)
·
FLEXIBILITY ACHIEVED THROUGH SCHEDULING AROUND CRITICAL
PATH
JOB SHOP AND FIXED POSITION LAYOUTS EXIST
BY DEFAULT DUE TO NATURE OF OPERATION OR PRODUCT
EFFICIENCY:
LINE
FLOW, WHEN APPROPRIATE, IS THE MOST EFFICIENT IN ITS USE OF LABOR,MATERIALS,
MACHINERY, SPACE. MATERIALS MANAGEMENT,
HANDLING, ETC.
JOB
SHOP IS CONSIDERED TO BE THE LEAST EFFICIENT PROCESS TYPE
THE
CONCEPT OF GROUP TECHNOLOGY IN A JOB SHOP INTRODUCES SOME
CHARACTERISTICS OF LINE FLOW PROCESSES WHEN:
·
A DOMINANT FLOW OF MANUFACTURING OPERATIONS AMONG
VARIED PRODUCT LINES CAN BE IDENTIFIED
·
SUB-ASSEMBLIES REQUIRING THE SAME SEQUENCE OF OPERATIONS ARE GROUPED TOGETHER AND ROUTED IN SEQUENCE
THROUGH A SERIES OF MACHINES/ OPERATIONS
·
"U-LINE": SIMPLIFIES MATERIAL FLOWS IS A SPUR OFF THE MAIN PRODUCTION LINE
GIVES A JOB SHOP LINE FLOW CHARACTERISTICS
5
STEPS TO CONSIDER WHEN DEVISING LAYOUTS:
1. EXAMINE PROCESS FLOW
·
IS THERE A DOMINANT FLOW?
·
IDENTIFY PROCESS CONSTRAINTS (IE. PAINT BOOTH,
X-RAY, ETC.)
2. GAGE EXTENT, IMPORTANCE AND
RELATIONSHIP OF FLOWS
DETERMINE PROXIMITY
REQUIREMENTS (MACHINES, SUPPLIES, ETC.)
3. DETERMINE SPACE NEEDS
TOOLING, MATERIALS, WIP,
STORAGE
4. ARRANGE LAYOUT
BASED ON NATURE OF FLOWS, REQUIRED PROXIMITIES, SPACE CONSTRAINTS
5. DETERMINE TRAFFIC FLOWS
·
BASED UPON PROCESS PATTERNS, MOVEMENTS OF MATERIALS,
PEOPLE, SAFETY
·
FINE TUNE
LAYOUT TO ACCOMODATE NATURE OF THE PROCESS