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

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