RunOut Method

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Run-Out Method

• Only so much capacity available each week so
  determine size of lots for all orders at the same
  time
• Based on most current demand and production rates
  not annual estimates

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Scheduling Low-Volume Systems

• Loading - assignment of jobs to process centers
• Sequencing - determining the order in which jobs
  will be processed

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Priority Rules

• FCFS - first come, first served
• SPT - shortest processing time
• DD - due date
• CR - critical ratio
• S/O - slack per operation
• Rush - emergency

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Sequencing Rules - Example

• A work center has 6 jobs to be processed. The
  required processing time and due date for each
  job is given in the following table.

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FCFS - First Come First Serve
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Evaluating Sequencing Rules

• Average completion time (average flow time)
  average amount of time jobs spent in the system
• Average no. of jobs in system
• Average no. of jobs waiting 1
• Average job tardiness (lateness) average amount
  of time that jobs completion date exceeds its
  promised delivery date
• Changeover cost - total cost of making machine
  changeovers for group of jobs

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CR - Critical Ratio
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Summary
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Experience Says

• FCFS - many shortcommings, but fair
• SPT - perform well, but watch out for orders with
  long processing times
• CR - works well on average job tardiness
  criterion, may focus too much on jobs that cannot
  be completed on time forcing more jobs to miss
  due dates.

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Two Work Center Sequencing

• Johnsons Rule technique for minimizing
  completion time for a group of jobs to be
  processed on two machines or at two work centers.
• Minimizes total idle time
• Several conditions must be satisfied

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Johnsons Rule Conditions

• Job time must be known and constant
• Job times must be independent of sequence
• Jobs must follow same two-step sequence
• Job priorities cannot be used
• All units must be completed at the first work
  center before moving to second

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Service Operations

• Quasi manufacturing operations
• Production occurs much as manufacturing
• Physical goods deminant over intangible services
• Kitchen area of Fast Food Restaurant
• Customer-as-Participant
• High degree of customer involvement
• Physical goods may or may not be significant
• Service either standard or custom
• ATM or Fast Food Restaurant
• Customer-as-Product
• Service performed on customers usually
  customized
• Patients

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Characteristics of Service Operations

• Intangible outputs that ordinarily cannot be
  inventoried
• Close customer contact
• Short lead times
• High labor costs relative to capital costs
• Subjective determined quality

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Other facts about service operations

• Enormous diversity
• Service businesses can be any size
• Twice as many nonretail service businesses as
  retail
• Technical training important
• Service workers well paid relative to
  manufacturing
• Need better planning, controlling, and management
  to stay competitive

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Operations Strategies for Service Operations

• Positioning strategies contain two elements
• Types of service design
• standard or custom
• amount of customer contact
• mix of physical goods and intangible services
• Type of production process
• Quasi manufacturing operations Kitchen area of
  Fast Food Restaurant, back rooms of Banks
• Customer-as-Participant ATM, Dept. stores or
  Fast Food Restaurant
• Customer-as-Product hair salons, medical
  clinics, hospitals, tailors

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Scheduling Services

• Difficult to plan and control day-to-day
  activities due to
• services produced and delivered by people
• Pattern of services is non-uniform
• Non-uniform demand
• Cannot inventory services during low demand so
  businesses use following tactics
• Preemptive actions such as off-peak incentives to
  make demand more uniform
• Make operations more flexible so easy to vary
  capacity
• Anticipate demand and schedule employees during
  each time period to meet demand
• Allow waiting lines to form

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Scheduling Quasi Manufacturing Operations

• Product-Focused Operations
• Resemble product-focused production lines
• Customer demand is forecast and capacity
  decisions made just as in manufacturing
• High volumes of standardized products
• Management focused on controlling production
  costs, product quality, and delivery of physical
  goods.
• Process-Focused Operations
• Managed like job shops in manufacturing
• Input-output control important to balance
  capacity between operations
• Gantt Charts used to coordinate flows between
  departments
• Sequence of jobs consider sequencing rules,
  changeovers, and flow times
• Work-Shift Scheduling

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Scheduling Quasi Manufacturing Operations

• Three difficulties in scheduling services
• Demand variability
• Service time variability
• Availability of personnel when needed
• Managers use two tactics
• Use full-time employees exclusively
• Use some full-time employees as base and fill in
  peak demand with part-time employees

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Scheduling Customer-as-Participant Operations

• Must provide customer ease of use/access
  features,,lighting, walkways, etc.
• Layouts must focus on merchandising and
  attractive display of products
• Employee performance crucial to customer
  satisfaction
• Waiting times used extensively to level demand
• Balance between efficiently utilizing operations
  resources and keeping customer satisfaction high
• Computer programms available
• with different queuing models to simplify analysis

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Scheduling Customer-as-Product Operations

• Wide range of complexity
• Every facet designed around the customer
• Highly trained, motivated, and effective
  workforce critical to success
• Waiting-line analysis can be helpful in
  determining staffing levels

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Scheduling Service Operations

• Appointment systems
• Controls customer arrivals for service
• Reservation systems
• Estimates demand for service
• Scheduling the workforce
• Manages capacity for service
• Scheduling multiple resources
• Coordinates use of more than one resource

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Service Operation Problems

• Cannot store or inventory services
• Customer service requests are random
• Scheduling service involves
• Customers
• Workforce
• Equipment

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Factors that Create Satisfied Customers

• Extrinsic quality of services
• The facilities comfort, convenience, and
  atmosphere
• The chemistry between customer and people in
  service system friendliness and courtesy
• Skill, conpetence, and professionalism of the
  personnel
• The value of the service, cost relative to the
  quantity of services received

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Computerized Scheduling

• Develops detailed schedules for each work centers
  indicating starting and ending times
• Develops department schedules
• Generates modified schedules as orders move
• Many packages available select one most
  appropriate for your business

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Current Best Practice

• In process-focused factories
• ERP/MRP II promises are met, shoploading is
  near optimal, costs are low, quality is high
• In product-focused factories
• EOQ for standardized parts containers, this sets
  S, lot sizes are lower, inventories slashed,
  customer service improved
• Scheduling is integral part of a computer
  information system (ERP)