OPERATIONS SCHEDULING

Scheduling

Business plan is transformed into a Master production plan;

Master production schedule (MPS) derive resource requirements and check availability of :

- Labour, skills/numbers,

- Plant & machinery,

- Finance,

- Utilities and services,

and decide and/or agree on the plan.

Scheduling

Within an organization, scheduling pertains to establishing the timing of the use of specific resources of that organization; It relates to the use of equipment, facilities and human activities; For example, manufacturer must schedule productions, hospitals must schedule admission, surgery, etc., and educational institutions must schedule classrooms, instructions, etc.; In the decision making hierarchy, scheduling decisions are the final step in the transformation process before actual output occurs.

Scheduling

Operations scheduling is at the heart of what is currently referred to as Manufacturing Executions systems (MES);

A MES is an information system that schedules, dispatches, tracks, monitors, and control production on the factory floor;

A work center is an area in a business in which productive resources are organized & work is completed;

The work center may be a single machine, a group of machines, or an area where a particular type of work is done.

Goals of Scheduling

Efficient utilization staffequipmentfacilitiesMinimization of customer waiting timeinventoriesprocessing time

Scheduling of operations depends on the type of operations

Manufacturing OperationsHigh-volumeIntermediate-volume Low-volume Service Operations

Scheduling of High-Volume Systems

Flow systemshigh-volume systems (i.e. repetitive systems) standardized equipment and activitiesidentical or highly similar operations on productsFlow-shop schedulingScheduling for high-volume flow system

Work Center #1

Work Center #2

Output

Scheduling of Low-Volume Systems

Job Shopsproducts are made to orderorders differ considerably in their processing requirementsJob-shop schedulingScheduling for low-volume systems with many
variations in requirementsLoading - assignment of jobs to process centersSequencing - determining the order in which jobs will be processed

Typical Scheduling & Control functions

Allocating orders, equipment, & personnel to workers or other specified locations (Loading); Determining the sequence of order performance (Sequencing job priorities); Initiating performance of the scheduled work (Dispatching); Shop floor control involving ( Expediting or Follow up) :Reviewing the status & controlling the progress, Expediting late & critical orders.

Loading involves assigning jobs to processing centers

Approaches to loadingInfinite loadingassigns jobs to work centers without regard to the capacity of the work center,possible to overload (exceed capacity) in some periods and under load in other periods.Finite loadingcapacity is not exceeded.takes into account capacity of each work center and processing times of jobs; projects actual job start and stop times.

Scheduling involves assigning start times to jobs at processing centers

Approaches to scheduling

Forward scheduling

scheduling ahead from a point in time (e.g., now)useful to answer the question How long will it take to complete this job?

Backward scheduling

scheduling backward from a future due dateuseful to answer the questions: Can we complete this job in time?When is the latest we can start this job and still complete it by the due date?

Sequencing involves ordering the processing of jobs

SequencingDetermine the order in which jobs at a work center will be processed.Results in an ordered list of jobsSequencing is most beneficial when we have constrained capacity (fixed machine set; cannot buy more) and heavily loaded work centersLightly loaded work centers = no big deal (excess capacity)Heavily loadedWant to make the best use of available capacityWant to minimize unused time at each machine as much as possible

Sequencing

Priority rulesSimple heuristics
used to select the order in
which jobs will be processed.Why use simple heuristics?Problem too complex = linear programming wont workSequencing jobs often does quite well

Scheduling Service Operations

Problems in Service Operations make scheduling even more difficult

Cannot store or inventory services.Customer service requests are random.Scheduling service involves:Customers,Workforce,Equipment.

Service Operations use many scheduling tools to ensure good service

Appointment systemsControls customer arrivals for service.Reservation systemsEstimates demand for service,Prices according to demandSchedules use of service.Scheduling the workforceManages worker capacity for service.Scheduling multiple resourcesCoordinates use of more than one resource.

Cyclical Scheduling is used in services with similar, repeating requirements

Hospitals, police/fire departments, restaurants, supermarkets.Rotating schedulesSet a scheduling horizon,Identify the work pattern,Develop a basic employee schedule,Assign employees to the schedule.