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Loading Jobs and Methods Definitivo
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LOADING JOBSLoading means the assignment of Jobs to
work or processing centers.
Operations Managers assign jobs to work centers so that cost and completion times are kept to a minimum
Loading work centers
Oriented to Capacity
Related to assigning specific jobs.
Work centers are areas in a business in which productive resources are organized and work is completed.
It may be a single machine, a group of machines, or an area where a particular type of work is done.
The work centers can be organized in a variety of ways including by function in a job-shop configuration; or by product in a flow, assembly line, or group-technology-cell configuration
A characteristic that distinguishes one scheduling system from another is how capacity is considered in determining the schedule.
The scheduling systems can use
LOADING JOBS
Infinite Loading
Finite Loading
Infinite loading:
Ignores capacity constraints, but helps identify bottlenecks in a proposed schedule to enable proactive management
With infinite loading jobs are assigned to work centers without regard for capacity of the work center.
Jobs are loaded at work centers according to the chosen priority rule.
LOADING JOBS
Priority rules are appropriate for use under the infinite loading approach.
This is known as vertical loading.
Finite loading:
Allows only as much work to be assigned as can be done with available capacity – but doesn’t prepare for inevitable slippage
Finite loading considers the capacity of each work center and compares the processing time so that process time does not exceed capacity.
With finite loading the scheduler loads the job that has the highest priority on all work centers it will require.
LOADING JOBS
Then the job with the next highest priority is loaded on all required work centers, and so on.
This process is referred to as horizontal loading
Characteristics of High-Volume OperationsHigh-volume aka flow operations, like
automobiles, bread, gasoline can be repetitive or continuous
High-volume standard items; discrete or continuous with smaller profit margins
Designed for high efficiency and high utilizationHigh volume flow operations with fixed routingsBottlenecks are easily identifiedCommonly use line-balancing to design the process
around the required tasks
Low-volume, job shop operations, are designed for flexibility.
Use more general purpose equipment Customized products with higher margins Each product or service may have its own routing
(scheduling is much more difficult)Bottlenecks move around depending upon the products
being produced at any given time
Characteristics of Low-Volume Operations
What an Input-Output Process is?
It is a technique that allows operation personnel to manage facility work flows.
The idea of this process is to know how much work is carrying out in order to adjust it
to the objective.
The advantages of Input-Output Control
Identifies overloading and underloading conditions
Prompts managerial action to resolve scheduling problems
Can be maintained using ConWIP cards that control the scheduling of batches.
F.e. In the case we need 120 hours
IDENTIFY THE BEST CONDITION
UNDERLOADING OVERLOADING
50 HOURS
50 HOURS
50 HOURS
50 HOURS
50 HOURS
The work is arriving faster than it is being processed
Inefficiency
Quality problems
The work is lower than it is being processed
Idle capacity
Wasted Resources
AIRBUS COMPANY
Input-Output Exercise
1º Week 2º Week 3º Week 4º Week
Planned Input 200 200 200 200
Actual Input 160 230 210 200
C. Deviation -40 -10 0 -0
Planed Output 220 220 220 220
Actual Output 200 260 190 180
C. Deviation -20 -60 -30 +10
C. Change in BackLog
? ? ? ?
CarCar, Ltd is a car enterprise which desires to develop an Input-Output Control for the Wheels Department for 4 weeks. The time stipulated per week is 200 hours for the Input, for the Output is 220. The real Input-Output is between 150-260 hours per week.
How much is the Cumulative Change in BackLog? What does this result mean?
Input-Output Exercise
1º Week 2º Week 3º Week 4º Week
Planned Input 200 200 200 200
Actual Input 160 230 210 200
C. Deviation -40 -10 0 -0
Planed Output 220 220 220 220
Actual Output 200 260 190 180
C. Deviation -20 -60 -30 +10
C. Change in BackLog
-40 -70 -50 -30
CarCar, Ltd is a car enterprise wich desires to develop an Input-Output Control for the Wheels Department for 4 weeks. The time stipulated per week is 200 houres. The real Input-Output is between 150-210 hours per week.
The work is arriving faster than it is being processed, so it means bad qualities and inefficiency.
How can be the Input-Output improved?
Through Go-Look-See Management, being the process in which managers actively move around the business engaging with their teams, their products, and the processes they operate.
Go to the source, observe and deeply understand the actual situation for yourself.
Gantt ChartsDeveloped in the late 1800’s by Henry
GanttLoad charts illustrate the workload
relative to the capacity of a resource
It shows the use of resources such working centers and labor
It also shows today’s job schedule by employeeWhen used in loading, Gannt Charts show the
loading and idle times of several departments, machines or facilities.
The display the relative workloads in the system so that the manager knows what adjustments are appropriated.
If a work center comes overloaded employees from other a low-loaded center can be transferred temporarily to increase work force.
Versatile equipment may also be transferred among centers.
Gantt Charts
Gantt ChartsShows relative workload in facilityDisadvantages
Does not account for unexpected eventsMust be updated regularly
DayWork Center
Monday Tuesday Wednesday Thursday Friday
Metalworks Job 349 Job 350
Mechanical Job 349 Job 406
Electronics Job 408 Job 349
Painting Job 295 Job 408 Job 349
Processing
Unscheduled
Center not available (for example, maintenance time, repairs, shortages)
Description Decemb
erJanuary
February
March April May June July
A. Train Project Team
B. Project Management Paperwork
C. Modify Purchased Package
D. Manual systems Flow
E. Modify In-House Procedures
F. Test and Implement Modifications to Purchased Package
G. Test and Implement Manual Systems Flow
H. Test and Implement Modifications to In-House Procedrues
Gantt Charts Exercise Answer key
What an Assignment Method is? It is a method of allocating organizational resources.
The Assignment Method involves assigning task or jobs to the resources.
To avoid the subactivity.
Optimize Workload capacity balance.
What is the objective of this method?
Minimize Total Costs Minimize the time required Maximize the production
The characteristics of the Assignment Method
Just one job or work is assigned to one project or machine.
It is used for production allocation.It is called as well The Hungarian method is
a combinatorial optimization algorithm that solves the assignment problem in polynomial time and which anticipated later primal-dual methods.
Models
JOB Wheels Airbag Lights
Worker 1 30 hours 35 hours 25 hours
Worker 2 15 hours 20 hours 19 hours
Worker 3 10 hours 13 hours 11 hours
Assignment Method ExerciseThe CarCar, Ltd. Co. wants to start the year with the following project: Assign Wheels, Airbag, and Lights, looking for the one with lower opportunity cost.
W A LJob 1 5 10 0 2 0 5 4 3 0 3 1
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Step One - Rows¹
W A LJob 1 5 7 0 2 0 2 4 3 0 0 1
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Step Two – Columns²
Assignment Method Exercise
Create zero opportunity costs by repeatedly subtracting the lowest costs from each row¹ and column².
Models
JOB Wheels Airbag Lights
Worker 1 30 hours 35 hours 25 hours
Worker 2 15 hours 20 hours 19 hours
Worker 3 10 hours 13 hours 11 hours
W A LJob1 5 7 02 0 3 43 0 0 1
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Step Three – Lines
Because three lines is needed, the solution is optimal.
Draw the minimum number of vertical and horizontal lines necessary to cover all the zeros.
We take the Zeros to the Original Table
We repeat the creation of Zero opportunity Cost resting the low number outside the line to the other numbers.
Enough
Not enough
W A LJob1 5 7 02 0 3 43 0 0 1
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Step Four - Assignments ORIGINAL COST TABLE
WheelsAirbagLightsJobWorker 1 30 35 25Worker 2 15 20 19Woker 3 10 13 11
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MINIMUM COST: 25+15+13=53