12) Sistem Produksi Berbasis Proyek [PDF]

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生産システム研究室



2003/12/10



Departemen Teknik Industri



TI3122 PERENCANAAN & PENGENDALIAN PRODUKSI



SISTEM PRODUKSI BERBASIS PROYEK Department of Industrial Engineering Institut Teknologi Bandung Jalan Ganesha 10, Bandung 40132



Departemen Teknik Industri



Definition Project can usually be defined as a series of related tasks directed toward a major output The characteristics of a project: ƒ It has a specific goal and deadline ƒ It is unique or somewhat unfamiliar to the existing work ƒ It contains complex interrelated tasks requiring specialized skills ƒ It is temporary but critical to the company



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生産システム研究室



2003/12/10



Departemen Teknik Industri



A hierarchical view of the project environment



•



.



Program 1



...



Program x



...



...



Program n



Project xm-1



Project x1



Project x2



Project xm



Task x21



Task x22



Task x23



...



Activity x221



Activity x222



Activity x223



...



Task x2p



Activity x22q



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Departemen Teknik Industri



A hierarchical view of the project environment



• • • •



Program: the term commonly used to denote very large and prolonged undertakings. Project: the term generally applied to timephased efforts of much smaller scope and duration than programs. Programs are some time viewed as consisting of a set of project Task: an elemental content of a project. A project is normally composed of contiguous arrays of tasks that all contribute to the overall project goal Activity: the atom of a project. Activities are smaller than tasks TI-3131 Perencanaan dan Pengendalian Produksi



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Project management (PM)



•



• • •



Project management (PM) is the process of managing, allocating, and timing resources in order to achieve a given objective in an expedient manner The objective may be in terms of time, monetary, or technical results PM is the process of achieving objectives by utilizing the combined capabilities of available resources PM represents a systematic execution of tasks needed to achieve project objectives 5



TI-3131 Perencanaan dan Pengendalian Produksi



Departemen Teknik Industri



Planning Scheduling



Organizing



Training Optimization



Project management



Risk management



Contract management



Cost control



Resource management



Software tools



Project design Performance control



Multidimensionality of project management TI-3131 Perencanaan dan Pengendalian Produksi



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Project management (PM)



• PM covers the following basic functions: Planning, •



•



Organizing, Scheduling and Control Project planning provides the basis for the initiation, implementation, and termination of a project. It sets guidelines for specific project objectives, project structure, tasks, milestones, personnel, cost, equipment, performance, and problem resolutions Project organization specifies how to integrate the functions of the personnel involved in a project. Directing (which involves guiding and supervising the project personnel) is an important aspect of project organization



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Departemen Teknik Industri



Project management (PM) • Project scheduling is the time phased arrangement of



project activities subject to precedence, time, and resource constraints in order to accomplish project objectives. It is often the core of project management efforts because it involves the assignment of time periods to specific tasks within the work schedule



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Project Planning 1. Setting goals 2. Defining the project 3. Tying needs into timed project activities 4. Orginizing the team



Tools Time and cost estimates Budget, Cash flow Personnel Material ability Engineering diagram



Project scheduling 1. Tying resources (people, money, supplies) to specific activities 2. Relating activities to each other 3. Updating and revising on regular basis



Tools Gantt Chart, CPM, PERT Cash flow schedules



Project controlling 1. Monitoring resource, costs, quality, budgets 2. Revising and changing plans 3. Shifting resources to meet time, cost, and quality demands



Before project



Tools PERT charts Reports describing 1. budget by department 2. delayed activities 3. slack activities 4.quality of work completed



During project Start of the project



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Departemen Teknik Industri



The project of manufacturing • In a large organization, the manufacturing system may be configured as a multi-project endeavor



• The following figure shows the typical components of a •



manufacturing enterprise organized as a project The project starts with a conceptualization of a product and needs some of distinct tasks for getting the product to the market



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Systems integration Market survey Process planning



Idea



Feasibility study



Cost



Quality specs



Training



Financing



Operations planning



Production



Schedule



Facilities Technology assessment TI-3131 Perencanaan dan Pengendalian Produksi



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Departemen Teknik Industri



Project Management Technique:



1. Critical path method (CPM) was developed in 1957 by J.E. Kelly of Remington Rand and M.R. Walker of duPont



2. Program Evaluation and review technique (PERT) was developed in 1958 by the Navy with Booz, Allen and Hamilton



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生産システム研究室



2003/12/10



Departemen Teknik Industri



The framework of CPM and PERT Basic steps: • Define the project and all its significant tasks or activities • Develop the relationship among the activities. Decide which activities must precede and which must follow others • Draw the network connecting all of the activities • Assign time and cost estimates and required resources to each activity • Compute the longest time path through the network. This is called the critical path • Use the network to help plan, schedule, monitor and control the project TI-3131 Perencanaan dan Pengendalian Produksi



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Departemen Teknik Industri



The questions answered by CPM or PERT



• • • • •



When will the entire project be completed? What are the critical activities in the project, that is, the ones that will delay the entire project if they are late? Which are the noncritical activities, that is, the ones that can run late without delaying the whole project’s completion? What is the probability that the project will be completed by a specific date? At any particular date, is the project on schedule, behind schedule, or ahead of schedule? TI-3131 Perencanaan dan Pengendalian Produksi



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生産システム研究室



2003/12/10



Departemen Teknik Industri



The questions answered by CPM or PERT • On any given date, is the money spent equal to, less than, • •



or greater than the budgeted amount? Are there enough resources available to finish the project on time? If the project is to be finished in a shorter amount of time, what is the best way to accomplish this at the least cost?



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Departemen Teknik Industri



Conventions



• •



Activities: a task that occurs between 2 events Event arrows and nodes



•



Activity-on-Arrow (AOA) Arrows are used to represent activities, while nodes represent starting and ending points of activities



•



Activity-on-Node (AON) Nodes represent activities, while arrows represent precedence relationships TI-3131 Perencanaan dan Pengendalian Produksi



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Convention .



Name and Symbol



Description A point in time, usually a completion date or a starting date



Event (node)



An activity or a certain amount of work required in the project



Activity (arrow)



Activity A Event 1



Activity B Event 2



Event 3



(network) A sequence of activities with beginning and ending events TI-3131 Perencanaan dan Pengendalian Produksi



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Departemen Teknik Industri



Example 1 Activity A B C D



Immediate predecessor A B



2 C



A 1



4 B



D 3



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Example 2 Beginning event 1 1 2 3 3 4 5



Ending event 2 3 4 4 5 6 6



Activity 1-2 1-3 2-4 3-4 3-5 4-6 5-6



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TI-3131 Perencanaan dan Pengendalian Produksi



Departemen Teknik Industri



Example 2 .



2



4



6



1



3



5



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Example 3 Activity A B C D E F G H



Immediate Predecessor(s) A B C, D D E F



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Departemen Teknik Industri



Example 3 .



2



5



A



C



G



E



1



7



4 B



F



D



H 6



3 E



C Dummy



2



5 G



A Dummy activity



1



7



B



C 3



4 D



6 F



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Critical Path Method (CPM) CPM is to determine the following quantities for each activity • ES: Earliest start time. All predecessor activities must be completed before an activity can be started. The ending time of the predecessor activities is the earliest time an activity can be started • LS: Latest start time. All successor activities must be completed without delaying the entire project This is the latest time an activity can be started without delaying the entire project • EF: Earliest finish. EF=ES+t • LF: Latest finish. LF=LS+t



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Departemen Teknik Industri



Critical Path Method (CPM)



• •



TS: Total slack time. TS is the amount of time an activity may be delayed from its ES without delaying the latest completion of the project. TS=LS-ES or TS=LF-EF FS: Free slack time. FS is the amount of time an activity may be delayed from its ES without delaying the starting time of any of its immediate successors



⎫ ⎧ FS ( j ) = Min ⎨ ES (i ) ⎬ − EF ( j ) ⎩ i∈S ( j ) ⎭



S(j): immediate successors of activity j TI-3131 Perencanaan dan Pengendalian Produksi



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Critical Path Method (CPM) • The critical path is the group of activities in the project that



•



have a total slack time of zero. This path is critical because a delay in any activity along this path would delay the entire project The total project completion time is calculated by adding the time values of those activities on the critical path



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Departemen Teknik Industri



Example 4 Activity 1-2 1-3 2-3 2-4 3-4



Duration 2 7 4 3 2



2 3



2 4



1 7



4



2 3



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Example 4 .



ES, EF



2 3



LS, LF



2



6



6



2



2



1



3



2



3 2 9



0



9 4



0



1



5



0



0



4



9



0



6 7



7



9 9



7



7



2



7 7



7



3 9



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TI-3131 Perencanaan dan Pengendalian Produksi



Departemen Teknik Industri



Example 4 Activity Duration 1-2 2 1-3 7 2-3 4 2-4 3 3-4 2



ES 0 0 2 2 7



EF 2 7 6 5 9



LS 1 0 3 6 7



LF



TS 3 7 7 9 9



1 0 1 4 0



• Determine free slack times for the respective activities.



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Program Evaluation and Review Technique (PERT) One distinguishing PERT and CPM is the use of 3 activities time estimates for each activity in the PERT technique. Only one time factor is given for each activity in CPM. The time estimates are: a=optimistic time b=pessimistic time m=most likely time te=expected time v=variance of activity completion time



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Departemen Teknik Industri



Program Evaluation and Review Technique (PERT) • The expected time of completion time for activity i a +of4completion m+b • The variance time for activity i te = 6



• The variance of project completion time 2 ⎛b−a⎞ vi = ⎜ ⎟ ⎝ 6 ⎠ V=



∑v



i i∈critical path



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Program Evaluation and Review Technique (PERT)



Activity 1-2 1-3 2-4 3-4



a 3 1 5 6



m 4 3 6 7



5 5 7 8



tb



v



4 3



1/9 4/9



6



1/9



7



1/9



If the expected project completion time is 20 weeks and the project variance is 100 weeks, what is the probability that the project will be Perencanaan dan Pengendalian Produksi finished on orTI-3131 before Week 25?



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Departemen Teknik Industri



Gantt chart • When the results of a CPM/PERT analysis are fitted to a calendar time, the project plan becomes a schedule



• The Gantt chart showing planned (or actual) progress of • •



activities is one of the most widely used tools for presenting the schedule The horizontal axis indicates the time scale The horizontal bars/lines represent activities



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Gantt chart .



Activity Duration W1 W2 W3 W4 W5 W6 W7 W8 W9 1-2



2 weeks



1-3



7 weeks



2-3



4 weeks



2-4



3 weeks



3-4



2 weeks



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TI-3131 Perencanaan dan Pengendalian Produksi



Departemen Teknik Industri



Gantt chart The basic Gantt chart does not show the precedence relationships among activities but it can be modified by linking appropriate lines



Activity



Duration



A



2 weeks



B



7 weeks



C



4 weeks



D



3 weeks



E



2 weeks



W1



W2



W3



W4



W5



W6



W7



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W8



W9



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Crashing



• • •



•



Additional resources can reduce activity time for certain activity within the project Although it can be expensive to shorten activity times, doing so might be worthwhile The questions are: ƒ What activities should be shortened? ƒ How much will this action cost? ƒ Will a reduction in the activity time in turn reduce the time needed to complete the entire project?



The least expensive method of shortening the entire project should be determined TI-3131 Perencanaan dan Pengendalian Produksi



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Departemen Teknik Industri



Cost-time Curves



Cost



Time



Cost



8 weeks 7 weeks 6 weeks



$300 $400 $600



$500



Y-Axis



$600



$400



$300



6 days



7 days



X-Axis 8 days



Time (weeks)



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Cost of reducing activity time • The objective is to reduce the entire project completion •



time by a certain amount at the least cost If Mi = maximum reduction of time for activity i Ci= additional cost associated with reducing activity time for activity i C Ki= cost of reducing activity time by one time unit K = M for activity i i



i



i



Ki =



Ci Mi 37



TI-3131 Perencanaan dan Pengendalian Produksi



Departemen Teknik Industri



Determining the least cost Activity 1-2 1-3 2-3 2-4 3-4



Duration 2 7 4 3 2



M 1 4 2 2 1



C K $300 $2000 $2000 $4000 $2000



$300 $500 $1000 $2000 $2000



Critical No Yes No No Yes



Min



2 3



2 4



1 7



4



2 3



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生産システム研究室



2003/12/10



Departemen Teknik Industri



Determining the least cost Activity 1-3 is to be shortened by 1 week in order to reduce the project completion time to 8 weeks Note that any further reduction in activity time along the critical path would cause the critical path to include activities 1-2, 2-3 and 3-4.



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Further Readings • Badiru, A.B., 1996, Project management in manufacturing •



and high technology operations, John Wiley and Sons, Inc., New York Heizer, J. and Render, B., 1996, Production and operations management, Prentice Hall International Editions, New Jersey



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