BITS PILANI, HYDERABAD CAMPUS
Report Line of balance scheduling technique (lobst)
Course No. PHA G616
Course Title Pharmaceutical Administration & Management
Instructor-in-charge Dr. Akash Chaurasiya
Submitted by Kanchan sonawane(2017H1460158H)
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Introduction: PAGEREF _Toc529741549 h 2History: PAGEREF _Toc529741550 h 2Assumption and Key points in LOBST: PAGEREF _Toc529741551 h 2Application: PAGEREF _Toc529741552 h 3Advantage: PAGEREF _Toc529741553 h 3Procedure: PAGEREF _Toc529741554 h 3Case study 1: PAGEREF _Toc529741555 h 6Case study 2: PAGEREF _Toc529741556 h 6Conclusion: PAGEREF _Toc529741557 h 8Reference: PAGEREF _Toc529741558 h 8
TOC h z c “Figure” Figure 1:sequential steps for construction of LOBST charts PAGEREF _Toc529741531 h 4Figure 2:LOBST charts (a) lobst chart (b) activity chart (c) planning chart PAGEREF _Toc529741532 h 5Figure 3: LOBST chart with bar chart. PAGEREF _Toc529741533 h 5Figure 4:(A) The estimated line of balance(B) Dotted line actual line of balance PAGEREF _Toc529741534 h 6Figure 5: The estimated line of balance PAGEREF _Toc529741535 h 7Figure 6:LOBST chart for case 2 PAGEREF _Toc529741536 h 8
Line Of Balance Scheduling Technique (LOBST) or Repetitive Scheduling Method (RSM)
Introduction:The line of Balance Scheduling Technique (LOBST) is a linear scheduling technique that allows the balancing of the operations such in a way that each activity is continuously and efficiently performed for each consecutive unit.
A LOB Chart depicts the rate at which the work is done including all of the activities to stay on schedule. Charting of the production plan results from detailed study collectively by plant management, the process engineering staff, and other representatives.
In other words, the production rate of an activity is linear where time is plotted on one horizontal axis , and units/stages of an activity on the vertical axis.
History:The LOB Scheduling Technique was originated by the Goodyear Company in the early 1940’s and was developed by the U.S. Navy in the early1950’s for the programming and control of both repetitive and non-repetitive projects.
This scheduling is useful for the projects where delivery is not at one point of time but is spread over many intervals of time according to prior agreed schedule between manufacturer and customer e.g. batch of combat aircrafts, batch of computers.
Assumption and Key points in LOBST:It is for limited number of activities that are repetitive activities. working group is called team/crew/Gang. Default working week is of 5 working days per week and of 8working hour per day. The Rate of Construction of an activity is the slope of the production line and it has to keep constant (i.e. the lines of activities should be parallel).
In order to maintain the rate of Construction to be constant it has be provided with the needed crews- who can achieve this construction rate (line of balance).
The LOBST is based on the underlying assumption that the rate of production for an activity is uniform.
The production rate of an activity is the slope of the production line and is expressed in terms of units per time.
This method manipulates worker’s hour and the optimizes the sizes of crews to generate the LOB diagram.
Worker hour estimates and optimum crew sizes are usually obtained through direct interaction with a scheduler, the site manager, or related subcontractors who has enough knowledge that reflect the actual conditions of a project and of its constituent activities.
It does not show direct relationships between individual activities.
It shows an output relationship between the different operations in that one operation must be completed at a particular rate for the subsequent operation to proceed at the required rate.
The resources required will also be constant in ideal scenario.
The LOBST is based on the assumption that the rate of production for an activity is uniform.
LOB has been applied to resource scheduling of coordination of subcontractors, highway, pavement construction project, modeling production activities for multi?facility projects, transportation projects etc.
Advantage:The LOB technique offers following advantages:
It allows project managers to see, in the middle of a project, whether they can meet the schedule if they continue working as they have been.
It exposes process bottlenecks, allowing the project manager to focus on those points which are responsible for slippage.
It helps avoiding many hiring and procurement problems in issues related to the flow of labor and material used during construction.
This scheduling technique has the capability to ensure a smooth procession of crews from one unit to other with minimal conflicts and decrease idle time for workers and equipment.
The delivery information used and needed in a line of Balance analysis is of two kinds, planned and actual. (1) Planned-the contractual delivery requirement, (2) Actual-the delivery made by the producer to the time of the analysis. Planned delivery and actual delivery are always collected and plotted in cumulative terms of end item sets. The procedure followed is depicted in figure 1.
Accumulation of data: The plan should include the span of operations particular to manufacturing process like raw materials requirement and their timely shipment, assembly operation. Detailed examination, storing and categorizing of data supplied by the contractor. A tour should be made of the plant to observe the physical layout and the actual processes involved, as well as to observe the physical attributes of the operations.
The determination of the sequence of operations:
A general chronological determination of flow should be made at this stage concerning the approximate sequence and order in which these materials and subassembly groups flow into final assembly operations. This should then be consolidated onto a flow chart which will delineate the steps of the process in sequence.
The determination of processing and assembly lead time:
This step involves a determination of the total time interval, time between the required availability of raw material, purchased parts, manufactured parts, subassemblies and the date of shipment of the completed end item. This time is inclusive of required processing time and other aspects such as in-plant storage or handling time.
Chart construction: After determining the raw materials, parts, fabrication stages,
subassemblies and assemblies- sequence of operations and lead time information data is presented graphically in the following manner: The production plan or assembly tree is constructed by using a time scale in units commensurate with the overall lead time. The time scale is normally set down in working days rather than calendar days.
program progress chart construction:
once the work has been started the data is plotted on the same graph and necessary decision are taken for scheduling of further work plan.
Figure SEQ Figure * ARABIC 1: Sequential steps for construction of LOBST charts
Figure SEQ Figure * ARABIC 2:LOBST charts (a) lobst chart (b) activity chart (c) planning chart
Figure SEQ Figure * ARABIC 3: LOBST chart with bar chart.Case study 1:This case involves the construction of building with 4 floors – each activity is sequential and can be performed only after one is completed. – foundation -brickwork-roof construction and internal works. It is estimated that 4 floors can be constructed in 20 weeks’ time span according to resources available as showen in figure 4(a).
Figure SEQ Figure * ARABIC 4:(A) The estimated line of balance (B) Dotted line actual line of balanceIt was observed that the Foundation work was on schedule and almost complete but Brickwork and Roof Construction were running behind schedule. The Internal Works did not start but the anticipated rate of work was plotted on the chart and by extrapolation the first unit(floor) was expected to be completed 3 weeks late. This delay was corrected by increasing the output for the Brickwork and Roof Construction and the internal Works by either taking measures to increase efficiency or increasing the resources committed to the operation that were not achieving the correct output.
Case study 2:100-segment pipeline project and the process of planning and scheduling a realistic, feasible, and profitable work plan was needed.
For the 6 activity types they initially plan the following for a project with the same soil type:
Table SEQ Table * ARABIC 1: Activity distribution
Clearing and survey 5-man crew 1 segment/day 100 days
Trenching 3-man crew ¼ segment/day 400 days
Placing Bedding select material 3-man crew ½ segment/day 200 days
Laying pipe and connecting joints 6-man crew ½ segment/day 200 days
Hydraulic testing 2-man crew 4 segments/day 25 days
Backfill and grading 4-man crew 1/3 segment/day 300 days
Figure SEQ Figure * ARABIC 5: The estimated line of balanceAs showen in figure 5, the Project was taking almost 700 days, due to completion of Bedding and Laying Pipe until all of the trenching was done after 408 days and the start of testing delayed to 383 days with multiple crew interference. So, looking at the chart in figure 5 there could have been delayed in the start of a following crew until there was enough work for them to work without waiting for the prior crew to provide them work areas as they do not want to have activity crews standing idle waiting for the next work area.
This was achieved by delaying the start of trade crews to avoid overlapping prior crews so that they will not be waiting for the next segment’s work area.
• The Bedding work was delayed 200 days so that it finishes just after the trenching finishes.
• The Testing work was delayed 375 days so it does not finish before Laying Pipe finishes.
This was the Line-of-Balance or ‘Linear Scheduling’ constructed as showen in figure 6.
Whereas they thought the project was going to take 110 days, at 11 days/segment, by keeping the crews fully working once they start, it would have taken 684 days because the Backfill and Grading cannot start until the 1st segment is tested. Was this realistic!
From this starting point, a contractor after looking at the above Line-of-Balance chart instinctively looks at reducing the time of the trenching, thus 2 trenching crews could have to be mobilized thereby reducing the trenching time from 400 to 200 days.
If trenching was reduced to 200 days, then Bedding and Laying Pipe can be done without interruption because all 3 tasks are planned to work at the same space. Backfilling crews was also studied to see if their production improved.
Figure SEQ Figure * ARABIC 6:LOBST chart for case 2Conclusion:
A method of showing the repetitive work that may exist in a project as a single line on a graph shows the duration of a particular activity the rate at which the work that makes up all of the activities has to be undertaken to stay on schedule. This scheduling techniques helps the manager to be on schedule but realistically the rate of all activities can never be same.
Reference:1. Application of line of balance scheduling technique (LOBST) for a real estate sectorissn: 2278 – 7798 international journals of science, engineering and technology research (IJSETR) volume 2, issue 1, January 2013.
2. Line of balance for more white papers see: http://www.Mosaicprojects.Com.Au/whitepapers.Html3. Implementation of line-of-balance based scheduling and project control system in a large construction company by mika soini ilkka leskehi, olli seppanen.
4.Line of balance, a graphic method of technology office of naval material department of the navy reproduced by navexosp1851, clearinghouse for federal scientific ; technical informal.