Improvement blah blah blahRalph Julius Sumagaysay AgultoJerome Villavicencio BayocbocJohn Gareth Celemen GeronMark Kevin Rosales MercadoJose Martin Banzon Tuazon

Abstract

The large Panel Line of Lubbock plant’s demand is steadily increasing and they are producing a daily output of 1400 panels per day. Salvatore Petitto, Lubbock’s plant new plant manager increased the target capacity of the line by 50% to 300 panels per day.

After the issues regarding the problems due to the low output has been raised, the team of engineers from manufacturing, manufacturing engineering and production control has come up with each processes’ capacity data. Computations regarding the capacity and cycle time are needed to find the bottleneck which is restricting the line from producing well above their current daily output which will lead to increase their customer satisfaction by committing on time.

In conclusion, the line has a potential to increase their output based on the data gathered, and procoat’s capacity is restraining the system’s capacity as the bottleneck with 2737.8 panels per day. Other problems such as low staffing for procoat process has risen as the root causes of procoat’s low throughput.

Background

HAL, Inc. is a major manufacturer of computer and computer components. In their Lubbock, TX plant they make printed circuit boards (PCBs) also referred to as “panels”) which are used by other plants in the company in a variety of computer products. The plant makes two families of products: small and large panels. Both product families, go through the following sequence of manufacturing operations: Treater Process, Lamination-Core, Machining, Internal Circuitize, Optical Test and Repair-Internal, Lamination-Composites, External Circuitize, Optical Test and Repair-External, Drilling, Copper Plate, Pro-Coat, Sizing and End-of-the Line EOL test.

By 1990, the number of large panels increased and capacity was estimated by the Manufacturing Engineering to be more than 2000 panels per day, but a more typical daily output was around 1400 panels per day. Manufacturing cycle times has steadily grown over time and was averaging close to 34 days and customer service was running at about 50%.

Just prior to these events, HAL Corporation had begun promoting the use of just-in-time (JIT) concepts within its plants. Linda Brown was charged of implementing JIT in the Lubbock plant however, she was promoted to a position outside the Lubbock facility before any concrete plan has evolved. During these times, no attention at all was devoted to the Large Panel Line.

In the fourth quarter of 1990, Salvatorre Petitto took over the plant and convinced that the plants are producing below its capacity, he summarily increased the target capacity for the Large Panel Line by 50% to 3000 panels per day. Upon meeting with first line managers, different issues arise like perversion of the schedule by the Manufacturing Section, maintaining a 20-day frozen zone, machine downtime and accumulation of WIP, understaffed line managers, the claim of Manufacturing engineering Section of 3000 panels per day is unrealistic, difficulty in stabilization of processes and uneven demand placed on the Large Panel Line.

Since there are different claims on the plant capacity and other problems were revealed without consensus on solutions, the analysis will include the assessment of the current performance of the plant, identification of the most promising areas of leverage and general guidance on how to reshape the overall system.

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Problem Statement

Mr. Petitto is in need of the experts to evaluate and to give a solution to their plant’s falling performance and he specifically needs an assessment of the current performance of the plant,

identification of the most promising specific areas for leverage and general guidance in how to reshape the overall system of the plant.

Scope and Limitation

The study is focused only on the processes involve in making Large Panel Board. It is also limited to the data given by the company and the processes involve in making Large Panel Boards.

Problem Solving Methodology

A. Analysis

The capacity of the different processes involved in producing Large Panel PCB is the main key in solving the dilemma faced by the plant.

The data that were given by the plant is sufficient enough to get the actual rate of each process, setup time, non-value adding time and the availability of each machine per process.

B. Design

In identifying the bottleneck of the system, we use the sequential approach to bottleneck analysis. This analysis which is

specified in Figure 1 is the flow of decision in getting the bottleneck of the system.

After we can identify the bottleneck operation, we can now study the plant layout for improvements on move time. Rel chart is one technique used in finding departments which should be close to each other and rearranging the facility layout.

Step-by-Step Execution of Problem Solving

A. Identify the value

Capacity is often defined as the capability of an object, whether that is a machine, work centre or operator, to produce output for a specific time period, which can be an hour, a day, etc (1).

The capacity of each process can be computed through the cycle time for each. The total process time for each operation in this plant is the summation of the total time needed to produce one lot of panels, the

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Figure 1Sequential approach to bottleneck analysis

setup time for each lot and the non-bottleneck time for each operation, refer to (1).

Total processing time=Process time per lot of panels+setup time+non−bottleneck time (1)

The time to produce one lot of panels (or process time) can be calculated by dividing the lot size by the product of the base rate of each machine, number of machines, efficiency of each machine and the availability of each machine which is stated in (2), while the availability of the machine according to Barlow and Proschan [1975] is “the probability that the system is operating at a specified time t” is stated in (3).

Process time per lot of panels=lot ¿¿Baserate∗Efficiency∗¿ of machines∗Availability ¿(2)

Availability=MTTF /(MTTF−MTTR)(3)

The capacity of each process is measured in total panels produced per day per process. It can be derived through equation 1 multiplying it with the lot size per process, refer to (4).

Capacity per day per process=Process time per operat ion∗Lot ¿¿ (4)

By using these equations, we can now start to assess the plants current performance in terms of the processes’ cycle times and output per day.

B. Map the Value Stream

The value stream map of the current system is shown in Appendix A.

C. Create Flow

D. Establish Pull

Kanban is one of the Lean tools designed to reduce the idle time in a production process. Reducing WIP is also the target of the Kanban system. The processes gets the needed outputs from the previous process only when it is needed thus making the entire system leaner and eliminates production wastes.

The Kanban system will be placed in every process to sustain continuity in production

while decreasing inventory. The number of Kanban is computed using the equation (3)

¿of Kanban=(D∗L )+ sc

(3)

Where:D = DemandL = Lead TimeS = Safety StockC = Container size or Lot size to be processed by the machine

E. Seek Perfection

Results and Discussion

A. Capacity

The values generated using the equations are summarized in table 1. These values will help us determine the bottleneck using the sequential approach.

Table 1Total Panels produced per day in each operation

Stations Total panels produced (panels per

day)

Lamination-Cores 3079.310345

Machining 2426.248546

Internal Circuitize 799.279919

Op Test/Repair -Internal

1776.063728

Lamination - Composites

1553.709677

External Circuitize 787.7866654

Op Test/Repair -External

1776.063728

Drilling 1100.183741

Copper Plate 1950.602038

Procoat 409.263461

Sizing 1323.182143

End of Line Test 2276.405188

Procoat is the process that restricts the whole system to achieve the targets set based on number of panels produced per day with an average of 409.26 panels. We can now say that the large panel line can only produce 409.26 panels on the average per day because the system’s capacity is also equal to the process with the lowest capacity.

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B. Cycle time

Cycle times can be calculated as per stations and as the whole cycle time of the Large Panel Line. Table 2 summarizes the cycle time.

Cycle time is also one of the main factors for bottleneck in the line. Long cycle times means that an operation is taking longer and is restricting other operations.

Internal circuitize poses as the main factor for long cycle time with an average cycle time of 1.46 hours. The total cycle time for the line will be the summation of all cycle time in the operation. The computations are shown in Appendix B.

The computed values reveal that the bottleneck is the Pro-Coat section having a capacity of 409.263461 panels/day and the internal circuitize with a cycle time of 1.463817584 hours. Having computed this capacity, it can be said that the daily output of 1400 panels per day and the claim of the Manufacturing Engineering which estimated capacity to be greater than 2000 panels/day is somewhat not possible and unreachable for the current state of the line. This would also mean that the target of almost 3000 panels per day in the large panel line will not be attained.

Implementation Action Plan

Kumar (2012) emphasizes the fact that “the efficiency of production depends on how well the various machines, production facilities and employee’s amenities are located in a plant. Only the properly laid out plant can ensure the smooth and rapid movement of material, from the raw material stage to the

end product stage.” (2)

With this, plant layout is a very important decision the top management has to take into consideration. Kumar (2012) also defines an ideal plant layout as “providing the optimum relationship among output, floor area and manufacturing process”. But since the data provided was limited to the different sections of the plant only arranged as shown in the old layout in Appendix E and there are no dimensions given, the group came up with a Rel Chart to depict spatially the relationships of the activities (refer to Appendix C) so as to know what sections or departments must be close to each other. Based from the Rel Chart, the group came up with the proposed plant layout shown in Appendix F.

The proposed layout of the plant (refer to Appendix F) minimizes the move time form one operation to the other, thus minimizing the non-bottleneck time which will result in increase in operations capacity.

Cycle time of the bottleneck internal circuitize can be minimized by adding

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Table 2 Cycle time per operation

additional machines or stations for this operations. Additional 1 machine station for internal circuitize will decrease its cycle time

to 0.975878389 hrs.

Kanban system helps the bottleneck operation by not starving during the operations. Since the bottleneck operations are the critical part of the line, the group suggests putting a Kanban system before the bottleneck operation. In this way we can make sure that the operation doesn’t starve. Starving of the bottleneck can be caused by a large lot size that has to be processed by an upstream operation which is the internal circuitize. Computation for the needed number of Kanban is calculated in Appendix G.

Demand is the actual capacity of the bottleneck operation while the lead time will be the cycle time for the upstream operation right before the procoat. Since we can assume that there are no fluctuations in the total demand, we can say that the safety factor is equal to 1 and the Kanban size is equal to the lot size that procoat can produce at a time. The number of Kanban needed for the bottleneck operations is equal to 18 with a size of 60 panels each.

Other Recommendations

References

(1) Murray M., “Measuring Capacity in Manufacturing”. Retrieved August 23, 2012 from http://logistics.about.com/od/strategicsupplychain/a/Measuring_Capacity.htm

(2) Kumar, A., “Plant Location and Layout”. Retrieved August 25, 2012 from http://www.du.ac.in/fileadmin/DU/Academics/course_material/EP_07.pdf

(3) Barlow, R., Proschan, F., “Statistical theory of reliability and life testing: probability models” Retrieved August 27, 2012 from http://en.wikipedia.org/wiki/Availability

kulang pa ng value streamcreate flowseek perfectionresults and discussion (konti nalang)

implementation action plan (REL chart, facility layout, kanban)other recommendations (additional staffing?)

47,600 (average)/2737.843276 = 17 days (manufacturing cycle time)

yun palang 20-day frozen zone ay ok lang base dun sa computation naten ng capacity.

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