JOHNSON ELECTRIC DC MOTOR CG105-60001 LINE BALANCING PROJECT REPORT Prepared for: Dr. Adnan Hassan Prepared by: Zoran Arputheselaan (MMN131021), Aneel Raj (MKM141047) & Muhammad Shahmi Bin Marsahid (MKM141025)

PRODUCTION OPERATIONS MANAGEMENT(MMN1113)

INTRODUCTION

Project Background Title of this project is Johnson Electric DC Motor CG605-60001 Line Balancing Project. It is a study

to improve the cycle time of each of workstations and to reduce bottleneck that will affect the output capacity. By reducing the bottleneck, labour efficiency can be increased which will affect to the lower operation cost and increase the line capacity and also achieving demand. In other words, total productivity can be increase due to constant input but increase in output. This is the key performance indicator to a manufacturing company that shows their performance and ability to meet customer expectations.

Layout decision is an important concept that need to be look at. Decision to setup a production layout in a manufacturing company need to consider on the space availability, equipment to be installed, headcount required, material movement and the product itself. The layout determined the capability and efficiency of a company in a long run. The objectives of layout strategies are to develop an effective and efficient layout so that meet customer demand and aligned with the business scope and requirement. There are many types of layout such as office layout, retail layout, warehouse layout, fixed-position layout, process-oriented layout, work-cell layout and product oriented layout.

Repetitive or product oriented layout was applied to the production line of the Johnson Electric DC motor due to high volume of demand and low product variety. There are two types of product oriented layout which is fabrication lines and assembly line. Our project is related on assembly line that having series of work stations. Problem occurs when the demand increase while the output cannot meet the demand even though based on calculation of the TAKT time, the line have the capability to meet them. Hence, problem found that the cycle time of some work stations is exceeding the TAKT time, which shows there is opportunity of improvement.

Even though the product oriented layout is suitable for high volume of output, there is some disadvantages of this layout: 1. Less in flexibility when to handle variety of production rates. 2. This layout required high investment to establish the process. 3. Any issue on the particular work station can affect the whole production rate or line jerk.

COMPANY NAME

Problem Statement In conjunction of achieving efficiency in manufacturing operation to have higher return with maintain or reducing the fixed and variable cost, analysing and segregating the assignment of tasks is being focussed. The workload or task need to be levelled to remove bottleneck and increase the line capacity. Line balancing was implemented to have better and balance of cycle time so that it not exceed the TAKT time. There is some problem faced on doing the line balancing on this project and the constraint is as below.

1. Unable to disclose real time data due to data confidentiality of the organisation 2. Current layout is in a repetitive straight line with a shortage of 2 operators making the time study collection data hard. This assumption will be modelled during the analysis phase.

Objectives There is some objectives that need to achieved on executing the line balancing project for Johnson Electric DC Motor. The objectives are as below: 1. To improve the process of Johnson Electric DC Motor production line 2. To increase the line efficiency 3. To reduce the bottleneck of the production line

Project Scope The project scope for this line balancing project is to purpose and introducing line balancing process in the manufacturing process of the Johnson Electric DC Motor CG605-60001. This project will improve the output of the production line and balance the segregation of the process so that bottleneck can be reduced.

COMPANY NAME

LITERATURE REVIEW

Line Balancing means balancing the production line, or any assembly line. The main objective of line balancing is to distribute the task evenly over the work station so that idle time of man of machine can be minimized. Line balancing aims at grouping the facilities or workers in an efficient pattern in order to obtain an optimum or most efficient balance of the capacities and flows of the production or assembly processes.

Assembly Line Balancing (ALB) is the term commonly used to refer to the decision process of assigning tasks to workstations in a serial production system. The task consists of elemental operations required to convert raw material in to finished goods. Line Balancing is a classic Operations Research optimization technique which has significant industrial importance in lean system. The concept of mass production essentially involves the Line Balancing in assembly of identical or interchangeable parts or components into the final product in various stages at different workstations. With the improvement in knowledge, the refinement in the application of line balancing procedure is also a must. Task allocation of each worker was achieved by assembly line balancing to increase an assembly efficiency and productivity.

I. Line Balancing Line Balancing is leveling the workload across all processes in a cell or value stream to remove bottlenecks and excess capacity. A constraint slows the process down and results if waiting for downstream operations and excess capacity results in waiting and absorption of fixed cost.

II. Single-Model Assembly Line In early times assembly lines were used in high level production of a single product. But now the products will attract customers without any difference and allows the profitable utilization of Assembly Lines. An advanced technology of production which enables the automated setup of operations and it is negotiated time and money. Once the product is assembled in the same line and it wont variant the setup or significant setup and its time that is used, this assembly system is called as Single Model Line. C Merengo, F Nava, A Pozzetti (1999)

III. Mixed Model Assembly Line In this model the setup time between the models would be decreased sufficiently and enough to be ignored. So this internal mixed model determines the assembled on the same line. And the type of assembly line in which workers work in different models of a product in the same assembly line is called Mixed Assembly Line.

IV. Multi Model Assembly Line In this model the uniformity of the assembled products and the production system is not that much sufficient to accept the enabling of the product and the production levels. To reduce the time and money this assembly

is arranged in batches, and this allows the short term lot-sizing issues which made in groups of the models to batches and the result will be on the assembly levels.

V. Non Value Added Costs a. Cost from Overproduction Production costs money. There is no need to produce such products which cannot be sold. This is the most deceptive waste in todays time and resources utilization is to be maximized. Overproduction includes making more than what is required and making products earlier than required.

b. Excess Inventory Cost Higher inventory cost is not beneficial for any company in todays variable demand business climate. Costs which are associated with the inventory are space, obsolescence, damage, opportunity cost, lagged defect detection and handling. In the case of obsolete inventory, all costs invested in the production of a part are wasted. Excessive inventory should be eliminated.

c. Processing Cost Efforts that add no value to the desired product from a customers point of view are considered as non-value added processing. Non value added operations should be eliminated. Vague picture of customer requirements, communication flaws, inappropriate material or machine selection for the production are the reasons behind this type of waste.

d. Defective Products Companies give much emphasis on defects reduction. However defects still remain the major contributors towards the non-value added cost. Cost associated with this is quality and inspection expenditure, service to the customer, warranty cost and loss of customer fidelity.

e. Transportation Cost Cost associated with material movement is a significant factor in the non-value added cost function. In a well-designed system work and storage areas should be near to its point of use. This consumes huge capital investment in terms of equipment required for material movement, storage devices, and systems for material tracking. Transportation does not add value towards the final product.

f. Motion Any motion that does not add value to the product or service comes under non-value added cost. Motion consumes time and energy and includes man or machine movement. Time spent by the operators looking for a tool, extra product handling and heavy conveyor usage are the typical example of the motion waste.

g. Waiting If line is not properly balanced and inappropriate material flow selection are the reasons behind waiting time. The time spent on waiting for raw material, the job from the preceding work station, machine down-time, and the operator engaged in other operations and schedules are the major contributors in the waiting time.

VI. Terms In Line Balancing Technique i. Cycle Time Cycle time is the Maximum amount of time allowed at each station. This can be found by dividing required units to production time available per day. Waldemar Grzechca (2011)

ii. Lead Time Summation of production times along the assembly line.

iii. Bottleneck Delay in transmission that slow down the production rate. This can be overcome by balancing the line.

iv. Precedence It can be represented by nodes or graph. In assembly line the products have to obey this rule. The product cant be move to the next station if it doesnt complete at the previous station. The products flow from one station to the other station, M E Salveson I (1995). A typical precedence diagram is mentioned in Fig.4 below to represent the activities.

Figure 4: Example of Precedence Diagram

v. Idle Time Idle time is the time specified as period when system is not in use but is fully functional at desired parameters.

vi. Productivity Define as ratio of output over input. Productivity is depends on several factors such as workers skills, jobs method and machine used.

RESEARCH METHODOLOGY

Eciency The efficiency of an assembly line can be determined via :

Using this efficiency formula, a firm can determine the sensitivity of the line to changes in production rate and workstation assignments

Steps in Performing Line Balancing

Step 1

Specify the sequential relationships among tasks using a precedence diagram. The diagram consists of circles and arrows. Circles represent individual tasks; arrows indicate the order of task performance.

Step 2

Determine the required cycle time (C), using the formula:

Step 3

Determine the theoretical minimum number of workstations (Nt) required to satisfy the cycle time constraint using the formula:

Step 4

Select the following heuristics rules as primary and secondary rules to assign the tasks to workstations, As defined by (Heizer, Jay , 2014) :

Step 5

Assign tasks, one at a time, to the first workstation until the sum of the task times is equal to the cycle time, or no other tasks are feasible because of time or sequence restrictions. Repeat the process for Workstation 2, Workstation 3, and so on, until all tasks are assigned.

Step 6

Evaluate the efficiency of the balance derived using the formula:

Step 7

If efficiency is unsatisfactory, rebalance using a different decision rule. The decision rules can be suggested as follows:

Rules Definition

Longest Task (Operation) time From the available tasks, choose the task with the longest processing time

Most following tasks From the available tasks, choose the task with the largest number of following taks.

Ranked positional weight From the available tasks, choose the task for which the sum of the times for each following task is longest.

Shortest task (Operation) time From the available tasks, choose the task with the shortest task time.

Least number of following tasks From the available tasks, choose the task with the least number of subsequent tasks.

1. Split the task2. Share the task3. Use a more skilled worker 4. Work Overtime5. Redesign the production line and production sequences

There are situations whereby the accumulated amount of the newly revised workstation is more than the calculated cycle times, in these cases, there is really no choice but to rebalance using the rules from No.1 to No.5.as stated above.

In Summary : Steps Involved in Assembly Line Balancing 1. Draw the precedence diagram 2. Determine the required cycle time (c) 3. C=(Production time/day) /Output per day (in units) 4. Determine the theoretical no of work stations (Nt = Sum of the task times/cycle time) 5. Select a rule which tasks are to be assigned to work stations and a secondary rule to break the ties. 6. Efficiency = Sum of the tasks times/[ actual no of workstations x Cycle time ]

DATA COLLECTION

The DC Motor Johsons CG105-60001 motor is a two stage stepper motor that is being used for major electrical appliances that are in the market now. This is due to the modular design of the motor using shared components withs its predecessor motors.

Parts List derived from complete assembly BOM

Element Qty Description

1 1 Motor Housing

2 1 Self Align Bushing

3 1 Magnet

4 1 Magnet Holder

5 1 Magnet Spring

6 1 Steel Shaft

7 1 Spacer & Washer

8 1 Winding Magnet Wire

9 1 Silicon Steel Lamination Stack

10 1 Commutator

11 1 Washer & Slinger

12 1 Sleeve Bushing

13 1 Carbon Brush

14 1 Terminal

15 1 Brush Spring

16 1 Brush Holder

17 1 Metal Endcap

A time study was conducted to collect the time needed for each process that is in the assembly line. The time was recorded using a time study template & a digital stop watch as per the picture below :

Elements Work Element Description Seconds Minutes Preceded By

1 Load 1 2 0.0333333333333333 -

2 Grease inside 1 45 0.75 1

3 Place 2 in 1 10 0.166666666666667 2

4 Place 4 & 5 in 3 8 0.133333333333333 3

5 Load 6 into 8 27 0.45 4

6 Load 7 into 6 & 8 7 0.116666666666667 5

7 Load 10 & 11 25 0.416666666666667 6

8 Load 10 & 11 into 6 & 8 7 0.116666666666667 7

9 Wrap 9 around 6 & 8 5 0.0833333333333333 -

10 Load 15 into 13 41 0.683333333333333 3

11 Load 15 & 13 into 6 & 8 5 0.0833333333333333 10

12 Load 16 into 15 & 13 10 0.166666666666667 8,11

13 Load 16,15,13 into 6&8 50 0.833333333333333 12

14 Combine 4&5 , 15&16 10 0.166666666666667 13

15 Combine 4,5,15,16,17 into 6&8 3 0.05 14

Total Task Time 4.25

Precedence Diagram

The precedence diagram for the current manufacturing line is as below :

RESULTS & DATA ANALYSIS Cycle Time Assuming we need 100,00 units per year, the plant operates at 50weeks/yr, 5days/week and 8hrs/day, our production rate an hour is:

Production rate = 100000 / (50)(5)(8) = 50 units/hr Based on work element table:

Total Task Time = 4.25min

this mean each worker can produce one unit of motor within 4.25 min. In other words this is the worker cycle time. Our theoretical cycle time based on the formula is :

Cycle Time= (8x60)/400=1.2mins

Min Num of Workstations To calculate the min um of workstation we need the total time for all tasks :

Total Time = 4.2503

Cycle Time= (8x60)/400=1.2mins

Min Num of Workstation = 4.2503/1.2 =3.54 or 4 stations.

The minimum number of workstation value will help us in providing the key criteria when improved line balancing is done.Based on the 8 heuristics of line balancing , we have to group the current line into 3 substations whereby the line will be equally balanced.

Longest Task Time In this rule, we have realigned the work elements in descending order according to their task times values as presented below with the compilation of each workstation not exceeding the Cycle Time which is 1.2mins or 72 seconds.

The idle time was calculated :

1. Station 1 - 1 sec

2. Station 2 - 3 sec

3. Station 3 - 0 sec (Bottleneck Station)

New Proposed Layout Circle layout was proposed.

Elements Seconds Preceded By Stat No Total Time

13 50 12

1 6514 10 13

15 3 14

1 2 -

2 45 1

2 633 10 2

4 8 3

5 27 4

3 666 7 5

7 25 6

8 7 7

9 5 -

4 6110 41 3

11 5 10

12 10 8,11

Eciency

Efficiency is calculated as : 4.25/(4x1.1)= 96%

Station 1

Station 2

Station 3

Station 4

In

Out

Rank Positional Weight

The ranked positional weight method used and computed for each element. From the list of tasks, we need to choose the task for which the sum of times for each following task is longest.

Elements Seconds Preceded By Stat No Total Time

1 2 -

1 652 45 1

3 10 2

4 8 3

5 27 4

2 666 7 5

7 25 6

8 7 7

3 619 5 -

10 41 3

11 5 10

12 10 8,11

4 6313 50 12

14 10 13

15 3 14

New Proposed Layout

Since circle layout was used previously, we have used a straight line layout for this instead.

Eciency Efficiency is calculated as : 4.25/(4x1.1)= 96%

CONCLUSION

This study proposed three facilities designs in which the Johnson Motors DC Motor is to be assembled. Moreover the author developed two assembly line processing layouts following the single straight line, & circle processing Rank Positional Weight & Longest Task time respectively.

It ultimates the rate of production in the two approaches .This is to determine which layout can provide better performance .The best layout of product found is the line stations is both for RPW & LTT method. Both the layouts gives an efficiency of 96%. But the author will strongly suggest the implementation of the circle layout due to its advantages over a straight line layout.

Station 1 Station 2 Station 3 Station 4In Out

REFERENCES

1. C Merengo, F Nava, A Pozzetti Balancing and sequencing manual mixed-model assembly lines International Journal of Production Research 37 (12) pp. 2835-2860.(1999).

2. Waldemar Grzechca Cycle Time in Assembly Line Balancing Problem journal of industrial engineering, pp. 171-174,(2011).

3. M E Salveson The assembly line balancing problem Journal of Industrial Engineering Volume: 6, Issue: 3, pp. 18-25,(1995).