Time Study on Winding of Bobbin for Automotive Relays in Assembly Line

IJSTE - International Journal of Science Technology & Engineering | Volume 3 | Issue 07 | January 2017 ISSN (online): 2349-784X

Time Study on Winding of Bobbin for Automotive Relays in Assembly Line Sajeeb Rahiman A.H. Associate Professor Muthoot institute of Technology and Science, Kerala, India

Alvin Thariyath Assistant Professor Muthoot institute of Technology and Science, Kerala, India

Vinay V.N Assistant Professor Muthoot institute of Technology and Science, Kerala, India

Arun Kappen Assistant Professor Muthoot institute of Technology and Science, Kerala, India

Mathew Prince Korah Assistant Professor Muthoot institute of Technology and Science, Kerala, India

Abstract The aim of the study is to propose a new method for winding of bobbin for automotive relays in the assembly line so as to increase productivity. The paper includes discussion of motion and time study implementation and its influence towards productivity improvement. The existing method is broken down into elements and analyzed in detail with the outline process chart and flow chart. The standard time is established with the time study procedures. A new method is suggested for the process.

The proposed method and original method is compared with process flow chart. The better standard time for the proposed method is established with the time study which increases the annual productivity by 6.7%.

Keywords: Motion and Time Study Analysis, Productivity Improvement, Outline Process Chart and Flow Chart, Standard Time, Winding of Bobbin ________________________________________________________________________________________________________ I.

INTRODUCTION

Work study is the systematic evaluation of the methods of performing activities so as to improve the effective use of resources and to set-up standards of performance for the activities being carried out. It is one of the most powerful tools that management can use to improve productivity [1]. Different work study techniques are ergonomics, operations research, work study and timeand motion study.

Motion and time study is defined as a scientific and systematic analysis method designed to determine the best way to execute the repetitive task and to measure the time spent by an average worker to complete a given task in a fixed workplace [2].

The components of relay include bobbin, coil terminal, winding wire, yoke, core, moving spring and contact, NO/NC terminal, base, armature, base plate, cover and actuator. The operation selected is winding of coil in the bobbin in the winding machine which is performed in the assembly department.

The procedure for time study can best be described step-wise, which are self-explanatory.  Step 1: Defining the objective of the study.  Step 2: Ensuring whether the standard method and conditions exist for the operation and the operator is properly trained.  Step 3: Selecting the operator to be studied when more than one operator is doing the same task.  Step 4: Recording the information on standard method, operation, operator, product, equipment, and conditions on the Time Study observation sheet.  Step 5: Dividing the operations into reasonably small elements, and record them on the Time Study observation sheet.  Step 6: Collecting and recording the data of required number of cycles by timing and rating the operator.  Step 7: Calculating the representative watch time for each element of operation. Normal time is obtained by multiplying it the representative watch time with the rating factor..  Normal time = Observed time x rating factor  Calculate the normal time for the whole operation by adding the normal time of its various elements.  Step 8: Add suitable allowances for fatigue and various delays.  Step 9: Determining the standard time of operation.

Standard time = Normal time + allowances

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Time Study on Winding of Bobbin for Automotive Relays in Assembly Line (IJSTE/ Volume 3 / Issue 07 / 010)

Symbol

Transportation Inspection

Table – 1 Symbols and operations Activities Represented Modification of object at one work place. Object may be changed in any of its physical or chemical characteristics, assembled or dissembled, or arranged for another operation, transportation, inspection or storage.

Change in location of object from one place to another.

Examination of object on check on quality or quantity characteristics.

Delay

Retention of object in a location awaiting next activity. No authorization is required to perform the next activity.

Storage

Retention of object in location in which it is protected against unauthorized removal.

Name Operation

II. RESULTS AND DISCUSSION The first step in productivity improvement methodology was the present work study. The process mapping is carried out to analyze the sequence of activities involved in the process during actual working. Flow process charts are used to identify the current methods followed. Time studies were then carried out and the data obtained was analyzed to establish production standards.

As the first step for time study each operation was broken into definite number of elements, which are not large or too short in time. Then an average cooperative operator is identified.

The operation selected, which is winding of coil in the bobbin in the winding machine is broken down into seven elements as: 1) Take out the bobbin from the mandrels and place it on the tray.

2) Insert new bobbins and wound the wire on the bobbin, hook the winding wire on mandrels and start the machine.

3) Winding in the machine.

4) Spool changing.

5) Take the bobbin from the store.

6) Reject the unwanted winding wire from the finished spool.

7) Take the process card and fill After suitably breaking down the process to elements, as the next step to analyze the elements in detail an outline process chart is drawn. The chart also indicates the time of each element in minutes.

Fig. 1: Outline process chart

The outline process chart is followed by a flow process chart. The chart is used to analyze the process elementally in detail.

Table - 2 Process flow chart 1

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Time Study on Winding of Bobbin for Automotive Relays in Assembly Line (IJSTE/ Volume 3 / Issue 07 / 010)

The next step is to conduct the actual time study and record the details in the time study work sheet.

A digital stopwatch is used to obtain the time required for the operator to perform each and every job elements. The time taken is recorded in the time study sheets. The stopwatch time study is used to analyze the process by qualified worker in an effort to find the most efficient ways in terms of time. The process of observing the operator performing the task and recording the time taken for each element is continued for several cycles.

4.71 Cycle No 1 2 3 4 5 6 7 8 9 10 Total Avg. Rating NT

Element 1

Table – 3 Time study work sheet 1 - original method Element 2 Element 3 Element 4 Element 5

WT

WT

OT

4.87 0.16 5.55 0.18 6.23 0.18 6.85 0.16 7.49 0.15 8.14 0.18 8.81 0.18 9.47 0.17 10.12 0.18 10.78 0.18 1.72 0.172 100 0.172

OT

5.1 0.23 5.78 0.23 6.42 0.19 7.07 0.22 7.69 0.2 8.36 0.22 9.03 0.22 9.67 0.2 10.33 0.21 11 0.22 2.14 0.214 90 0.193

WT

OT

5.37 0.27 6.05 0.27 6.69 0.27 7.34 0.27 7.96 0.27 8.63 0.27 9.3 0.27 9.94 0.27 10.6 0.27 11.27 0.27 2.7 0.27 100 0.27

Element 6

Eelement 7

WT

OT

WT

OT

WT

OT

WT

OT

13.27

2

13.82

0.55

14.82

1

15.22

0.4

2

0.55

1

0.4

The time taken to perform each element of the processes recorded in the time study work sheet. Then proper allowances are assigned. (e. g. Allow time for necessary but non-productive activities, such as rest, cleaning eyeglasses, etc.) Appropriate work standards are determined, so as to calculate the standard time of operation.

No 1 2 3 4 5 6 7

Table – 4 Time study work sheet 2 - original method Elements NT Frequency Take out the bobbin from the mandrels 0.172 0.172/4 Insert new bobbins and wound winding wire on bobbin. Hook the 0.193 0.193/4 winding wire on mandrels and start the machine Winding time 0.27 0.27/4 Spool changing 2 2/833 Take the bobbin from the store.

0.55 0.55/250 Reject the unwanted winding wire from finished spool 1 1/833 Take the process card and fill 0.4 0.4/100 Total normal time Relaxation allowance 13% of NT Standard time Standard time/ 1000 pieces Number of bobbins wound/ spool = spool weight/ coil weight for one bobbin = 5000g/6g Bin capacity

NT/Piece 0.043 0.048 0.068 0.002 0.002 0.001 0.004 0.168 0.022 0.19/PEICE (0.19/60)1000 = 3.16hr 833 250

III. PROPOSED IMPROVEMENT IN THE PROCESS The challenge is to identify an improvement in the activities of the process.

It is observed that the bobbins from the winding machine are arranged in the bin immediately after taking them from the winding machine. From the analysis done through flow process chart it is proposed that the proper arrangement in the bin can be done at the time of next set of winding in the machine so that time is saved.

We had drawn flow process charts after rearranging the activities in the workstation, which can be used for comparison.

Flowcharting a process did help in organizing the tagging of various activities for process mapping.

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Time Study on Winding of Bobbin for Automotive Relays in Assembly Line (IJSTE/ Volume 3 / Issue 07 / 010)

Table - 5 Process flow chart for proposed method

No 1 2 3 4 5 6 7

Table 6 Time study work sheet 3 – Proposed method 0.00 Element 1 Element 2 Element 3 Element 4 Element 5 Element 6 Element 7 Cycle No WT OT WT OT WT OT WT OT WT OT WT OT WT OT 1 0.15 0.15 0.37 0.22 0.64 0.27 2 0.78 0.14 1 0.22 1.27 0.27 3 1.42 0.15 1.62 0.2 1.89 0.27 4 2.05 0.16 2.28 0.23 2.55 0.27 5 2.69 0.14 2.92 0.23 3.19 0.27 6 3.33 0.14 3.54 0.21 3.81 0.27 7 3.96 0.15 4.18 0.22 4.45 0.27 8 4.61 0.16 4.81 0.2 5.08 0.27 9 5.23 0.15 5.43 0.2 5.70 0.27 10 5.84 0.14 6.05 0.21 6.32 0.27 8.32 2 8.87 0.55 9.87 1 10.27 0.4 Total 1.48 2.14 2.7 AVG 0.148 0.214 0.27 Rating 100% 90% 100% NT 0.148 0.193 0.27 25 0.55 1 0.4 Table - 7 Time study work sheet 4 – Proposed method Elements Nt Frequency Nt/Piece Take out the bobbin from the mandrels 0.148 0.148/4 0.037 Insert new bobbins and wound winding wire on bobbin. Hook the 0.193 0.193/4 0.048 winding wire on mandrels and start the machine Winding time 0.27 0.27/4 0.068 Spool changing 2 2/833 0.002 Take the bobbin from the store.

0.55 0.55/250 0.002 Reject the unwanted winding wire from finished spool 1 1/833 0.001 Take the process card and fill 0.4 0.4/100 0.004 Total normal time 0.162 Relaxation allowance 13% of NT 0.021 Standard time 0.141/PIECE Standard time/ 1000 pieces (0.183/60)1000 = 3.05hr Number of bobbins wound/ spool = Spool weight/ coil weight for one bobbin = 5000g/6g 833 Bin capacity 250

The proposed method has a better standard time compared to the original method. The calculations shown will depict the effect it can cause on the overall productivity of the organization.

Table – 8 Statistical evaluation Total working hour for the worker per day After allowances the working hour per day Total bobbins would per day with the first method of standard time3.16 hr Total bobbins wound per day with the better method of standard time 3.05 hr Number of bobbins that can be additionally wound with the better method Number of winding machines Total number of bobbins additionally wound Number of shifts per day

(7.33/3.05)1000 (7.33/3.05)1000

8 x 83.66

8.5 hr 7.33 hr 2,319.62 2, 403.27 83.66 8 669.28 2

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Time Study on Winding of Bobbin for Automotive Relays in Assembly Line (IJSTE/ Volume 3 / Issue 07 / 010)

Total number of bobbins additionally wound per day 669.28 x 2 Taking 25 working days, additional pieces wound 1338.56 x 25 This is 6.7% of the total order of 5 lakh for a month

1338.56 33, 464

IV. CONCLUSION Analysis of the operation of winding the coil in the bobbin with outline process chart and flow process chart is done. An improvement in performing the elements is suggested with the help of the analysis. Time study of the original and proposed methods revealed that the new method gives a reduced standard time than the original method. The estimation shows that the proposed method yields winding of an additional number of 33,464 in 25 days. The estimated addition is 6.7% of the total order for a month.

REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]

Aft, L.S. 2000. Work Measurement and Methods Improvement. John Wiley and Sons. ISBN: 0471370894.

Barnes, R.M. 1980. Motion and Time Study: Design and Measurement of Work. John Wiley and Sons 7th edition. ISBN: 0471059056.

Doty, L.A. 1989. Work Methods and Measurement for Management. Thompson Learning. ISBN: 053 “Work Study for Labor Productivity Improvement Utilizing Process Mapping and MOST” by Norashikin Binti Rahman Faculty of Manufacturing Engineering April 2007 - Universiti Teknikal Malaysia Melaka George Kanawaty (1986). Introduction to Work Study. Forth revise edition, International Labour Office (ILO) Publication, Geneva.

Khalid S. Al-Saleh (2011). Productivity improvement of a motor vehicle inspection station using motion and time study techniques. Journal of King Saud University, Engineering Sciences, (23) 33-41.

Lawrence S. Aft (2001). Work Measurement and Method Improvement. John Wiley and Sons Inc., New York.

Mayank Dev Singh, Shah Saurabh K, Patel Sachin B, Patel Rahul B & Pansuria Ankit P (2012). To improve productivity by using work study & design a fixture in small scale industry. International Journal on Theoretical and Applied Research in Mechanical Engineering, 1(2), 75-81.

Metin Dağdevirena, Ergün Eraslanb,*, Fatih V. Çelebic (2011). An alternative work measurement method and its application to a manufacturing industry.

Journal of Loss Prevention in the Process Industries 24, 563-567.

Abdul Talib Bon1, Aliza Ariffin. An impact an impact time motion study on small medium enterprise organization.

Barnes R. M., (1970). Motion and Time Study - Design and Measurement of Work, John Wiley & Sons, New York.

V.H.Tatawawadi, J.P.Modak (2005). Measurement of productivity of a small scale industry manufacturing electric motor, remaining within the domain of time study, method study and ergonomics, Udyog Pragati, October-November, 29(4) 1-19.

Abdul Talib Bon, Daiyanni Daim (2010). Time motion study in determination of time standard in manpower process. 3rd Engineering Conference on Advancement in Mechanical and Manufacturing for Sustainable Environment April 14-16, Kuching, Sarawak, Malaysia.

Hussain Bux Marri and Ghulam Yasin Shaikh (2012).The Role of Productivity Improvement Tools and Techniques in the Textile Sector during Manufacturing. Proceedings of the 2012 International Conference on Industrial Engineering and Operations Management Istanbul, Turkey, July 3 – 6, Omid Nejati, Mohammad Rafei, Amir Shahbazi Gandomkari, Ahmad Asadi Amirabadi (2013).Determining the Optimum Number of Locomotives in the Steel Industry Using Motion and Time Study Techniques, J. Basic. Appl. Sci. Res., 3(3)939-943.

Shikdar A.A., Das B. (2003). The relationship between worker satisfaction and productivity in a repetitive industrial task. Applied Ergonomics 34,603–610.

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