productivity improvement in bottleneck machine for automated cylinder block line

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 9, Number 18 (2014) pp. 5197-5208 © Research India Publications http://www.ripublication.com

Productivity Improvement in Bottleneck Machine for Automated Cylinder Block Line

Ajinkya P. Patil#1 and Yash B. Parikh#2

#1PG Student, Department of Mechanical Engineering, Symbiosis Institute of Technology, Pune, India.

#2Assistant Professor, Department of Mechanical Engineering, Symbiosis Institute of Technology, Pune, India.

[email protected] 2 [email protected]

Abstract

Production lines in the industries are not that simple. Many parts of different sizes are produced through various combinations of the equipments. Bottleneck machines are those which are of high importance in any production line. In this paper a detailed study about productivity improvement for the automated cylinder block line was carried out. Initially the production output of cylinder block line was studied for the duration of six months starting from June 2013 to November 2013. From this study it was concluded that cylinder block line was facing intricacy in attaining the desired number of cylinder blocks in comparison to what was expected. Further, breakdown study revealed that the high pressure washer machine was vastly responsible in hampering the productivity of the cylinder block line. To overcome this dilemma an extensively study was carried out taking critical problems into consideration to improve the productivity of the cylinder block line. Modifications were successfully implemented which in turn helped attaining the higher productivity for the cylinder block line. Keywords: Productivity, Bottleneck Machine, Breakdowns, Modifications, Improvement.

Introduction Productivity is defined as the ratio of what is produced to what is required to produce it. Productivity measures the relationship between outputs such as goods and services produced, and inputs such as cost, labour, material and other resources. Increasing the productivity is always considered to be main driver of competitiveness in the price

5198 Ajinkya P. Patil and Yash B. Parikh

sensitive market [1]. Manufacturing facility mainly focuses on the equipment management and their maintenances to meet its profitability goal [2]. In manufacturing process there is always one part of the process usually a machine that is slowest and it may affect the production, this is called as the bottleneck machine. Bottleneck stays in one place and continuously slows down whole line. Industrial washing has significant importance as it removes the oil, chips and shop dirt/dust accumulates on the components before they get packed. The machine considered for the study is a high pressure washer machine, which is referred to as a bottleneck machine because of its high importance. It cleans the cylinder block by following three main processes namely cylinder block washing, drying in a vacuum station and then cooling it to the room temperature. This machine not only restricts components to get spoiled but also enhances their precision and performance. In such a critical scenario if the high pressure washer machine works with less efficiency then it affects the entire cylinder block line and makes it a less productive. The problem considered here for the study dealt with finding the root causes which hampered the productivity of the high pressure washer machine. To overcome the problems faced certain remedial measures were also established. The basic structure of the high pressure washer machine is shown in the figure below. It has mainly three stations which are washing station, Vacuum station (with the help of vacuum) and cooling station.

Fig. 1. High pressure washer machine (Courtesy: Valiant, USA.) Case Study This study was carried out in the car manufacturing unit in Pune, Maharashtra, India. This study was conducted during the period of June 2013 to March 2014 and the values chosen are meant for justifying the research initiatives only. The study

Productivity Improvement in Bottleneck Machine 5199

involved taking readings and observations pertaining to the efficiency loss of the high pressure washer machine during the month of June 2013 to November 2013. After which a remedial measure was established and successful implementation of the same was done in the month of December 2013. Post implementation of the remedial measure again the study was carried out during the month of January 2014 to March 2014 which showed significant improvement in the productivity of high pressure washer machine. Calculations on efficiency of high pressure washer machine from June, 2013 to November, 2013 (before implementation): Initially the study focuses on obtaining the total efficiency of the cylinder block line from the month of June, 2013 to November, 2013 along with the total breakdown of the cylinder block line. (See Table I) Further investigation focuses on finding the time available with the high pressure washer machine which is considered here as a bottleneck machine and to calculate the total efficiency of cylinder block line for the said months. Also the breakdowns pertaining to the productivity loss at high pressure washer machine were also calculated.

TABLE I

Sr. No

Months Total Working Time (Minutes)

Total Breakdown Time ( Minutes)

Total Efficiency of Cylinder

Block Line (%) 1 June’13 14440 2152 85 2 July’13 15360 1685 89.03 3 August’13 13440 2421 81.98 4 September’13 20160 2357 88.3 5 October’13 20160 3010 85.069 6 November’13 12480 1943 84.43

Total efficiency of an automated cylinder block line from June’13 to November’13. The study revealed that the major portion of the productivity loss in cylinder block line during the said months were due to the often breakdowns of high pressure washer machine. The following calculations were carried out to understand the status of productivity of the bottleneck machine. The sample calculations shown below are for the month of June’2013. The remaining results have been tabulated. (See Table II) Total working time of the cylinder block line for the month of June, 2013 = 14440 Minutes Total breakdown time of the cylinder block line for the month of June, 2013 = 2152 Minutes Total efficiency of the cylinder block line for the month of June, 2013 = (14440 – 2152)/(14440) * (100) = 85% Status of productivity of high pressure washer machine for the month of June, 2013: Total breakdown time of the cylinder block line for the month of June, 2013 = 2152 Minutes


Total breakdown time of the high pressure washer machine for the month of June, 2013 = 260 Minutes Total Productivity of the high pressure washer machine for the month of June, 2013 = (2152 – 260) / (2152) * (100) = 87.92%

Fig. 2. Total efficiencies of cylinder block line and high pressure washer machine from June’13 to November’13. After analyzing the productivity of high pressure washer machine, which has mainly three sections, namely washing station, vacuum station and cooling station, the fish-bone diagram (See Figure 4) was prepared to further investigate the possible problems in the bottleneck machine. Further, each of these problems was analyzed for their individual contributions towards the productivity loss of high pressure washer machine. The sample calculations shown below are for all the three sections for the month of June’2013. Total available time of the cylinder block line for the month of June, 2013 = 14440 Minutes Total breakdown time of the cylinder block line for the month of June, 2013 = 2152 Minutes Calculations of the productivity of high pressure washer machine for the month of June, 2013: Total available time of High Pressure Washer Machine for the month of June, 2013 = 9488 Minutes Total breakdown time of High Pressure Washer Machine for the month of June, 2013 = 1345 Minutes Total productivity of High Pressure washer machine for the month of June, 2013 =


(9488 – 1345) / (9488) = 85.58 % Total loss of productivity for the month of June, 2013 = 14.42 % Calculations for contribution made by washing station: June, 2013 Total breakdown time of bottleneck machine for the month of June, 2013 = 1345 Minutes Breakdown time of bottleneck machine because of washing station for the month of June, 2013 = 939 Minutes Percentage contribution by washing station in productivity loss of high pressure washer machine in the month of June, 2013 = (100) - (1345 – 939) / (1345) = 69.81% Calculations for contribution made by vacuum station: June, 2013 Total breakdown time of bottleneck machine for the month of June, 2013 = 1345 Minutes Breakdown time of bottleneck machine because of vacuum station for the month of June, 2013 = 330 Minutes Percentage contribution by vacuum station in productivity loss of high pressure washer machine in the month of June, 2013 = (100) - (1345 – 330) / (1345) = 24.53% Calculations for contribution made by cooling station: June, 2013 Total breakdown time of bottleneck machine for the month of June, 2013 = 1345 Minutes Breakdown time of bottleneck machine because of cooling station for the month of June, 2013 = 76 Minutes Percentage contribution by cooling station in productivity loss of high pressure washer machine in the month of June, 2013 = (100) - (1345 – 76) / (1345) = 05.66%

Fig 3 Contribution of total breakdowns for June 2013


Fig 4-Fish Bone diagram of the bottleneck mahine. Table II Contributions made by parameters towards total breakdowns (Before Improvement) Sr. No

Duration of Study (Month)

Total Productivity

(%)

Loss Of

Productivity (%)

Contribution by each Parameters (%)

By Washing Station

By Vacuum Station

By Cooling Station

1 June’13 85.58 14.42 10.06 3.53 0.81 2 July’13 85.67 14.33 12.60 1.01 0.72 3 August’13 86.90 13.1 09.63 3.17 0.3 4 September’13 87.45 12.55 08.00 4.34 0.21 5 October’13 85.34 14.66 09.20 5.01 0.45 6 November’13 86.38 13.62 10.30 3.06 0.26


Fig-5 Trend Analysis of issues related with washing, vacuum and cooling station (Before Improvement) Major causes for the breakdown in Washing, Vacuum and Cooling station: Further, to detect the root cause of the breakdown, detailed analysis was carried out which showed the numerous factors affecting the productivity in washing, vacuum and cooling stations. Each of these parameters were some or the other way contributing in loss of productivity of high pressure washer machine. Following tables shows the contribution made by each parameter in percentage from June, 2013 to November, 2013.

TABLE –III Factors contributing in loss of productivity in washing station

Sr. No.

Description of the Problem

Break down Time (Minutes)

Contribution of Breakdowns in (%)

1 Unscheduled stoppage of machine 125 9.29 2 Robot stops at home position 200 14.86 3 Robot collision detected 350 26.02 4 Low water level

(transducer fault) 75 5.57

5 High water level (transducer fault)

150 11.15

6 Fault with blower motor 39 2.89 Total breakdown in percentage- 69.81


TABLE IV Factors contributing in loss of productivity in vacuum station

Sr. No.


Breakdown Time in ( Minutes)

Contribution of Breakdown In Percentage

1 Flickering of input plitz

100 7.43

2 Fault in system pump

80 5.94

3 Vacuum Zone Block Error

150 11.15

Total Breakdown in Percentage 24.53

TABLE V Factors contributing in loss of productivity in cooling station

Sr. No.


Break down Time (Minutes

Contribution of Breakdown In Percentage

1 Issue with Coolant 30 2.23 2 Fault in Conveyor 46 3.42

Total Breakdown in Percentage 5.66

Fig 6- Contribution of total breakdowns from June to November, 2013.


Concentrating on Major Parameters Affecting Productivity Loss From the above analysis it was clear that the major contribution towards loss in productivity of bottleneck machine was due to problem in mainly washing station. The percentage problems related to vacuum and cooling station were negligible in comparison with washing station. Study further investigates the major problems towards finding the remedial measures to correct them. Problems related to washing station: Study revealed that six different factors were affecting the smooth functioning of washing station. From the list major contribution was due to collision in robotic arm of the machine. Description of the problem: Robotic arm of the washing station was used to lift the cylinder block in washing station. This robotic arm lifts the cylinder block from the fixture which was made up of dowel pins and adapter plate. The problem was mainly because of these dowel pins used to get jammed to cylinder blocks. After measuring the dimensions of these dowel pins it was revealed that the dowel pins used were not of standard size. So when robotic arm gripper tried to pick up the cylinder block from the adapter plate, it also tried to lift the adapter plate. The designated pay load carrying capacity of robotic arm gripper was between 45 – 50 kgs, if the load was more than this, it could lead to damage of gears of robotic arm as well as falling of cylinder block mid way leading to damage of the cylinder block. So to overcome this problem was a crucial task. Solution: By analysis we found that the problem occurred because of the dowel pins getting stuck to the adapter plate. To overcome this problem we had designed a thin plate. This thin plate was manufactured in-house and was welded to the turn table. This thin plate was introduced between the adapter plate and the cylinder block. Also there were provisions made in design of the thin plate that it was getting locked to adapter plate by double acting cylinder. Now when robotic arm gripper picks up the cylinder block from the fixture, this thin plate descent and separates the cylinder block from the dowel pins and adapter plate. The schematic layout before and after improvement are shown in the figure. (See Figure 7 and 8)

Fig. 7 Layout of fixture of washing station (Before Improvement)


Fig. 8 Layout of fixture of washing station (After Improvement)

D: Comparison of Results Post Implementation: To understand the effectiveness of the implementation of fixture redesigned of washing station, we had gathered the data from the month of December 2013 to March 2014. The results showed significant improvement in the problem considered. (See Table V)

TABLE V Contributions of total breakdowns (After Improvement)

Sr. No.

Duration of Study

(Month)

Total Productivity

(%)

Loss of Productivity

(%)

Contribution by each Parameters (%)

Washing Station

Vacuum Station

Cooling Station

1 December ‘13

88.20 11.80 07.30 4.13 0.37

2 January ‘14 90.92 09.08 06.60 2.15 0.39 3 February

‘14 91.67 08.33 05.80 2.01 0.52

4 March ‘14 92.10 07.90 05.39 2.06 0.45


Fig. 9 Trend Analysis of issues related with washing, vacuum and cooling station (Before Improvement) V Conclusion The study presented here utilizes systematic improvement methodology to identify the problems. Productivity of the bottleneck machine was largely affecting the cylinder block line. The detailed analysis revealed the issues with washing, vacuum and cooling stations of the bottleneck machine. Other problems like issues with sensors, abnormal sounds from the system, fault with the transducer to detect the water levels (both low and high water levels), because of their less magnitude were not focused in the present study. Only the major issue related to washing station was focused upon. The design modification of the fixture of the washing station had showed great sign of improvement in improving the productivity of the bottleneck machines. References

[1] Jubin James, Bobby John and Mahesh Rangaraj, Productivity Improvement by Enhancing the Bottleneck Station in an Alternator Production Plant with Layout Improvement and its Cost Analysis, International Journal of Scientific and Research Publication, 2013, Volume 3, ISSN2250-3153.

[2] John P.Dispukes, Factory Level Metrics: Basic for Productivity Improvement, International Conference on Modeling and Analysis Of Semiconductor Manufacturing (MASM), 2002.

[3] A.Gunasekaran, P.Cecille, Implementation of Productivity Improvement Strategies in a Small Company, 1998, Volume 18(5).


[4] Shyam R Nair, Design of a Robotic Arm for Picking and Placing an Object Controlled Using Lab View, International Journal of Scientific and Research Publication, 2012, Volume 2, ISSN 2250-3153.

[5] Michal Leporis and Zdenka Kralova, Simulation Approach to Production Line Bottleneck Analysis, International Conference on Cyberrnetics and Informatics, 2010.