DOI : 10.17577/IJERTV8IS040160
- Open Access
- Total Downloads : 90
- Authors : Mohan. Y , Deepak S , Sudharsan R , Yashvanth U
- Paper ID : IJERTV8IS040160
- Volume & Issue : Volume 08, Issue 04 (April – 2019)
- Published (First Online): 11-04-2019
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Experimental Investigation on Reducing the Quality Concern of Blow-Hole In Cylinder Block
Mohan. Y [1], Deepak S [2], Sudharsan R [3], Yashvanth U [4]
Department of Automobile Engineering Hindustan Institute of Technology and Science, Chennai, Tamil Nadu
Abstract:- In this research paper an Automotive component having Blowhole defect has been taken. The said component is an Automotive 3-Cylinder engine block with displacement of 799cc. since it is the important component it has to be of the higher quality so there is no room for shortcuts. In this paper various analysis of part is done using Quality Control tools (QC Story). In order to be efficient and effective we follow Plan-Do- Check-act (PDCA) cycle for identifying the optimum process parameter in order to improve the casting quality and reduce the rejection rate at factory end. From the Pareto chart and Cause & Effect diagram, the major causes are prioritized and controllable factors identified.
Keywords: Blow-hole, QC Story, Pareto chart, Cause & Effect diagram, PDCA.
-
INTRODUCTION
Die casting process is a process used in order to manufacture complex shapes. Cylinder block is made of High Pressure Die Casting (HPDC). Defect rate in casting process increase the loss of production time and cost to the company. In this paper, we going to solve the real time problem faced by one of the manufacturing company. The major defect identified is Blow-hole near gating area. This Blow-hole leads to major leak in the casting. Blow-hole is found after machining of 2mm in Cylinder block. The defects were identified by past production lots and reports provided by the quality department. The Blow-hole defect can be minimized by taking precautionary measures in casting process. Blow-hole in the Cylinder block leads the casting to scraps.
The manufacturing company is Automotive MNC company, here they are facing high rejection rate in Cylinder block, failing to deliver the required quantity on time.
Fig 1, shows the foundry stage PPM rejection trend plotted for the months of Sep-Nov FY18. The gap in Sep is 2000 PPM, in Oct is 3706 PPM, in Nov is 4529 PPM. The overall average PPM for a period of Sep-Nov FY18 is 13,500 PPM. The actual rejection PPM doesnt meet the target PPM even in a single month. Hence it seemed like a chronic problem.
Sep18
Oct18
Nov18
Average Total
Inspected in nos
17,000
17,000
17,000
17,000
Scrapped in nos
210
233
247
230
Rejection in PPM
12,000
PPM
13,706
PPM
14,529
PPM
13,500
PPM
Table 1: Rejection trend table.
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METHODOLOGY FOR BLOW-HOLE ANALYSIS
QC Story is a methodology in Total quality management (TQM), which is intended to solve a problem. QC Story is based on the principle of Plan-DO-Check-Act (PDCA). Generally, a Qc Story is a 7 steps procedure, but elaborated to 9 steps for better efficiency.
First all the rejection data of casting is collected from the quality department. Then by using the QC tools such as Pareto chart and Cause & effect diagram the work is carried out. Fig 2, shows the QC story procedure
Fig 2: QC Story procedure.
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
0
Cylinder block – Foundry stage Rejection trend
13,706 14,529
12,000
10,000 10,000 10,000
SEP OCT NOV
-
Pareto Chart
The Pareto analysis of cylinder block was carried out for the period of 3-months from September-November FY18. It is inferred that Pareto analysis prioritizes Blow- hole defect as top priority contributing to 65.36% of overall defects, followed by oil leak, water leak and others being 17.97%, 10.29% and 6.38% respectively. Fig 3, shows the defect rate for the 3-months.
Target PPM Rejection PPM
Fig 1: Foundry stage rejection trend.
CYLIBER BLOCK OVERALL DEFECT RATE SEP-NOV FY'18
700 93.62
83.33
100.00
100.00
95.00
90.00
Cause effect diagram is one of the approaches to enumerate the possible causes. Fig 5, shows the cause-effect diagram with significant problem.
600 85.00
80.00
75.00
500
QUANTITY
QUANTITY
400
300
200
100
CUMMULATIVE %
CUMMULATIVE %
65.36
451
124
71 44
70.00
65.00
60.00
55.00
50.00
45.00
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
-
-
DATA MEASUREMENT PLAN
0
BOTTOM FACE OIL LEAK WATER LEAK OTHERS
0.00
QUANTITY 451 124 71 44
PARETO 65.36 83.33 93.62 100.00
DEFECTS
QUANTITY PARETO
Fig 3: Overall defect rate September-November FY18
Data collection was done to know about the current scenario of the rejection trend of the component and then it was further segregated to know major error producing area and then that data was converted into Pareto chart. Fig 4, shows the location wise Blow-hole defect for 3-months September- November FY18.
BOTTOM FACE DEFECT LOCATION
97.12
450
91.35
99.56 100.00
100.00
90.00
400 81.37
Process/ Input
Operational definition
Data source & location
Sample size
Who will collect the data
Abnormal injection curve.
To investigate the effect of process parameter setting.
Daily testing parameter report.
10
samples from a lot.
Technician.
Low metal pressure.
Temperature taken at Spout of press pour at which a casting metal is poured.
Daily testing parameter report.
2-3
times in a single lot.
Technician.
Soldering mark in defect location.
Observed from the Cylinder block casting.
Daily log sheet.
2-3
times in a single lot.
Technician.
Gate area temperature high.
Temperature taken at gate area of the casting.
Daily testing parameter report from the lab.
2-3
times in a single lot.
Technician.
Process/ Input
Operational definition
Data source & location
Sample size
Who will collect the data
Abnormal injection curve.
To investigate the effect of process parameter setting.
Daily testing parameter report.
10
samples from a lot.
Technician.
Low metal pressure.
Temperature taken at Spout of press pour at which a casting metal is poured.
Daily testing parameter report.
2-3
times in a single lot.
Technician.
Soldering mark in defect location.
Observed from the Cylinder block casting.
Daily log sheet.
2-3
times in a single lot.
td>
Technician.
Gate area temperature high.
Temperature taken at gate area of the casting.
Daily testing parameter report from the lab.
2-3
times in a single lot.
Technician.
68.29
350
80.00
70.00
300
QUANTITIY
QUANTITIY
60.00
Table 2: Data measurement table.
250
CUMMALTIVE %
CUMMALTIVE %
50.00
200
150
100
50
0
42.57
192
116
59 45 26 11 2
40.00
30.00
20.00
10.00
0.00
Table 2, shows the data measurement plan for the performance measure such as Abnormal injection curve, Low metal pressure, Soldering mark in defect location, Gate area temperature high. Data source, sample size, data
G4 G1 G2 G3 G8 OTHERS G5
Quantity 192 116 59 45 26 11 2
Pareto 42.57 68.29 81.37 91.35 97.12 99.56 100.00
LOCATION
Quantity Pareto
Fig 4: Location wise Blow-hole defect Sep-Nov FY18.
-
Cause & Effect diagram
The various causes for Blow-hole defect was found using Brain storming, significant reasons were identified. The systematic methodical approach is being devised for controlling the defect rate.
Fig 5: Cause effect diagram.
collection techniques are indicated.
-
-
ACTION TAKEN
Fig 6: Blow-hole defect cut piece.
As shown in the above fig 6, the blow-hole was found at the gate area location on the Cylinder block casting. G1 and G4 gate location was found Significant and the root cause of the problem was identified.
The corrective action was taken in the die since the cooling is insufficient at defect location. The temperature at G1 and G4 was high and it corrected by increasing the depth of cooling points in the die.
Table 3: Change in Die measurement
Die Temperature Before & After
BLOW-HOLE DEFECTAFTER CORRECTION IN DIE
Diameter
Depth
Before
8 diameter
165mm
After
8 diameter
190mm
Diameter
Depth
Before
8 diameter
165mm
After
8 diameter
190mm
4.5
4 4
4 4
3
3
3
3
3 3
2
2
2
3
2
4 4
4 4
3
3
3
3
3 3
2
2
2
3
2
4
3.5
3
2.5
2
1.5
1
0.5
0
160
140
120
100
80
60
40
20
0
G1, 142
G1, 109
G2, 106
G3, 104
G4, 102
G5, 106
G6, 106
G1, 109
G2, 106
G3, 104
G4, 102
G5, 106
G6, 106
G2, 107 G3, 109
G4, 135
G5, 105 G6, 106
28-Jan 29-Jan 30-Jan 31-Jan 01-Feb 02-Feb 03-Feb 04-Feb 05-Feb 06-Feb 07-Feb 08-Feb 09-Feb 10-Feb 11-Feb
Fig 8: Rejection trend of January-February FY18.
Current level of Blow-hole
1.35% (Average of 3 months)
Achieved level of Blow-hole
0.94%
Reduction in defects
0.41%
Production plan / month
17.000 nos
Number of rejection / month
160 nos
Cost saving / month
7.68,000
Current level of Blow-hole
1.35% (Average of 3 months)
Achieved level of Blow-hole
0.94%
Reduction in defects
0.41%
Production plan / month
17.000 nos
Number of rejection / month
160 nos
Cost saving / month
7.68,000
5.1 Cost benefit analysis
G1 G2 G3 G4 G5 G6
Temperature before correction Temperature after correction
Fig 7: Temperature Before & After Correction in Die.
-
PROJECT RESULT
The Blow-hole defect analysis was carried out using QC tools and the 3-month data was collected from the log sheet available at the company. Using that the rejection trend was found and the Blow-hole contributes about 65.36% defect rate from all other defect. So the significant cause was found and corrected.
Fig 8, shows the Rejection trend for the of January-February FY18. The Blow-hole defect rejection rate is reduced. The target achieved is 0.94%.
Table 4: Cost benefit analysis 6.CONCLUSION
The main objective of the project work is to reduce the
Blow-hole defect rate in Cylinder block manufacturing thus the defect rate reduced drastically from 1.34% to 0.94%. The profitability for the foundry was increased directly by over coming the Rejection rate of Blow-hole.
7.REFERENCES
-
Praevadee KaewkongKha, Somkiat Tangjitsitcharoen – IOSR Journal of engineering.
-
Surjit Kumar Gandhi, Anish Sachdeva and Ajay Gupta Reduction of rejection of cylinder blocks in a casting unit: A six sigma DMAIC perspective. Journal of project management.
-
Yogesh S.Dhumal, S N Teli, Siddesh Lad Problem solving methodology by Quality control story.