six sigma
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caaccs109261620.pptxApplication of Six Sigma Methodology to Reduce Defects of a Grinding Process
Case study 1
Done by: Connor Austin & Abdulla Aldhaheri
CODE: CAACCS1092616
Company Profile
Name: Unknown
Location: India
Type: Automotive Company
The company with manpower of approximately 2550 people is manufacturing common rail direct injection (CRDI) system pumps for vehicles.
Drivers For Change
Rejection level was too high.
The goal of visually inspecting all parts could not be reached.
Six Sigma Project
Define
Measure
Analyze
Improve
Control
Define
The team selected for this project includes the Senior Manager—Manufacturing as the Black Belt (BB). The other members of the team were Planning Manager, Maintenance Manager, Quality Control Senior Engineer and one Machine Operator.
Reduce rejection by 50%
The scope of the project was focusing in the fine grinding for improvement.
Measure
The Six Sigma team found the rejection were mainly due to the occurrence of different types of defects, such as burr, shades, deep lines, patches and damage on the component after machining.
Measure Cont.
Company used an equation called the Kappa equation to determine if their measurement system was acceptable.
The Kappa value that was calculated was .814, which is greater than .6. So, the measurement system was accpetalbe.
Measure Cont.
Analyze
Find the potential causes of defects.
Gather data from the process in order to obtain a better picture of the potential causes.
Analyze Cont.
Improve
The parameters selected through these discussions were load applied, initial load setting, coolant flow rate, upper wheel rpm, lower wheel rpm and cage rpm.
decided to experiment all these parameters at three levels.
Improve Cont.
The team concluded from the risk analysis that each method had its own impact on the process.
A program was started to implement each method in order to improve the process. A two week timeframe was used to implement the solutions.
Control Phase
The solutions that the team found were standardized in order to produce consistent results.
Control Phase Cont.
A control chart was implemented to keep an eye on assignable causes in the future.
For every shift, data on number of defects observed during 100% visual inspection were collected and these values were plotted.
Six Sigma Tools Used
Pareto Chart
Cause and Effect Diagram
Histogram
KPIV and KPOV
Key Process Input Variables
Load Applied
Initial Load setting
Coolant Flow Rate
RPMs
Key Process Output Variable
Reduction in rejection by 50%
Results Achieved
After implementation the rejection percentage went from 16% to 1.19%
The approximate Six Sigma level increased from 2.47 to 3.76.
Goal was achieved as the rejection rate was significantly improved.
Lessons Learned
The company learned the power of statistical thinking and its impact on processes.
The results obtained by this project will provide start-up data for further implementations in future.
Management cooperation was important to complete the project.
Questions?
References
http://pure.strath.ac.uk/portal/files/5714277/jiju.pdf
