This thesis is entitled “Improving casting process by reducing small part defect using six sigma approach in PT. I declare that this thesis entitled “Improving the casting process by reducing the small part defect using the six sigma approach in PT. LOL as a battery manufacturing vendor had a commitment to product quality.
To reduce the number of defects, especially in the small part of MH, the casting process should be improved using Six Sigma with the DMAIC approach. After conducting the observation in the casting process, it is known that most of the defect is categorized as shrinkage with the percentage of 12% from 1,072,172 units of MH small part production in June-September 2016 using Pareto chart. The root causes of shrinkage must be analyzed, and one of the main causes was the setting of parameters in the casting process.
The purpose of the design of the experiment is to find the best new parameters, these parameters aim to reduce the number of shrinkage in small part MH. Small part: Small part is a part in battery, it is aimed to put the screws on the battery poles, it is made by lead.
INTRODUCTION
- Problem Background
- Problem Statement
- Objectives
- Scopes
- Assumptions
One of the examples is the application of six sigma DMAIC to reduce defects in rubber gloves. LOL as a battery manufacturing vendor a small part is produced for motorcycle batteries and casi batteries. This small part is the important part of the battery, it is intended to place the screws on the battery posts.
Because the battery has strict safety standards from the Indonesian government, the quality for each part in the battery must meet the safety standard, in other words the quality of the small part produced by PT. To make a small part for the battery, the entire performance of the process must be controlled. The purpose of performance control is to prevent inconsistency or defective output in a small part.
In order to reduce the defect on a small part and increase the productivity and also reduce the loss caused by defect, the casting process should be improved by using six sigma DMAIC methodology with two-way anova as a tool, since there are two factors that affected the quality. of goods in molding process. How to reduce defects in casting process using Six Sigma DMAIC methodology in PT.
LITERATURE STUDY
Casting
Defect
- Types of defects in Casting
Six Sigma
DMAIC Phase
- Define Phase
- Measure Phase
- Analyze Phase
- Improve Phase
- Control Phase
Control Chart
- Analyze of patterns in control chart
Experimental Design
- Two-Way ANOVA
RESEARCH METHODOLOGY
Research Framework
- Initial Observation
- Problem Identification
- Literature Study
- Data Collection
- Calculation and Data Analysis
- Conclusion and Recommendation
The steps of this research are initial observation, problem identification, literature study, data collection, calculation and data analysis, as well as conclusion and recommendation. There will be a brief explanation of each step to give a brief vision about this research. The initial observation is analyzing the lower case casting process for the front fork on the PT.
The researcher observes every aspect related to the production system, including material, man and machine in the casting process. From the observation the researcher can collect some important data that can be used for this research. LOL manufactures their product every day according to the requirements already stated in the company, but there are some products that are defective as a result of the casting process.
There will be a problem background explaining the error problem that occurs in PT.LOL. The goal of the research is the answer to the problem already set, which is to reduce the error in the casting process in PT. Apart from this, it will clearly explain all the methods that will be used in this research.
More details about this entire research literature study can be seen in chapter two. The data needed for this research are several kinds of defects that occurred in the casting process of the front fork bottom case and the number of defects for each type of defect. Apart from that, there is a Pareto chart that determines the highest failure rate that often happens in the business.
The cause as the reason why this problem can happen in this company, while the effect as the future result of this problem happening in this company. Next is running the defect using two-way ANOVA with two factors in the casting process which are temperature and speed. The result will be the answer to the problem of reducing the fabric defect that occurs in PT.
Detail Framework
- Define Phase
- Measure Phase
- Analysis Phase
- Improve Phase
- Control Phase
DATA COLLECTION AND ANALYSIS
Data collection
Product Description
Production process
DMAIC Approach
- Define
- Measure
- Analyze
- Improve
- Control
Comparison before and after new parameters
- Defect percentage before versus after improvement
- Sigma level before versus after improvement
- Cost Analysis before and after improvement
CONCLUSION AND RECOMMENDATION
Conclusion
Using the pareto chart, it is shown that the largest defect category that occurred in the minor part MH is shrinkage. Using a cause and effect diagram, the correlation between crucible temperature and cooling time leads to shrinkage defects. By using two-way ANOVA, new parameters are found, the best parameters in the molding process are 450oC crucible temperature and 8 seconds cooling time.
The Six Sigma methodology carried out for this research is able to reduce the number of small part defects in the casting process.
Recommendation
MiniDMAIC: An Approach to Root Cause Analysis and Resolution in Software Development Projects, Quality Management, and Six Sigma. Park, Common Myths of Six Sigma Demystified, International Journal of Quality & Reliability Management, Vol. Lim, A Six Sigma and DMAIC application for reducing defects in a rubber glove manufacturing process.
