Defects Reduction in Spheroidal Graphite Iron Casting Process of a Jackscrew Manufacturer

2021 ◽  
Vol 891 ◽  
pp. 174-182
Author(s):  
Supachart Muangyai ◽  
Parames Chutima

This research focused on defects reduction in spheroidal graphite iron casting process of a jackscrew manufacturer in which graphite nodularity was lower than a given specification (75%). This situation could lead to serious issues and accident to end-users. The Six Sigma approach of DMAIC was employed to identify and eliminate the problems. The result obtained after implementing the Six Sigma showed that the process capability was improved from-0.47 to 2.04, and the average per cent graphite nodularity was increased significantly from 61.49% to 86.43%.

2013 ◽  
Vol 462-463 ◽  
pp. 578-584
Author(s):  
Kulpiya Seri ◽  
Senjuntichai Angsumalin

This research applies Six Sigma approach in order to reduce defect by increasing the assembly process capability index (Cpk) of Integrated Circuit (IC) production process. This study applies five phases (DMAIC) of Six Sigma approach beginning with define (D), measure (M), analyze (A), improve (I) and control (C) phases, respectively. The response of the research identified in the define phase is the chipped width with Cpk of 0.66 determined from the measure phase. The half-factorial experiments are implemented in the analyze phase to find the significant factors which are water temperature, water pressure and feed rate. In improve phase, the additioanl expriments are performed according to the Box-Behnken design in order to determine the non-linear relation between the chipped width and all mentioned factors. The optimal setting of each factors are determined by applied the response surface optimizer. Under the optimal setting, the control charts are used in the control phase to monitor the chipped width. The resulted Cpk of the response is increased to 1.39 which is greater than the one-sided accpetable process capability of 1.25.


2019 ◽  
Vol 10 (1) ◽  
pp. 189-210 ◽  
Author(s):  
Nandkumar Mishra ◽  
Santosh B. Rane

Purpose The purpose of this technical paper is to explore the application of analytics and Six Sigma in the manufacturing processes for iron foundries. This study aims to establish a causal relationship between chemical composition and the quality of the iron casting to achieve the global benchmark quality level. Design/methodology/approach The case study-based exploratory research design is used in this study. The problem discovery is done through the literature survey and Delphi method-based expert opinions. The prediction model is built and deployed in 11 cases to validate the research hypothesis. The analytics helps in achieving the statistically significant business goals. The design includes Six Sigma DMAIC (Define – Measure – Analyze – Improve and Control) approach, benchmarking, historical data analysis, literature survey and experiments for the data collection. The data analysis is done through stratification and process capability analysis. The logistic regression-based analytics helps in prediction model building and simulations. Findings The application of prediction model helped in quick root cause analysis and reduction of rejection by over 99 per cent saving over INR6.6m per year. This has also enhanced the reliability of the production line and supply chain with on-time delivery of 99.78 per cent, which earlier was 80 per cent. The analytics with Six Sigma DMAIC approach can quickly and easily be applied in manufacturing domain as well. Research limitations implications The limitation of the present analytics model is that it provides the point estimates. The model can further be enhanced incorporating range estimates through Monte Carlo simulation. Practical implications The increasing use of prediction model in the near future is likely to enhance predictability and efficiencies of the various manufacturing process with sensors and Internet of Things. Originality/value The researchers have used design of experiments, artificial neural network and the technical simulations to optimise either chemical composition or mould properties or melt shop parameters. However, this work is based on comprehensive historical data-based analytics. It considers multiple human and temporal factors, sand and mould properties and melt shop parameters along with their relative weight, which is unique. The prediction model is useful to the practitioners for parameter simulation and quality enhancements. The researchers can use similar analytics models with structured Six Sigma DMAIC approach in other manufacturing processes for the simulation and optimisations.


2021 ◽  
Vol 4 (1) ◽  
pp. 36-43
Author(s):  
Cyril Ocheri ◽  
A. D. Omah ◽  
C. N. Mbah ◽  
R. E. Njoku ◽  
N. A. Urama ◽  
...  

The wire rod mill of the Ajaokuta Steel Company Limited produces coils, wire rods and re-bars of different sizes. Without the furnace hangers, it will be difficult for the mill to continue to operate. This paper describes the production of furnace roof hangers that are required for re-heating furnace using the spheroidal graphite iron (SGI), highlighting the sand-casting process, charge calculation, and the chemical compositions. The facilities within the foundry shop of the steel company are used to produce furnace roof hangers. The available materials used for the casting of the hangers are the pig iron, scrap ends, foundry returns and magnesium. The process of production was performed through the reheating furnace for the heating of 120 m x 120 m x 120 m billets. One ton induction furnace of low frequency was used as the melting vessel. Also, 6 kg of magnesium was introduced in the ladle before the liquid metal was teemed into it. A Spectro analytical instrument was used to determine the chemical compositions of the materials before and after the casting processes. The analysis of the chemical compositions of produced sample of SGI are presented and discussed.


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