Process capability improvement of an engine connecting rod machining process

Abstract

Statistical process control is an excellent quality assurance tool to improve the quality of manufacture and ultimately scores on end-customer satisfaction. SPC uses process monitoring charts to record the key quality characteristics (KQCs) of the component in manufacture. This paper elaborates on one such KQC of the manufacturing of a connecting rod of an internal combustion engine. Here the journey to attain the process potential capability index (C p ) and the process performance capability index (C pk ) values greater than 1.33 is elaborated by identifying the root cause through quality control tools like the cause-and-effect diagram and examining each cause one after another. In this paper, the define-measure-analyze-improve-control (DMAIC) approach is employed. The definition phase starts with process mapping and identifying the KQC. The next phase is the measurement phase comprising the cause-and-effect diagram and data collection of KQC measurements. Then follows the analysis phase where the process potential and performance capability indices are calculated, followed by the analysis of variance (ANOVA) of the mean values. Finally, the process monitoring charts are used to control the process and prevent any deviations. By using this DMAIC approach, standard deviation is reduced from 0.48 to 0.048, the C p values from 0.12 to 1.72, and the C pk values from 0.12 to 1.37, respectively.

Quality Assurance through Process Improvement - A Concise Review

“…The Post-hoc test establishes the extent of influence of the causes on the CTQ characteristic of concern. In connecting rod and crankshaft components of engine manufacturing, ANOVA is successfully employed for identifying the major root causes and subsequently for identifying the extent of influence of these root causes on process deviations [11,12]. Among the varied areas of applications of ANOVA, one such area is manufacturing of shafts used in submersible pumps [13].…”

“…Remedial actions are taken to correct and prevent variations in the process. Another noted area of application of FMEA is the engine manufacturing process [11,12]. In the area of engine manufacturing, FMEA is carried out for the Failure Modes of the following observed CTQ characteristics namely, thrust face width of connecting rod and crankshaft stub-end hole diameter after boring operation.…”

Curbing variations in packaging process through Six Sigma way in a large-scale food-processing industry

“…India is the largest milk producer in the world (about 100 million MT) and consists of nearly 1/5th of the world bovine population (Deloitte 2009). Further, (Sharma and Rao 2013) revealed that the DMAIC approach is the best methodology for problem solving tools to improve the manufacturing process capability levels.…”

Residuals based process capability indices for two-stage processes

“…Boyles (1994) proposed S pk index based on the process yield of the process. Sharma and Rao (2013) employed define, measure, analysis, improvement and control (DMAIC) approach to reduce the variation of the engine connecting rod machining process and as a result to improve the capability of the process. Also, Sharma and Rao (2014) used DMAIC approach to improve the capability of the engine crankshaft manufacturing process.…”