A DMAIC approach for process capability improvement an engine crankshaft manufacturing process

Abstract

The define-measure-analyze-improve-control (DMAIC) approach is a five-strata approach, namely DMAIC. This approach is the scientific approach for reducing the deviations and improving the capability levels of the manufacturing processes. The present work elaborates on DMAIC approach applied in reducing the process variations of the stub-end-hole boring operation of the manufacture of crankshaft. This statistical process control study starts with selection of the critical-to-quality (CTQ) characteristic in the define stratum. The next stratum constitutes the collection of dimensional measurement data of the CTQ characteristic identified. This is followed by the analysis and improvement strata where the various quality control tools like Ishikawa diagram, physical mechanism analysis, failure modes effects analysis and analysis of variance are applied. Finally, the process monitoring charts are deployed at the workplace for regular monitoring and control of the concerned CTQ characteristic. By adopting DMAIC approach, standard deviation is reduced from 0.003 to 0.002. The process potential capability index (C P ) values improved from 1.29 to 2.02 and the process performance capability index (C PK ) values improved from 0.32 to 1.45, respectively.

Quality Assurance through Process Improvement - A Concise Review

“…This is made possible by tracing the DMAIC approach to solve the deviations in the thrust face grinding operations of the connecting rod machining process [11] and deviations in the crankshaft stub-end hole diameter of the crankshaft manufacturing process [12]. The valve guide length and valve stem clearance are the CTQ characteristics which are needed to be maintained during the exhaust valve manufacturing [49].…”

“…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.…”

“…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].…”

“…The applications of manufacturing process capability improvement studies covers wide areas namely, engine manufacturing process [11,12], crane hook manufacturing process [20], plasma machining [21], CNC turning process [22], blow moulding process [23], polyjet printing [24], brake lever manufacturing [25] aircraft turbine engine blade manufacturing [26], photolithography process control in wafer fabrication [27], manufacture and process capability evaluation of square bumps [28], golf club-shaft manufacture in leisure sport industries [29], tool condition monitoring for grinding wheel in IC manufacturing of silicon wafer [30] and LED assembly in electronics industry [31]. All the works cited depict the process improvement procedure and fosters the fact that any noticeable permanent improvement is possible only through inprocess control and not through end inspection.…”

Residuals based process capability indices for two-stage processes

“…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.…”