Statistical Process Control Research Paper

ABSTRACT

The deployment of statistical process control (SPC) in manufacturing environment is a prominent global phenomenon. Statistical process control is largely used in industries for monitoring the process parameters. It is a standard method for visualizing and controlling process on the basis of measurements of randomly selected samples. The decisions about what needs to be improved, the possible methods to improve it, and steps to take after getting the results from the charts all made by humans and based on wisdom and experience. In this thesis it contains about how to check the behaviour of CNC machines while manufacturing of gears. In production industries defect increases, the cost of production, expand required labour hours and decrease

It is also called a tool to increase the productivity in industries. Statistical Process Control (SPC) was pioneered by Walter A. Shewhart at bell laboratories in the early 1920s. Shewhart developed the control chart in 1924 and the concept of a state of Statistical control is equivalent to the concept of exchange ability developed by logician William Ernest Johnson also in

X-chart shows average set of continuous measurements after manufacturing of each gear by checking them with equipments and R-chart shows the range set of continuous measurements of same manufactured gears which are shown in X-chart [7]. Histograms are also come under the category of showing variation in jobs, it is a visual tools to examine distribution. A histogram is a bar graph that shows how frequently data fall within specific cells, i.e ranges of values. It makes it relatively simple to estimate where the process is centred and how much fluctuation there is about to centre [6]. This is all a part of variation shows by the machines but to know the capability or behaviour of machine and to know whether the process is good, bad, poor or excellent certain capability indices are required that is Cmk, Cpk, and performance index Ppk [2]. Too know the behaviour of machine each job after manufactured is to be check. When a point on chart lands outside the control limits, or when certain anomalous behaviours are observed, the operators are alerted to investigate or perform other actions, it will convenient to imagine the output as representing measurements of quality in manufacturing [7]. The machine capability study concentrates exclusively the characteristics of the machine i.e to extent possible, the influence or effects of variables external to the machine (noise