Process capability is the ability of the process to meet the desired specifications. The capability analysis defines how the product specifications are compared with the inherent variability in a process. Controlling for quality is the major priority for the manufacturing companies in today's competitive world. The accuracy of machined parts is the result of properties and characteristics of the total machining system and its environment. For this purpose statistical process control (SPC) is a very effective tool. The aim of present study is to analyse the process capability of carburettor manufacturing and to find out the root cause for variability in process and machining parameters. The main function of a carburettor is to provide the air-fuel mixture to the
engine. The main jets of carburettor that supply fuel to combustion chamber are the pilot jet, needle jet and main jet. The machining data is taken for the pilot jet, needle jet and needle jet clearance. Process capability analysis is done with the help of MINITAB 16 and the results are shown in the form of graphs. It was observed that the process capability indices were less than 1.33 for the measured dimensions of the carburettor which shows that the process is adequate and some improvements can be done. The possible reason for the deviation seems to be the machining parameters like over life
use of tools, improper cooling. The tools use are over life and a slight delay in replacing them can cause such variation. Another important reason is the coolant used its life and filtration system of coolant.
Cause and Effect diagram, Control Charts, Process Capability, Process Capability Indices