Total quality in an organization means simply the quality work that is expected in every job. There are no exemptions. When something is done; it should be done right in the first time. When a product is made; it should be defect-free. When a service is provided; the customer should be pleased with the result.
There is a variety of definitions of quality attributed to the historical leaders in the quality evaluation. Walter Shewhart; the author of quality control via control charts; described quality as having both an objective and a subjective side. The objective part of quality relates to measurement specifications with minimum of variation from target values. The subjective side relates to the commercial value (costs; use and esthetics). Joseph Juran described quality as â€śfitness to useâ€ť. Edwards Deming claimed that quality was in the eye of the beholder. For the consumer; quality represented satisfaction at a price that the consumer was willing to pay. Phil Crosby defined quality as â€śconformance to requirementsâ€ť (Juran; 2000).
The various definitions arenâ€™t contradictory in any way. They depend more on the focus of the definer. In a few words; quality is: fitness to use; conformance to specifications; producing the very best product; excellence in products and services; total customer satisfaction and exceeding customerâ€™s expectations.
When a company produces a product or services; it utilizes many interrelated processes and each process includes several or many steps to accomplish a specific task. There may be several sources of data. All different processes are combined to yield the final product or service.
Statistical Process Control (SPC) is a procedure in which data is collected; organized; analyzed and interpreted so that a process can be maintained at its present level of quality or improved to a higher level of quality. SPC can be applied wherever work is being done. Initially; it was applied to production processes; but it has evolved to any work where data can be gathered. SPC involves the use of statistical signals to identify sources of variation; to improve performance and to maintain control of processes at higher quality level. SPC leads to a system of prevention which will replace the system of detection. Statistical signals are used to improve a process systematically so that production is maintained (Dietrich; 2000).
Statistical process control can improve quality by reducing product variability and can lead to improvements in production efficiency by decreasing scrap and rework. SPC is a trouble indicator. For each statistical application; such as control charts; histograms; there is an excepted form or pattern. When the actual form or pattern differs from the excepted; it is usually a signal that the problem exists. The potential problem must be investigated and eliminated. So the primary goals of SPC are: to minimize production costs â€“ it can eliminate costs associated with making; finding and repairing or scrapping substandard products; it reduces product variability to the level that is well within specification; it leads to process predictability (Hamrol; 2005).
The basic tools for SPC are: flowchart; paretodiagram; checksheets; cause-andeffect- diagram; histogram and most important - control charts.
Keywords: SPC; control charts; recognition