Abstract
KEYWORDS:
statistical process control, continuous improvement, process stability, process performance, process capability
ABSTRACT.
No industrial process or machine is able to produce consecutive items which are identical in appearance, length, weight, thickness and so on. The differences may be large or almost immeasurably small, but they are always present. These differences are known as variation. Variation is the reason that engineers include tolerances in their specifications. The process control is a feed-back system providing a signal when variations are present. If this information is gathered and correctly interpreted, appropriate actions can be taken to correct the process and achieve constant outputs. The concept of quality control in manufacturing was first advanced by Walter Shewhart of the Bell Telephone Laboratories. Statistical Process Control is a statistical analysis of the predictability and capacity of a process to give uniform products. It is an intermediate stage towards a complete preventive control that can be applied to improve processes or to already improved processes. On the other hand, statistical process control is one of the requirements of ISO 9001. Any organization that wishes to be certified by a regulatory body must implement in its quality system techniques and tools concerning statistical quality control. Modern methods for statistical process control have in view statistical - mathematical models used for monitoring, analyzing, stabilizing and optimizing manufacturing processes. To achieve improvements it is necessary to establish continuous programs for training all manufacturing people and management in SPC and statistical tools. Continuous improvement is possible if Total Quality System is developed in the company. From a capability point of view, continuous improvement means the continuous increasing of capability index