Metal casting industries are actively involved to reduce the scrap rejection and rework during the manufacturing process of the components. To achieve this, the production concerns must follow the quality control procedures correctly and perfectly without any negligence. Timely implementation of the modified techniques based on the quality control research is a must to avoid defects in the products. In this review paper, some of the solutions and quality control aspects are explained in a simplified manner to eliminate the unawareness of the foundry industrial personnel who work in the casting manufacturing quality control departments. This review paper provides very valuable information to the young manufacturing and mechanical engineers who have interest to start their career in the manufacturing concerns of medium and large scale captive foundries. This paper discusses all about the general quality control aspects in a detailed manner. Besides, statistical quality control (SQC) is also highlighted to understand its recent application and techniques adopted in the developing metallurgical engineering foundries.
Quality is defined as the fitness for use or purpose at the most economical level. It is an integral part of the process of design, manufacture and assembly. It can be assured by having effective procedures and controls at various stages. Manufacturing industries like foundries do not enjoy monopoly but they have to face competition. To overcome this problem and to retain the share of the market, it is necessary to constantly improve the quality of the cast product without the increase in the price of the products [1] and [2]. The price is influenced by the cost of production, which in turn is influenced by rework or rejection. Attention to quality assurance can reduce the wasteful rework. Aiming for quality in the first instance can reduce the cost of casting production. This quality production results in the company's growth and profitability. Quality in a product is difficult to define and invariably involves a consideration of the service environment. The most meaningful definition involves the concept of fitness for a given purpose or application at a prescribed life of number of hours, months or years in service. For a given set of service conditions, quality and reliability are interrelated to a certain extent. The minimum quality acceptable in any application is that level of quality necessary to ensure that the prescribed portion of the components will pass through the predicted service life without failure. If all the cast components survive the designed period of service under the given environmental conditions, then this constitutes 100% reliability [2]. The basic concepts of quality are that the finished cast products must meet established specifications and standards and hence customer's satisfaction will be derived from the quality products and services. Both of these can be attained by integrating quality development, quality maintenance and quality improvement of the product. These three aspects of a product can be achieved through a sound foundry quality control system [3] and [4]. The various meanings of quality are the fitness for purpose, conformance to requirements, grade, degree of preference, degree of excellence and measure of fulfillment of promises. The cast products should have certain abilities to perform satisfactorily. The factors governing are suitability, reliability, safe and foolproof workability, durability, affordability, maintainability, aesthetic look, satisfaction to customers, economical and versatility. The factors controlling the quality of casting design depends on the type of the customer in the market, profit consideration, environmental conditions and special requirements of the cast products. There exists a close relationship between quality and reliability. It is given as the sum of the quality now and quality later, which equals to reliability. The quality circles help in the improvement of product quality and productivity [5] and [6]. It implies the development of skills, capabilities, confidence and creativity of the people through cumulative process of foundry engineering education, pertinent training, work experience and participation [3]. A quality circle is defined as a way of capturing the creative and innovative power that lies within the work force and it is a group of employees, 3–12 doing similar work.
It is concluded that careful supervision with effect motivation of individual employees in achieving the quality is a must in reducing the rejection and scrap in metal casting manufacturing engineering industries. It is to be emphasized that quality is contributed to by all the members of an organization from the chief executive to the worker and is not the job of only foundry quality control staffs. In foundries addition to the quality control department, a scrap prevention team is needed to improve the quality and this should be felt by each employee.
