Alagappa Chettiar College of Engineering & Technology
Government of Tamilnadu
Karaikudi – 630004, Tamilnadu.
PONRAJ JOHN KENNEDY.A
Third Year Mechanical Engg,
A.C.College of Engg & Tech.
Evolution of casting techniques can be classified into three generations. In the first and oldest generation mould is made by means of squeezing and jolting the green mould sand. In the second generation the organic binder are used to stabilize the moulding materials. In the third generation or the latest generation the physical means such as gravity, vacuum or magnetic field is used for stabilization of the free flowing dry moulding materials. The development of unbounded casting process improves flexibility and enhances mould ability. The concept of unbounded casting is to change the kind of binder or to avoid substantial binder.
Magnetic moulding is a type of unbounded moulding process in which a dry and free flowing magnetic steel shots or granules are used as mould materials. The pattern for the required job is made of using expendable polystyrene materials. An electromagnetic field is created using electro magnets and this magnetic field is used as the binding force.
In this paper, the design and fabrication issues of Magnetic Moulds are explained. The cost analysis and sample castings produced by this method and the factors influencing their accuracy are elaborated.
Organizations in today’s competitive environment face dynamic and unpredictable demand from customers. The need to manufacture small quantities of highly customized products with perfect quality and 100% on time delivery at low cost is forcing companies to abandon the old ideas and to develop new manufacturing techniques. A number of manufacturing techniques are evolved during the last few years and Magnetic moulding is one among such techniques. Magnetic moulding is a type of unbounded moulding process in which a dry and free flowing magnetic steel shots or granules are used as mould materials. The pattern for the required job is made of using expendable polystyrene materials. An electromagnetic field is created using electro magnets and this magnetic field is used as the binding force. After pouring and solidification is over the magnetic field is cutoff and the casting can be easily taken out from the mould box without doing the knocking out operation, which is normally done, in conventional sand castings. Magnetic moulding requires only less floor space and it is easy to prepare the mould as it just requires setting the magnetic field using electromagnets. In Magnetic moulding sound castings can be produced, as heat transfer rate is high because of metallic conduction.
PROCEDURE OF MAGNETIC MOULDING:
In magnetic moulding steel shots or steel granules are used as the moulding material the binding force used in magnetic moulding process is magnetic force. STEP1: CONSTRUCTION OF HORSE SHOE MAGNET
Horse shoe magnet is made of steel sheets cut and laminated to form core of U shape. It is wound with copper wire on the base .the winding consist of two parallel stretch of windings each of 300 turns .in a horse shoe magnet with a mould box inserted between the square poles in a magnetic path, the flux lines will be passing through the magnetic media. Hence complete magnetic coupling is achieved.
STEP2: PATTERN MATERIAL MAKING AND ASSEMBLY
In magnetic moulding process, foamed polystyrene is completely...