Skip to main content

LOAM MOULD AND ITS MAKING

Loam is clay and sand mixed with water to form a thin plastic mixture from which molds are made. Loam sand also contains fire clay or ganisters. The loam must be sufficiently adhesive so that it can cling to the vertical surfaces. Loam molds always require special provision to secure adequate ventilation. The object is to open out pores in the otherwise compact, closely knit mass, by artificial means. Thus various kinds of organic matter such as chopper straw, and particularly horse manure, is mixed up with the sand . A typical loam sand mixture is ,

1. Silica - 22 % 

2. Clay  - 5 %

3. Coke - 10 %  

4. Moisture - 18-20 %

This is applied as plaster to the rough structure of  the mold usually made of brickwork and the exact shape is given by a rotating sweep around a central spindle.

Cast iron plates and bars are used to reinforce the brickwork which retains the molding material. Loam molds may also be prepared by use of a skeleton pattern made of wood. The surfaces of  loams are blackened and are dried before the assembled.

Loam molds are employed chiefly in the making of large castings for which it would be too expensive to use full patterns and ordinary flask equipment. Objects such as large cylinders , round-bottomed kettles, chemical pans, large gears, and other machine parts are produced in loam molds. 


Loam Mould and Its MAking



Labels:

Comments

Post a Comment

Popular posts from this blog

SIMPLE CARBURETOR - CONSTRUCTION AND WORKING

CONSTRUCTION OF SIMPLE CARBURETOR :  The main Components of Simple Carburetor are : Float Chamber, float, nozzle, venturi, throttle valve, inlet valve, and metering jet . In the float chamber, a constant level of petrol is maintained by the float and a needle valve.  The float chamber is ventilated to atmosphere.  This is used to maintain atmospheric pressure inside the chamber. The float which is normally a metallic hollow cylinder rises and closes the inlet valve as the fuel level in the float chamber increases to certain level. The mixing chamber contains venturi, nozzle and throttle valve. The venturi tube is fitted with the inlet  manifold. This tube has a narrow opening called venturi. A nozzle is provided just below the centre of this venturi. The nozzle keeps the same level of petrol as that of the level in the float chamber. The mixing chamber has two butterfly valves.  One is to allow air into the mixing chamber known as choke valve. The other is to al...
Post a Comment
Read more

MELTING FURNACES FOR FERROUS METALS : CUPOLA AND ITS WORKING

Various types of melting furnaces are used in different foundry shops, depending upon the quantity of metal to be melted at a time, and the nature of work that is carried out in the shop.  The primary objective in cupola is to produce iron of desired composition, temperature and properties at the required rate in the most economical manner. Besides, this furnace has many distinct advantages over the other types, e.g., simplicity of operation, continuity of production, and increased output coupled with a high degree of efficiency.  Description Of a Cupola : The Cupola Furnace consists of a vertical, cylindrical steel sheet, 6 to 12 mm thick, and lined inside with acid refractory bricks or acid tamping clay. The refractory bricks or the tamping clay used consist of  silicon oxide acid (SiO2) and alumina (Al2O3). The lining is generally thicker in the lower where the temperatures encountered are higher than in the upper region. The shell is mounted either on a brick work fo...
Post a Comment
Read more

ELECTRICAL COMPARATORS AND ITS WORKING

Electrical Comparators are used as a means of  detecting and amplifying small movements of a work contacting elements. An electrical comparator consists essentially of  a pick-up head or transducer for converting a displacement into a corresponding change in current and a meter or recorder connected in the circuit to indicate the electrical change, calibrated to show in terms of displacement. Generally, an amplifier is needed to provide the requisite sensitivity and to match the characteristics of different parts of  the circuit. Electrical comparators can be classified according to the electrical principle used in the pick-up head. Most of the comparators use either a differential transformer, an inductance bridge, a strain gauge or a capacitor as a means of detecting movement of the gauging element. There are different types of  electrical comparators. One kind called an electrolimit gauge is used to check or measure the outside diameter of a  roll. The objec...
Post a Comment
Read more