Introduction to Basic Manufacturing Processes and ... - always yours

204 Introduction to Basic Manufacturing Processes and Workshop Technology
3. Ladle
Fig. 11.4 Closed round molding box
It is similar in shape to the crucible which is also made from graphite or steel shell lined with
suitable refractory material like fire clay. It is commonly used to receive molten metal from
the melting furnace and pour the same into the mold cavity. Its size is designated by its
capacity. Small hand shank ladles are used by a single foundry personal and are provided with
only one handle. It may be available in different capacities up to 20 kg. Medium and large
size ladles are provided with handles on both sides to be handled by two foundry personals.
They are available in various sizes with their capacity varying from 30 kg to 150 kg. Extremely
large sizes, with capacities ranging from 250 kg to 1000 kg, are found in crane ladles. Geared
crane ladles can hold even more than 1000 kg of molten metal. The handling of ladles can
be mechanized for good pouring control and ensuring better safety for foundry personals
workers. All the ladles consist of an outer casing made of steel or plate bent in proper shape
and then welded. Inside this casing, a refractory lining is provided. At its top, the casing is
shaped to have a controlled and well directed flow of molten metal. They are commonly used
to transport molten metal from furnace to mold
11.4 POWER OPERATED EQUIPMENTS
Power operated foundry equipments generally used in foundries are different types of molding
machines and sand slingers, core making, core baking equipment, power riddles, mechanical
conveyors, sand mixers, material handling equipment and sand aerators etc. Few commonly
used types of such equipments are discussed as under.
11.4.1 Moulding Machines
Molding machine acts as a device by means of a large number of co-related parts and
mechanisms, transmits and directs various forces and motions in required directions so as to
help the preparation of a sand mould. The major functions of molding machines involves
ramming of molding sand, rolling over or inverting the mould, rapping the pattern and
withdrawing the pattern from the mould. Most of the molding machines perform a combination
of two or more of functions. However, ramming of sand is the basic function of most of these
machines. Use of molding machine is advisable when large number of repetitive castings is
to be produced as hand molding may be tedious, time consuming, laborious and expensive
comparatively.