China precision machining In the following sections, the details of sand casting process which represents the basic process of casting would be seen. Because going into the details of the process, defining a number of casting vocabulary words would be appropriate. Reference may please be made to Fig. 2.1
ds the sand mould intact. Depending upon the position of the flask in the mould structure it is referred to by various names such as drag-lower moulding flask, cope-upper moulding flask and
cheek-intermediate moulding flask used in three-piece moulding. It is made up of wood for temporary applications and more generally of metal for long-term use.
Pattern is a replica of the final object to be made with some modifications. The mould cavity is made with the help of the pattern.
This is the dividing line between the two moulding flasks that makes
up the sand mould. In split pattern it is also the dividing line between the two halves of the pattern.
China precision machining This is a board normally made of wood which is used at the start of
the mould making. The pattern is first kept on the bottom board, sand is sprinkled on
it and then ramming is done in the drag.
The small amount of material sprinkled on the inner surface of the moulding cavity to give a better surface finish to the castings.
It is the freshly prepared refractory material used for making the mould cavity. It is a mixture of silica, clay and moisture in appropriate proportions to get the desired results and it surrounds the pattern while making the mould
It what constitutes most of the refractory material found in the mould. This is made up of used and burnt sand.
Core: It is used for making hollow cavities in castings.
A small funnel shaped cavity at the top of the mould into which the molten metal is poured.
The passage through which the molten metal from the pouring basin reaches the mould cavity. In many cases it controls the flow of metal into the mould.
Runner: The passageways in the parting plane through which molten metal flow is regulated
Gate: The actual entry point through which molten metal enters mould cavitybefore they reach the mould cavity.
Chaplets are used to support cores inside the mould cavity to take care of its own weight and overcome the metallostatic force.
Chill are metallic object which are placed in the mould to increase the cooling rate of casting to provide uniform or desired cooling rate.
It is reservoir of molten metal provided in the casting so that hot metal can flow back into the mould cavity when there is a China precision machining reduction in volume of metal due to solidification.