state difference between molding and casting??
They are different processes.
In molding, there is a fixed tool which is reused for many parts. The tool is made to be a negative of the desired final product. It is filled with molten material (typically plastic resin), the material hardens, the mold opens, and the part is ejected. The mold is reused for many parts. There is very little labor.
In casting, there is a positive stand-in for the finished part. The stand-in is called a "pattern". A material is packed around the pattern to form a negative cavity. This material loosely holds is shape, but is not a permanent, reusable form. In most cases (there are exceptions for lost wax and lost foam casting), the cavity is opened and the pattern removed. The closed cavity is filled with molten material (typically metal), and the material is allowed to harden. After it is hardened, the temporary form is brushed away from the finished part. The process is labor intensive, but there is no need to make a permanent tool that can withstand the heat of the molten material.
The exception is die casting, which is more like molding in that the tool is of fixed for, reusable, and there is no pattern. Typically die casting is used for metals with low melting points, such as white metal and zinc alloys.