The cavity in the mold has the shape of the desired product.
How and from which material a mold is made depends on which product is made with it. The products to be made can be of, for example, plastic, metal, ceramic, or glass. These materials are sprayed or poured into the mold in the liquid state (heated if necessary). Then (if necessary after cooling) the mold is removed, and the object is left over. Pottery is also given shape in a mold, as well as bronze bells, for example. Making a mold is a specialist work in mechanical design techniques.
Injection molds made in order to manufacturer plastics or rubbers can be expensive to manufacture depending on the complexity, but by producing a large number of products the unit price can remain low, making the product economically interesting. The design of injection molds is a profession in itself. When designing a mold, the shape of the product must naturally be taken into account, as well as the properties of the plastic to be used. In particular to prevent shrinkage phenomena and associated deformations. Furthermore, the properties and size of the injection molding machine and the requirements to achieve the planned production capacity (cycle time) in our mold making factory must be taken into account. Since about half of the cycle consists of cooling the plastic, most attention is paid to this. The design of injection molds is therefore a process in which quality, speed and cost price are the most important parameters.
Variables and considerations for designing molds:
high temperatures (such as pouring molten metal in the mold)
cooling the mold and the molded product
precisely no high temperatures (pouring ceramic clay, or some types of plastic)
high pressure (injection molding of most plastics)
removing the mold without damaging the molded product or the mold
choice of material for the mold for single use or mass production
the number of cavities, for possible simultaneous making of multiple products
the possible reaction between the material of the mold and the material of the molded product