mechanical engineering

Stress: When any object of certain material is subjected to tensile or compressive or shear force, there may be a chance that its dimension will be affected. If the dimension of a material is changed due to application of forces we can say that the material is under stress or experiencing the state of stress. Stress is defined as the Force per unit cross section area. Stress = F/A Stress is

Extrusion Process Principles Extrusion process is very common in the plastic industry. It is used for high volume plastic production. In extrusion process the color pigments along with other performance enhancing additives are combined with resin which is then pushed through the rotating screws. The heat and pressure generated within the barrels of screw is dispersed and melts the plastic

Plastics can be classifies into two broad categories - Thermosets and Thermoplasctics. A brief description of these two classes will be discussed here. Thermosets are the kind of plastics which are not recyclable. They undergo a kind of chemical change at the time of heating. As a result  they can be shaped once because of this permanent chemical change. This process is known as heat hardening.

Cope and drag in Sand Mold : Cope and Drag are the two parts of the casting flask. Cope is the upper part and drag is the lower part. Even if the casting process is flaskless , the same terms are used for the upper ans lower parts. Generally the flask is made of wood or metal. It contains molding sand. When metal is poured into the mold cavity the flask supports the mold. Gating system:

Investment or lost-wax castings: The Lost-wax method, sometimes, also called simply as precision-investment casting has been used for many years by jewelers and dentists. Since world-war-II, the method has been adapted to the production of small and precise, industrial fasting. Basically, the method involves the use of expendable (heat disposable) pattern unrounded with a shell of refractory

Die casting process is very different from sand casting as the mould used here is permanent. The mould is not expandable and need not to be broken after the cooling and solidification. Here the mould is called the die.  Please Read :  Comparison of different casting process  A complete Guide to casting process  Gravity die casting: When the molten is metal is poured under a gravity