Mold Casting and Welding Processes

The metal casting process is one in which molten metal is poured into a mold or cavity and allowed to solidify. Metal casting can be classified into two categories: expendable and permanent mold casting processes. In the introduction, you study the expendable mold casting process, with an emphasis on the shell molding and investment casting processes. Learn the steps involved in both shell and investment casting; types of shell molding patterns; the characteristics, advantages, and disadvantages of shell molding; and investment casting processes. A short video on how the investment casting process is carried out will be shown. Then, you will study how permanent mold castings are made. Its steps, characteristics, applications, advantages and disadvantages will be explained. You will also be taught the die casting and centrifugal processes, which are important casting processes. The design and the setup of the hot and cold chambers of the die casting machine will be highlighted. Thereafter, you will consider how the cost analysis of casting is normally done. The equations of the total cost of casting which includes all costs, both direct and indirect, that results from the design, production, distribution, and use of the cast over its lifetime will be explained. Also, various casting defects and their causes will be examined.

The end products in manufacturing processes can be obtained from the raw material by either constant mass operation (casting) or the mass addition process, which is joining. In this section, you will be introduced to the joining processes with a focus on welding. You will study the classifications, mechanisms, limitations, and drawbacks of welding processes. Types of joints will also be considered. Then, you will cover the principle, sources of heat, and some processes of fusion welding such as arc, resistance and oxyfuel gas welding. Heat density will be discussed. Thereafter, you will be taught the solid-state welding processes which include diffusion, friction and ultrasonic welding. The effects and steps relating to the cooling of the weld (solidification) and the applications of electron beam, laser beam and plasma arc welding in the physical world will also be examined.

Furthermore, you will be introduced to the liquid state welding processes. You will be shown a schematic diagram that exhibits the detailed processes involved in arc welding. You will study the principles, characteristics, sources of heat, and the structure of arc welding. The steps and methods of initiating an electric arc as well as the consumable and non-consumable electrodes of the arc welding will be highlighted. Then the shielded metal arc welding, also known as stick arc welding, will be considered. A short video clip on stick arc welding will be shown to give a clear idea of what it involves. Thereafter, the arc welding processes that use non-consumable electrodes and their various features will be discussed in detail. Also, you will learn about the various types of welding defects, their causes, and preventions. Anyone studying manufacturing processes or related courses such as metalworking will benefit from this fascinating course, which has optimal certification.