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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

Sand casting: In sand casting which is also known as sand molded casting, an object is produced by sand mold. The process involves pouring of the molten metal in to the mold cavity. The molten metal is then cooled to the room temperature. The metal is solidified. After cooling, the metal object is separated from the mold. Sand casting process has its advantages and disadvantages. So care

We know that casting is the process of pouring molten metal in a desired shaped cavity and allowing it to solidify. After the solidification we get the desired shaped object. Please read : Comparison of different casting processes. What is casting ? Main application of castings Basic Steps of Sand casting Basic Operation of the casting process First we have to make a pattern Then the

Pattern allowances: There are some allowances which are responsible for the difference in the dimensions of the casting and the pattern. These allowances are considered when a pattern is designed for casting. In this article we will discuss those allowances - 1. Shrinkage allowance: After solidification of the metal from further cooling (room

Discovering Brazing (Braze Welding) Brazing is a gas welding process in which you join metals by using heat that surpasses the 800 degree Fahrenheit mark and a nonferrous (iron-free) filler rod with a melting temperature below that of the base materials. The most important point about brazing is that you can use it to join dissimilar metals — cast iron to steel, brass to steel, or copper to

Electrochemical Machining (ECM) is based upon Faraday's law of electrolysis. Faraday's law states that the the mass of a metal altered by the electrode is proportional to the quantity of electrical charges transferred to that electrode. In ECM the removal of metal is controlled by the anodic dissolution in the electrolyte. In ECM - The workpiece acts as the anode The tool act as cathode.

What is Match - Plate Pattern The match plate pattern is almost similar to the mounted pattern but it can have part of the casting in the cope and part in the drag like split piece pattern. These parts are generally attached to the plate / board in opposite sides in the perfect positions. When the plate is removed and mold is in close position the cavities in the cop and drag match perfectly.

In this process the material of the workpiece is removed by the repetitive impact actions of abrasive particles. The erosion takes place by the abrasive particles which are carried by a liquid medium in the from of a slurry . A shaped vibrating tool is used to produce the impact. The term shaped is used to explain that the process is capable enough to create 3D profiles in correspondence to the

In Water jet Machining no abrasive is used. Water jet alone is used for cutting. In WJM, materials like concrete, asbestos, wood, rocks, coal, textiles and leather can be cut. The material is removed by means of erosion. These days hydraulic coal mining as well as tunneling, descaling and cleaning is also done by this process. Water Jet Machining (WJM) Principles As

Like all joining processes (in fact, like all processes!), welding offers several advantages but has some disadvantages as well. The most significant advantage of welding is undoubtedly that it provides exceptional structural integrity, producing joints with very high efficiencies. The strength of joints that are welded continuously (i.e.,full length, without intentional skipped areas) can easily

The History of TIG Welding Russel Meredith applied for a patent for TIG or GTAW in 1941. He is most credible for the invention of TIG welding. The main application of TIG or GTAW is found in effective welding of light aircraft. MIG welding of GMAW was invented before TIG welding but light aircrfat welding needed more reliable welding as well as more fusion power and TIG welding is very

If it is assumed that a single process is good enough to approach practical problems in production then it is a total non-sense. There are a lot of methods useful for manufacturing goods. The most difficult part is selecting the right method of production. For manufacturing a product one should bear in mind its appropriate configuration, financial conditions and adequate supplies of materials and

Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW) are suitable for aluminum welding. Aluminum alloy castings need the same technique applied to aluminum sheets and many different wrought products. Many castings are vulnerable to thermal strains because of delicate designs and varying cross sectional areas. Sometimes aluminum alloy castings need heat treatments before welding. TIG

Heat treatment of metal is a term used to describe an operation or a series of operations which involves heating and cooling of a metal or an alloy when it is in the solid state for obtaining some desirable properties (without changing the chemical composition ). The main objective of Heat Treatment of Steel 1. Enhancing the hardness of the steel. 2. Stress reliving from the metal after hot

What is Casting : Casting is one of the most ancient processes of manufacturing metallic components. Also with few exceptions it is the first step of manufacturing metallic components. The Basic steps of casting 1. Melting the metal. 2. Pouring it into a previously made mould or cavity which