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√ As the plastic industry developed a second type plunger machine appeared. known as two stage plunger. √ This type of equipment involved two plunger units set on top of other the one to plasticize the material and feed it to another cylinder that consist of a chamber to heat the plastic material by conduction and plunger that operates as a shooting plunger and push the plasticize material into the mould. Advantages    • Faster than conventional machine (single plunger) .  • No Pressure loss encountered in compacting the granules.   • Allows larger parts with more projected area. Disadvantage :  • Extra construction for pre plasticizing so cost is more.

ADDlTlVE - A substance added to a plastic compound to alter its characteristics. Examples are plasticizers, and flame retardants. ALLOY - A combination of 2 or more plastics which form a new plastic.  AMORPHOUS - A plastic material in which the molecular structure is random and becomes mobile over a wide temperature range. ANNEAL ~ To heat a moulded part up to a temperature just below its melting point and slowly cooling it back; down to room temperature. This relieves moulded stresses. ANlSOTROPlC SHRlNKAGE - S hrinkage that occurs more in one direction (usually the direction of flow; reinforced materials shrink more across the direction of flow) than another. AUTOMATIC OPERATlON -The term used to define the mode in which a moulding machine is operating when there is no need for an operator to start each cycle. BARREL - A metallic cylinder in which the injection screw (or plunger) resides in the moulding machine . Also called CYLINDER. BLEND - A m

1. Intense industry competition often results in low profit margins. 2. Mould costs are high. 3. Moulding machinery and auxiliary equipment costs are high. 4. Lack of knowledge about the fundamentals of the process causes problems. 5. Lack of knowledge about the long term properties of the materials may result in long-term failures.

1. The Screw type Injection Moulding Machine consists of a hopper, a reciprocating screw and barrel assembly, and an injection nozzle. 2. This system confines and transports the plastic as it progresses through the feeding, compressing, degassing, melting, injection and packing stages. 3. A single screw injection Moulding machine for themoplastic showing the plasticizing screw,al a barrel band heaters to heat the barrel, a stationary platen, and a movable platen.

1. The plunger type injection moulding machine is available horizontal or vertical type and operated pneumatically or hydraulically.The clamping and Injection may be Semi or automatic. 2. In a semi Automatic type the clamping cylinder & the Injection cylinders are operated by levers which is connected the pneumatic or hydraulic cylinders. In Automatic type, the cylinders are actuated automatically to a set timers.

1. The cost of the machines is increased depending on their functions and Size . 2. The simplest Injection Moulding machine is a hand injection moulding machine With a very low cost . 3. The simplest mode of injection moulding machine may be considered as hand operated mode, which is an apt equipment to underStand the interaction of major operating parameters . 4. The machine consists of Barrel, Plunger, Band Heaters along with energy regulator, Rack & Pinion system for injecting the material by the plunger, a torpedo and nozzle.  5. The clamping is done manually on a working table. The machine is fitted on the working table. Heating is set manually .  6. The capacity of . the machine is available from 0.5 Oz to 2 Oz. Once heating is achieved the production starts manually. 7. The quality of the product is completely depend upon the skill of the operaton .The heating set point is achieved by heat & trial method. 8. Although Temperature contr