Introduction   This low-pressure injection molding machine employs 2-plate direct lock type, which can be divided into the following four parts: -Molding part for vertical opening and closing of mold - Injection part for plasticizing of mold resins, - System part for controlling - Hydraulic running part for running Structure of Injection Unit Injection unit is a key component of Low preesure injection molding machine that injects the adequate amount of plastic resins, which are properly mixed and heated, to the mold. The major parts of injection unit can be divided as follows. 1. Barrel Barrel is a major part that melts resins transmitted from hopper through screws and structured in a way that can heat up resins to the proper temperature. A band heater, which can control temper atures in five sections, is attached outside the barrel. Melted resins are supplied to the mold passing through barrel head, shot-off nozzle, and one-touch nozzle. 2. Screw * Screw Head Screw head melts and mixes the resins transmitted through the screw one more time. * Check Ring It is to prevent a backward flow. It is divided into two types, which are Not - Turning type like screw head and Turning type. * Push Ring Push ring is designed to prevent screw head from getting loose and keep resins from flowing backward by touching 3. Injection Cylinder Hydraulic motor located inside bearing box, which is connected to injection cylinder load, rotates screw, and the melted resins are measures at the nose of screw. There are many types of injection cylinders that supply necessary power to inject resins according to the characteristics of resins and product types at appropriate speed and pressure. This model employs the double cylinder type. Injection cylinder is composed of cylinder body, piston, and piston load. 4. Screw Revolution drive It puts screw to turn by the connected hydraulic motor for procedure of the screw funcition. This device is assembled with bearing box, spindle and bearings. 5. Slide Base Slide base supports the injection unit and guides the back and forth movement of injection cylinders and bearing box. 6. Nozzle Touch Cylinder Nozzle touch cylinder is a hydraulic cylinder unit that is used to put the nozzle and the mold together or apart to inject melted resins. 7. Hopper Hopper stores resins supplied to the screw. In recent years, hopper load is used to automatically supply resins to the hopper. 8. Shut off Nozzle Shut off nozzle is designed to prevent injuries of operators by scattering resins when nozzle is not connected to the mold. 9. One touch nozzle clamp Clamp This unit is designed to promptly connect the mold with the injection unit in order to prevent outflow of melted resi Mold Clamp System 1. Fixing Platen Fixing platen is a structural element, with 4 ejector holes located around the central point, which supports the entire mold unit. It also supports the bolster and the mold power transmitted from the upper mold, and it is equipped with bolster clamp, life, stopper, and mold open/close cylinders that open and close the mold. 2. Mold Platen Mold platen is a structural element facing the bolster, and it has T-shape grooves that take in the upper mold. Mold plate is connected to the clamping cylinder piston of moving plate in a way that it moves vertically as mold open/close cylinders are running vertically. It is designed to put pressures on the mold by the vertical movement of clamping cylinders or detach the mold from molding products. 3. Moving plate Moving platen is connected to the mold. It opens and closes (moving up and down) the mold> via mold close/open cylinders, and it generates molding clamp with its built-in clamping cylinders that supply clamping pressures on injected resin. In addition, the moving platen is built with lock system that secures it to tie-bar to prevent it from being pushed back and safety system that secures it when it is up to keep if from dropping due to gravity. 4. Loke System Lock system is designed to secure the moving platen to the tie-bar to prevent the moving platen from being pushed back when clamping pressure is applied to the mold located between the molding platen and the fixing platen. 5. Clamping Cylinder Clamping cylinders generate to keep the mold from being pushed back and supply clamping pressure on injected resin. They are built on the moving platen and connected to the mold platen by piston load 6. Mold Open/Close Cylinder These cylinders open and close the moving platen, and they are built on right side of the fixing platen diagonally across from the left side of the platen. They are connected to the moving platen by pistons. 7. Tie Bar Tie bars support clamping power, and 4 tie bars are located between the fixing platen and the support platen. They also guide the movement of the die platen. Tie bars may be broken if mold has a bad parallel balance or repeated run is done with a clamp power over the standard. Therefore, the operator must be care, must appropriate oil or grease to guide part and must maintain cleanness. 8. Tie bar Support Tie bar support is designed to provide support at the upper part to the tie bars, which are supported by the fixing plate at the lower part. 9. Ejector Cylinder Ejector cylinders, located at the center of the fixing plate, are designed to send out products after molding movement through the eject bar by moving up and down. Products or the mold may be damaged when the power generated by the upward moving ejector and stroke do not match; extra caution should be exercised. 10. Safety Part Low pressure Injection molding machines are built with following safety system to ensure safe molding operation. * Photoelectric Safety Device Installed on the ejector operation side, it stops closing movement of the mold when the lifted moving platen is dropping due to its gravity. * Mechanic Safety Device Installed on the upper part of the moving plate, it stops closing movement of the mold by the saw-toothed lock device when the lifted moving platen is dropping due to its gravity * Safety Bar When it is necessary to put a body part into the inside of the mold to repair or remove foreign objects, safety bar located on the left side of operation area can be pushed into the area between bolster and moving platen to prevent closing movement of the mold. * Start Button Switch This switch is used when an operator(s) starts the cycle. The number of operators can be chosen so that 1 or 2 operators can use the machine. Selected safety bar can be pushed into the area between bolster and moving platen to prevent closing movement of the mold. * Emergency Stop Switch There are five locations where the emergency stop switches are located; inside the control box located on the right side of operation area, near the safety bar located on the left side of operation area, inside the injection manual control box, and upper area of hydraulic tank. When used, pumps and the all operations will stop. * Alarm Buzzer The alarm buzzer will sound when 1cycle is activated or when a bolster is being moved. 11. Bolster & Moving unit This unit, located on each side of injection molding machine, is designed to install the low mold, and it moves horizontally by hydraulic motor.