Nissei puts an "Ultra Compact Electric Injection Molding Machine" for micro molding use to practical use.
Nissei Plastic Industrial Co., Ltd. has recently put an ultra compact electric injection molding machine, "ELJECT AU3E," to practical use and started its sales to overseas markets. The machine has the world's smallest class mold clamping force of 29.4 kN (3 tons) for micro molding, aiming to mold products of 0.2 gram in weight or less. Recently, as a remarkable tendency in the plastics molding, further miniaturization of products, reduction of weight and the molding of thin-walled products are required. Accordingly micro molding has attracted considerable attention as minute, fine and small quantity molding. In production sites too, there is a trend to shift from existing multi-cavity integrated production to small number cavity production. The advantages of the above are easiness and streamlining of production number control, molding the precision parts of high quality and simplification of an inspection process by means of single-cavity molding, and a saving of resin consumption. Molding machine characteristics of the ultra compact electric injection molding machine, "ELJECT AU3E," developed for micro molding use are: (1) A screw pre-pla system. (2) Precision plasticization. (3) A high performance nozzle. (4) A specially designed hopper throat. (5) A quick-response backflow prevention unit. As for the screw pre-pla system of (1), its injection mechanism is composed of a screw portion which conducts plasticization and metering, and a plunger portion which conducts injection filling. Especially, equipped with an 8-mm small-diameter plunger (there is another specifications with a 12-mm diameter) for higher injection resolution, it materializes stable molding with the maximum injection volume of 1.36cm3 and the minimum one-shot volume of 0.2cm3. Moreover, by means of equipping the small-diameter plunger, an excess of runner is reduced, improving the yield of material and leading to achieve plastics-saving. In regard to the precision plasticization of (2), crystalline resin is frequently used for micro molding, and the machine is equipped with a special screw, permitting precision melting of various super engineering plastics such as POM of which molding temperature is 200 degree C and LCP of 300 degree C and over. Regarding the high performance nozzle of (3), the machine is equipped with a special screw used for our company's dedicated machine for connectors, that ensures prevention of stringiness and drooling of resin. The specially designed hopper throat port of (4) controls temperature and is specially shaped to prevent poor biting that a small-diameter screw causes easily. The quick-response backflow prevention unit of (5) completes closing in 0.025 second after the start of injection by means of the resin backflow prevention unit for which a ball-check system is adopted, and at the same time materializes stable closing. A two tie-bar traction system is applied to the mold clamping mechanism, so that the whole machine is made compact. Besides it makes installing/uninstalling of a mold easier. Furthermore, a linear guide way is used for a movable platen. It is of a high precision structure in order to improve static (parallelism, perpendicular) and dynamic (stability at mold opening/closing) characteristics of the mold clamping unit. As an example of micro molding with this molding machine which has the characteristics mentioned above, we introduce a case of the molding of a micro switch cam. The resin used is LCP, the number of cavity is one, and the molding cycle is 4.77 seconds. Refer to a photo and a graph on the separate sheet 1. The photo shows a molded micro switch cam. The graph shows a trend of quantity of products at the time of micro switch cam molding. In the molding of this micro switch cam, the quantity of a runner has been reduced by 30% as compared with the existing molding. Up until now, in a case of the molding of small-sized parts of several milligrams in weight, designing with a larger runner more than necessary has been conducted because they have been molded by a machine with a larger mold clamping force than this molding machine. Refer to a photo and a table on the separate sheet 2. In addition, the machine is equipped with a built-in mold temperature controller, a cooling water chiller and casters. This all-in-one type machine can be relocated easily and permits molding operation at any location just by connecting a power supply. Moreover, the ejection of products to the lower side of the mold clamping mechanism improves product collection workability, and contributes to space-saving of the inside of a plant. The controller, "NC9300T," with a 6.5 inch TFT color liquid crystal screen of a thin type broad visual field, is mounted. The machine secures a high level of safety and is in accordance with the safety standards of the European Specifications. Main specifications of the "AU3E type"
[Separate sheet 2] Plastic Saving
|
||||||||||||||||||||||||||||||||||||||||||||
|