HOME>Technology>The necessity of Mold Temp. Sensor   Mold Temperature Distribution Animation(without Mold Temp. Sensor) We had experienced a very difficult and hard time due to chronic problem caused by partial temperature deviation which is occurred by the heat capacity of resin filled in the mold. In case of a large-sized molding product (wide and deep), such as TV monitor or TV Back Cover, since it is 1 point gate, the transmitted heat capacity varies according to the distance, which makes the temperature distribution on the surface of mold be different each other and the difference of temperature is different by region according to the structure of cooling circuit. In case that resin that is heated by high temperature is filled in the mold via Gate, the mold temperature varies due to the difference of heat capacity to be transmitted. While only self-own resin heat is transmitted to a region far away from Gate, a considerable resin heating capacity is transmitted to the spot around Gate. For that reason, the mold temperature around Gate shows 68-degree and the edge shows 28-degree. In case of the resin fill in, the heat capacity decreases bit by bit according to the distance, so the Gate is filled in with the temperature of 240-degree and the edge is 174-degree. In the early stage, the inferior molding products occurred in large quantities as much as 80-120 pieces; lots of heat capacity was transmitted to the Gate and the mold temperature showed 68-degree and it took us a lot of time to cool the filled resin, so the production cycle time was 90sec., which meant low productivity. Therefore due to high inferiority rate and low productivity, the production cost was so high. In case of edge of mold, the mold temperature was 28-degreee and the resin temperature filled in was 174-dgree. If raising the injection pressure for molding the finished products, we could not help wasting the raw materials.   Mold Temperature Distribution Animation(with Mold Temp. Sensor) Because of the great difference in the temperature by zone, the solution depends on controlling the change of temperature freely by zone not controlling only one zone. For controlling the temperature by zone, each two temperature sensors are installed on the fixed side (cavity) and the moving side (core), respectively, of the molding unit in mold, the high temperature zone of the mouth of Gate, and the edge of molding products; the cooling circuits are classified; and the mold temperature by zone is managed individually. By controlling the mold temperature so that the zone of gate is 48-degree and the zone of edge is 58-degree for preventing the solidification of resin, it is possible to produce a finished product from the first injection product since resin with the temperature of 202-degree is filled in.