Characteristics of cast copper heater on mold
In the mold process, the cast copper heater can make the heater, heat preservation and cooling and clamping structure of the mold an indispensable part of the composite mold design. Structural design directly affects the appearance and internal quality uniformity of the product, and also affects the molding efficiency of the product.
1. Design requirements for cast copper heaters
The cast copper heater is a heating method that must be used in the design of almost all plastic molding molds. It can be designed in various forms such as one-way wiring and two-way wiring. The material can be seam pipes and seamless pipes, which are characterized by low heat loss and thermal efficiency. High, simple wiring, can be designed as 220V or 380V according to needs, the wiring is flexible and diverse. However, due to the limitations of its materials and processing technology, it is necessary to pay attention to its characteristics in mold design.
(1) The cast copper heater usually has a long cold end at both ends, which cannot play a heating role.
(2) The power design of the cast copper heater section should not exceed the limit of 10 watts/cm. Such as 20 cm long heating tube, the power should not exceed 200 watts as much as possible. If the design power exceeds this limit, the surface load of the heating tube is high, and the steel tube is prone to oxidation and corrosion, causing a short circuit.
(3) For mold design with a temperature higher than 250°C, it is difficult to use a heating tube. Because under this condition, the heating tube, the connecting terminal, the copper wire for connection and other media are very easy to oxidize, resulting in a circuit break. Therefore, special treatment is required for the electrical transmission medium to avoid exposing the conductive wire to the air as much as possible to extend the service life of the wire.
Safety measures such as insurance and air switch are indispensable in the design. The operation site must be kept clean and tidy, with good insulation, and be diligent in checking electrical failures during operation to prevent unnecessary danger.
2. Installation drilling of cast copper heater
From the perspective of heat transfer, the installation of the cast copper heater should be as close as possible to the mold surface to facilitate the transfer of heat from the heating tube to the mold as soon as possible. For example, the diameter of the mold hole is 18mm, and the diameter of the heating tube is set to 17.8mm. In fact, there is not much contact area between the heating tube and the mold. The essence of heat transfer is radiation, and conduction is secondary.