The hot nozzle is used to ensure that the plastic in the runner and gate is kept molten by heating. Since the heating rod and heating ring are located near or in the center of the flow path, the entire flow path from the barrel outlet of the injection molding machine to the gate is in a high temperature state, so that the plastic in the flow path remains molten. Usually, it is not necessary to open the runner to remove the condensate after stopping, and it is only necessary to heat the runner to the required temperature when restarting. In short, the hot nozzle is an extension of the cylinder of the injection molding machine.

Hot nozzle system structure

Hot nozzle systems generally include two types: open hot nozzle and needle valve hot nozzle.

The open hot nozzle is generally composed of a nozzle, a shunt plate, a hot nozzle, a temperature control box and accessories. The needle valve hot nozzle is generally composed of an oil nozzle, a diverter plate, a hot nozzle, a temperature control box, a cylinder or cylinder, a valve needle, accessories, etc. The nozzle form of the hot nozzle is divided into large water inlet and pointed nozzle. The shunt plate is used for multi-cavity or multi-point feed and single-point eccentric feed for a practice exam. The size of the diverter plate is mainly determined by the distribution of the cavity on the mold, the nozzle arrangement and the gate position. The temperature control box includes a host, cable, connector, male and female wiring socket, etc. Hot nozzle accessories usually include: heaters and thermocouples, runner seals, connectors, junction boxes, etc. It mainly controls the temperature of the diverter plate and the hot nozzle.

Advantages and disadvantages of hot nozzle technology

Interest

1, save raw materials, reduce costs. (Although the cold head can still be recycled, due to human factors, the mixing ratio of recycled materials, etc., in order to maintain normal operation, some cold head must be accumulated, resulting in the retention of funds.)

2, shorten the molding cycle, improve machine efficiency. Because there is no limit to the cooling time of the runner system, the parts can be ejected in time after forming and curing. Many thin-walled parts produced with hot-nozzle molds can have a forming cycle of less than 5 seconds.)

3, improve product quality (in the hot nozzle molding process, the temperature of the plastic melt is accurately controlled in the flow system. The plastic can flow into each mold cavity in a more uniform state, resulting in a consistent quality part.)

4, improve the level of automation. The plastic is a finished product formed by a hot-nozzle mold. No need to trim the runner and recover the cold runner. Many foreign product manufacturers combine hot nozzle with automation to greatly improve production efficiency.

However, every technology has its disadvantages, and hot-tip technology is no exception:

1, the mold structure is complex, the cost is high, the maintenance cost is high.

2, the start-up process takes a while to stabilize, resulting in more waste products at first.

3. If melt leakage and heating element failure occur, product quality and production schedule will be greatly affected.