What are the composition and design principles of the gating runner system?
The pouring runner system refers to the distance between the bush opening on the main channel and the mold cavity in the molding parts.Listen to it as a channel through which the plasticized melt enters the forming cavity.The casting system can be divided into the mutual position of the casting system in FIG. 3-4.2_ mainstream channel,3_ diverging channel;5 - cold material tank;6 - gate runner and hot runner casting system.There is no runner in the special pouring form, and the nozzle is directly extended into the mold, close to the cavity of the mold, and directly into the mold cavity through a small needle hole.
The structure of the flow passage of the pouring material is shown in FIG. 3-4. It is mainly composed of several parts, such as bush mouth, main channel, shunt channel, cold material trough and gate.It can also be seen from the figure that the distance from the bush mouth to the cavity of the mold forming product is the flow passage from the nozzle to the cavity.
(1) composition of pouring runner system
1) mainstream, it is connected to the injection molding machine nozzle with a passage. Usually and injection molding machine nozzle on the same axis, cross section is circular, and with a certain toppling, molten material does not change direction in the mainstream way.
Impeller channel is a channel that enters the various cavity of the multimode from the main channel, i. e. the channel between the main channel and the liner port, usually on the parting surface.
The torque bush is a thin short passage from the end of the shunt channel to the mold cavity and is the smallest and shortest section of the pouring system.
The cold material well is generally located on the moving die opposite the main flow passage or at the end of the diverging channel.
(2) design principles of casting system
Plastic products quality, and the design of gating system, therefore, need to pay attention to the design of gating system, generally speaking, the design of gating system must pay attention to the following principles.
It is necessary to ensure that the process of filling the mould is fast and not disordered, and to create good exhaust conditions.
In order to meet the forming characteristics of the plastics used, the gating system is designed according to the different forming characteristics of various plastics.
In order to reduce the resistance of melt flow, the front impact of the melt on the small diameter core and fragile metal inserts should be avoided.
When a module is multicavity, the volume of each cavity shall not differ too much, otherwise it is difficult to guarantee the quality of products.
Both sides should consider the convenience of removing and repairing the inlet without affecting the appearance of the product.
Depending on the size, shape, wall thickness and technical requirements of the product, the selected parting surface is integrated, taking into account the form of the pouring system and the number of feeding outlets.
When selecting the position and shape of the inlet, the shape of the tool should be determined according to the shape and technical requirements of the tool.
In mass production, the process should be shortened as much as possible and the molding cycle should be shortened under the premise of ensuring quality.
The cold material at the end of the nozzle should not enter the mold cavity, and the location where the cold material is stored should be considered in the pouring system.