Needle Valve Preform Mould Structural Design Is Reasonable And Reliable
Needle Valve Preform Mould technology is different from the ordinary injection mold technology, a cutting-edge technology, that is, in a mold in a number of mold cavity in the direction of overlapping design. This mold usually has a number of sub-surface, each sub-surface can be arranged one or more cavity. Simply put, the Needle Valve Preform Mould is equivalent to the multi-layer single-layer mold stacked together, installed in an injection molding machine for injection molding.
The structure of the Needle Valve Preform Mould is composed of a series of hot-runner system, special mold system, load-bearing system, bidirectional ejection system, open-mode linkage system and so on.
Needle Valve Preform Mould technology has the following characteristics:
Needle Valve Preform Mould production efficiency than ordinary single-layer mold double or many times, significantly reduce the cost of injection molding. From the structural characteristics of view, the Needle Valve Preform Mould will be combined with a number of vice mold in a mold, make full use of ordinary injection molding equipment can meet the production. Mold filling, holding pressure and cooling time and single-layer mold the same, which determines the production efficiency of the Needle Valve Preform Mould will be more than ordinary single-layer mold times or even times, greatly improving the product per unit time production.
Needle Valve Preform Moulds can be mounted on the same injection molding machine as a single-layer mold without the need to invest in the purchase of additional machines and equipment, thus saving the cost of machines, equipment, plant and new labor.
Needle Valve Preform Mould manufacturing requirements are basically the same as ordinary molds. According to statistics, a double double-layer mold manufacturing cycle than the two single-layer mold manufacturing cycle short 5% to 10%.
Produced by the production, laminated injection mold structure design is reasonable and reliable, product size consistency, mold costs reduced by 30%, forming efficiency doubled or doubled.
Needle Valve Preform Moulds are suitable for mass production of flattened large-sized products, small multi-cavity wall thin products, the larger the volume, the lower the production cost of the products.
Needle Valve Preform Mould technical characteristics
Usually, the injection molding machine and conventional mold with the use of its own injection and opening stroke only use the rated 20% to 40%, did not give full play to the performance of injection molding machine. Compared with the conventional mold, the clamping force of the laminated injection mold is only increased by 5% to 10%, but the yield can be increased by 90% ~ 95%, which greatly improves the equipment utilization rate and the productivity and reduces the cost.
Laminated injection mold as a new type of mold technology has been the continuous development, especially with the hot runner technology, making it a development of today's plastic mold a cutting-edge technology. The traditional conventional mold design theory has not been applied to the design of laminated injection molds, so it is urgent to develop a new mold design theory to guide the design of laminated injection mold. The design of the laminated injection mold will be described below.
Injection molding machine maximum injection volume
Laminated injection mold can be used cold runner, you can also use hot runner. When using the cold runner, the need to consider the amount of plastic used to pour the system condensate; when the use of hot runner, that is, to achieve no back to the production of materials in the hot runner and the central nozzle of the material does not affect the mold required injection , Can be ignored . Therefore, in the injection molding machine to check the maximum injection volume depends on the specific circumstances.
Injection molding machine injection pressure
Injection pressure check is mainly to test whether the injection pressure to meet the needs of molding. For the laminated injection mold, most of the thin-walled, large projection area, long process of plastic parts, in the filling process requires a higher injection pressure and injection speed. The laminated hot runner mold due to the use of hot runner technology, relative to the laminated cold runner mold, can better transmit the injection pressure, so the required injection pressure than the laminated cold runner mold small; But because of the increase in the process, the projected area increases, the required injection pressure than the single-layer cold runner mold. In the check injection pressure, should be based on a variety of plastic injection molding process, combined with computer simulation flow analysis to determine the injection pressure of plastic parts, and then injection molding machine rated injection pressure comparison.
Maximum clamping force of injection molding machine
The layers of the laminated injection mold are provided with "back to back", and theoretically, any number of laminations can be realized on the same injection molding machine without increasing the clamping force. However, since the center main nozzle and manifold of the laminated injection mold increase the flow path, the projection area of the plastic part plus the pouring system on the parting surface is increased; and the flow path is extended due to the stack , The pressure loss than the conventional single-layer mold, the corresponding increase in injection pressure, resulting in increased cavity pressure, so the clamping force has increased, check the same single-layer mold required clamping force increased by 10% to 15% Is relatively safe.
Injection molding machine opening stroke
The laminated injection mold is open and molded at two or more points. When the injection mold is checked, the thickness of the mold is not considered for the injection molding machine with hydraulic-mechanical clamping mechanism. When the laminated injection mold with a lateral classification of the core pulling mechanism, you need to consider the impact of the distance between the core. If the gear ratio of the same gear ratio or the elbow link mold opening device is used to synchronize the mold opening mechanism, the stroke of each layer of the laminated injection mold is not limited by the height of the product. The opening stroke is the largest in the multi-layer mold (N is the number of layers of the laminated injection mold).
Main nozzle length
The central nozzle can not be too long or too short, so that when the mold is closed, the central nozzle will not exceed the maximum distance from the injection nozzle of the injection molding machine in the frame. Since the center main nozzle is to be moved together with the intermediate portion of the mold in the mold, it is ensured that the central main nozzle remains in the mold part after opening the mold to prevent the spout of the central nozzle tip from dropping into the mold cavity wall on. (We are using the needle valve is used to control the hot system to enter the mouth of the phenomenon of material)
Laminated injection molds can use either a common runner pouring system (ie, a cold runner pouring system) or a hot runner pouring system. Hot runner pouring system can better convey the injection pressure, is conducive to improving the quality of plastic parts molding, and easy to achieve automated production, but there are certain requirements for plastic varieties, and hot runner system is expensive. When using the cold runner, the plastic parts of the molding quality is slightly worse, but the mold processing is easy, so the cost is low. Therefore, what kind of gating system should be based on the specific circumstances.
Mold temperature control system
Mold temperature is one of the important factors that affect the quality of plastic parts. The design of the laminated injection mold should ensure that the temperature conditions of the layers are consistent. For the laminated hot runner injection molds, in order to reduce the heat transfer loss of the hot runner system due to heat transfer, the contact area between the mold and the hot runner plate should be reduced and the corresponding insulation pads and the increased water transport should be provided.
Open mold mechanism
In order to make the plastic parts shrink, the plastic parts in the cavity of the residence time (cooling time) should be equal, so the laminated injection mold should ensure that the layers of the cavity of the sub-surface at the same time open. Gear rack drive mechanism and mechanical (toggle type) linkage mechanism often as a laminated injection mold of the mold body, the former technical performance is better, but also more economical, but the latter is more flexible. The use of hydraulic auxiliary mold is easier to control the opening time, but the structure is larger.
According to the cooling time equivalent requirements, the laminated injection mold should be the top of the cavity of the plastic parts at the same time out, the use of mechanical ejector, cylinder ejector, spring or high pressure air stripping mechanism to achieve this requirement.