Introduction to two-color injection molding technology process and mold characteristics


Two-color injection molding technology is also called two-component injection molding technology. This is a technology that uses two plastic materials to mix and inject plastic products. Its technical connotation is actually to use a mold component to shape the shape and form in the mold. Work welding, so the fundamental principle is to plasticize two different plastic materials, and then use molds for welding installation to achieve the purpose of two-color injection molding.
 
1. Two-color injection molding technology type
1.1 Core rotating two-color injection molding technology
 
This technology is also known as the two-color injection molding technology of the rotating core. Its technical principle is to first use the injection equipment to inject the first raw material plastic into the small holes of the mold. When it is molded, it becomes the first plastic , And then rotate the mold 180°, and use the same injection equipment to inject the second raw material plastic. After the second plastic is molded, the final encapsulation work is performed, and a basic two-color injection molding work is completed.

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 This technology is relatively simple to use and operate. Generally, workers with a little training can operate freely, and it can greatly increase the design freedom of plastic products. At the same time, it can be processed with simple tools.

 
1.2 Shrink mold core two-color injection molding technology
 
       The shrink mold core two-color injection technology mainly uses hydraulic devices to compress the mold. First, under the control of the hydraulic device, the core that can move up and down is pushed to the top ascending position like a piston, and the plastic material is injected. After the first material is solidified, the movable core is controlled to fall, and then Inject another plastic raw material, and then control the hydraulic device to make the core ascend and press, and wait for it to solidify and form.
 
The plastic products pressed by this technology are initially manufactured, and then the molded plastic parts are taken out for subsequent processing. The operation of this technique is relatively simple, and the timing of the movement of the hydraulic device must be controlled.
 
1.3 The principle of the two-color injection technology of the rotation of the stripping plate
 

       Before this technology works, the first raw material must be injected. During the injection, the other parts of the mold are closed, and the injection mold will be gradually cut and separated. The rear part of the insert will gradually retreat, but it still exists on the parting plate part, and the mold retreats dynamically , The ejector rod and the pellet rod part of the entire injection molding machine are cooled and fallen off after the path, and the first part is completed;浙江杭科模具有限公司

  The next step is to carry out the second part of the injection molding operation, which is roughly the same as the first part, but the second injection uses two nozzles to inject at the same time. After the curing, the two parts are ejected together to complete an injection cycle.

 
 1.4 Core sliding two-color injection technology
 
       The working principle of the core sliding two-color injection technology is to classify the cores into two for use. During the first injection, the used cores are slid to the designated position, and the clamping injection is implemented. The first raw material The plastic is injected into the mold, and the mold is opened once after cooling.
 
The transmission device slides the first core out, slides the second core to the cavity, and then injects the plastic for the second time. After it is cooled and formed, one injection cycle is completed, and the two composites The finished product slides out. This technical model is more suitable for the needs of large two-color injection molded plastic parts.
 
2. Introduction to the characteristics of two-color injection molding process
2.1 Two sets of structure of two-color injection machine
 
       Due to the influence of the purpose of making the product, the two-color injection molding machine needs to be equipped with two identical plastic injection devices. This is not only the requirement of the process, but also the ability to be able to rotate.
 
These two sets of injection devices with the same specifications need to have the same functions in addition to the same structure. During injection molding, the raw material temperature, injection pressure and injection rate of the two sets of equipment can be adjusted consistently, so that the injection molded plastic products All indicators of the company are maintained at a consistent level, and then related fusion and welding work is carried out. If the parameters of the two sets of equipment are inconsistent, try to adjust to a consistent level.

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2.2 The machine structure difference between two-color injection molded components and ordinary injection molded components
 
      Due to the unique characteristics of plastic products produced by two-color injection molding components, there are some obvious differences in the mechanism settings of the machine and ordinary injection molding materials.
 
First of all, the temperature of the melt used in two-color injection molding components is higher, which is a certain gap compared with ordinary injection components. It requires high temperature to maintain the ability to operate and flow in the mold; secondly, the injection pressure is also higher, not only because of the use of They are two different plastic raw materials. To press and weld them, strong pressure is needed to fuse them, and they are designed to overcome the huge resistance of the molten material flowing in the mold to ensure the smooth progress of injection molding.
 
 2.3 Material parameter setting of two-color injection molding technology
 
       Two-color injection molding technology uses two different materials for the production of plastic products. Therefore, materials need to be considered before injection molding. Not only must the quality standards of the selected materials be considered, but also the temperature and pressure of the materials during injection molding. control.
 
       Since the mold used in two-color injection molding technology is different from that of ordinary injection molding, it requires the use of two-color injection molding technology material parameters to have a higher melt temperature to ensure that the melt does not solidify before the injection is completed. At the same time, the injection device must be used to control the pressure of the raw material so that it can reach all parts of the mold smoothly, so as to achieve the purpose of injection molding.
 
3. Two-color injection products and mold design points
3.1 Structural characteristics of two-color injection molded products
 
       The structure of two-color injection molded products is very different from that of ordinary plastic products. Because two different materials are used for injection molding, the products have two different properties and characteristics, which are fundamentally different from ordinary injection molded products; Before injection molding, a detailed two-color injection molded product structure design is required, and the compatibility of the two materials should be fully considered.
 
       Design the mixing ratio and connection method of the two materials in combination with the function and use environment of the plastic product, analyze the complexity of the process in detail, and consider the design of the use strength, so that the two-color injection product can meet the relevant material standards And requirements.
 
3.1.1 The choice of two materials
 
       Two-color injection molding technology uses two different materials for injection molding. Therefore, the selection of two different materials is also an important process. Generally, two different colors of plastic are selected, which can greatly improve the strength and durability of the injection molded product. At the same time, it is easier to fusion molding. However, products for special purposes may need to take advantage of the extremely different properties of the two materials, which requires solving the problem of the difficulty of fusing two materials with larger differences.

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Mainly there will be delamination and shedding problems, which is a fatal blow to injection molded products. Therefore, the shrinkage rate and different interface conditions need to be carefully considered, and the proportion of materials used must be adjusted.
 
3.1.2 Design of the internal structure and shape of the product
 
       The design of the product structure and shape first needs to be considered from the purpose and purpose of the product, and careful research is carried out in terms of size and internal structure.
 
       Generally, it is necessary to increase the contact area of ​​the two materials to enhance the firmness. Here, more small grooves and convex grooves can be designed in the product for inlay and stitching, which achieves the purpose of increasing the contact area of ​​the two materials , It can better improve the strength and service life of the product during injection molding, and enhance the practicality.
 
3.2 Rotary mold two-speed injection mold
 
       This kind of mold requires different considerations in the molding part. First, the concave-convex grooves of the two injection molds need to be carefully designed to ensure that they can be tightly closed when they are connected. At the same time, when the demolding mechanism is designed, the second injection can be performed before demolding work. Different injection molding methods have to be differentiated in detail. After the vertically rotating injection machine is demolded, the product is ejected to complete the related operations. However, the ejection of the injection machine cannot be used to eject the mold and the hydraulic device is required for demolding. mold.

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4 Conclusion

In summary, the two-color injection molding technology has been developed over many years, but it has only been gradually valued and applied in recent years, because the finished products produced by it have good adaptability to the use environment, and the production efficiency is extremely high. Different actual requirements can be well met, so it is gradually being widely used, and it has good economic benefits in the automobile industry and other fields, and it is a technology with great development potential.

Two-color injection molding technology is also called two-component injection molding technology. This is a technology that uses two plastic materials to mix and inject plastic products. Its technical connotation is actually to use a mold component to shape the shape and form in the mold. Work welding, so the fundamental principle is to plasticize two different plastic materials, and then use molds for welding installation to achieve the purpose of two-color injection molding.

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Introduction to two-color injection molding technology process and mold characteristics

Two-color injection molding technology is also called two-component injection molding technology. This is a technology that uses two plastic materials to mix and inject plastic products. Its technical connotation is actually to use a mold component to shape the shape and form in the mold. Work welding, so the fundamental principle is to plasticize two different plastic materials, and then use molds for welding installation to achieve the purpose of two-color injection molding.


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