1、 Two color injection advantages:
Two color mold can make two kinds of resins and colors with different characteristics into a single two-color product, which can reduce the assembly and post-processing engineering of molding products. Save the cost of dissolving and printing, increase the beautiful visual effect of products, and improve the grade and added value of products. It not only has the function of antiskid and increasing friction, but also has the flexible resin material, which makes it more ergonomic and feels better. The two-color injection molding products have the advantages of high quality stability, easy control of product deformation, short molding cycle, high output, 7% lower loss and 20% - 30% lower manufacturing cost
2、 Two color forming principle
Bicolor injection molding usually refers to the molding of two colors or different kinds of plastics. Because the two groups of injection units and nozzles of the bicolor machine are separated independently, most of the colors of the finished products are bicolor and distinct, not mixed together. The biggest difference between the two-color injection molding machine and the general injection molding machine is the design of the movable template of the injection unit. Generally speaking, the two-color machine has two groups of independent injection units, while the general injection machine has only one group of injection units. Two or two groups of injection units are configured in various forms according to the design of each manufacturer. As for the design of movable formwork, it is necessary to provide the mechanism of rotation. The common design, such as adding a turntable or a rotating shaft mechanism, provides 180 ° reciprocating rotation function, so that the mold can generate cyclic alternating action. Other special two-color dies do not need a rotary table or a rotating shaft mechanism, but are rotated alternately or horizontally by the die.
3、 Production process characteristics of injection molding two color products
1. The two-color injection molding machine is composed of two sets of plastic injection devices with the same structure and specification. According to the production mode, the nozzle shall have special structure or be equipped with two sets of forming dies with the same structure that can rotate and transpose. During plasticizing injection, it is required that the melt temperature, injection pressure, injection melt volume and other process parameters in the two sets of plasticizing injection devices are the same, and the fluctuation difference of process parameters in the two sets of devices should be minimized as far as possible.
2. Compared with the common injection molding plastic products, the melting material temperature and injection pressure of the two-color injection molding plastic products should adopt higher parameter values. The main reason is that the mold flow channel is relatively long, the structure is relatively complex, and the flow resistance of the injection melt is large.
3. The raw materials with good thermal stability and low melt viscosity shall be selected for the two-color injection molding plastic products to avoid decomposition due to high melt temperature and long residence time in the flow channel. The most widely used plastics are polyolefin resin, polystyrene and ABS.
4. In the injection molding of two-color plastic products, in order to make two kinds of different color melts weld in the mold well and ensure the molding quality of the injection molding products, high melt temperature, high mold temperature, high injection pressure and injection rate should be adopted.
4、 Two color mold structure
The traditional two-color injection mold has two forms: "punch translation" and "punch rotation".
① The die of "punch translation" has two dies and one punch. When the first barrel is injected, the punch is closed to the first die. Complete the first injection of plastic. After the first plastic solidifies, the concave and convex die are separated, and the semi-finished product formed by the first plastic stays in the convex die, and moves with the convex die to the position aligned with the second concave die. After the injection molding machine is closed, the second barrel is injected with the second plastic. After the second kind of plastic solidifies, the injection molding machine opens the mold and takes out the complete product.
② The bicolor die in the form of "punch rotation" has two recesses and a punch composed of two back-to-back groups, which can be rotated. The two sides of the injection molding machine equipped with two barrels, the second barrel is preferably designed in the vertical direction of the motion direction of the injection molding machine. Two different plastics can be injected at the same time. When the two kinds of plastic injected solidify, the injection molding machine opens and automatically ejects the complete product. After taking out the product, turn the "rotatable punch" 180 degrees. The injection molding machine is closed for the next cycle.
Because the first and second barrels of the "punch translation" mode are injected in turn, while the first and second barrels of the "punch rotation" mode are injected at the same time. Therefore, for the same product, the efficiency of "punch rotation" mode is twice that of "punch translation" mode.
5、 New technology of two color mould
The two-color injection molding machine is equipped with two barrels. The mold is single cavity and has the common cavity required by the first plastic ("hard glue") and the second plastic ("soft glue"). This technology requires a single die and punch, which is fundamentally different from the first two production modes. After the first plastic is injected into the first barrel, wait for the first plastic to partially solidify or solidify. The power cylinder at the beginning of the control drives the blade which plays the role of isolation, and retreats to the level with the profile of the punch. At this time, the second barrel is injected with the second plastic. After the second plastic is completely solidified, the injection molding machine opens and takes out the complete product. The injection molding machine is then shut down for the next cycle. The obvious advantage of this technology is to simplify the mold and reduce the demand for the working space of the injection molding machine (smaller two-color injection molding machine can be used to reduce investment and energy consumption). Moreover, the output can be increased by many times compared with the previous "glue wrapping method", and the defective products caused by putting the contracted and deformed "hard glue" back into the mold cavity can be avoided fundamentally.
6、 Difference between rubber coated mold and two-color mold:
1. Two color mold: two kinds of plastic materials are injected on the same injection molding machine, which are divided into two parts, but the product is only molded once. Generally, this kind of molding process is also called double material injection molding, which is usually completed by a set of molds and requires a special two-color injection molding machine. Two color mold can make two kinds of resins and colors with different characteristics into a single two-color product, which can reduce the assembly and post-processing engineering of molding products. Save the cost of dissolving and printing, increase the beautiful visual effect of products, and improve the grade and added value of products. It not only has the function of antiskid and increasing friction, but also has the flexible resin material, which makes it more ergonomic and feels better. The two-color injection molding products have high quality stability, easy to control product deformation, short molding cycle, high output, 7% lower loss and 20% - 30% lower manufacturing cost.
2. Rubber covered mold (secondary molding): two kinds of plastic materials are not necessarily injected on the same injection molding machine, and they are formed in two times; after the products are taken out of one set of mold, they are put into another set of mold for secondary injection molding. Therefore, the general molding process is usually completed by two sets of molds without special two-color injection molding machine. The mold structure is the same as that of single color injection mold, which is mainly controlled by adjusting the flow rate of injection parameters. The rubber covering mold is mainly soft rubber and hard rubber, of which soft rubber is commonly used as artificial rubber, TPU, TPR and other rubber materials, and hard rubber can be ABS, PC, PP and so on.
≫ & gt; win mold training school applet
≫ & gt; Yousheng China mould data net applet
≫ > excellent introduction of high-end precision five axis CNC Practice machine tool from Kede
≫ & gt; the example course of Moldflow analysis written by Mr. Yousheng Shi
≫ & gt; Yousheng original UG ﹣ 3-4-5 axis postprocessing Download
≫ & gt; Yousheng original PM 3-4-5 axis Post Processing Download
≫ & gt; the craftsman of great powers - "exactly the same" missile parts Carver
Hot articles
Free technical services for netizens
Free talent service for enterprises
← add Xiaobian wechat to join the technology exchange group of Yousheng
Click "read the original" to understand the class plan