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2-shot Mould Good Adhesion And Fusion

Jie Mei Precision Mould Ltd | Updated: Jun 06, 2017

2-shot Mould refers to two kinds of plastic materials in the same injection molding machine injection molding, two molding, but the product only die once the mold. Generally this molding process is also called double injection molding, usually by a set of molds, and the need for special two-color injection molding machine. 2-shot Mould s are increasingly popular on the market today, this process can make the appearance of the product more beautiful, easy to change the color and can not spray, but the design and injection molding requirements.

1. The basic principles of 2-shot Mould  design:

(1) hard glue to do 1, soft to do 2 times;

(2) transparent to do 1, non-transparent to do 2 times;

(3) the molding temperature of the plastic to do a high, the molding temperature is low to do 2 times;

The above is the basic principle of doing the two-color mode, otherwise the mold will be white; In addition, when the sealant as far as possible by breaking sealant, and not inserted through the sealant, even if it is recommended to modify the product customers should try to rely on broken sealant.

2. Mold embryo guide column guide sleeve must be up and down symmetry, before and after the mold symmetry.

3. After the mold to rotate 180 degrees, before the mold does not move.

4. Product spacing must be the distance between the nozzle of the injection molding machine shall prevail, some foreign color injection molding machine nozzle spacing is adjustable, and some are not adjustable, the domestic non-adjustable.

5. Two separate ejection systems, the top stick is two. After the two models of the same mold, thimble are the same, is a rotating relationship, must not be made a translation relationship.

6. Thimble needle plate can only be reset with a spring, can not be forced to reset the screw, because the back mold to rotate.

7. Side lock must be in the center of the mold on the four sides, and before and after the mold symmetry, or when the back-mold rotation after 180 and the former model is not on.

8. If the distance between the glue and the injection molding machine gun nozzle spacing, the top stick hole to be made of the waist type, because the injection molding machine head rod spacing is not adjustable. Note that most of the domestic color injection molding machine nozzle is not adjustable.

9. Note that the direction of the parallel nozzle of the injection molding machine provided by the customer is the X-axis or Y-axis, so as to set the layout of the product.

10. The direction of water entering and leaving the water must be in the side of heaven and earth, and each of the water and water must be in the same side, not into the water in the day, the water on the ground side, because the posterior mold to rotate 180 degrees, Size can not exceed the height of the injection molding machine outlet, or can not pick up water.

11. The first injection of the product to be placed on the non-operating side, because the first injection after the product to rotate 180 degrees for the second injection, just to the operation side, easy to take the product.

12. The mold code of the exit mold is not on the side of the operation and the non-operation side, because their products are fully automatic.

13. Sub-surface of the note: the latter part of the mold to be combined after the two products to obtain the sub-model for the post-mold; before the mold parting surface to take a single product can, not take the product after the merger Partial surface.

14. The tolerance of the front and rear flanges is negative 0.05mm, the tolerance between the two flanges is plus or minus 0.02mm, the gap between the top stick and the top hole is 0.1mm, the center distance of the front and rear guide guide guide pillar is positive and negative 0.01mm, mold frame on both sides and depth should be added to the tolerance, or when the posterior rotation after 180 degrees, due to high and low inconsistency and produce batch front. The frame depth tolerance is negative 0.02mm.

15. If the mold embryo factory has been processed after the mold, the factory to handle the mouth and the top hole when the hole to the four guide column guide hole spacing as the base of the number, or too much deviation, easy card Die mold. Ordering embryo to be marked when the 2-shot Mould  embryo, four guide pillars and box symmetry, after the mold rotation 180 degrees to match with the former mold.

16. If it is a post-mold rotation of the two-color, then the more simple .. two before the core of the same ... side of the plastic injection after the hard glue. Rotate 180 degrees (Note when the product can not fall, the gate can be automatically separated ), Go to the other side and then injection of soft plastic ... injection hard gel without arranging thimble ... just arranged in the soft side of the core can be ... another shrink to pay attention to ... if the soft completely Hard plastic wrapped around .. only need to put the plastic shrinkage ... if the contours are connected to the hard plastic glue should be shrinking water.

17. If it is a set of mold 2-shot Mould , then it is a straight barrel, a 90-degree barrel shotcrete, do not need to rotate, just a core, soft and hard plastic separation method by row glue.

18.Cavity of the two shapes are different, respectively, forming a product. The Core of the two shapes are the same.

19. mold before and after the mold to rotate 180 °, must be consistent. Design must do this check action.

20. Note the location of the top pinhole, the minimum interval of 210mm. Large molds should be properly increased the number of top stick holes. And, because the injection molding machine itself with the thimble is not long enough, so our mold must be designed to extend the thimble, thimble out of the mold base plate about 150mm.

21. Two positioning loops must be designed on the back plate.

22. The total thickness of the front panel plus A plate can not be less than 170mm. Please carefully check the other reference data of this type of injection molding machine, for example, the maximum capacity thickness, the minimum tolerance thickness, the top hole spacing and so on.

23. The depth of the front side SPRUE should not exceed 65mm. The upper side (large outlet) SPRUE top to the center of the mold embryo interval is not less than 150mm.

24. In the design of the second injection CAVITY, in order to prevent CAVITY plug (or wipe) injury for the first time has a good product plastic bit, you can design a local shelter. But must be careful to consider the strength of each seal, that is: in the injection molding, whether there will be a large injection pressure, the plastic deformation, resulting in the second injection may have the possibility of batch.

25. Injection molding, the first injection molding product size can be slightly larger, so that it can be molded in the second time with another CAVITY more tightly to reach the role of sealant.

26. before the A, B board mold, pay attention to whether the former Slider or Lifter can first reset and crush the product? In this way, it is necessary to make a way to make the A, B board first die, after the former model SLIDER or LIFET to reset. 27. Both CAVITY and CORE are shipped as full and balanced as possible.

28.99% of the situation is the first injection of hard plastic products, and then injection of soft plastic products locally. As the soft plastic deformation.

29. Note that in the second injection molding, plastic activities can impulse the first time has been a good product, so that the plastic deformation? Suppose there is such a possibility, we must think of ways to improve.

30. 2-shot Mould  must be carefully selected gate position. A product of the best choice of latent into the glue, so that products and flow can be automatically cut off. When you can not use latent into the glue, you can consider the three-plate mold or hot runner mold. If the material is a point gate, to do Boai, to avoid a point into the residual material and touch the secondary material.

31. Two-color injection mold often used rotary injection mold. Rotary injection molds Two positions on the punch / die require size, accuracy, and with the die / punch with a good. When you can not use the two-color injection molding machine on the top of the stripping mechanism, the turntable must be set on the hydraulic ejector stripping mechanism.

32. 2-shot Mould  injection molding usually use different colors of the same plastic, can also be two different plastic raw materials, this time we must consider the interface of the two materials, shrinkage difference, processing parameters and so on. Two-color injection products generally ABS, PC and other hard plastic with TPE soft plastic-based, due to the cost or application of the relationship, to fully consider the use of the two materials may not be between the good adhesion and fusion, (Usually there will be embossed lines of the phenomenon or need to do the mold cavity) there is a lot of thickness and so on the thickness of the problem! In order to make the two plastic "sticky" more tight, to think about the material between the "sticky" and the appearance of the mold roughness. Two-color injection has a dedicated TPU material; and the appearance of the mold more smooth, they "sticky more tight.

33. In general, the shrinkage of a 2-shot Mould  depends on the primary material. Because a material has been plastic products to support the contours of the secondary material will not shrink more. As for how to determine a material and secondary materials, there are many factors to consider, such as raw material mobility, plastic products, and so on.

34. pay attention to the positioning of the front and rear mold; all inserted, by breaking the slope of the slope as much as possible, to 0.1mm or more.

35.ABS / PC, ABS / PC + ABS, ABS / PMMA two-color injection molding, the need to first injection of high temperature PC, PC + ABS or PMMA. If it is transparent case mold most of the flip-chip structure.

36. Transparent large color injection for the structural design is the need to pay attention to the place:

A. The location of the gate must be agreed with the mold factory in advance;

B. The thickness of the material recommended to use more than 0.8mm transparent, non-transparent 0.7mm or more, non-transparent as far as possible with light, with LED lights when shading;

C. transparent part of the sub-surface and the width of the same width of the hole, the width recommended 0.5mm, surface connected Shun, to avoid the side to see, through the very far, unsightly, to minimize the hole;

D. non-transparent pieces of the thickness of the above bars and other structures as far as possible between 0.5-0.6mm, to avoid shrinking;

E. At present, it is not recommended to do with the main lens of the two-color injection molding, mold and product cost is too high, the mold manufacturers of equipment and technical level of considerable requirements, do, need to give the whole process to solve a detailed solution For the assessment, for the middle part of the need to review;

F. For a large area of two-color injection molded parts, two key tests are falling and hot and cold shocks, in which the transparent and non-transparent parts are easily disengaged. Hot and cold impact -40 -65, time 48 hours.

G. Two-color pieces on the structure as simple as possible, complex to do with the above pieces, non-transparent pieces of the width of the ribs as far as possible in 0.5-0.6mm, to avoid shrinking.

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