At present, the methods of producing two-color mold products are encapsulation and two-color injection. Molds called "encapsulated type" and "two-color type" are used, respectively. The difference is that the overmold refers to the mold for secondary molding. First, the first product is injected into the first mold, and then the "semi-finished product" is injected into the second mold for the second product. The second product wraps the first product and completes the two-color product. Then, let's learn about it together.Suzhou double color moldToolsExperience summary!

The basic principles of mold design:

1) The shrinkage rate of the encapsulation mold. The shrinkage of the rubber package compound mold is determined according to the type of product material, product structure, and the requirements of dimensional accuracy. However, in general, the first forming mold is calculated according to the usual shrinkage rate, and the second product is soft. Rubber does not need to shrink.

2) The overmold is usually wrapped with soft rubber and hard rubber. Soft rubber often use TPU, TPE, TPR and other rubber materials. The hard rubber may be ABS, PC, etc. In most cases, the hard rubber part of the product is injected first, and then the soft rubber part of the product is injected. Because the soft rubber is shot, the soft rubber will be washed away and deformed during the second shot.

3) Two-color molding usually uses the same plastic of different colors, but it can also be two different plastic raw materials. The softening temperature of the mixed rubber of the primary molded article is 20% higher than the softening temperature of the mixed rubber of the secondary molded article. Otherwise, the mixed rubber of the first molded product will dissolve and decompose, and color mixing will occur. The division between different materials must consider the fluidity of the material and choose the appropriate wall thickness. Since the secondary molded product will pass over the primary molded product, the insufficient wall thickness of the secondary molded product will cause poor filling, which will easily lead to undesirable conditions such as glue breakage, shrinkage, and welding marks.

4) When the overmolding mold uses point feed and potential rubber, please minimize the diameter and length of the flow path connected to the rubber port, and pay attention to the cooling of the gate. Otherwise, the flow path connected to the rubber port is easily broken in the mold and difficult to take out. Potential rubber, nozzle needle need to do three steps.

The basic principles of Suzhou two-color mold design:

Make hard candy once, fudge twice;

Transparency 1 time, opacity 2 times. In special cases, it must be non-transparent. When making the first time, the rubber material must be resistant to high temperature and cannot be decomposed by the second transparent rubber material. The plastic with high forming temperature is made once and the plastic with low forming temperature is made twice. In the case of hard rubber, the one with large proportion of rubber is set as the first time and the one with small proportion is set as the second time. The above is the basic principle of two-color molding, otherwise the mold is at risk of being scrapped. In addition, when passing the sealing rubber, do not pass the sealing rubber. Please try to pass the sealing rubber by contact. Even if the customer recommends modifying the product, please pass the sealing rubber as much as possible by contact. The guide sleeves of the edge lock, mold and guide post must be symmetrical from top to bottom. Otherwise, the rear mold does not match the front mold after rotating 180 turns. Two-color is also divided into single-cavity two-shot (mold rotation after injection, or sliding control does not need to rotate), rotating two-color) parallel injection nozzle two-color and right-angle two-color)

5) The shrinkage rate of Suzhou two-color mold is determined by the type of product material, product structure, dimensional accuracy requirements and other factors, but generally speaking, the shrinkage of the first product and the second molded product of the two-color mold is synchronized. At this time, it is necessary to consider the interface between the two materials, the difference in shrinkage, whether the first material is more resistant to high temperature than the second, and will not be decomposed by the second rubber.

6) The parameters of Suzhou two-color mold are: the distance between muzzles, the ejection amount of each gun nozzle, and which gun nozzle of which color to use; The position distance and maximum protrusion stroke of ko; The size and loading weight of the turntable; For the configuration of water, oil and circuit on the turntable, the nozzle depth shall not exceed 40mm on the panel, and two retaining rings must be designed on the rear mold bottom plate.

7. The front mold of Suzhou two-color mold does not move. The rear mold must be rotated 180 degrees around the center of the turntable before it can be assembled with the front mold. If not, the mold cannot be closed. This check action must be performed during design. Pay special attention to the position and dimension of the blank guide sleeve, side lock, guide auxiliary device, nylon plug and other components;

8. The injection molding machine interval on the mold must be based on the injection nozzle interval of the injection molding machine. The nozzle spacing of a two-color injection molding machine can be adjusted, and some cannot be adjusted. It is necessary to understand the parameters of the customer's production and trial-produced injection molding machine, but the KO hole spacing of the injection molding machine cannot be adjusted, so the KO hole spacing should not be adjusted together when adjusting the spacing of the injection molding machine. Single cavity double shot.

9) Attention must be paid when designing a single cavity injection molding system. The two bonding positions of the mold are formed into a rear core, a cavity is designed, there is only one mold, and only one injection molding system. Because the first molded product is not injected during production, but is injected after the second molding. Using the mold parts related to the power drive of the cylinder body and the mold opening and closing, the second color is in a state of two positions, and the technology of forming separately in the two states is also called the two-color single-chamber two-shot technology. It is the two-color structure with the lowest cost and the highest production efficiency, and the structure is designed with priority. The mold is driven by the cylinder to slide, hold the insert to move a rubber thickness stroke, and perform two forming operations in a state of two positions.

10) Two cavities are designed in a set of molds, and the core is driven by the rack and pinion mechanism to rotate the product with the first cavity to the second cavity for forming; only the rack and pinion mechanism is added to the rear mold, The core rotates with the product without the drive mechanism and manipulator of the injection molding machine as the power to replace the chamber, and it can be used for two-color injection molding machines without drive mechanism and manipulator.

The above is the two-color mold experience summary, if you need to know moreSuzhou plastic mold production, remote control mold, Suzhou two-color injection molding, can contact us at any time!