Multi-color and multi-material injection molding products refer to two or more than two color materials or different materials through one or more than one flow path injection molding plastic products.
Multi-color injection molding products are formed by injection molding of plastic materials of different colors. Each material is not allowed to infiltrate each other during the molding process. It must be strictly separated from each other, for example, various buttons with keys and car lights.
First, the common material combination type
Multi-material injection molding products not only require the combination of different color materials, but also need to combine different types of plastic materials, including:
(1) Combining soft and hard products
In most cases, the soft and hard bonded products are formed by the combination of thermoplastic materials and thermoplastic elastomers (such as TUE, TPU, etc.). Such combination can make the products have a hard and corrosion resistant matrix, and is also provided with a sealed anti-vibration, or more comfortable The feel, such as handle products.
When forming in combination with different materials, the adhesion between the raw materials must be taken into consideration, and the different shrinkage ratio, coefficient of thermal expansion, and molding process temperature must be considered. When the design allows, mechanical connection through the internal mechanism can be considered. Or chemical reaction to enhance the bonding strength.
(2) Products combined with liquid silicone rubber (LSR)
Compared with thermoplastic elastomers, LSR has better temperature resistance and mechanical properties. The application of multi-material injection molding technology is getting more and more attention.
Due to the high mold temperature of the LSR, mold insulation during the mold design becomes a challenge. When molding the LSR, the mold usually requires the design of a cold runner system. This cold runner system must be fully insulated from the hot runner system of the molded thermoplastic material. In addition, the materials that can withstand the molding temperature of LSR are also very limited. For example, PA, PPS, and PETP are suitable materials for LSR molding.
(3) Products combined with electroplating/conductive materials
The use of a material with electroplating/conductivity and a combination of non-electroplating/conducting properties makes it possible to manufacture three-directional transmission conductor parts.
(4) In-mold assembly products
Two kinds of materials that are incompatible with each other can be combined by injection molding to become a connected and movable part. We call it an in-mold assembled part. Due to the size of the molded parts, the shrinkage ratio is different and incompatibility. , The injection molded parts of the two materials can be 'active', such as in the car's air outlet, toys and mechanical connection parts.
Second, different injection units
Multi-color multi-material injection molding machine consists of two or more injection units. According to the arrangement of the injection unit (secondary injection station), it can be classified as V type, L type, P type and W type.
These types of multi-color and multi-material injection molding machines have their own characteristics, and users need to choose according to their own needs. Among them, V-type and L-type are widely used in European injection molding machines, while most Japanese and domestic machines are used in P-type. .
At present, most of the multi-color and multi-material injection molding machines on the market are manufactured by injection molding machine manufacturers according to the needs of users. In many cases, these machines can only produce specific products, while the independent auxiliary shooting stations can be used. The transformation of the existing machines has greatly improved the utilization rate and flexibility of the equipment, and also reduced the initial investment in equipment. This is a flexible, environmentally friendly and low-cost multi-color multi-material equipment program.