Process requirements for multicolor injection molding
Soft and hard glue two-color design:
The melting point of the two materials must have a certain temperature difference. It is generally recommended that the melting point of the two materials should be 60° and above 30°. The melting point of the first shot material should be high, generally the first shot is PC or PC/ABS, and the second shot is TPU or TPE.
Widen the contact area as far as possible, make grooves and so on to increase the adhesive force, or the first shot adopts core-pulling, the second shot part of the material injection into the first shot, the first shot mold surface as rough as possible.
Two basic compatibility conditions must be met for the matching materials of multicolor injection molding, namely adhesion compatibility and process compatibility.
Transparent and opaque bijective designs
· Birefringence design for small lenses
The first shot does not transparent, the second shot does the lens, the first shot tries to use PC melting point high, the second shot USES PMMA.
· Transparent and non-transparent birefringent design for decoration
The first shot is non-transparent material, the second shot is transparent material, the non-transparent material is commonly used is SABIC PC material temperature high, the second shot is transparent material PMMA or PC.PC needs to be sprayed with UV protection, PMMA can choose UV or enhanced, if there are characters on the surface must choose UV.
Two-color injection mold features
Moving mold is the same, injection process is rotating, need to exchange, so moving mold must be the same.(There are special cases, molding cavity can be different)
After injection molding of the first shot of the mold, the runner can not be left on the mold, it is better to be hot runner, or you can use the manipulator to grab, the worst is also if the latent gate, can automatically fall off, or the second shot on the mold can not be consistent production is also prone to die accidents.
The product is shot twice. After the mold opening, the first shot must be left at the moving mold side. Generally speaking, it is the choice to leave the two shot products at the moving mold side.
Process evaluation of multicolor injection molding:
Two-color injection molding has been a very mature molding process, in the initial stage of mold development, can be through a variety of CAE software analogical analysis, through the analog operation of the model can accurately determine the mold and the formation of each parameter.
Material analysis is a key issue to be considered in the research and development stage of dual-color injection molding. With the increasing market demand, a variety of materials appear in the field of dual-color injection molding. Reasonable material selection has become a very key link in the research and development stage.A more rigorous approach is that CAE software can be used for the simulation test of surface compatibility and binding degree, and data selection can be carried out.
In the mold development stage, the waterway is a crucial link, because in the two-color injection process, if the cooling is not sufficient or unstable, will cause defects in the size and appearance of the product, so in the development stage must do a careful review of th distribution of the waterway.
Analysis in LSR and other fields
In LSR and other emerging domestic forming processes, we can also determine the problem points that may occur in the forming process through some software analysis, so as to reduce the defective rate in the production process.
Above all, multi-color injection molding technology after years of development, the branch of the molding is increasingly perfect, can good application in various fields, high manufacturing efficiency at the same time, the different is able to meet the actual requirements, thus being widely used, in the automotive industry, electronics, medical and other fields has a very good economic benefit, is a technique of great development potential.Among these branches, sandwich injection molding, cube mold and LSR molding have distinct advantages in environmental protection, high efficiency, excellent application performance and other aspects. These technologies have gradually become a hot trend in the industry and gradually come into People's Daily life.We also hope that the multi - color molding process can bring more exciting for our production.