Due to its various designs and patterns, the two-component injection molding machine has been widely used in many industries, such as the mobile phone industry, pen-making industry, automobile industry, home appliance industry, hand tool industry, daily necessities industry
, etc. This study took the automobile industry as the target and applied the two-component injection technology in the field of automobile lamps, especially the solutions to various injection problems.
Photo／Rotary table two-component injection molding machine, which is suitable for two-component and multi-component products, widely used in the automotive lighting industry.
One of the key factors for multi-component injection molding is the variability of computer control programs.
Even for the same type of products, if different mold designs are used, different control programs must be adopted. After the customers purchase the multi-component injection molding machine, when a new mold is designed, an excellent supplier should be able to quickly modify or upgrade the existing machine to satisfy the injection requirements.
Read more>>Automobile parts application
Photo／Two-component injection molding machine applied on two-color headlights.
Multi-component Molding Technology for Automobile Lamps
The two-component molding with in-mold labeling (IML), two-component molding with in-mold assembly (IMA), two-component molding with stack mold, two-component molding with IML, IMA and stack mold, and two-component molding with sandwich injection, can all be completed in one machine.
As the national economy develops, the automobile industry has become a pillar industry in China and has put forward higher requirements for automobile lamps.
The quality of automobile lamps is important for driving safety. Thus, laws and regulations of all countries in the world have strict requirements on automobile lamps. The design must meet not only the safety requirements, but also other demands. For example, its appearance should blend in with the entire vehicle, be beautiful and practical, and comply with aerodynamics, in order to make the driver and passengers feel comfortable and convenient. In this case, the design of automobile lamps also changes with the development of the automotive industry.
Photo／FB-R Series with the product insertion function, three-component and four-component products can also be molded to expand the scope of use. The photo shows four-color tail lights.
Materials and Technological Characteristics of Automobile Lamps
Generally, an automobile lamp is composed of a base and a housing. The base is often made from thermosetting material - BMC (bulk molding compound), and the housing is made of PMMA, PP or ABS with two or three colors. For two-color automobile lamps, special attention should be given to the injection part of the two-component injection molding machine, and the center distance of the two screws should correspond to that of the two-component injection molding.
The Following Should Be Noticed during Injection Production
Factors that Impact Stable Molding of Automobile Lamps
Responses of Control Unit: overlong switching point, noise interference, unstable command output, and unstable temperature
Noise of Hydraulic System: unstable pressure, valve positioning quality, hysteresis, and damping changes of oil tubes
Differences in Mechanical Systems: internal leakage of oil seals, damping, friction differences, screw non-return valve positioning, and non-return effect
Uneven Plasticization: variation in plasticization quality; mold temperature control
FAQ about Design of Plastic Tubes for Tail Lamps
(1) The screw does not feed when idling
(2) The torque required by the screw is too large to rotate
(3) The plastic is not completely melted
(4) The screw metering is unstable
(5) The plastic mixing is uneven
(6) The temperature of low-temperature molding plastic rises rapidly
(7) There are bubbles on the molded product
(8) The molded product is easily to turn black and yellow on the inside
(9) The screw is easily to be eroded and worn-out, and has a short service life
Design Points of Screw Barrels
The screw barrels are the key components of the injection molding machine, and responsible for the transportation, melting, mixing, metering of the plastic raw materials. The barrels are closely related to the quality of the molded product.
Purposes to improve the plasticizing screw：
(1) Improve shearing and mixing
(2) Uniform mixing
(3) Enhance plasticizing capability
(4) Ensure uniform melting temperature
Design Points of Special Screw for Tail Lamps
(1) L/D ratio: 21~23
(2) The surface must be extremely smooth to avoid material accumulation.
(3) Thickness of electroplated coatings is increased to enhance corrosion resistance.
(4) Compression ratio: 2.3; feed section: about 50%; compression section: about 30%; metering section: about 20%
Read more>> Solutions for two-component large parts
Further reading>> A look at development trend for new energy vehicle parts!