The 5g era is coming, and the material of mobile phone shell is changing from plastic to metal and to non-metal. Plastic is favored by the middle and low-end market because of its low cost. From IML to IMT process, the plastic becomes rich and beautiful, which can approximate the 3D optical texture of the simulated glass back cover, and has become the choice of many CMF designers. LDS has been widely used in plastic back shell antennas in the 4G era, but whether it can adapt to the high-end curved glass 3D back cover in the 5g era still needs to continue layout research and development. IMT technology can be further extended to ime technology, which integrates electrical and decorative functions and can be applied to the future automotive intelligent surface. As a low-cost and efficient product form, the injection molded transparent PC back cover with better impact strength and durability has attracted more and more attention from traditional plastic manufacturers.

LDS Technology

The principle of LDS technology is to excite the metal particles of the plastic shell containing metal components by laser, and make the copper sheet emerge on the plastic through environmental protection electroplating technology. This copper sheet can directly turn the mobile phone shell into an antenna to receive signals in three-dimensional space.

Manufacturing process of LDS Technology:

Integrated design of antenna and structural parts → injection molding → thunder carving → chemical plating → RF test → surface treatment → assembly / post decoration.

At present, one of the main applications of LDS in smart phone terminal antenna is called LDS antenna. The ordinary mobile phone antenna is installed on the mobile phone motherboard. LDS antenna technology is a direct laser forming technology, which uses a computer to control the movement of the laser according to the trajectory of the conductive pattern, projects the laser onto the formed three-dimensional plastic device, and activates the circuit pattern in a few seconds. With this technology, the antenna can be directly laser on the mobile phone shell, meeting the design requirements of light and thin mobile phones with small space.

Advantages of LDS Technology:

Mobile devices (smartphones, tablets, laptops) tend to have large screens, thin bodies, and integrated multi-function. The requirements for antennas are becoming more and more stringent. LDS antenna technology provides flexible and complex three-dimensional design, which has surpassed the technical application of traditional solid antenna in small-size and mobile devices. Its advantages are:

1. Different types of antennas are integrated; For example, GSM, CDMA, WiFi, Bluetooth, FM radio.

2. Save space in the slim and complex structure of portable mobile devices.

3. The interference in different types of antennas is reduced, and the probability of signal decline caused by users' direct touch to the antenna is reduced.

4. It can be widely used in smartphones, laptops and tablets.

Development trend:

In the future 5g era, the terminal antenna of high-end smart phones needs to cover the back cover of 3D glass. The curved structure of 3D glass is not suitable for the placement of 5g antenna contacts, which is a current technical problem. Recently, according to media reports, BYD has the technical reserve to mass produce 5g antenna on 3D glass back cover. Whether LDS antenna is suitable for curved 3D glass needs to continue layout research.

IMR Technology

In mold transfer process is a kind of in mold decoration. IMR process has become the mainstream process of notebook computer shell treatment, and has been widely used in mobile phone terminals.

The principle of IMR process: printing ink on PE film can also evaporate the metal material on PE film into a whole roll type. Add a positioning system on the molding machine. After aligning the printing position of the film with the position to be printed in the mold cavity, mold the film with plastic. After molding, the molded product is combined with the ink, but separated from the film, and the molding action of the next mold continues. After UV irradiation, the surface of the molded product is hardened.

IMR technology can achieve different decorative effects (leather, cloth, bamboo, stone, etc.), and its advantage is that it can display patterns with different effects by changing the film.

Development trend:

The most important thing in IMR product development is the successful condition of coating transfer. There are restrictions on height, corner radius and draft angle, so the products using IMR technology in the past can only be made into four corners that are round. We call it arc machine, which has no side wall height at all. At present, matte and high gloss have been shipped in large quantities, and soft touch leather IMR with soft touch has been adopted for the whole C key, and the wear-resistant standard is higher than that of paint.

IML Technology

The remarkable characteristics of in mold insert injection molding (IML) process are: the surface is a hardened transparent film, the middle is a printed pattern layer, and the back is a plastic layer. Because the ink is sandwiched in the middle, it can prevent the product surface from scratching and friction, and the color can remain bright for a long time, which is not easy to fade.

IML technology production process:

Printing - molding - cutting - inlaying into the mold - injection molding - in mold inserts injection molding finished products

IML technology product effect:

1. Diversification of printing appearance effect: through the combination of transfer printing soft touch, color, electroplating and other printing technologies, various appearances can be diversified.

2. Research and develop ultra-thin IML, the thinnest IML can reach 0.80mm, and the deformation degree is less than 0.5mm; The deformation degree of 6-inch battery cover is less than 1.0mm; The thickness of local glue reduction can be 0.6mm.

Development trend:

In terms of the existing equipment and process flow of IML technology, the improvement has evolved into IMT technology that is more suitable for future user needs and technical requirements, thus reactivating the development space of traditional plastic molding plants.

IMT Technology

In mold decoration (IMT) technology is a new technology that integrates and extends in mold insert injection (IML) technology and in mold transfer (IMR) technology.

This technology applies the separation technology of IMR technology diaphragm and ink, and takes into account the monomer molding and injection molding manufacturing methods of IML technology. Its multi-layer protective film can effectively protect the quality of the main decorative layer.

Advantages of IMT process:

1. The thickness of the product can be as thin as 0.70mm;

2. Deformation stability;

3. No peeling risk;

4. By extending the process, such as spraying UV, we can better meet the functional requirements of the product surface, such as fingerprint resistance, wear resistance, gloss. Through 3D texture printing layer and the application of magnetic control splash technology, we can achieve 3D optical texture effect.

At present, IMT technology is a popular solution for smart phone back cover. Tongda said that the IMT project was very successful, providing solutions other than the glass back cover. More IMT solutions matching the low-end market will be launched in 18 years. The emergence of IMT technology will replace the oil spray, UV shading, electroplating, vacuum color plating, silk screen printing, pad printing and transfer printing technologies in the industry. In the current industry, this will drive the leap forward innovation in the product appearance industry, realize irregular product appearance decoration effects, such as three-dimensional, color gradient, R angle, etc., and provide a better innovation and platform for the appearance design industry. The new IMT technology combines the currently popular decoration method of 3D optical texture PVD, which has higher appearance value and greater radian than the traditional one. At present, IMT technology has changed from a new technology of 3D optical texture PVD to double-layer 3D optical texture PVD.

Development trend:

IMT process has sold well, but the problem IMT faces now is that the straight through rate needs to be improved. In the 5g era, IMT technology is likely to become very popular. It is reported that many domestic manufacturers are deploying, and some enterprises have begun mass production. In the future, IMT technology can be integrated with the evolution of electronic technology into ime technology, adding circuit layers, installing electronic components, giving the diaphragm electronic functions and a variety of visual, tactile and sensory effects, which can be applied to the intelligent surface of future vehicles.

PC glass like injection molding process

As a low-cost and efficient product form, the injection molded transparent PC back cover has better impact strength and durability. It is attracting the attention of more and more traditional plastic manufacturers and is expected to become the mainstream mobile phone back cover scheme in 2019. It is understood that many manufacturers are accelerating the layout and injection molding of transparent PC mobile phone back cover. Raw material manufacturers are also verifying that the special materials for PC injection molded mobile phone back cover can meet the requirements of high hardness, low stress and no rainbow lines.

Advantages of PC glass like injection molding process:

In comparison, the injection molding process of PC glass is easier to load and more efficient. It can imitate the effect of 2.5d/3d glass shell, and can be decorated by spraying (without coating) and pasting.

Development trend:

In 2018, composite board was widely used as the back cover of glass imitation mobile phones, but at present, there is little room for production capacity limitation, product deformation, high investment risk, process improvement and cost reduction. However, the cost of glass and ceramics is too expensive and fragile. Its large-scale production and output make it more suitable for high-end models. When the cost of glass and 3D composite board is difficult to reduce in a short time, plastic injection molded mobile phone back cover as an efficient and low-cost substitute came into being and rose rapidly.