Industry | Report
Joining Technologies Adapt to Electronics Products Updates

n a market-driven economy, demand expansion for new electronics products, such as smartphones, electric vehicles (EVs), and industrial equipment has prompted innovations in manufacturing technologies. Accordingly, adhesive and joining technologies that are used in the manufacturing process of electronics products have also advanced, for example, smartphones and tablet computers are assembled using a joining process that does not use a single screw.

Diversifying Joining Technologies
There are four typical joining technologies used in the manufacture of electronics products. They are resistance (welding of metals using resistance heating); pulse heat (thermocompression using resistance heating element, soldering); laser (welding using laser beam, soldering, welding); and ultrasonic wave welding (resin welding using friction heat generation, metal joint welding using oxide film breakdown).

In the diffusion joining technology, materials are heated in a vacuum at temperatures lower than their melting points, to which pressure is applied, and joined by the movement (diffusion) of atoms. The adoption of diffusion joining technology for metal components, for which the manufacturing process of semiconductors is used, has also been advancing.

Business Expansion with Joining Technologies
Makers of manufacturing equipment for electronics products have been endeavoring to expand new businesses by using advanced joining technologies.

FUJI Corporation has been working to increase sales of Tough Plasma atmospheric-pressure plasma unit. The company has started sales of the manufacturing equipment in China, in addition to Japan. Tough Plasma reforms the surface of metals and other materials using the property of radicals of plasma to enhance adhesive strength.

Japan Unix applies laser and ultrasonic bonding technologies to soldering robots.
Photo 1: Japan Unix applies laser and ultrasonic bonding technologies to soldering robots.
Examples of laser processing
Photo 2: Examples of laser processing
Amid the accelerating adoption of electronic components in vehicles, the adoption of resin materials has also been increasing to reduce the body weight of automobiles and enhance environmental friendliness, and hence, business opportunities for Tough Plasma have been expanding.

Japan Unix Co., Ltd. has been expanding its global business of soldering robots that employ semiconductor lasers and ultrasonic waves. Interest in the automation of production has increased worldwide, particularly in China, and sales of soldering robots have been steadily increasing. The company has released the UNIX-DF Series PC network-enabled soldering robot, supporting its efforts to implement internet of things (IoT) technology.

Alone Co., Ltd. has expanded its metal machined components business, which applies diffusion joining technology. Multiple sheets of metals, such as stainless steel, copper alloy, iron and nickel, are laminated and joined using diffusion joining after they undergo fine photoetching processing in accordance with patterns using chemical agents. They are processed into three-dimensional (3D) metal components. Joining of several layers to more than 100 layers is also possible.

Application of Laser Processing
Businesses that apply laser processing technology have also been expanding.

In laser processing technology, metals and other materials are joined by irradiating amplified light. It has excellent directivity, and is suitable for fine processing. It is similar to a mechanism to condense sunlight using concave lens, and can be used for joining and cutting.

Marubun Corporation has been bolstering its laser portfolio, including industrial laser products, such as high-output semiconductor lasers, fiber lasers, and ultra-short-pulse lasers, as well as laser modules. The company handles products of 10 companies, including nLIGHT, OSRAM, and Amplitude Systems.

A metal component made by laminating 1,000 sheets of metal plate with a thickness of 50μm
Photo 3: A metal component made by laminating 1,000 sheets of metal plate with a thickness of 50μm, on which meshes of several hundred micrometers are provided, using diffusion bonding (Alone)
Hakuto Co., Ltd. has developed a laser welding system, under its own brand, that combines a fiber laser made by FIN LASE from Finland and a galvano scanner head. The company puts hopes on the expansion of its business for plastics and lithium-ion batteries for automotive application.

Soldering to Aluminum Base Material
KOKI Company Limited has been working to bring soldering to aluminum base material to practical application.

Although metals are soldered, aluminum cannot be soldered. Therefore, metal plating is applied on aluminum, on which soldering is carried out. The company has been developing solder products that suit plating.

Nihon Superior Co., Ltd. has commercialized ALUSAC-35 lead-free solder for joining aluminum, and has been pitching it for the joining of the coil section of motors, in which aluminum wire is used, and a commutator. The company has strengthened its brazing materials and equipment that apply solder bonding, and has been expanding sales of these products for use in air conditioners. The company provides brazing materials in ring shape to fit the diameter of base materials, such as pipes for refrigerant.