Tamura Manufacturing Co., Ltd. developed laser welding materials for LED lighting circuits

August 08, 2022

At the "14th Printed Circuit Board Exhibition" in Japan, Tamura produced a laser welding material that can automate the welding process of LED lighting and smart phone circuit boards.

The LED lighting circuit board is a product called "SP-NALT", which is specially designed for Nissin spinning precision machines. It can package LED chips on PET film circuit boards in the "roll-to-roll" process. "NALT-01 "Development. With this device, the LED chip can be packaged without using a reflow oven, so the installation area and electricity cost of the production line can be significantly reduced.

The problem faced in laser welding on PET boards is that solder materials generally melt at 220 ° C, and PET heat resistance temperature is lower than this temperature, so it is necessary to develop short-time rapid heating during laser welding. Non-scattering materials. In addition, the flux is also improved since fluidity must be ensured when the solder material is applied using a tin coating device.

For the variety of smart phone board soldering, the solder paste "LSM20" which can control the solder ball scattering during laser welding to about 0.3 mm has been developed. When the solder is used, the solder ball is scattered to about 1.2 mm, which is difficult to solder for a smart phone board with a high package density. By using a special thermoplastic resin, Tamura Co., Ltd. hardens the resin while melting the solder, and suppresses the scattering of the solder balls.

In terms of the use of new solder materials, it is envisaged to automate the soldering of large-sized components such as earphone jacks and connectors on the board. At present, the parts are generally welded by reflow soldering in the industry, so large-sized parts are often required to be manually added for the purpose of increasing the strength of the welded portion. In addition, this welding material is also expected to be used to correct the misalignment of components and the welding of three-dimensional components such as shield components.