Laser Soldering Process with Rectangular Spot Applied in FFC Cable Processing

Process Background

With the increasing maturity of board-level and system-level packaging applications in the microelectronics field, Flexible Flat Cables (FFC), used as data transmission cables between moving parts and motherboards or between PCBA boards, have seen broader adoption. These cables offer excellent processing flexibility, allowing for the arbitrary selection of wire counts and spacing, which simplifies connectivity. They significantly reduce product size, lower production costs, and enhance manufacturing efficiency. FFC cables are ideal for use as data transmission lines between moving parts and motherboards, between PCBA boards, or in compact electronic devices.

FFC/FPC Soldering Wiring Diagram

Such product structures are typically manufactured using reflow soldering processes. However, with product upgrades and increasing functional diversification, some components cannot withstand reflow ovens, creating challenges for mass production of such products.

The rectangular spot laser soldering process enables localized heating of the soldering area without direct thermal impact on non-soldering regions. The product itself does not require overall heating, eliminating thermal effects on the board substrate and effectively reducing soldering thermal stress. Compared to conventional laser soldering processes, this method features a larger beam action area with more uniform energy distribution, allowing for simultaneous multi-point soldering and significantly higher production efficiency.

Application Fields

The rectangular spot laser soldering system can be widely applied in microelectronic interconnection fields such as automotive electronics, consumer electronics, and home appliances.

System Composition

Coaxial Temperature Measurement Visual Rectangular Spot XY-Adjustable Laser Welding Head Diagram  （Suitable for PCB spot welding, soldering, non-metallic material welding, plastic welding, sintering, 3C electronics industry, telecommunications industry, semiconductor industry, photovoltaic energy, automotive microelectronics, thermal-sensitive components, medical electronics, buzzers, data cables, and mobile phone camera modules.）

This system consists of a multi-axis robot, temperature feedback system, CCD coaxial positioning system, constant-temperature semiconductor laser, and a self-developed rectangular spot laser welding head.

According to the distribution of solder joints and the thermal conductivity characteristics of the product, combined with the independently developed rectangular spot welding system, it can adjust homogenized rectangular spots of different sizes to cover the welding area, achieving synchronous multi-point welding across the region.

Dual-X Dual-Y Dual-Station Solder Paste Feeding and Soldering System

The system can adopt a dual-station machine format, utilizing a Googol eight-axis motion control card to manage the platform. Y1 and Y2 axes are designated as two workstations where products are placed for processing. The X1 axis is equipped with a welding head and an optional wire feeding mechanism, while the X2 axis is fitted with a solder dispensing head, a positioning camera, and an optional height measurement sensor.

The system is compatible with various solder supply methods, synchronizing the solder feeding process with welding operations. By integrating zone-synchronized soldering, it maximizes process efficiency. The rectangular spot welding system consists of an adjustable lens assembly for real-time spot size modulation and a temperature measurement system. During welding, the system monitors the soldering area temperature in real time to ensure soldering quality and yield.

System Advantages

1. Adjustable Welding Spot Size (700×900 μm to 8×19 mm) – Compatible with various solder joint layouts to meet diverse soldering requirements.

2. Proprietary Temperature Feedback System – Temperature control range: 200°C to 1000°C with ±5°C precision. Real-time monitoring of solder joint temperature effectively prevents PCB scorching and poor solder melting.

3. Three-in-One Coaxial Optical Path – Laser, CCD, and temperature measurement beams are perfectly aligned, solving the industry challenge of multi-optical-path alignment and eliminating complex calibration.

4. High-Precision Coaxial CCD Positioning & Process Monitoring – Provides clear visualization of solder joints and automatic coordinate correction, compensating for minor component size and positional deviations. Enables high-volume, precision soldering in production lines, addressing rising labor costs. The CCD system also allows real-time process monitoring.

5. Superior Stability vs. Soldering Iron Robots – Eliminates variability from soldering iron tips, ensuring consistent and reliable welding. Ideal for seamless integration with other automated production line processes.