This article will help you understand what laser soldering is

　　What is laser soldering

　　Laser soldering is an advanced welding technology that uses laser as a heat source to accurately control and rapidly heat low-melting-point solder, causing it to melt and flow into and fill the tiny gaps between the metal parts to be welded, forming a strong welded joint. Different from traditional soldering iron welding technology, laser soldering adopts a non-contact processing method, using the high-intensity energy of the laser to concentrate on a small area to achieve efficient and precise welding results.

　　The main features of Songsheng Optoelectronic laser soldering include:

　　High precision and non-contact: Laser can focus on extremely small points, suitable for welding of precision electronic devices, avoiding damage or contamination that may be caused by physical contact.

　　Rapid heating and cooling: Laser heating is fast and the heat-affected area around the solder joint is small, which helps protect sensitive components and speeds up the production process.

　　Constant temperature soldering with high yield: The original PID online temperature adjustment feedback system can effectively control constant temperature soldering to ensure soldering yield and precision.

　　Excellent consistency and repeatability: facilitates automatic control, ensures stable quality of each welding, and is suitable for large-scale industrial production.

　　Wide applicability: Suitable for welding a variety of materials and complex structures, especially suitable for high melting point materials or occasions requiring deep welding.

　　Comparison with soldering iron welding:

　　Advantages of laser soldering:

　　Higher welding accuracy and speed, suitable for precision parts.

　　Reduce the risk of thermal damage and protect surrounding components.

　　High degree of automation, suitable for mass production, improving production efficiency and welding quality consistency.

　　Advantages of electric soldering iron:

　　The cost is low, the equipment is simple, and it is easy to operate and maintain.

　　Suitable for small-scale production, repair or DIY projects, with high flexibility.

　　The technical threshold is low and no complicated training is required to get started.

　　Respective limitations:

　　Laser soldering requires a large initial investment and requires high operation and maintenance requirements.

　　The welding efficiency of the electric soldering iron is low, and the welding quality is affected by the operator's skills, so it is not suitable for high-precision requirements.

　　In summary, laser soldering, with its unique advantages, has shown significant application value in fields that pursue high precision, high efficiency and automated production, while electric soldering iron welding is used in cost-sensitive, small-scale operations or scenarios that require manual flexibility. Still practical.

　　The core of laser soldering lies in the precise control of laser power and its energy distribution on the solder joint. Ideal energy distribution needs to ensure that the tin material and the base metal reach the most suitable temperature range for welding at the same time to achieve the formation of high-quality solder joints. in particular:

　　Avoid overheating of tin material: If the main energy of the laser is concentrated on the tin material, although the tin material can be quickly melted, it may cause "instantaneous high temperature", causing the tin material to melt too quickly and the temperature of the base material to lag, causing the tin material to be unable to fully wet the base material. surface. In this case, the solder may form balls or fail to adequately fill gaps, resulting in poor solder joint form and reduced strength and reliability.

　　Balance the heating of the base material and tin material: Moderately allocate the laser energy to the base material, which can promote the uniform rise of the surface temperature of the base material and match the melting rate of the tin material. This not only ensures that the tin material maintains good fluidity and activity, but also keeps the surface of the base metal clean and fully activated, which is conducive to the metallurgical bonding between the tin material and the base metal, forming a strong, void-free and full-shaped solder joint.

　　Precise control of laser power: The key is to accurately adjust the laser power and its pulse width, frequency and other parameters according to the material characteristics, solder joint size and required welding depth to achieve precise heating of the welding area, which not only ensures effective heat transfer, but also Control the heat affected zone to minimize, thereby achieving ideal welding results.

　　In short, the successful implementation of laser soldering relies on the fine control of laser power and energy distribution to ensure the thermal balance between the tin material and the base metal to obtain high-quality welding joints and avoid various welding problems caused by uneven heating. defect.

　　What are the types of laser soldering?

　　At present, laser soldering is mainly divided into four types, namely tin wire laser welding, solder paste laser welding, tin ball laser welding and galvanometer laser welding.

　　Tin wire laser welding

　　Tin wire laser welding technology is a precision welding method. Its operating mechanism is as follows: First, the precisely controlled laser beam is focused on the metal pad to be welded, and is heated gently and efficiently until the pad reaches the ideal preheating temperature. This process ensures even heat distribution and creates optimal conditions for subsequent welding. Then, the tin wire is accurately delivered to the preheated pad surface, and the laser is immediately adjusted to the appropriate power to instantly melt the part of the tin wire that contacts the pad. Driven by surface tension and capillary action, the molten tin smoothly infiltrates and fills the tiny gaps between the pads and component pins or connection parts, forming a strong and smooth solder joint. This process not only greatly improves welding quality and reliability, but also effectively reduces the heat-affected area and protects surrounding sensitive components through precise energy management. It is the preferred solution in modern precision electronic assembly and high-density packaging applications.

　　As a mainstream application form of laser soldering technology, wire-feed laser soldering integrates the advantages of high automation and precision control. Through the tacit cooperation of the intelligent wire feeding mechanism and the automatic working platform, it adopts a modular control system to ensure the precise transportation of solder wire and the precise release of laser energy. The integrated operation of the entire process not only improves operating efficiency, but also ensures This ensures consistent and high-quality welding results.

　　A major innovation of this technology is its "one-stop" operation mode, which does not require multiple clamping or adjustments, and the material is maintained in a stable position from beginning to end until the welding task is automatically completed. This design greatly expands its application scope in many fields, ranging from precision electronic devices to complex structural components.

　　Compared with traditional welding technology, wire-fed laser soldering has several outstanding advantages, including:

　　No additional consumables loss: The welding process is simplified, no flux or other auxiliary materials are required, and the cost is reduced.

　　Efficient penetration welding: With the high energy density of laser, deep welding is achieved, the welding strength is high, and there are no false welds.

　　Zero stress welding: The thermal stress exerted on the welded parts is minimal, protecting the integrity of the welded structure.

　　The solder joints are beautiful and durable: the solder joints formed are full and bright, with smooth edges and no burrs, and no welding slag residue, which improves the appearance quality and long-term reliability of the finished product.

　　This technology is widely used in the manufacturing of various high-tech products, such as through-hole pin welding on PCB circuit boards, connection of precision coils, assembly of 5G communication antenna components, etc., fully demonstrating its uniqueness in the field of modern precision manufacturing Value and adaptability.

　　Solder paste laser welding

　　Solder paste laser welding is a precise and efficient welding process. Its core steps are as follows:

　　Preset solder paste: First, apply an appropriate amount of solder paste accurately on the pad to be soldered. Solder paste contains alloy powder, flux and other additives, which can quickly melt and flow under the action of laser to ensure good wettability and welding quality.

　　Precision laser heating: Subsequently, a high-energy-density laser beam is used to precisely illuminate the solder paste-coated pad. The laser energy is effectively absorbed by the solder paste and pad, and is quickly and locally heated to above the melting point of the solder. At the same time, the heat-affected area is controlled to reduce thermal damage to surrounding sensitive components.

　　Alloying and cooling: As the temperature increases, the alloy powder in the solder paste reacts metallurgically with the pad surface material to form a strong alloy layer. This process is called alloying. Subsequently, the welding area is rapidly cooled naturally or through auxiliary means to solidify the solder joints and complete the welding process.

　　The advantages of this process are:

　　Precise control: The precise focusing ability of the laser ensures the precise transmission of heat, suitable for the welding needs of high-density and fine solder joints.

　　Non-contact processing: avoids the physical contact of traditional welding tools and reduces mechanical stress damage to solder joints and surrounding components.

　　Efficient and fast: Laser heating speed is fast, the welding cycle is short, and it is suitable for large-scale automated production.

　　High-quality solder joints: The formed solder joints are uniform, high-strength, and have a smooth surface after welding, which helps to improve the overall reliability and aesthetics of the product.

　　The process flow chart of solder paste laser welding usually includes key steps such as solder paste printing, laser irradiation, cooling and solidification, etc. It visually displays the entire welding process from preparation to completion, providing clear guidance for actual operations.

　　Solder paste laser soldering technology shows unique advantages in enhancing the connection strength of components and pre-tinning treatment, such as melting solder paste through precisely controlled laser energy to strengthen the edge of the shielding cover or ensuring the solid welding of the magnetic head contacts. This technology is particularly good at welding flexible circuit boards, such as the assembly of plastic antenna bases. Its uncomplicated circuit layout allows for efficient solder paste welding, achieving smooth, smooth solder joints with reliable connections.

　　In response to the welding challenges of precision micro components, solder paste laser soldering highlights its precise control and filling capabilities, optimizes the welding quality, and can perform well even in extremely limited space.

　　Compared with traditional welding methods, several significant advantages of solder paste laser soldering include:

　　Precise positioning and local heating: It can accurately control the heating area and reduce the thermal influence range, which is especially important for PCBs with high-density wiring. The minimum welding spacing can be reduced to 0.12 mm, which greatly improves the welding efficiency in dense pad environments.

　　Enhanced through-hole penetration: The concentration of laser energy significantly improves the welding penetration of through-hole pads, ensuring the integrity and reliability of deep welding.

　　However, during the laser soldering process, due to the high concentration of energy, uneven heating of the solder paste may cause the solder paste to crack or even spatter, posing a risk of short circuit. Therefore, it is particularly important to use high-quality anti-spatter solder paste specially designed for laser welding to reduce spatter and ensure welding quality and safety.

　　Solder paste laser welding technology is widely used in product manufacturing in many high-tech fields, covering the FPC connection of optical communication modules, the combination of PCB and FPC, pin components, patch component fixing, cable and PCB bonding, and even The welding of precision motor coils, etc., reflects its wide application value and adaptability in modern electronic manufacturing.

　　Solder ball laser welding

　　The principle of solder ball laser welding is to send the solder ball particles to the nozzle through the ball feeding mechanism, and then irradiate the laser to melt the solder ball, and spray the liquid tin on the surface of the product through nitrogen gas. Its process flow chart.

　　Tin ball laser welding is a precision and efficient welding technology that uses preset small particles of pure tin (tin balls) as welding materials. These solder balls are uniformly melted after being precisely heated by the laser, with almost no spatter produced during the process. After melting, they are quickly cooled and solidified to form a plump and smooth solder joint. No additional cleaning or surface treatment steps are required, which greatly simplifies the process and ensures The cleanliness of the welding area and the aesthetics of the solder joints.

　　Compared with traditional welding methods, solder ball laser welding shows many significant advantages:

　　Excellent efficiency and cleanliness: There is no need to use flux, and the welding process is more environmentally friendly and clean. At the same time, with the efficient energy conversion of the laser, the welding speed is fast and the overall efficiency is significantly improved.

　　Consistent welding quality: The precise control of the laser ensures that each solder joint is heated evenly, thereby obtaining a welding effect with consistent appearance and high stability, which is very suitable for high-precision and high-density welding requirements.

　　Minimal thermal impact: The precision of laser focusing limits the heat-affected area to the minimum, effectively protecting surrounding sensitive components and material structures, and reducing the risk of thermal deformation and damage.

　　Due to the above advantages, solder ball laser welding technology is widely used in the manufacturing of various high-tech products, including but not limited to:

　　Precision electronic component connections: For example, the fine pad connections inside the camera module ensure the stable installation of key components such as image sensors.

　　Flexible circuit board welding: Provide reliable and beautiful welding solutions in high-density connections between FPC and FPC or FPC and PCB.

　　Semiconductor packaging: The welding of high-end integrated circuits such as wafer-level chip packaging and ball grid array (BGA) meets the stringent requirements for welding reliability of high-performance electronic products.

　　In summary, solder ball laser welding has become an indispensable advanced welding method in many precision electronic manufacturing fields due to its high efficiency, cleanness, stability and small thermal impact.

　　Galvanometer laser welding

　　The principle of galvanometer scanning welding is to dot or smear the solder paste on the soldering pad in advance, and then scan it back and forth with the laser to heat the solder paste and the product pad to reach the soldering temperature, thereby achieving the purpose of soldering. Paste soldering supplement. Its process principle.

　　Galvanometer scanning welding can achieve matching welding in pad areas with different regular shapes, and can be spot welded or surface welded. Common welding products include FPC and PCB&FPC, pin fittings, chip components, wire and wire&PCB, motor coils, etc.

　　Songsheng Optoelectronic Galvanometer Constant Temperature Vision Coaxial Processing System is specially designed for galvanometer scanning processing that meets high-precision positioning requirements. The image observed by the CCD is completely coaxial with the focus of the laser beam. When matched with the F-Day lens and the black light source, it can achieve " What you see is what you get” laser processing. The absolute position accuracy of laser processing after correction can reach less than 0.02mm, and when used in conjunction with the software, it can almost overcome the processing position error caused by the temperature drift of the galvanometer.

　　The scanning objective adopts a telecentric design, which eliminates most of the problems caused by general scanning objectives and makes the marking range uniform and uniform. The integrated design makes the system stable and reliable, and the internal coaxial CCD optical system makes the imaging quality better, and the software is easier to identify compared with traditional modes. It is specially prepared for precision welding. Through the marking points on the workpiece to be processed, the movement of the cross table can be controlled to the designated position to avoid welding problems caused by errors in the workpiece. At the same time, the visual positioning system can also be used as a monitoring device, and CCD imaging can observe the working situation in real time.

　　Direct semiconductor laser welding system with temperature feedback: The temperature feedback function can control the temperature of the welding. It can control the temperature of a tiny area with a diameter of 1mm. The temperature accuracy is ±2℃. Through precise control of the temperature, the welding can be fully controlled. effect and avoid damage to the welding workpiece.

　　The integrated design makes the system stable and reliable, including galvanometer, infrared coaxial temperature measurement, CCD coaxial imaging system, laser coaxial transmission system and scanning objective lens series, etc.

　　Microelectronics applications and laser soldering

　　Microelectronics technology is a new technology developed with integrated circuits, especially ultra-large-scale integrated circuits. The theoretical basis for its development is modern physics established from the end of the 19th century to the 1930s. In essence, the core of microelectronics technology lies in integrated circuits, which are formed during the continuous development of various types of semiconductor devices. In the information age, microelectronics technology has had a great impact on human production and life.