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Mar 31,2025
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Application of Laser Marking Machines in the PCB Industry

In the field of electronic device manufacturing, printed circuit boards (PCBs), as core components, the precision and efficiency of their manufacturing processes directly determine the performance and quality of electronic products. Laser marking machines, as advanced processing equipment, have deeply integrated into the PCB industry with many unique advantages and have become a key force in promoting the innovation of PCB manufacturing technology.

Principles and Classification of Laser Marking Machines

Working Principle

Laser marking machines use a high - energy - density laser beam to irradiate the surface of the workpiece, causing the surface - layer material to vaporize instantaneously or undergo a chemical reaction that changes its color, thus leaving a permanent mark. After being focused, the laser forms a tiny spot, which acts like a precision tool for high - precision marking on the surface of the object, and the marking line accuracy can reach the millimeter - to - micrometer level. Take the scanning - type laser marking machine as an example. The operator inputs the required marking information into the computer through the marking software. The software converts the information into signals to control the laser and the X - Y scanning system. The expanded and collimated laser is focused by the F - θ field lens and scans on the surface of the PCB to complete the marking process.

Classification Methods

       Classification by Light Source

  • CO₂ Laser Marking Machine: It uses CO₂ gas as the working medium and generates a laser with a wavelength of 10.64um through glow discharge. After being scanned by a galvanometer and focused by an F - Theta lens, it is marked under the control of a computer and a laser marking control card. This equipment has high power and strong stability and is suitable for wide - range cutting of thick sheet metal and non - metal materials such as wood, plastic, and glass. In the PCB industry, it is often used for the processing of non - metal substrate materials.
  • YAG Laser Marking Machine: It uses a YAG crystal as the laser medium and outputs near - infrared light with a wavelength of 1.06μm, which is easily absorbed by metal materials, causing material evaporation. It is often used for marking metal materials and parts and is widely used in the marking and processing of the metal parts of PCBs. It has the characteristics of stable operation and high processing quality.
  • Fiber Laser Marking Machine: It uses a rare - earth - doped glass fiber as the gain medium. Under the action of pump light, a high - power density is formed to achieve laser oscillation output. It has excellent beam quality, high cutting accuracy, fast speed, strong flexibility, good cut - edge quality, high energy efficiency, and low maintenance cost, and is the most widely used in the PCB industry.
  1. Classification by Marking Method
  • Mask - type: It consists of a laser, a mask plate, and an imaging focusing lens. The laser beam is uniformly irradiated on the pre - carved mask plate, and the transmitted part is focused on the material surface through a lens to achieve marking. The marking speed is fast, and one laser pulse can complete one mark, which is suitable for online flying marking of a large number of products. However, its flexibility is poor. Different marking contents require replacing the mask plate, and the energy utilization rate is low.
  • Dot - matrix type: Multiple parallel small lasers simultaneously emit pulsed lasers. After being reflected by mirrors and focused by lenses, the laser pulses are focused on the surface of the processed material to ablate small pits to form characters and patterns. Generally, a small - power RF - excited CO₂ laser is used, and the marking speed can reach up to 6000 characters per second, which is an ideal choice for high - speed online marking. However, it can only mark dot - matrix characters, has limited resolution, and has difficulties in marking complex patterns or Chinese characters.
  • Scanning type: It consists of a computer, a laser, and an X - Y plane scanning system. The laser and the scanning system are controlled by a computer and marking software, allowing the laser to scan on the surface of the processed material to form a mark. It has a fast marking speed and high accuracy, can perform fine marking and even bitmap marking, and has strong adaptability. It is the current mainstream marking method.Specific Applications of Laser Marking Machines in the PCB Industry

PCB Marking and Traceability

In the PCB production process, to effectively manage the entire life cycle of products, it is necessary to mark key information on the PCB board, such as production batches, characters, barcodes, and QR codes. Laser marking machines can accurately and clearly mark this information to meet the product traceability requirements. From production and manufacturing to after - sales service, by reading the laser marks on the PCB board, information such as the production batch, production date, and raw material source of the product can be accurately traced, helping enterprises improve their quality control level and after - sales service quality.

PCB Surface Treatment
  1. Removing Surface Coatings: In PCB manufacturing, some process steps require the removal of surface coatings in specific areas. For example, before welding or connection, the surface solder - resist layer needs to be removed. The laser marking machine can accurately remove the coating using a high - energy laser beam without damaging the substrate, providing a good foundation for subsequent processes.
  1. Surface Micro - processing: With the development of electronic products towards miniaturization and high integration, the requirements for the precision of PCB surface micro - processing are increasing day by day. Laser marking machines can achieve micron - level processing accuracy and can perform micro - groove processing, micro - structure fabrication, etc. on the PCB surface. When manufacturing high - density interconnect (HDI) boards, tiny vias are processed by laser marking machines to achieve electrical connections between different layers.
PCB Drilling and Micro - hole Processing
For the drilling requirements of PCBs, especially for micro - hole processing, laser marking machines, especially ultraviolet laser marking machines, have significant advantages. Traditional mechanical drilling is difficult to achieve high - precision micro - hole processing. Laser marking machines can efficiently and accurately complete micro - hole processing by instantaneously melting or vaporizing materials with a high - energy - density laser beam. When manufacturing high - density PCBs such as mobile phone motherboards, laser marking machines can process a large number of micro - holes with a diameter of several tens of microns or even smaller. The processed hole walls are smooth and free of burrs, which is beneficial for subsequent electroplating and other processes.
Advantages of Laser Marking Machines in the PCB Industry
High Precision
The spot size after the laser marking machine is focused is extremely small, and it can achieve micron - level processing accuracy, meeting the strict requirements of the PCB industry for fine processing. Whether marking tiny characters or processing micro - holes, high precision can be ensured, significantly improving the quality and performance of PCB products.
Non - contact Processing
The laser marking process is non - contact, without mechanical extrusion or stress, and will not cause physical damage to the PCB board. It is especially suitable for processing small and fragile PCBs. Compared with traditional mechanical processing methods, problems such as substrate deformation and scratching caused by mechanical contact are effectively avoided.
Small Heat - affected Zone
When the laser marking machine is processing, the laser energy is concentrated in the working area, and the heat - affected zone is small, which can reduce the impact on the performance of the surrounding materials. When performing surface treatment or micro - hole processing, it can ensure that the electrical and physical properties of other parts of the PCB board are not affected.
High Flexibility
Through computer software control, laser marking machines can easily achieve marking of different patterns, texts, and symbols without the need to replace hardware facilities such as molds. For PCB products of different batches and with different design requirements, the marking content and parameters can be quickly adjusted to adapt to diversified production needs.
High Efficiency
The scanning - type laser marking machine has a fast marking speed and can complete the marking and processing of a large number of PCB boards in a short time, greatly improving production efficiency. In large - scale production, its high - efficiency advantage is particularly prominent, helping enterprises reduce production costs.
Challenges and Solutions in the Application of Laser Marking Machines in the PCB Industry
High Equipment Cost
Laser marking machines, especially high - performance and high - precision equipment, are relatively expensive, increasing the initial investment cost of enterprises. Enterprises can reasonably select laser marking machines of different grades according to their own production needs and budgets. With the development of technology and the intensification of market competition, the price of laser marking machines is expected to gradually decrease. In addition, enterprises can allocate equipment costs by increasing equipment utilization and optimizing production processes.
High Requirements for Operators
Laser marking machines involve multiple technologies such as optics, mechanics, and electronics. Operators need to have certain professional knowledge and skills to operate the equipment skillfully and ensure processing quality. Enterprises should strengthen the training of operators to make them familiar with the operation principles, parameter settings, and daily maintenance of the equipment
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