Application of Laser Welding Machine in Mold Repair

Application of Laser Welding Machine in Mold Repair

Advanced Technology to Improve the Efficiency and Quality of Mold Welding
I. What is Mold Laser Welding?
• Introduction: The Role of Laser Welding in Mold Repair

Mold laser welding is a high – precision technology that uses a high – energy density laser beam to locally melt and repair the damaged parts of the mold. It mainly addresses problems such as wear, cracks, and notches that occur during the use of molds (including but not limited to steel molds, aluminum alloy molds, and even hard molds, etc.).

• Basic Principles and Advantages of Laser Welding (High Precision, No Deformation)

There are two modes of principles: heat conduction welding and deep penetration welding. The former melts the surface of the material through laser heat conduction to form a molten pool (with a power density of approximately 10⁴ – 10⁵ W/cm²), which is suitable for thin – walled parts (YAG). The latter forms a “keyhole effect” by vaporizing the metal (with a power density > 10⁵ W/cm²) to achieve deep penetration welding, and the depth – to – width ratio of the weld seam can reach 10:1 (fiber optic). This technology features a micron – level spot size of 0.2 – 1.5mm and precise control of the weld layer thickness of 0.2 – 0.6mm, solving problems such as large thermal deformation and damage to the electroplated layer in traditional argon arc welding. It is especially suitable for the repair of cracks, chipping, and wear in precision molds such as injection molds and die – casting molds.

II. Advantages of Laser Welding Machines
High precision, low heat – affected zone
Fast welding speed, low cost
Can repair complex parts and extend the service life of molds
Precise and Efficient: After being focused by the optical system, the energy density of the laser beam can reach 10⁶ W/cm², the heat – affected zone is only 0.2 – 2mm, and the deformation rate is reduced by more than 80%, eliminating the need for secondary processing.
Wide Material Adaptability: It can weld high thermal conductivity/high hardness materials such as titanium alloys and aluminum – magnesium alloys, and can even achieve the connection of dissimilar metals (such as copper – titanium, nickel – copper).
Environmentally Friendly and Economical: There is no electrode pollution, and the weld seam has no pores under the protection of argon gas. The repair cost is only 30% of that of the traditional process of stripping and re – plating, and the maintenance cycle is shortened to a few hours.
Compatible with Automation: It supports CCD visual positioning and waveform parameter programming, and is suitable for mass repair scenarios such as automotive molds and 3C electronic components.
III. Application Scenarios of Mold Welding
• Mold Repair and Remanufacturing

Solve problems such as mold wear and cracks
Increase the service cycle of molds
• Precision Mold Repair

Especially suitable for local repair of precision molds, reducing material waste

• Precision Injection/Die – Casting Mold Repair: For example, repairing fine cracks in mobile phone shell molds. After welding, the surface roughness ≤ Ra0.8μm, and it can be directly polished for use.

• Maintenance of the Electroplated Layer of Stamping Molds: For local damage to chrome – plated molds, the damaged range of the electroplated layer after laser welding is < 0.1mm, avoiding the cost of 30,000 to 40,000 yuan for re – plating the entire mold.

• Lightweight Transformation of Large Molds: Adjust the mold size by surfacing solder with a thickness of 0.01mm, replacing the traditional recasting process and reducing material waste by 60%.

• Repair of Special Alloys in Aerospace: For example, after laser repair of A – MAX steel molds, the tensile strength reaches 93.95% of that of the base metal, and the fatigue life is increased to 83.69% of that of new parts.

IV. Application Examples of Laser Welding in the Mold Industry
• Case 1: Repair of Injection Molds

Describe how laser welding repairs the worn parts of injection molds and improves production efficiency

• Case 2: Repair of Cracks in Die – Casting Molds

Repair cracks in die – casting molds through laser welding to avoid high replacement costs

In the practice of FAW – Volkswagen Automotive Co., Ltd., in the repair case of a 10mm diameter pit caused by foreign object damage on the drawing punch of the front outer door panel of a certain model, technicians used an ALM200 laser welding machine (spot diameter 0.4mm) with a 0.4mm welding wire for single – layer welding. Through parameter control of a pulse duration of 5ms and an argon gas flow rate of 5 – 7L/min, zero – damage repair of the electroplated layer was achieved. It only took 30 minutes of welding and 30 minutes of grinding to restore the yield rate of mold parts to 99.8%, saving 85% of the cost compared with the traditional process of stripping and re – plating. This case verifies the unique advantages of laser welding in electroplated layer protection. Its precise control of heat input makes the damage range of the electroplated layer less than 0.1mm. At the same time, the multi – layer oilstone grinding process (gradually smoothing with a particle density of 120→250) successfully eliminates welding marks and achieves a mirror effect with a surface roughness of Ra0.8μm. In the field of 3C mold repair, Dongguan Deyi Laser has developed a dual – robot coordinated laser spot welding system for the 0.1mm – level crack problem of mobile phone shell molds. With a spot diameter of 0.3mm and a CCD visual positioning accuracy of ±0.02mm, it can achieve efficient repair of 950 pieces per hour, increasing the yield rate from 78% of traditional argon arc welding to 99.5%, saving rework costs of 1.2 million yuan per year. The system uses a 0.2mm welding wire for ultra – precision welding, with a spot diameter of less than 0.1mm. The surface can be directly polished for use after welding, solving the problem of controlling the heat – affected zone in the repair of micro – molds and becoming a benchmark solution for the maintenance of precision molds in the 3C industry.

V. Selecting a Suitable Laser Welding Machine
• Selection of Laser Welding Machines for Mold Repair (Power, Welding Materials)

Power Matching: Select according to the material thickness. For thin plates with a thickness of less than 0.5mm, a YAG pulse welding machine is recommended, and for thick plates, a continuous fiber laser with a power of more than 1kW is required.

Precision Control: Give priority to models with a spot diameter ≤ 0.2mm and adjustable defocus amount to ensure that the error of the weld width is < ±5%.

Function Expansion: Mold repair requires the installation of a 10 – 15 times microscopic monitoring system and an argon gas dual – channel protection system. For high – end scenarios, a robot coordinated module can be optionally equipped.

Common Laser Welding Machine Brands in the Market and Their Technical Characteristics

VI. Conclusion
• Laser welding technology brings efficient and precise repair solutions to the mold industry, effectively reducing costs and extending the service life of molds. With its “minimally invasive repair” feature, laser welding technology is reshaping the mold maintenance paradigm. Data shows that using this technology can extend the service life of molds by 3 – 5 times and reduce the single repair cost by 70%. It is recommended that enterprises, combined with their own product characteristics, give priority to selecting laser welding solutions that support multi – waveform modulation and have a material database to gain an edge in the high – value – added manufacturing track.