Real production challenge: The Production Manager at a leading MCB manufacturer stated that their manual silver contact welding failed at a rate of 1.2% because of inconsistent heat and pressure. To solve this problem they needed to find an automated, repeatable solution that met IEC standard requirements, and would therefore reduce rework expense.

Choosing a Manufacturer of Welding Machines from China means more than just comparing the price lists of different manufacturers. For those in an industry that includes low-voltage electrical manufacturing, the welding process can impact both the reliability and safety of their final products. Examples of the different welding processes an industry may use include resistance welding for silver contacts, ultrasonic welding of terminals, and automated soldering of printed circuit board assemblies (PCBAs). This document will introduce ten Chinese manufacturers with proven success in providing precise, automated welding processes for circuit breakers, contactors, and thermal overload devices.

This guide covers:

• Different types of welding machines are available to be used for electrical manufacturing today, with examples including resistance, laser and ultrasonic welders.
• Top 10 welding machine manufacturers in China with a focus on electrical component assembly
• Key technical specifications and applications of their flagship products
• How to select the right welding solution for your production line
• Frequently asked questions about automated welding in the electrical industry

1. Welding machine categories for electrical component assembly

The most frequently used welding technologies to create MCBs, MCCBs, contactors and surge protectors are:

• Resistance welding (Spot / Projection): It is a cost-effective method of connecting silver contact terminals with copper terminal connections (and bimetal designs) providing speed and providing a strong mechanical bond while ensuring an extremely low contact resistence(<100µΩ) as well as being ideal for equipment such as electrical power distribution systems.
• Ultrasonic welding: Used to join sensitive parts, including fine copper wire, thermoplastics and nonferrous metals, it produces very strong connections to the materials being joined without causing them to melt.
• Laser welding: Provides high-precision hermetic seals or welding of dissimilar materials. Used in specialty components such as relays and sensors.
• Automated soldering (Selective / Reflow): Used for PCBA assembly in smart breakers or electronic trip units.

For the electrical industry, precision resistance welding and automated soldering/welding lines are the most widely adopted due to their repeatability and ability to integrate with assembly and test benches.

2. Top 10 Chinese welding machine manufacturers (focused on electrical applications)

These manufacturers have developed a reputation for producing high-quality automated equipment with precise capabilities for welding various types of electrical components. Their products are sold around the world and are commonly used to weld two types of metals together (i.e., silver tips, copper braids, bimetals) and for sealing materials.

2.1 Benlong Automation Technology Co., Ltd.

Specialty: For low voltage electrical items, there is full line joining, assembly, and testing of weldments. Some main welded products are displayed in the products page:

• Silver dot + Contact automatic welding machine: To achieve precision in the welding of silver contacts to copper terminals or moving arms. The weld pull force will be in excess of 200N (more than) or exceed 1.33 on the CPK scale.
• MCB thermal trip set automatic welding line: Assembling and welding thermal bimetal components.
• MCB magnetic trip set automatic welding machine: For yoke and armature assemblies.
• MCB Bimetallic + Moving Contact + Copper Braid automatic welding machine: Integrates three key components for MCBs.
• Ultrasonic Welding machine: For fine wire bonding and plastic assembly.

Benlong has more than 160 patents with a National High Technology Enterprise designation. It is fully IEC compliant. They offer customers a complete solution by providing welding systems, assembly systems and testing systems that work together as a single turnkey solution.

2.2 SBT (Shenzhen) Intelligent Welding Equipment Co., Ltd.

Specialty: Medium-frequency inverter DC resistance welding control equipment and transformers are known for their ability to perform high-accuracy welding on tiny, small electric connections and fine wires of diameters less than 0.050″.

2.3 Guangzhou Jasic Technology Co., Ltd.

Specialty: A global leader in manufacturing industrial welding equipment (TIG, MIG, Stick). An electric utility allows them to supply fully automatic TIG welding systems that are used in making wire harnesses and connecting wires to busbars made of copper.

2.4 Wenzhou Dacon Electric Co., Ltd.

Specialty: Semi-Automatic Projection Welding Workstations Use Of

For the construction of MCB and MCCB internal parts, semi-automatic projection welding workstation equipment is used for welding silver contacts onto copper terminals.

2.5 Shanghai KY Industrial Co., Ltd.

Specialty: For applications requiring precision, like sealing sensors or small electronic components in smart devices, you can use a laser welding system.

2.6 Zhejiang Jinkaide Welding Technology Co., Ltd.

Specialty: Bimetal strip resistance welding and thermal relay components. The equipment used to produce thermal protection devices and thermal switch assemblies.

2.7 Suzhou Xinyu Electronic Welding Equipment Co., Ltd.

Specialty: Automated circuit board assembly (PCBA) soldering and selective soldering for electronic overcurrent protection devices in molded case circuit breakers (MCCB).

2.8 Wuxi Lienco Automation Technology Co., Ltd.

Specialty: The ultrasonic welding of metals such as copper, aluminum and battery pack connections (relevant in the context of renewable energy and EV infrastructure) is very suitable for use with these types of materials.

2.9 Shenzhen Junsheng Instrument Co., Ltd.

Specialty: Automated assembly lines often incorporate inverter welding power supplies and monitoring systems. Inverter welding power supply technology can be integrated into automated assembly lines to monitor and log data about the welding process.

2.10 Zhejiang Hongli Automatic Equipment Co., Ltd.

Specialty: Automated welding lines for small electrical components including Cable and terminal welding They provide custom engineered solutions utilizing a combination or vision and positional systems.

3. Key selection criteria for welding machines in electrical manufacturing

When you evaluate a manufacturer of a welding machine, take into account several different technical data related to your part.

CriteriaWhy it is importantWelds need to provide adequate strength and repeatabilityWith regard to silver contacts, pull tests should produce a force of >150N and low contact resistance (<100 µΩ). To ensure the safety and reliability of welds, request CPK data (≥1.33).Welding machine integration with automationCan the welding machine be readily integrated into an existing assembly or test bench? Look for PLC communication (Modbus, Ethernet/IP).Data traceabilityAdvanced systems monitor and log weld current, voltage and displacement of each joint allowing for complete traceability and SPC analysis.Electrode dressing and tool lifeAutomatic electrode milling or dressing systems minimize downtime and provide consistent weld quality for high-volume production.

4. Application examples in electrical component manufacturing

• Welding silver contacts to MCB terminals: Reduces contact resistance and prevents overheating. Automated resistance welding is the standard.
• Welding bimetal strips for thermal trip units: To prevent harming the sensitive bimetal, precise control of energy is required. It is recommended to use medium-frequency DC inverter welding.
• Connecting copper braids in transfer switches: Ultrasonic welding provides a reliable, low-resistance bond without melting the copper.
• Soldering PCBA for smart breakers: Accurate control of temperatures in selective soldering or reflow ovens is essential for electronic components.

5. Frequently asked questions (FAQ)

What is the most common welding type for silver contacts in circuit breakers?

The method that is most frequently used for welding components is resistance welding, especially medium frequency inverter DC projection welding, as it has good heat controls, very quick cycles (0.2 to 0.5 seconds per weld) and provides outstanding consistency of the welded components required in mass production of MCB and MCCB.

How do I verify the quality of a welded silver contact?

A mix of in-process measurements and periodic destructive tests allow for the validation of quality control. The in-process measurements consist of the monitoring of the weld energy, current, and displacement curve. The destructively tested measurements consist of minimum manufacturer specified pull (force) tests and a micro-resistance test (usually <100 µΩ). Most modern welding systems will automatically log the above referenced values and warn of outlier criteria.

Can a standard welding machine weld both copper and silver parts?

However, the machine should be able to adjust its parameters, as silver has a very good conductivity rating but also has a lower melting temperature than copper. A welding machine with programmable schedules allows the user to save different parameters (force, current and time) for several different types of material combinations. The most effective method for welding silver to copper is to use a stepped or dual-pulse profile to avoid expulsion and create a strong joint.

What is the typical return on investment (ROI) for an automatic welding line?

By replacing two manual welders on this line (that runs 10,000 units a day) with one automated welder, the payback period for investment in these machines is typically 6 to 12 months. Cost savings are realized by reducing labor, decreasing rejected/reworked products (the defection rate of manual welds is 1-3% compared to <0.1% with automated welding), and increasing throughput.

Welding Machines from China – When selecting a welding machine from China, you should consider only suppliers who specialize in providing automation and precision equipment for your specific electromechanical devices. The best manufacturers, such as Benlong Automation, do much more than just produce a welder; they produce complete integrated production lines that include welding, assembly, testing and data traceability, all of which comply with IEC 60898/60947 Regulations. Focus on strength, consistency (Cpk ≥1.33) and ability to integrate into your current systems as well as on high-quality after-sales support from the supplier. A suitable automatic welding solution will significantly reduce defects, improve product quality and provide a good return on investment due to rapid delivery.