What is spot welding? It is a joining technique widely used in the manufacturing industry. It helps join different metal combinations with excellent joint strength and versatility while ensuring high production rates.

Let’s equip you with insights into the world of spot welding, discover its stages, and learn how to achieve an effective spot welding process!

What is Spot Welding?

Spot welding, also known as resistance spot welding, is an electric resistance welding method that welds sheet metal products by joining contact metal surface points with the heat from resistance to electric current.

It contacts copper alloy electrodes on the sheet surfaces to apply pressure and electric current. Then, heat is created as a result of the passage of current through resistive materials, normally low-carbon steels.

The resistance between the magnitude and the electrodes and the current’s length decide the heat of the welding spot. In addition, the amount of heat or energy must be suitable for the type of electrodes, the sheet’s material properties, and its thickness.

Benefits of Spot Welding for Businesses

Spot welding is a fundamental joining method that provides robust connections for manufacturing operations at a low cost. Significant advantages of this technique include:

  • Precise: Spot welding ensures relative precision in applying welds to specific points on the workpiece.
  • Efficient: The spot welding process is fast and does not require filler materials.
  • Economical: Spot welding minimizes energy usage and consumes a small amount of consumables.
  • Automatic: The process facilitates automation to ensure consistent and repetitive welds for higher productivity.
  • Versatile: Spot welding can be workable for various conductive metals.
  • Minimal Distortion: The localized heat from spot welding minimizes the total metal distortion to ensure the integrity of the workpiece.
  • Durable: Spot welding creates solid and durable welds.

How Does Spot Welding Work?

Spot welding is resistance welding, one of the most long-lasting welding methods. It combines sheets of metals together without the need for filler materials. Instead, it applies pressure and heat to the weld area with shaped alloy copper electrodes that deliver an electrical current through the weld pieces.

Once the material melts, it fuses the parts together at the point the current is turned off. Meanwhile, the electrodes maintain pressure, and the molten “nugget” solidifies to generate the joint.

The electric current creates the welding heat, which is then delivered to the workpiece through copper alloy electrodes. Copper features a high thermal conductivity with low electrical resistance, making it suitable for the electrodes. Thus, heat is generated preferentially in the workpieces instead of the electrodes.

In spot welding methods, the thermal conductivity, the electrical resistance of the metal, and the amount of current application time will determine how much heat is applied.

How Does Spot Welding Work?

What are The Materials for Spot Welding?

Spot welding is most efficient when applied to metals with low thermal conductivity and high electrical resistance, like low-carbon steel. Though spot welding can still work for high-carbon steels that do not have these properties, the resulting welds may have brittle and hard microstructures present, which are more prone to fractures and cracking.

Below are the materials, including metal and electrode materials, that are the most suitable for spot welding:

  • Metal’s materials: low carbon steel, stainless steel, magnesium, aluminum, zinc alloys, nickel alloys, Monel, Inconel, titanium, silicon bronze.
  • Electrode’s materials:
    • High-conductivity materials include pure copper, copper cadmium, copper chromium, and other non-refractory copper alloys.
    • Low-conductivity materials include tungsten (W) and molybdenum (Mo).

Applications of Spot Welding

Spot welding can join almost any metal and alloy sheet up to a maximum of 3 mm thick. Various industries use spot welding, both automated and semi-automated, including automotive, aerospace, kitchenware, architecture, electrical, and construction.

Applications of Spot Welding

  • Automotive: Spot welding is mostly used in the automobile body manufacturing industry, where Aluminum sheets are joined to form a car body. Only automated spot welding machines and robots are used in the automotive industry.
  • Electronics: A wide range of electrical parts and products need spot welding in their construction, including PCB boards, batteries, sensors, connectors, solar cells, and panels. Also, some batteries spot welding instead of soldering.
  • Kitchenware: Various kitchenware, including spatulas, pizza cutters, handles, and cups, need spot welding in their construction.
  • Orthodontics: Regarding teeth brace, dentists often realign the teeth and other various orthodontics methods in which a spot welding technology in small size helps join one end to another.
  • Repairing: Spot welding plays an important role in the repairing process of automobiles, metallic furniture, and architectural parts, and re-shaping a damaged car.

Technology Revolution of Spot Welding

Take a look at the remarkable technological transformation of spot welding in general, which has improved efficiency, precision, and versatility in joining metal components.

  • AC spot welding: This older method is less efficient (24-27% energy efficiency). It requires a higher welding current and longer weld times to achieve the desired weld nugget size. It has no feedback system.
  • DC spot welding: This mid-frequency (1000Hz) method is more efficient (37% energy efficiency). It needs a lower current and shorter weld times for the desired nugget size. But like AC, it has no feedback system.
  • Adaptive DC spot welding: Also mid-frequency (1000Hz) and 37% efficient. However, it has a closed-loop feedback system that adjusts for issues like worn tips, dirt, or gaps to ensure the proper nugget size.
  • Adaptive DC with weld analyzer: This adds an ultrasonic device that measures the weld nugget size right after welding. Combining adaptive DC welding with this real-time analyzer could reduce or eliminate the need for offline weld quality checks and inspectors on the production line.

Technology Revolution of Spot Welding

Tips to Choose a Quality Spot Welding Service

To ensure reliable and consistent spot welding, the most important thing is to work with a professional spot welding service provider. Consider the following factors to be able to select the best partner:

  • Complexity of the welding project: It is essential to understand the complexity of the welding project, which varies based on the welded materials, the required precision, the project’s scale, and the specific welding processes.
  • Certifications and qualifications: Certifications and qualifications are testaments to a provider’s commitment to quality, safety, and industry standards. For example, the American Welding Society (AWS) certification agrees that a welder’s expertise and adherence to recognized procedures and welding work can meet standards for strength and durability.
  • Experience and expertise: The chosen welding provider should have deep knowledge and many years of hands-on experience. A provider with an established track record in managing complex, high-stakes projects is more likely to meet or even exceed industry standards.
  • Welding equipment and technology: Consider what type of welding machines and technology the service provider uses. Since different welding processes require different equipment, check to see if the provider possesses the necessary equipment and technology to address your projects.
  • Quality control processes: Quality control will ensure consistency in every weld based on standards of strength, durability, and compliance with industry regulations. A comprehensive quality control system at every stage of the welding process, from material inspection to the weld examination, can be a huge plus point.
  • Turnaround Time: A swift turnaround should be considerable, especially in terms of project repairs, upgrades, or urgent constructions. However, the speed should not decrease the integrity of the welds.
  • Compare Quotes: consider the bottom line and all services offered. Ensure the scope of work in each quote aligns with the project’s scope.
  • References and Past Projects: A provider’s references and past projects are tangible proofs of their capacities and experiences in which industries and projects scale.
  • Communication and Customer Service: A provider that effectively communicates with their customers is more likely to fully understand the project’s specifications, challenges, and goals. They should have clear, ongoing dialogue from first contact to project completion, making sure to bring customized solutions that work effectively for specific customer requirements.

Tips to Choose a Quality Spot Welding Service

Consulting Spot Welding Service of Fischer ASIA

Fischer ASIA provides comprehensive services for spot welding applications to add more value for our customers. We can incorporate welded components into customer products and assemblies using advanced equipment that is capable of transforming individual stamped metal parts into finalized welded sub-assemblies. Our experienced engineers can optimize spot welding processes and parameters to ensure high weld quality compared to relevant industrial standards and specifications.

Beyond producing metal stamping parts and molds, Fischer ASIA also provides complete component assembly services. Our capabilities extend to fabricating and assembling entire products from multiple individual parts.

Feel free to contact Fischer ASIA for a full spot welding service, including weld design, material selection, fixture development, and process control.

FAQs About Spot Welding

To address common questions and clear up any confusion about this widely used metal joining process, keep reading the following frequently asked questions and their answers about what is spot welding.

1. How does spot welding improve production speed?

The spot welding process is very fast, which enhances production efficiency. It utilizes very high temperatures at the contact point to create quick and strong weld joints. The high-speed spot welding technology allows large currents in units of 1/1000 of a second to finish the spot welding process in an incredibly short time while still maintaining excellent spatters. This technology can weld in 1/15 to 1/20 of the energizing time of conventional current control.

2. How does spot welding reduce labor costs?

Spot welding processes can be semi-automatic or totally automated, which helps reduce reliance on human labor while enhancing stability in mass production. In addition, spot welding work does not require special skills, so its labor is rather affordable.

3. What are the cons of spot welding?

Spot welding comes with several disadvantages, including high initial costs and unalignment with thicker metal sheets.