Spot welding is an efficient technique for joining metal components in various industries, including automotive and aerospace. This technique is the precise application of heat and pressure to fuse two or more metal surfaces together. How can we secure an optimal metal combination?
Let’s explore useful spot welding tips to help you achieve strong welds and maximize productivity!
What is Spot Welding?
Spot welding is a type of resistance welding besides other types including rivets, screws, brazing, and soldering. But spot welding is more widely used to join low-carbon steel parts. However, it is also commercially viable for welding high-strength alloy steels, stainless steels, aluminum, nickel, copper, and titanium alloys.
Spot welding joins two or more metal sheets together using RSW to pass electric current between them. Electrodes are the parts conducting the current, pressing the electrodes against the metal surface to clamp the parts tightly and weld them together.
Useful Spot Welding Tips to Ensure Best Results
There are some careful considerations to ensure optimal results in resistance spot welding, in which four important factors include pressure, weld time, current, and tip diameter:
Considering The Amount of Pressure
While too little pressure makes the joining areas small and weak, too much pressure can cause cracks in the weld because of the quenching effect of the welding tips. Therefore, it is important to apply an appropriate amount of pressure. It is recommended that the depth of depression on the sheet surfaces by welding electrodes not exceed 25 percent of the sheet metal thickness.
Considering The Weld Timer
A weld timer monitors how long the current flows into the welding transformer. However, welding does not work while the timer is still ticking. As a result, a weld cannot be created before the timer runs out, especially if the welding current is only flowing for part of the cycle. The solution here is to make the timer run longer to prevent overheating of the welding tools and transformer.
Considering Welding Current
Weld time should be raised for weld current at the low end of the range, which can lead to overheating of the welding tools and the welder’s transformer. Meanwhile, a high weld current can cause expulsion, so weld time should be decreased.
Considering The Tip Diameter
When new, the TITE-SPOT Pliers have welding tips sharpened to a 3/16″ diameter. The tips can get thicker up to 1/4″ diameter before needing to be sharpened again. New welding tips have a flat face, but this face quickly becomes curved with use, which is desirable. The curved radius should be about 1.5 to 2 inches.
9 Useful Spot Welding Tips and Tricks to Improve The Performance
It is normally difficult to distinguish between a weak spot weld and a strong one, so how can you stay out of trouble and improve your spot welding performance? Below are some spot welding tips and tricks for improving your resistance spot welding performance.
Determine The Weld Lobe
The wide plastic range of low-carbon steel makes it possible to be spot welded by different machine settings. However, to ensure weld strength and prevent expulsion or poor weld quality, we must determine the ideal setting. We can obtain that by experimenting with the welding machine, checking the results with a tensile tester, or zeroing in on the optimum parameters.
Dress Tips Early and Often
To maintain resistance spot weld quality, it is important to frequently dress or exchange electrode tips before they have excessive wear. Poor maintenance can lead to mushrooming and increase the required current for optimal weld strength, resulting in weak welds and rejected parts.
Get Trained on The RSW Process
Each RSW setting on a spot welding machine leads to different results, so it is vital to understand how they work and adjust them to optimal results.
Select The Right Welding Machine
The appropriate welding machine can help us achieve optimal Class A welds while saving 25% of its amperage and force. Expert machine builders can give you useful suggestions for the right size according to the materials and operating speed.
In addition, the chosen machine can ensure RWMA 50% duty cycle standards. It then needs to have tip alignment, marking requirements, and the ability to accommodate new high-strength steel.
Use The Right Setup Tools
To maximize the use of spot welding recipe charts, a specialized resistance welding amp meter should measure how much the secondary RMS welding current is transferred to the tips. A direct-reading gauge is also necessary to measure the actual weld force between the tips.
Use a Tensile Tester
Testing spot welds is more than just dropping welded parts on the floor; it should be more scientific. To visually assess weld strength and nugget diameter, we can use a mechanical peel or chisel test. In case of pulling small welded sample coupons to failure, the best tool to use should be a tensile tester. A dedicated spot weld should have greater shear strength than that of the parent material.
Design for Resistance Welding
Metal workers can look at charts to see the minimum required overlap of the metal pieces that can be welded together. Spot-welded sheet metal parts should have wide enough flanges to prevent expulsion.
Schedule Regular Preventive Maintenance
Because of the corrosion and arcing of the copper-to-copper secondary connections delivering current from the transformer to the tips, the machine cannot perform as well as it did at the beginning. Therefore, it is vital to clean, tighten, and disassemble the entire secondary loop once a year. At the same time, metal formers should frequently check the force-delivery system to see if there are any air leaks and mechanical wear.
Electrode Designs and Materials
Proper materials, designs, and construction can ensure consistent weld quality, prevent electrode sticking, and optimize electrode life. Besides the correct materials and tips and shank profiles, the manufacture of the electrode itself should have proper bonding.
The Best Materials for Spot Welding
What materials work best for spot welding? Check out the list below, which is divided into the best options for metals and the best ones for electrode materials.
Best for Metals
Spot welding performs best on metals with low thermal conductivity and high electrical resistance, like low-carbon steel. Though spot welding can still work on metals without high-carbon steels, the welds are more likely to fracture and crack due to their brittle and hard microstructures.
This is a list of metal materials that spot welding can work well on:
- Low-carbon steel: It has good electrical conductivity and weldability, and it is widely used in a range of industries.
- Stainless steels: Spot welding can join certain grades of stainless steels, it might require adjustments in welding parameters because they have higher electrical resistance that is potential for oxide formation.
- Galvanized steel: This metal has a protective zinc coating that can be spot welded, but requires special attention to prevent expulsion.
- Magnesium: Magnesium alloys coming with lightweight properties can be spot welded with careful control of welding parameters.
- Aluminum: Aluminum and its alloys are also suitable for spot welding
- Zinc alloys: It includes certain zinc-based alloys, such as zinc-aluminum alloys.
- Nickel alloys: The metals have high strength and resistance to deformation at elevated temperatures, but they can be spot-welded well.
- Monel: Monel contains 52 to 67% of nickel and copper, combined with small amounts of iron, manganese, carbon, and silicon.
- Inconel is a superalloy based on nickel-chromium. It is often used in harsh environments with high temperatures, pressure, or mechanical loads.
- Titanium: This metal has a high melting point, is reactive with oxygen, and tends to form brittle intermetallic compounds during welding.
- Silicon bronze: To achieve optimal spot welding on silicon bronze, we need to consider the alloy’s high electrical and thermal conductivity, potential for oxide formation, and porosity issues.
Best for Electrode Materials
An electrode in spot welding is a solid conductive material that delivers electric current into non-metallic substances like solids, liquids, gasses, plasmas, or vacuums. An electrode is often made of highly conductive materials like metals, but they can also come from non-metallic conductors, including:
High-conductivity electrode materials
Non-refractory copper alloys are considered Class 1 and 2 electrode materials under ISO 5182. They are often employed for high-conductivity electrodes because of their optimal electrical and thermal conductivity, corrosion resistance, metal-to-metal wear resistance, and appearance. They include:
- Pure copper
- Copper cadmium
- Copper chromium
- Other non-refractory copper alloys
Low-conductivity electrode materials
Low conductivity electrode materials are refractory metals that are considered Class 3 electrodes under ISO 5182, including:
- Tungsten
- Molybdenum
- Certain refractory metal alloys
Experience Spot Welding Service with Fischer ASIA
At Fischer ASIA, our services go beyond producing metal stamping parts and molds, we provide comprehensive solutions for the fabrication and assembly of entire components. These services of spot welding operations and manual assembly allow us to integrate various parts into the final finished product.
- Product development process
- Production of high-quality metal stamping and deep-drawing parts
- Management of suppliers for purchased parts
- Precise assembly of parts
- Customized packaging design and management
In particular, our component assembly process adheres to LEAN principles to maximize productivity and maintain unwavering quality standards. We implement quality checkpoints throughout our processes and align with our zero-defect policy. This ensures our customers receive products with their expected quality requirements.
FAQs about Spot Welding Tips
Take a look for frequently asked questions on the topic of spot welding tips for metal:
- What are the advantages of Spot Welding regarding businesses’ benefits?
Spot welding helps employees avoid dangerous working conditions while reducing material cost and labor costs to enhance overall cost efficiency. It also ensures dimensional accuracy for precise component assembly and reliable production with consistent weld quality.
- What industries can businesses apply to spot welding?
Spot welding is widely used in industries requiring robust and reliable metal joining, such as automotive manufacturing, aerospace, fabrication, and metalworking.
- Can spot welding be automated?
Yes, spot welding can be automated. Many manufacturers utilize spot welding robots to enhance cost-effectiveness and consistent weld quality. Automation can also facilitate accessing difficult-to-reach areas for welding and efficient use of floor space.
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