An automatic longitudinal seam welding machine joins sheet metal along its longitudinal axis to form a continuous, straight, and reproducible weld seam. The welder no longer needs to guide the torch manually: clamping systems, the welding head, and the control system handle the most important steps in the welding process. Schnelldorfer Maschinenbau has been designing these seam welding machines for the welding industry since 1980, with weld lengths up to 4,100 mm and material thicknesses up to 15 mm. Let us tell you what matters most when it comes to an automatic longitudinal seam welding machine.
How an Automatic Longitudinal Seam Welding Machine Works
An automatic longitudinal seam welding machine first securely clamps the workpieces into the clamping system. The welding head then moves precisely along the joint on a guide rail, producing a straight longitudinal seam along the entire length of the weld. The welding process is largely automated and requires only minimal operator intervention.
One important factor is clamping force: It presses the sheets against the water-cooled support along the entire joint zone and holds them securely in place during heating. This significantly reduces both warpage and dimensional deviations.
The automatic torch guidance system then takes over seam positioning, while the control system maintains parameters such as current, feed rate, and gas flow at constant levels throughout the entire welding process. Our systems achieve welding speeds of up to 800 mm/min, while the welding power source delivers up to 350 A. This consistency results in a level of reproducibility that would be impossible to achieve manually on this scale.
What welding processes does a longitudinal seam welding machine use?
An automatic longitudinal seam welding machine can use various welding processes. Depending on the material, thickness, desired seam quality, and production speed, MIG, MAG, TIG, or plasma welding may be used. The choice among these processes is usually based on the material being processed and the required surface finish.
Welding Processes at a Glance
- MIG: Metal Inert Gas welding, primarily used for aluminum and copper. High welding speed and good weld quality.
- MAG: active shielding gas; the standard process for steel and carbon steel. Very cost-effective, especially for high-volume production.
- TIG: TIG arc welding with a non-consumable tungsten electrode, providing maximum control over the molten pool. For exceptionally clean and precise welds.
- Plasma: a confined arc with high energy density for thin-walled and challenging materials. Deep penetration and a narrow heat-affected zone.
Typical Materials for Automatic Longitudinal Seam Welding Machines
An automatic longitudinal seam welding machine processes steel, stainless steel, aluminum, and copper up to a material thickness of 15 mm. Brass, titanium, and various special alloys can also be safely welded using appropriately adjusted parameters.
The range extends from 0.20 mm-thick sheet metal to 15 mm-thick material. A variety of machines and sizes are available for this purpose. They differ primarily in terms of maximum weld length, component size, and material thickness.
Our product line covers a range from 0.20 mm thin sheet metal to 15 mm material thickness, with various machine sizes graded according to sheet thickness and weld length. For example, the LINEARWELD XL EXTL, with welding lengths of up to 4,100 mm, covers the upper range, while compact series are designed for short seams and thin sheet metal. You can find an overview of our products for straight seams at any time in the machine overview.
The Advantages of Automatic Longitudinal Seam Welding Machines Over Manual Welding
The biggest advantage is probably obvious: An automatic longitudinal seam welding machine delivers greater welding precision, consistent weld quality, and high repeatability in mass production, whereas manual welding machines and their results depend heavily on the welder's skills.
Automatic Longitudinal Seam Welding Machine vs. Manual Welding
| Criterion | Automatic machine | Manual Welding |
| Seam quality | precise and uniform along the entire weld length | varies depending on how you're feeling that day |
| Reproducibility | High repeatability in mass production | Varies from component to component |
| Performance | Continuous operation, up to 800 mm/min | Pauses and Entry Points |
| Load | Operators are largely relieved of physical strain | Uncomfortable postures for the operator, as well as exposure to smoke |
| Error rate | Fewer errors due to constant parameters | depending on experience |
Automatic longitudinal seam welding machines are used here
Automatic longitudinal seam welding machines are used wherever straight, tight, and repeatable welds are required on sheet metal, pipes, or containers. They are particularly common in the following areas:
- Automotive Industry: Manufacturing of tanks, such as fuel tanks with permanently leak-proof seams
- Food Industry: Manufacture of packaging, water tanks, and stainless steel tanks where smooth surfaces and hygienic seams are important
- Mechanical Engineering: Housings, containers, and other elongated components with high precision requirements
- Construction Industry: Manufacture of pipes where the weld diameter, component size, and material thickness determine the machine's design
Schnelldorfer Maschinenbau: Your Manufacturer of Automatic Longitudinal Seam Welding Machines
Schnelldorfer Maschinenbau develops, designs, and manufactures longitudinal seam welding machines at its Schnelldorf facility and supports each system throughout its entire life cycle. Since 1980, the company has focused on welding technology and, drawing on decades of experience, develops comprehensive technical solutions for the automation of complex welding tasks. Our experts are also happy to develop special-purpose machines and customized automation solutions for you—because we don’t just design individual units; we safely integrate your system into your existing production processes. And even after commissioning, we’re here to support you: Our team handles maintenance and spare parts supply to ensure your machine runs smoothly.
See for yourself: Contact us if you're looking for a welding machine. We look forward to working on your project!
Frequently asked questions (FAQ)
What are automated welding processes?
Automated welding processes handle torch guidance, feed, and parameter control mechanically, allowing the welding process to proceed without continuous operator intervention. As a result, automatic longitudinal seam welding machines operate continuously and achieve a high degree of repeatability in mass production. In addition to metals, plastics such as polyethylene can also be welded automatically.
What is the most difficult welding process?
TIG welding is considered the most demanding process because the torch and the filler material are guided separately with both hands. In manual welding, the result therefore depends heavily on the welder’s skill. In an automatic longitudinal seam welding machine, this dependence is eliminated because the machine maintains a constant torch-to-workpiece distance and feed rate.
What is the simplest type of welding?
MAG welding is the easiest to learn manually because the wire is fed automatically and only one hand is needed to guide the torch.
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