Robot Welding

Application

What is robot welding?

Robot welding means guiding the welding torch (or electrode) along a programmed path with a robot arm — instead of by hand. The robot guarantees a constant torch pose, uniform travel speed and repeatable seam quality across thousands of cycles.

The most important driver for automating welding today is not cost saving but the acute shortage of welders: apprenticeship numbers have been declining for years, retirement-driven attrition affects every other shop. Anyone who does not automate today risks losing orders tomorrow for lack of capacity.

Which welding processes are automated?

• MIG/MAG (GMAW) — around 70 % of all robot welding applications. Fast, versatile, good for steel, aluminium, stainless steel.
• TIG (GTAW) — for high-quality seams on stainless steel, aluminium, titanium; typical in pharma, chemicals, semiconductor, aerospace.
• Plasma and laser beam welding — for thin sheet, precision applications, high speeds.
• Laser hybrid — combination of laser + MIG for deep penetration profiles at high speed.
• Spot and stud welding — especially in body-in-white.

Cobot or industrial robot — two variants

For welding applications there are two fundamentally different cell concepts. The choice depends on batch size, seam length and cycle rate:

Typical applications

• Body-in-white and subassembly welding in the automotive sector
• Frame and structural welding in mechanical and plant engineering
• Steel construction: girders, frames, brackets, vessels
• Sheet-metal fabrication: housings, cabinets, control-cabinet assembly
• Stainless-steel fabrication for pharma, chemicals, food industry (TIG seams, high-gloss polished)
• Small and medium series in contract manufacturing — exactly where cobot cells play out their biggest economic advantage

The NEXOS configuration

• Robot — cobot or industrial robot depending on the variant (see above).
• Welding power source — Fronius TPS/i, Lorch, EWM, Kemppi, Migatronic or customer request. We integrate digitally (robot ↔ power source communication via DeviceNet/EtherCAT).
• Torch & cable assembly — air- or water-cooled depending on duty cycle, TCP calibration fixture for high repeat accuracy.
• Wire feeder — standard units from the power-source manufacturers, with refill monitoring.
• NEXOS.Cube as the cell frame with integrated NEXOS.Protec enclosure — visual and UV protection against glare, noise protection, spatter shielding.
• Welding fume extraction — filter cabinet directly next to the cell, compliant with TRGS 528 (welding fumes at the workplace).
• Welding table & fixturing — modular on a fixture plate (16 or 22 mm system grid) with reproducible clamps. Optional as workpiece positioner or rotary table for two-station operation.
• Optional: NEXOS.LinDrive as 7th axis — extends reach for long seams or multiple workpiece stations.

Sequence of a typical cell

1. Load and fixture workpiece (operator or robot handling)
2. Cycle start via two-hand control or door interlock
3. Robot moves to start point, power source is set programmatically (current, voltage, feed rate per seam program)
4. Ignite arc, travel the seam with optional seam tracking
5. Seam change without operator intervention — the program runs the entire subassembly in one clamping
6. Completion signal, allow extraction to run down
7. Remove workpiece and place it; in two-station operation the positioner swings directly into the load position

Why it pays off

Market data (2026) for robot welding cells:

• Cobot welding cell: total investment 60,000-120,000 € (robot + power source + cell + enclosure). Typical payback 12-24 months with >100 identical welds per week.
• Industrial-robot cell: total investment 150,000-300,000 €. Payback 1.5-3 years in series operation.
• Productivity: robot welding is typically 4-8x faster than manual welding with consistent quality.
• Seam quality: defect rate typically <0.1 % with the robot vs. 3-5 % in manual operation.
• Welder skills shortage: payback via labour cost saving is only half the story — the other half is simple availability. Without a welder you cannot deliver the order without a robot.

Scalability

• Stage 1 — single cobot cell: cobot + fixed welding table. Classical entry with high flexibility.
• Stage 2 — two-station operation: workpiece positioner or rotary table — while the robot welds station A, station B is loaded. Cell utilisation close to 100 %.
• Stage 3 — LinDrive as 7th axis: cobot on an external linear axis, tending multiple adjacent stations or very long seams.
• Stage 4 — industrial-robot series cell: when moving to series production with >500 identical subassemblies per day, an industrial robot with fixed programmed cycles is recommended.
• Stage 5 — connected manufacturing: integration with NEXOS.DSP for weld data acquisition, quality documentation per ISO 3834, arc-on-time OEE.

Expansion options

• Seam tracking — optical camera or arc sensor for automatic path correction with component tolerances (distortion, fit)
• Visual inspection after welding — camera checks the seam for porosity, undercuts, penetration
• Automatic torch cleaning — cleaning station to remove weld spatter, extending service life
• Workpiece feeding — instead of manual loading, a second cobot or feeder magazine
• Digital twin via NEXOS.XR — virtual programming of new components, collision checking, operator training

Key sizing parameters

What we need from you for the design:

• Welding process (MIG, MAG, TIG, spot, laser)
• Material (mild steel, stainless steel, aluminium, ...)
• Sheet thickness — determines power-source rating and torch cooling
• Seam lengths and typical seam types (fillet, butt, 3D paths)
• Workpiece size and weight — determines cell size, robot reach, workpiece handling
• Batch size per order and number of different workpiece variants
• Quality requirements (visual, X-ray, tensile/bend test, ISO 3834 classification)

Safety — what welding adds on top

For welding, the safety analysis is different from handling applications:

• UV radiation — closed cell with visual protection against glare for other workers in the hall
• Welding fumes — extraction per TRGS 528, filtered and if needed exhausted outside
• Spatter — cell walls and floor built to be spatter-resistant
• Fire risk — fire-fighting equipment nearby, fire detectors inside the cell if needed
• Collaborative operation is only partially possible with welding — the cobot itself is mechanically safe, but the arc and spatter make a safety enclosure almost always necessary