What Thicknesses of Materials Can Laser Welding Machines Weld?

In modern manufacturing, laser welding machines—thanks to their unique advantages—are now used across a wide range of industries. One of the most critical performance indicators is the span of material thickness they can weld. Laser welders can join materials from ultra-thin foils to comparatively thick plates, a capability rooted in their multiple welding modes and highly flexible parameter control.

Ultra-thin materials (~1 mm or less)  

For foils or thin sheets around 1 mm, laser welders excel in heat-conduction mode. A finely focused, high-energy-density beam—spot size in the micron range—creates a localized hot zone on the surface. Heat then conducts inward, melting and bonding the material with a heat-affected zone (HAZ) kept below 0.1 mm. This avoids distortion or burn-through, delivering precise, strong welds that satisfy the stringent demands of electronic components. When hand-held laser welders join stainless-steel sheets (0.2–0.5 mm), positive defocusing produces smooth weld surfaces, preserving the base-metal properties while ensuring joint strength.

Medium-thickness materials (1–5 mm)  

In this range, laser welders remain highly capable. Automotive body construction, for example, relies heavily on 1–3 mm low-carbon steel or aluminum alloy sheets. Deep-penetration (keyhole) welding is employed: a high-power beam rapidly melts and vaporizes the metal; the resulting vapor pressure opens a small “keyhole.” As the laser advances, the keyhole deepens, liquid metal flows around it, and—when the beam ceases—the molten pool solidifies into a deep, narrow weld. A 1.5 kW laser, properly tuned for speed and pulse frequency, can weld 3 mm carbon steel at tens of centimetres per minute, achieving a high depth-to-width ratio that boosts both joint strength and lightweighting goals.

Thick-plate applications (≥5 mm)  

For medium and heavy plate (up to 20 mm and beyond), laser welders remain effective, but they demand higher power and finer process control. Pressure-vessel fabrication often uses 6–20 mm stainless steel. A 6 kW (or higher) laser, combined with optimized parameters—appropriate assist gas (Ar, N₂), precise beam focusing, and carefully set travel speed—enables single-pass welds of substantial thickness. Case studies show stable 8 mm single-pass welds in stainless steel with a 6 kW source. When thickness exceeds 20 mm, multi-pass techniques or hybrid processes (laser + arc) combine the strengths of both methods to guarantee weld quality and productivity.

Key influencing factors  

Weldable thickness is governed by:  

• Laser power—higher power yields greater penetration.  

• Welding mode selection—heat-conduction, keyhole, or brazing—tailored to thickness and material.  

• Material properties—melting point, thermal conductivity, etc.  

• Assist-gas type and flow, beam quality, focus accuracy, travel speed, and defocus distance.

Among laser-welder brands, PDKJ stands out. Its advanced laser source delivers stable, finely adjustable power that matches any thickness requirement. Whether precision welding of thin sheets or high-efficiency joining of thick plates, PDKJ ensures consistent energy output and reliable weld quality.

To experience PDKJ’s capabilities in person, please visit us at EMO Hannover 2025, September 22–26, Hall 13, Stand F21. See live demonstrations, speak with our technical specialists, and discover new possibilities for your welding applications.

If you have welding machine requirements, please contact Ms. Zhao

E-Mail: pdkj@gd-pw.com

Phone: +86-13631765713