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Laser Spot Welding - Laser Keyhole Welding

Laser Keyhole welding beats conventional spot welding machines on all fronts

Most manufacturers are looking for ways to save money and improve efficiency without negatively impacting quality. Manufacturing operations that are using resistance spot welding can reap significant productivity and quality benefits in some applications by converting to laser keyhole spot welding.

Implementing fiber laser keyhole spot welding can result in a welding process that is three to four times faster compared to resistance spot welding, while also increasing weld quality and repeatability.

Laser keyhole spot welding offers numerous benefits in the right applications, including precise control of penetration depth, a very small beam size for a small heat-affected zone, great consistency, and an extremely fast process.
However, laser keyhole spot welding may not be the right fit for every job. 

Laser spot welding

Fiber Laser Spot Welding

Laser spot welding is a non-contact process which uses a laser to create a single weld spot to weld metals together. Lasers are capable of delivering a pulse of light with accurate, repeatable energy and duration. When the pulse is focused into one place – a small spot – (adjustable anywhere from approximately 0.1 to 3.0 mm in diameter) on the part, the energy density becomes quite large. The light is absorbed by the material causing a “keyhole effect” as the focused beam drills into, vaporizes, and melts some of the metal. As the pulse ends, the liquefied metal around the keyhole flows back in, solidifying and creating a small spot weld. This entire process just a few milliseconds.

Lasers can fire many pulses per second, and, by moving either the work piece or optics, allow either separate “spot” welds or a series of overlapping spot welds to create a laser seam weld that can be structurally sound and/or hermetic.

In some sheet metal applications that require resistance spot welding, an automated laser keyhole welding process can save time and improve weld quality. The process is well-suited for welding some dissimilar metals, which can be difficult to weld properly with resistance spot welding because of differences in the physical, chemical, and mechanical properties of the base metals.

Laser keyhole welding uses a powerful laser beam to weld two workpieces together. A high-energy-density laser hits a small pinpointed spot on the material. When light hits the top surface, it melts and vaporizes the metal. The pressure of the metal vapor pushes the liquid metal downward and aside, generating a keyhole. As the laser beam is moved across the surface, the keyhole follows the beam and creates a weld that is typically deep and narrow

In suitable applications, laser keyhole welding offers:

  • Precise control of penetration depth, which eliminates any deformation or indentation on the back side of the bottom part. This reduces the time and money spent on postweld grinding or touchups.
  • A very small beam size — less than 1 mm — that results in a small heat-affected zone. This offers benefits when welding thin materials or metals in which controlling heat input is important.
  • An extremely fast process that is typically three to four times faster than manual resistance spot welding.
  • Consistency and predictability, which result in high-quality finished welds and reduced time and money spent on rework.

Laser Spot Welding Benefits:

Our WOBBLE-3 handheld laser welders

can join a wide range of steels, nickel alloys, titanium, aluminium and copper.

Weld sizes:
Width: 10 nm - 3000 nm
Depth: 10 nm - 5 mm
Welding speeds:
Range from 0 - 5 meter per second

Advantages of laser spot welding with our Wobble-3

The advantages of the laser technique, compared with arc or resistance welding processes are summarised as follows:

 

Low heat inputs to the materials, minimizing distortion
High process speed; Easily automated process
No weaving required
The only consumable is shielding gas, apart from normal laser requirements
It forms a narrow deep weld, small heat-affected zone
It can be applied in confined areas
Access to only one side of the material is required.
Easy to integrate into production lines 
Small heat affected zone
Contactless welding 
Very fast welding
Low costs per weld for high volume spot-weld application