There are different ways in which metal can interact with the laser beam. Different combinations of virmer laser beam metal cutting equipment are available for creating deep weld seams or joining workpieces on the surface. It can be used for both soldering and assembly with conventional welding techniques.
Weld seams and weld spots can be found in various places, such as intercity express trains, gear parts of cars and trucks, airbag sleeves, and pacemakers.
How does a laser cleaning machine work?
The laser beam welding versatile tools:
It can create perfect weld spots meters long with a diameter of just one millimeter.
Minimal distortion can create when using a large depth/width ratio to create very small seam geometrics.
Lasers create melting point materials and high heat connectivity.They can also sometimes join materials that would be impossible or difficult to weld due to the low melting point and short regulated melting period. If necessary, you can use a filler substance.
A laser beam creates a weld to fuse metals or thermoplastics together during the laser welding process. Laser welding can create narrow, deep welds between square-edged pieces in thick materials, and high speeds of meters per minute can be done in thin materials due to the concentrated heat source.
Kinds of Laser Beam Welding:
Conduction limited welding and keyhole welding are the two basic types of laser welding. Depending on the power density across the beam hitting the workpiece, the interaction of the laser beam with the material will take different forms.
When the energy density is typically less than 105W/cm2, conduction is limited to welding. The laser beam does not penetrate the material; the surface absorbs by material.
In this case, the width-to-depth ratio of conduction-limited welds is often significant.
Using extensive power density, laser welding uses a keyhole mechanism and large power density and performs very well.
The material in the path of the laser beam melts and vaporizes when the laser beam is focused onto a small enough area to provide a power density typically >106-107 W/cm2; before that,
Conduction can dissipate a sufficient amount of heat.
Once inside the workpiece, the focused laser beam creates a “keyhole”-shaped cavity filled with metal vapour (which in some cases can even ionize, forming a plasma).
By expanding vapour or plasma, the molten walls of the keyhole can prevent it from falling into the cavity.
Furthermore, its hole creation significantly enhances the coupling of the laser beam with the workpiece. The joint is then moved about the laser beam or welded along the joint to accomplish deep penetration welding—welds with a more excellent depth-to-width ratio result.
Molten material at the leading edge of the keyhole flows backwards around the keyhole cavity due to surface tension, cools, and solidifies to form the weld. As a result, the weld cap now has a chevron pattern that indicates the origin of the weld.
Single-sided, line-of-white deep penetration (or keyhole) laser welding is a non-contact joining technique. Laser beams have a highly concentrated energy density, which enables them to weld various metal materials with high aspect ratios (narrow weld width: considerable weld depth). Although highly reactive materials require inert gas protection, this can be done at atmospheric pressure.
Laser welding has a relatively low heat input compared to the arc welding process.
When laser beams are focused into spots less than one millimetre in diameter, they can be used to apply power densities to joints ranging from 103 to 107 W/mm2. Below the laser beam engagement point, these power densities are sufficient to form a “keyhole” weld. Thanks to its efficient laser beam absorption of the hole, low heat input welding can be made.
Higher productivity may result from the ability to process thinner materials at higher speeds, or thicker materials require only one pass to make deep penetration welds. Because laser welding is automated, it can be used to provide welding operations that are reliable, repeatable, and autonomous.
Deep laser welding:
Deep penetration laser welding is desirable when welding components that require thermal distortion or materials that benefit from low heat input because the heat input is often less intense than with arc welding methods.
The industry has used laser welding, a flexible fusion welding technology, for various purposes, including joining shipbuilding structures and aircraft fuselage panels.
This technique can join various materials, including carbon steel, stainless steel, and titanium, aluminum, and nickel alloys. The criteria for high-volume production, high-quality welds, and low weld distortion drive the industrial adoption of laser welding.
TWI has extensive experience developing and qualifying laser welding processes for various industrial applications.
