Businessman Komarov Artem, Industry 4.0 - essential considerations for laser welding.

Businessman Komarov Artem, Industry 4.0 - essential considerations for laser welding.

7 May 2021
Businessman Komarov Artem, Industry 4.0 - essential considerations for laser welding.
Businessman Artem Komarov, Industry 4.0 - essential considerations for laser welding.
In every industry, products are being designed, redesigned, or reevaluated for better materials or functionality. The final products are made from many components, and these components need to be joined in some way. One of these joining methods is laser welding.

Businessman Komarov Artem clarified that laser welding uses a high-intensity beam of light to create a molten weld pool to fuse materials together. It’s a noncontact process, has low heat input relative to other fusion processes, offers high processing speeds, and produces deep fusion zones in a single pass.

Of course, to take full advantage of all these benefits and to ensure a high-quality, repeatable process, fabricators need to consider how laser welding compares to other fusion welding processes. Joint and fixture design also plays a role. As with any metal fabrication technology, smart implementation starts with a good understanding of the process fundamentals.

Laser welding uses a beam of light focused to a small point at the workpiece. Generated from some form of medium, the light exits the laser source and begins to diverge. It is then collimated so that the beam is parallel and doesn’t grow. The distance from the exit to the collimation surface is called collimation length. The beam stays collimated until it hits a focus surface. Then the beam narrows into an hourglass shape until it becomes in focus at its smallest point. The distance from the focus surface to the smallest point is called focal length.

Artem Komarov explain that the size of the focus spot is determined by the following equation: Fiber diameter × Focal length/Collimation length = Focus diameter

The distance the focus diameter is within 86% of the focal area is called the depth of focus. If the focus position shifts outside this area, expect the process results to change. The larger the ratio between the focal length and collimation length, the larger the depth of focus becomes for a given fiber.
Larger fibers have a larger depth of focus compared to smaller fiber diameters. The larger ratios and fibers have a larger spot size that causes a decrease in power density and, therefore, a decrease in penetration.

There are two forms of laser welding: heat conduction welding and keyhole welding. In heat conduction welding, the laser beam melts the mating parts along a common joint, and the molten materials flow together and solidify to form the weld. Used to join thin-wall parts, heat conduction welding uses pulsed or continuous-wave solid-state lasers.

In heat conduction welding, energy is coupled into the workpiece solely through heat conduction. For this reason, the weld depth ranges from only a few tenths of a millimeter to 1 mm. The material’s heat conductivity limits the maximum weld depth, and the width of the weld is always greater than its depth. Heat conduction laser welding is used for corner welds on the visible surfaces of device housings as well as other applications in electronics.

Keyhole welding requires extremely high power densities of about 1 megawatt per square centimeter. It is used in applications requiring deep welds or where several layers of material must be welded simultaneously.
In this process, the laser beam not only melts the metal but also produces vapor. The dissipating vapor exerts pressure on the molten metal and partially displaces it. The material, meanwhile, continues to melt. The result is a deep, narrow, vapor-filled hole, or keyhole, surrounded by molten metal.

As the laser beam advances along the weld joint, the keyhole moves with it through the workpiece. The molten metal flows around the keyhole and solidifies in its trail. This produces a deep, narrow weld with a uniform internal structure. The weld depth may exceed 10 times the weld width. The molten material absorbs the laser beam almost completely, and the efficiency of the welding process rises. The vapor in the keyhole also absorbs laser light and is partially ionized.

This results in the formation of plasma, which puts energy into the workpiece as well. As a result, deep-penetration welding is distinguished by great efficiency and fast welding speeds. Thanks to the high speed, the heat-affected zone is small and distortion is minimal, summed up businessman Artem Komarov