Laser welding technology has been in use for about 30 years. Until now, it has been used selectively and has always been in fierce competition with traditional welding methods. Due to modern, additive production methods such as 3D printing of metallic objects, laser welding is currently rapidly gaining in importance.
What Is Laser Welding Machine?
Laser welding machine is an eco-friendly power welding tool with handheld laser welding gun, CNC controller, or single-arm robot to join pieces of metals or thermoplastics. Laser beam provides a concentrated heat source, which is used for spot welding, butt joint, lap joint, lap edge, lap, T butt, seam welding, narrow welds, deep welds, and kissing weld with high welding rates. The process is frequently used in high volume applications with automation, which is based on keyhole or penetration mode welding.
Laser welding machines are engine driven welders used for a variety of applications from welding very small parts together commonly used by manufacturing businesses in the engineering, medical and electronics industries, through to welding thicker materials in the automotive and aerospace industries. Laser welding is a versatile, low cost way of achieving high quality spot welds for different materials and thicknesses.
A laser welding machine is also known as laser beam welding machine, laser welder, laser beam welder, laser welder machine, laser beam welding equipment, laser beam welding gun, laser beam welding tool, seam welding machine, laser bonding machine, laser brazing machine, laser joining machine, laser soldering machine.
Types of Laser Welding Machines
There are multiple modes of laser welding that we can categorize the machines into. Therefore, we can categorize laser welding technology in various ways. Let’s start defining the laser welding machines by the different categories:
Categorization is based on the type of laser
The pulsed laser mechanism is ideal for metals that are light in nature and have low thickness. Thus, the pulsed laser makes intermittent exposure on the metallic body. Keeping it safe from burning or melting.
Furthermore, this type of laser welding is ideal for welding sheets of metal, razors, jewelry, and even medical prosthetics like screws.
The continuous laser is ideal for welding on parts that have a high thickness and are strong. Moreover, this welding technology is good for refractory surface metals too.
This type of welding is costlier than the pulsed type welding but in the long run, saves a lot of money and labor for you.
Categorization based on the source of laser
Currently, there are three main types of sources of laser for laser welding machines that use one of these laser sources i.e. Fiber laser, CO2 laser, and Nd: YAG laser. Each of these laser sources has their own benefits and are suitable for the different types of welding materials.
Fiber Laser Welding Machine
The fiber laser welding machine is ideal for working on metallic parts. Furthermore, it offers great reliability and efficiency. According to estimates, the accuracy of the laser welding machine using fiber laser is close to 25%.
The CO2 laser welders can provide a great continuous welding beam that creates efficient and durable welds. It can easily penetrate metals and non-metallic bodies.
The Nd: YAG lasers are less energy efficient as compare to the fiber laser welding machines. However, there are certain applications like greater laser control that you cannot achieve with other types of laser sources.
Summing up, you will get laser welders of all types, technologies, and sources. You will have to decide which type of laser welder will suit your business the best.
Before discussing the selection of the best laser welders, let’s have a look at the main applications of laser welding machines in the industry.
How Does a Laser Welder Work?
Laser Welding Technology
The laser welding technology works based on the principle of heat generation by the laser source. Sources of laser in the method also vary and different sources of lasers are suitable for different types of materials and their physical and chemical properties.
Thus, when the beam of high laser energy is focused on a spot of the metal sheet it creates the metal sheet to melt at the spot. The depth of the hole is managed by the various methods of welding and varies accordingly.
This process takes place at the seam of the two metals or materials to be welded together. However, there are multiple methods of laser welding that depend on the type, thickness, and quality of materials to be weld.
Laser Welding Methods
There are multiple methods of laser welding that are largely in use in various industries. Let’s discuss some of these laser welding techniques for you to get a better idea of the process of laser welding.
Conduction welding is a method that provides you with a wide weld that is shallow. There is a further categorization of this method of welding as follows:
The direct heating method uses thermal conduction from the source of heat. Subsequently, this results in the melting of the base material and ultimately making the weld with the other material.
- Energy transmission method
In comparison, the energy transmission method is slightly different and makes use of an intermediate material that conducts the heat from the source to the weld. Usually, it is the absorbent ink that acts as the intermediary material for the transfer of energy.
Similarly, butt joints are also possible by directing the heat energy at an angle of the joint.
- Conduction/Penetration Mechanism
This mechanism works on medium energy and creates a deeper hole than the conduction method but is shallower than the penetration method.
- Penetration or Keyhole Welding MechanismThe other way to weld by using a laser is by using the keyhole method. This method focuses the beam of the laser onto the material and creates deep penetration of heat. Thus, a hole is created on the spot by this method.This hole is later filled with metal vapor that forms a bonding material with the other metal. Therefore, the resulting weld makes a great depth to width ratio and creates tight welds that are durable.
Parts and functions of laser welding systems
Laser welding is an efficient and precise welding method using high energy density laser beam as heat source.
Laser welding is one of the important aspects of the application of laser material processing technology.
In the 1970s, it was mainly used for welding thin-walled materials and low-speed welding.
The welding process belongs to heat conduction type, that is, laser radiation heats the surface of the workpiece, and the surface heat diffuses internally through heat transfer. By controlling the parameters such as laser pulse width, energy, peak power and repetition frequency, the workpiece melts and forms a specific molten pool.
Because of its unique advantages, it has been successfully applied to the precision welding of micro and small parts.
A complete laser welding machine is mainly composed of five parts.
Part I: laser welding host
Laser welding host mainly produces laser beam for welding, which is composed of power supply, laser generator, optical path part, control system and so on.
Some low-power lasers are usually built into the automatic worktable of laser welding.
Part II: cooling system
The cooling system provides cooling function for the laser generator, which is generally equipped with 1-5 HP water circulating chiller.
Part III: laser welding automatic worktable or motion system
The system is used to realize the automatic welding function of laser by moving the laser beam according to the welding track according to specific requirements. Generally, there are three motion control forms:
- The workpiece moves and the laser head is fixed;
- The laser head moves and the workpiece is fixed;
- Both the laser head and the workpiece move;
The whole system compiles the motion control program through CNC programming to control the movement of the worktable according to the requirements, and the simplified programming system has the advantages of simple operation, no professional technology or educational foundation, and can support and grasp quickly.
Common workbench systems on the market include:
- Manipulator motion system;
- 3D workbench;
- Four axis linkage workbench;
- Gantry welding workbench;
- Cantilever workbench, etc;
Both of them can realize precise welding motion control.
Part IV: tooling fixture
Generally, in the process of laser welding, the laser welding fixture is mainly used to fix the welded workpiece, and enable it to be loaded, unloaded and positioned repeatedly, so as to facilitate the automatic laser welding.
Therefore, fixture is one of the essential equipment in laser welding production. Especially in batch production, whether the fixture is designed in place will directly affect the production efficiency and yield.
Part V: observation system
Generally, the laser welding machine shall be equipped with an observation system, which can carry out real-time microscopic observation on the workpiece, which is used to facilitate accurate positioning when compiling the welding program and inspect the welding effect during the welding process. Generally, it is equipped with CCD display system or microscope.
Laser Welding Vs. Arc Welding
The main difference between laser welding and arc welding is how the joint is heated. Laser welding uses a powerful beam of light, and arc welding uses an electrically driven arc.
So, the laser alone imparts heat to the metal with LBW. Nothing contacts the base metal at the joint except the laser beam, and the beam can shoot over long distances, allowing it to access places an arc cannot.
Also, most of us are very familiar with arc welding (e.g., MIG, TIG, stick, flux-cored). But that is not as true for laser welding. Conventional welding has been around for a while, and it is more widely understood.
Arc & Filler
One of the first things that jump out is the lack of an arc or electrode in laser welding.
In addition, since there is no filler material used in many laser welds, LBW results in flat, smooth welds. With arc welding, you get raised beads that often have burrs.
Another major difference is found in the necessary fit up. You need a tight, clean fit for laser welding, or the weld is compromised.
The LBW fit needs to be almost “perfect.” Fit-up needs to be good with conventional arc welding but not perfect, like laser welding. So, arc welding is more tolerant to imperfections in the joint layout since it also employs a filler material.
The initial investment for TIG, MIG, stick, and flux-cored welders is significantly less than laser welding. For many shops, the initial cost of laser welding is prohibitive.
Laser welding is also a complicated, expensive process to set up. So, in general, the more conventional arc welding is more approachable from cost and setup.
But when it comes to speed, laser welding speeds through the work once you set it up. Speed is one of LBW’s strongest advantages, if not the strongest.
But keep in mind that laser welders require plenty of maintenance, including downtime and added cost.
Another big difference is the optics found in laser welding. They are high-tech and “cool.” But they are also sensitive and not durable enough for places like construction sites. So, arc welders are more useful in rough environments.
One last point, LBW imparts less overall heat to the base metal, in some cases 85% less than arc welding. So, laser welding is hard to beat with thin stock and foils.
You can get nice welds with no blow-throughs, even with foil. That is hard to do with arc welding.
With thick metal, arc welding may have an advantage. For thick stock, you need a strong laser and that means very high costs and a powerful, dangerous laser.
For these reasons, laser welders are often limited in the thicknesses they can handle.
Tightly controlled industrial operations in a secure space are needed to safely use a laser powerful enough for the really thick stuff.