What is a laser welder?
Laser welding machines are taught for laser material welding. According to its working method can often be divided into laser mold welding machine (manual laser welding equipment), automatic laser welding machine, jewelry laser welding machine, laser spot welding machine, as well as fiber optic transmission laser welding machine, vibration mirror welding machine, handheld welding machine and other special laser welding equipment including sensor welding machine, silicon steel sheet laser welding equipment, keyboard laser welding equipment. Can be welded graphics are: points, lines, circles, squares or any flat graphics drawn by the software.

Laser welding machine with high degree of automation and simple welding process. Non-contact operation method, to meet the requirements of clean environmental protection. Using laser welding machine to process the workpiece can improve the efficiency. The finished workpiece has a beautiful appearance, small welding seam, large welding depth and high welding quality. Laser welding machine is widely used in dental denture processing, keyboard welding, silicon steel sheet welding, sensor welding, battery seal cover welding, etc. However, the cost of laser welding machine is relatively high, and the precision requirement for workpiece assembly is also relatively high, and there are limitations in these aspects.

How does the laser welder work?
Laser welding uses high-energy laser pulses to locally heat the material in a small area. The energy of the laser radiation diffuses into the material through heat conduction, and the material is melted to form a specific molten pool. It is a new type of welding method, mainly for the welding of thin-walled materials and precision parts. It can realize spot welding, butt welding, stitch welding, sealing welding, etc., with high aspect ratio, small weld width, and small heat affected zone. Small deformation, fast welding speed, smooth and beautiful welding seam, no need to handle or simple processing after welding, high welding seam quality, no porosity, precise control, small focus spot, high positioning accuracy, easy to realize automation.

The working principle of laser welding machine: laser welding can be realized by continuous or pulsed laser beam. The principle of laser welding can be divided into heat conduction welding and laser deep penetration welding. The power density is less than 104~105 W/cm2 for heat conduction welding. At this time, the penetration depth is shallow and the welding speed is slow; when the power density is greater than 105~107 W/cm2, the metal surface is recessed into "holes" under the action of heat to form deep penetration welding. Features of fast welding speed and large aspect ratio.

The principle of thermal conduction laser welding is: laser radiation heats the surface to be processed, and the surface heat diffuses into the interior through thermal conduction. By controlling the laser pulse width, energy, peak power and repetition frequency and other laser parameters, the workpiece is melted to form a specific molten pool .

The laser welding machine used for gear welding and metallurgical sheet welding mainly involves laser deep penetration welding.

Laser deep penetration welding generally uses continuous laser beams to complete the connection of materials. The metallurgical physical process is very similar to electron beam welding, that is, the energy conversion mechanism is completed through the "key-hole" structure.

Under sufficiently high power density laser irradiation, the material will evaporate and form small holes. This steam-filled hole is like a black body, absorbing almost all of the incident beam energy. The equilibrium temperature in the cavity reaches about 2500 0C. The heat is transferred from the outer wall of the high-temperature cavity to melt the metal surrounding the cavity.

The small hole is filled with high-temperature steam generated by continuous evaporation of the wall material under the irradiation of the light beam. The four walls of the small hole are surrounded by molten metal, and the liquid metal is surrounded by solid materials (and in most conventional welding processes and laser conduction welding, the energy first Deposited on the surface of the workpiece, and then transported to the inside by transfer).

The flow of liquid outside the wall of the hole and the surface tension of the wall layer are maintained in a dynamic balance with the continuously generated steam pressure in the cavity. The light beam continuously enters the small hole, and the material outside the small hole is continuously flowing. As the beam moves, the small hole is always in a stable state of flow.

That is to say, the small hole and the molten metal surrounding the hole wall move forward with the forward speed of the leading light beam. The molten metal fills the gap left by the small hole and condenses, and the weld is formed.

And the above process happens very quickly, so the welding speed can easily reach several meters per minute.

Different Types of Laser Welding
Remember conduction welding and keyhole welding? – They're the types of laser welding you can perform to accomplish the welding and the cutting you need.

Keyhole Welding

This process involves the heating of the workpiece or the metal in a way that vaporization of the contact surface occurs.

Thus, creating a keyhole that has a plasma-like condition with temperatures that go upwards of 10,000 Kelvin.

You’ll be able to achieve keyhole welding if you utilize high-powered lasers that go upwards of 105 W per mm2.

Conduction Limited Welding  

Conduction welding is a procedure that involves heating the metal just above its melting point. As opposed to keyhole welding, you don’t need the contact surface to vaporize.

Outputs of conduction limited welding would lie between medium to moderate weld strength. A key benefit of this type of welding is the smoothness and the aesthetic appeal of the final weld.

How to choose the right laser welder?
The following key elements need to be considered.

1. optical characteristics: spot size (laser bar diameter, fiber diameter and type, output head parameters), focal plane height, depth of field, spot position, spot incidence angle.
2. control characteristics: feedback control mode, power waveform selection. The optical characteristics of the laser welding machine can be determined at the time of proofing, the user can intuitively judge the welding effect when the product is first trial, here no longer repeated, focusing on the laser control characteristics affect the consistency of laser welding.

Laser welding machine currently on the market from the control characteristics are mainly divided into two categories: negative current feedback and negative laser power feedback.

Negative current feedback is a control laser pump xenon lamp current, so that the xenon lamp current each time to maintain a constant control method. However, the laser output power is not linearly proportional to the current of the pumped xenon lamp, and as the pumped xenon lamp is used for a longer period of time, the electro-optical conversion efficiency decreases significantly, which will reduce the output laser energy and thus affect the consistency of the welding results. Gender.

Laser power negative feedback is a control method that adds a photodetector to the output of the laser cavity to control the xenon lamp pump current by comparing the detected laser power with the desired laser power.

Laser power negative feedback is divided into real-time negative feedback and non-real-time negative feedback. Real-time negative feedback is a control method that compares the detected laser power with the required laser power within a laser power pulse to control the xenon lamp pump current. Non-real-time negative feedback is a control method that compares the laser power waveform detected in the previous pulse with a set waveform and then determines the current level of the laser pumped xenon lamp in the next pulse.

In addition, laser welders with negative laser power feedback control can easily control the laser power waveform. In fact, using different laser power waveforms for different materials can result in more exquisite welds, sometimes even when conventional methods fail to weld. Materials can also be welded better by changing the laser power waveform.

When choosing a laser power waveform, in general, the wider the pulse width, the larger the weld joint, and the higher the peak power of the laser power waveform, the deeper the weld joint, given the same laser energy output. There is not yet a complete set of laser power waveform setting method. Users can gradually explore the laser power waveform suitable for their products in the process of use.

The choice of laser welding machine is very important to the yield rate of batch processing; therefore, users can try to use laser power real-time negative feedback welding machine to improve the qualification rate of products when conditions allow.

Benefits of using a handheld laser welder
1.Ultimate and highest accuracy and precision

Probably the main advantage you can gain is the accuracy of the weld. Since you can control it manually, the way you weld depends on your movements.
Even if you have to weld small parts and components, laser welding is not a problem.

2.Consistency of the weld

Since you set the speed, power and pattern manually, your welds will be consistent even if you have to weld a large number of parts.
Add to that the fact that you can weld faster, and laser welding is really something you need to consider.

3.The ability to create and produce complex welds

Some welding techniques, such as MIG welding and TIG welding, are not the best for complex welds; this is because of the limited electrodes available.
That's when laser welding goes up a notch. No matter how complex a particular weld looks, a laser welder can achieve it.

4.Stronger, more durable welds

Last but definitely not least, you can have a much stronger weld.
You don't need filler material to weld it, and it provides excellent strength and durability.
These are just some of the most sought-after advantages of laser welding.

Now that you know the advantages of laser welding, what are the advantages of handheld laser welders?
Let's move on to discuss the benefits of using a handheld or manual laser welder.

1. Better Control

Control in terms of mode, speed, power, heat, etc., in motion. You can set it to the minimum or maximum value according to your preference.

2. Versatility of weld seam

Another advantage of using a handheld laser is that you can use it for a variety of objects and materials.

In addition, you can weld different objects and materials!

3. No electrodes required

We also know that you do not have to use any type of electrode for this purpose. Therefore, you can expect less cost and damage to the output.  

4. Easy Focusing

The laser beam you will use for welding or cutting is easy to focus.
You'll have the optics as a calibration guide, and you'll never have to think about quality.

5. Other benefits include:

No need to shield against vacuum or radiation
Can be focused on a small area
Can be operated in tight spaces

Many people choose an automatic laser welder over a handheld laser welder. While this is great, it will be better to start it manually because you will also learn a lot from it.