Laser spot welder includes 2 types: YAG laser and QCW laser. Today, we will explore the two types of laser spot welding machines based on YAG laser and QCW laser.
I. What is a YAG laser
With the advancement of laser technology, yttrium aluminum garnet (YAG) crystal materials have been adopted for laser device manufacturing. There are two main types: Nd: YAG (neodymium-doped YAG lasers) and Yb: YAG (ytterbium-doped YAG lasers). Key performance parameters of YAG lasers include output power, laser wavelength, pulse width, and pulse repetition frequency.
YAG laser is the core component of a laser spot welder. It includes the mould laser welding machines, galvanometer-based laser welding systems, and multi-axis automatic welding equipment. Miniaturization and integration are the main development aspects of YAG laser welding machines. Continuous improvements in laser component performance have significantly reduced the cost of YAG lasers.
II. What is a QCW laser
A QCW (Quasi-Continuous Wave) laser is a solid-state laser. It operates in a pulsed mode with high-frequency bursts of short-duration pulses, typically in the microsecond range. Unlike continuous wave (CW) lasers that emit a steady beam, QCW lasers deliver energy in rapid, repeated pulses, allowing them to achieve high peak power levels while maintaining a lower average power.
QCW laser has a higher peak power and a deeper welding depth than YAG laser. The laser control program controls the duty cycle of the pulse, which reduces the damage to the material.
III.What is the laser spot welding
A laser spot welder refers to emitting laser light at a certain frequency, which emits light intermittently rather than continuously. The continuous laser emission method is called continuous laser welding. Next, two examples will illustrate the difference between laser spot welding and laser continuous welding.
- A laser spot welder is just like connecting paper with a staple. You want to stack two thin metal sheets together and need to use a few precise points to fix them. But you don’t want them to deform due to extensive heating.
Example:
- Mobile phone battery contacts. At first, remove the back cover of the phone. Then, connect the battery to the motherboard by the four small golden dots (each with a diameter of about 0.5mm). Here we can use a laser spot welder. Ther welding progress is like using miniature staples to “nail” key positions, which is both firm and does not damage the surrounding circuits.
- Welding of eyeglass nose pads: Small welding points (almost invisible to the naked eye) that fix silicone nose pads on the metal frame to ensure that the thin and light frame does not deform.
- A laser continuous welder is just like bonding seams with tape. Two pieces of material need to be completely sealed or connected along a line to prevent water leakage or withstand continuous tension.
Example:
- Sealing of Insulated Cup Inner Container. The vacuum layer of the stainless steel insulated cup needs to be sealed with a laser spot welder. It can instantly melt a continuous and seamless weld seam (similar to sealing the seam completely with tape). The seal area can ensure no air leakage for 10 years.
- Electric vehicle battery pack shell. The laser spot machine can be used for welding aluminum alloy shells that are 1 meter long. Laser spot welding is three times faster than traditional manual welding, greatly improving production efficiency.
IV. How to choose the laser spot welder
Method 1: Choose the spot laser machine based on the budget
Normally, the price of QCW laser spot welder is higher than that of YAG laser spot welder. Because the QCW laser spot welding machine is lighter, more compact than the YAG laser machine, and it don’t require water tank to cool laser machine.
Method 2: Choose the spot laser machine based on the laser energy
The energy generated by the YAG laser spot welder is greater than that of the QCW spot welder. If the welding depth is greater than 1.5mm, it is recommended to choose a YAG laser spot welding machine.
