Skip to main content

Our new Website is under construction

This page is still under construction

Wobble-L provides proven return on investment with stable long-term installations and clean working enviroment, while remaining flexible enough to support all new innovation in metal joining.

Which Laser Source for welding?

What type of laser source do i need to weld my product?

There are a number of laser sources available for laser welding, and each has specific performance characteristics that align with certain application categories. During the selection process it is important to keep in mind that welding is a balance among such factors as penetration, speed, weld stability, and accommodation of production part fit-up and tolerances. The end user should have sufficient understanding of which lasers are best suited to their welding application. This understanding can be self-acquired or through partnering with experienced laser system integrators and laser OEMs. 
 

Pulsed and continuous beam operation at laser welding

Continious Wave (CW) Laser Source Versus Pules Wave Laser Source

Continious Wave welding gives Very strong Welds while Pulsed Wave welding gives very light but deep welds

CW LASER Versus QCW LASER versus YAG LASER

Continue Wave Welding Versus Continue Wave/Quasi Continue Wave (Pulse) Welding Versus Pulse Welding

YAG Laser

YAG: pulsed lasers

YAG LASER 600 Wat Strobo lamp pulsed

Good but old technology - none economical - fully replaced by new technology lasers

YAG = Peak powers and pulse widths perfect for MICRO WELDING

Micro welding = Nd:YAG lasers

The pulsed Nd:YAG laser has been around for many decades and has by far the largest install base. In today’s laser landscape, it is best suited to spot welding application under 0,8~1,2 mm penetration and seam welding heat-sensitive packages.

With the Nd:YAG laser, the active gain medium is neodymium, which is doped into a host crystal of yttrium aluminum garnet. This solid rod of material is typically 2,5-5,0-mm in diameter and around 80~150 mm long.

Micro welding Nd:YAG lasers are optically pumped using flashlamps and typically emit light with a wavelength of 1064 nm, but can be frequency doubled (532 nm, green). The laser’s optical design is relatively simple; its heart is the power supply that drives and controls the flashlamp voltage and allows precise control of peak power and pulse width during the laser pulse using internal optical feedback.
With excellent pulse control, the Nd:YAG laser also offers high peak powers in small laser sizes, which enables welding with large optical spot size. This translates to maximized part ft-up and laser to joint alignment accommodation. An example is a 25 W laser that can provide 6 kW of peak power, suffcient to weld steel and aluminum with a 600 micron spot size.

What are YAG pulsed fiber lasers?

QCW Fiber Laser

QCW: pulsed and Continious fiber lasers

What are QCW pulsed fiber lasers?

What are Quasi Continuous Wave fiber lasers?

A QCW (Quasi Continuous Wave) fiber laser retains all of the well-known benefits of continuous-wave (CW) fiber lasers, but there is one key feature that increases peak power by a factor of 10X over CW lasers—increased numbers of pump diodes are simply spliced into the active fiber. Limiting the duty cycle of these diodes to 10% requires a far smaller power supply but the laser provides 10X higher instantaneous (peak) power when in this pulsed mode. In some versions, pulse energy as high as 60J is possible in low-millisecond pulses.

The peak power of a laser pulse is strongly related to the ability of a particular laser to “couple in” or break down the reflectivity of a metallic surface to start producing a weld. As true QCW pulsed lasers have an order-of-magnitude higher peak power, this coupling ability is greatly enhanced. This unique feature has now allowed the QCW laser to compete very successfully with older technology flashlamp YAG lasers and with CW fiber lasers in the field of low-power laser welding.

As the initial target application for this QCW laser was spot welding, it is very important to note that a 150W CW laser will need 67ms to produce a modulated pulse of 10J. In this scenario, the peak power of the beam is the same as the CW power: 150W. 

The lowest-power QCW laser, however, can typically produce 10J at 15Hz in 8ms at a peak power of 1250W for a conduction-limited spot weld. Clearly, greatly reduced collateral heating of the welded component will occur in 10ms as compared to 67ms.

The peak power of a QWC laser is always 10 times larger than the average power. So, a 150/1500 laser emits 150W of average power and 1500W peak power in the pulsed regime, with a maximum of 10% duty cycle. 

In essence, if peak power is required for any particular laser process, then this laser type can provide it in a far more cost-effective package than a CW laser with an equivalent peak power. Newer versions of this QCW laser can include a 10μs minimum pulse duration option.
It should also be noted that the maximum pulse duration limit is inversely proportional to peak power: 10ms for 1500W, 15ms for 1000W, 50ms for 300W and lower. So far, longer pulses and higher duty cycles are therefore available if high peak power requirements are low, such as when welding lower reflectivity metals.

QCW in Continious Wave (CW) or pulsed or modulated mode

Another unique feature enabled by diode pumping with single emitters that justifies the prefix “quasi-” in QCW is that this laser can also be run in either pulsed or CW mode. In CW mode, the QCW laser typically has 30% higher average power throughout the range. QCW fiber lasers in CW mode can be modulated to minimize heat input to the component during cutting in this modulated CW regime. Also in this CW mode, low mode fibers combined with galvanometer scanners allow very highspeed, high-aspect-ratio ‘micro keyhole’ welds, although extremely good fit-up of the components is required.

QCW FIBER LASER SERIES

QCW fiber laser controls the CW fiber in a pulse-controlled method to obtain the higher peak power and laser energy of the pulse laser, and the higher beam quality of the fiber laser, which can achieve the best welding effect.

Advantages
  • Constant beam quality within a full power range
  • Superior power output and energy stability
  • With high peak power can weld high anti-materials, such as copper, aluminum, etc.
  • Can replace many of the older YAG laser welding applications to reduce maintenance costs, and QCW can be easier upgraded to meet majority of existing systems

What material can a QCW Laser Weld?

What material thickness can a 150/1500 Watt QCW laser Weld in CW Mode?

Thickness in mm             Welding Methods    
Material SUS Steel AU CU Ni   Butt Welding thru Splicing Welding Penetration Weldding
0,1 mm Y Y Y Y Y   Y Y Y
0,4 mm Y Y Y Y y   Y Y Y
0,8 mm Y Y N N Y   Y Y Y
1,2 mm Y Y N N Y   Y Y N

What material can a QCW Laser Weld?

What material thickness can a 300/3000 Watt QCW laser Weld in CW Mode?

Thickness in mm             Welding Methods    
Material SUS Steel AU CU Ni   Butt Welding thru Splicing Welding Penetration Weldding
0,2 mm Y Y Y Y Y   Y Y Y
0,5 mm Y Y Y Y y   Y Y Y
1,0 mm Y Y N N Y   Y Y Y
1,5 mm Y Y N N Y   N Y N

Metallic welding and joining with QCW laser

Using nano second pulsed lasers (like QCW) for welding metals, needs careful adjustment of the pulse conditions and the process setting to actually achieve good joints, after all, the prime application of these types of pulses is to remove material, not to melt and allow it to resolidify. The pulses need to be optimised to give a maximum peak power and pulse energy but these characteristics can be modified by using them at higher frequencies. This has the effect of reducing the peak power and moving the output closer to a quasi CW gated pulse whilst maintaining the average power.  At these higher frequencies the pulses move from an ablative to a more melting interaction with materials.

Quasi-continuous-wave fibre laser is ideal for spot welding, cutting, seam welding and drilling applications.

Some applications

  • Spot welding
  • Seam welding (thin material)
  • Drilling and light cutting
  • Joining of aluminium to copper for electrical applications in automotive, transport and aerospace industries
  • Fuel cell manufacture for applications including transport and bulk energy storage
  • Medical devices
  • Packaging
  • Electronics and sensors
     

CW Fiber Laser

CW: Continious Wave fiber lasers

What are CW continue fiber lasers?

Continuous wave (cw) fiber lasers

For high speed seam welding applications this laser is operated in continuous wave mode, which means that the laser output remains on until being turned off. For spot welding either a single weld or a seam, the laser output can be pulsed or, more correctly, modulated – turning the laser on and off rapidly. The CW laser’s peak power is the same as its maximum average power, so focused spot sizes are generally under 100 microns to attain suffcient power density for welding with power levels under 1 kW. Due to the small optical spot size, lap and fllet weld geometries are preferred, but this is solved by the WOBBLE technology.
Butt welding is possible if there is good part fit-up. An alternate for not so good fit-up parts is using a scan head that can create motion lateral to the weld direction, known as wobble, which can effectively widen the weld to decrease joint alignment sensitivity.