K-TIG Vs Hybrid Laser Beam Welding

Process Comparison

What are K-TIG’s Advantages Over Hybrid Laser Beam Welding (HLAW)?

Hybrid Laser Beam Welding is a more complex variant of Laser Beam Welding and combines a laser with an additional arc welding method such as MIG/GMAW.

Such combinations improve the tolerance to variations in joint fit-up and allow improved weld finishes. High quality welds can be achieved in a variety of materials however the operational complexity and cost of hybrid laser systems is prohibitive for most applications.

By contrast, K-TIG is a simple process, easily operated and affordable to the majority of fabricators.

The controller makes it foolproof to run the welds in a consistent manner. It’s very simple and very easy to use

Attila Szabo, Principal Joining Engineer, GE

The Benefits of Switching

How does K-TIG overcome the issues of Hybrid Laser Beam Welding?

 K-TIG overcomes the most common issues associated with Hybrid Laser Beam Welding:

  • Equipment Cost: K-TIG comes at an incredibly low cost of $100,000 USD (approximately) for a complete, high energy density welding system that can be incorporated into a pre-existing mechanised motion system. HLAW, on the other hand, carries an $800,000 USD price tag and offers a far more inconsistent process with laser power level having a huge bearing on the final cost of the system.
  • Penetration: Beyond 15mm defects will form readily with a HLAW system. A K-TIG system can easily perform single pass welds on 16 mm thick titanium, 14 mm zirconium, 13 mm austenitic stainless steels, Hastelloys, Inconels and a wide range of nickel and cobalt alloys, and 9 mm in conductive materials such as ferritic steels & carbon steels. This makes K-TIG a far more flexible system.
  • Weld Quality: Both processes rely on keyhole technology to perform welds. Keyhole technology makes high quality welds because it provides an exit point for vaporised impurities that would otherwise be trapped in the solidifying weld as porosity. HLAW, like all laser welds, do have trouble with keyhole stability at higher thicknesses due to focal shift and lens distortion, both of which can create defects.
  • Fit-Up Tolerance: The typical max joint gap permitted for HLAW is 0.5 mm.  The filler metal from the GMAW helps to fill in the gap near the face of the weld, but does not penetrate very deeply, thus leaving the laser to fuse the rest of the joint thickness.  The process can manage up to 20% mismatch. K-TIG can maintain keyhole stability even with joint gaps in excess of 1 mm and can easily handle mismatches in the joint of more than 20%.
  • Welding Cycle Times: Both processes are capable of performing single pass penetration of thick joints at a very high travel speed, resulting in minimal weld passes accomplished in incredibly short times, meaning you can get the same performance out a far cheaper system.
  • Complexity: Laser is widely regarded as a complex, beam welding process. The addition of GMAW makes it even more complex, and the laser/GMAW torch set-up and fit-up of joints are very critical.  Focus shift and lens degradation can cause process drift from established parameters and results. K-TIG on the other end is incredibly simple. The arc structure and keyhole can both be automatically maintained by the controller and they both develop spontaneously and the weld parameters are basic and simple to adjust.
  • Weld Appearance: The wire from the GMAW side of the process usually produces a positive crown.  The root bead, however, is left rough with some undercut and spatter, and requires dressing or grinding. The K-TIG process naturally creates a smooth and uniform appearance that requires no post-weld maintenance.
  • Keyhole Stability: HLAW, like all laser welding, relies on photons of light being focused through a fixed lens to achieve its keyhole.  The lens can become contaminated during welding, and it can distort due to high heat in thick sections and create focal shift, which dramatically alters the welding results. K-TIG’s keyholes have inherent stability because of the surface tension in the weld pool and the high travel speeds. K-TIG keyholes are also self-correcting by nature, due to their ability to respond dynamically to changes in the arc force.
  • Keyhole Close-Out: The HLAW process is capable of a smooth and orderly slope-out of the weld, including closing the keyhole and gradually reducing the penetration until the weld is terminated.  However, with the addition of filler metal from the GMAW side, lack of fusion at the overlap is possible.  The laser high energy density can occasionally lead to "spiking" defects (voids) during the slope-out. By contrast, K-TIG makes this entire process incredibly easy by removing the need for a complex constricted arc or plasma gas and making use of the high energy density arc and patented torch design.
  • Process Consistency: The biggest issue with process consistency in HLAW is thermal distortion and contamination of the lens for thick section welding. Both cause significant drift in the process and can create defects. K-TIG offers excellent process consistency throughout the duration of the weld, largely due to the simplicity of the process and the lack of erosion due to a large electrode.
  • Maintenance Costs: Switching to K-TIG will slash maintenance costs because K-TIG requires almost no maintenance. The system is very robust and there are very few consumable components. HLAW requires substantial maintenance, including the frequent replacement of focusing lenses. The system is also extremely sensitive to all forms on contamination, including contamination found in a normal weld shop environment.
  • Skill of Operator: HLAW requires expert management of its critical variables to ensure a quality weld. Training a skilled operator can take between 4 to 6 weeks. K-TIG can perform the same functions as HLAW but an unskilled operator is sufficient and only 3 hours of training is required for an operator to complete quality welds. Supervisors only need 1-2 days of training.

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I’m currently using Hybrid Laser Beam Welding; can I switch to K-TIG?

Yes, and you need to make the switch right away. Your productivity will go up, your costs will go down and the quality of your welds will increase. You’re doing your business a disservice by not switching to K-TIG.

 

How Do I Change to K-TIG?

It really couldn’t be easier.

If you’re currently using HLAW, the upgrade process is simple. Your existing welding automation system can still be used.

Literally all you have to do is setup the K-TIG system, and integrate the controller into your existing automation system. 

Be a hero in your organisation.

Book a live demonstration to see what K-TIG could do for your company.