Feedback from old users of laser welding machine

Hi All, a few things. Been around TIG welding for 50 yrs. in my dad’s fab shop. Been laser welding as an engineer for 24 yrs. There are waaaaay too many people to call out by name for their bad takes, ill-informed comments, and downright lack of welds and weld strength. So, I’ll just hit some of the high points. Penetration is a function of machine size. The bigger the machine, the more penetration. So, a really big TIG, ‘might’ be able to get more penetration than a small laser. But that’s hardly the point.
1 – TIG/MIG/Stick is all based on electricity flowing thru the weld joint. Electrons do NOT like being next to each other, so as soon as they hit the metal, they try to get away from each other, while finding the path of least resistance to the ground clamp. So, the heat generated is more horizontal, as opposed to downward. Why do you think thicker plates have to be beveled when butted together? Because the penetration is just not there, so the bevel allows you to get ‘deeper’ into the joint to get ‘artificially’ full pen. Then, you have to back fill with multiple passes with filler rod to build up the joint to its original thickness.

2 – Laser welding machine shoots straight, and when it ‘keyholes’ (google it), the molten metal is pushed out of the keyhole by metal vapor pressure, allowing the laser light to travel deeper into the joint to fuse it. When the laser moves away, the liquid reflows back down into the hole to maintain your original full thickness. Single pass. The Laser welding machine 2KW Laser welding machine will give you FULL PENETRATION of 5/16″ s/s plate, WITHOUT a bevel, in ONE pass. At a faster feed rate, mind you. A – as some have mentioned here, a simple metallurgical cross section will show the laser weld fuses the joint line on the ‘inside’ of the joint, while TIG/MIG/Stick relies (must have) filler wire/rod to ‘build up’ the fillet on the ‘outside’ of the joint to increase strength.. B – I’ve developed numerous laser welds in my career to replace ‘electrical’ welding. Never once the other way.

3 – I have seen a 1″ thick piece of COPPER, laser welded, with FULL P E N E T R A T I O N lap weld, no bevel. Grated, not handheld laser, but just using this as an example that photons are much Much MUCH more efficient at welding than electrons.
In fairness, the only place where TIG would have an advantage over ‘hand held’ laser welding, is in very tight, very complex weld joints. This is ONLY because the TIG is sooooo slow, you can make the turns easier. The laser is so fast, the limiting factor is frankly the human holding it. We need to up our game to be able to follow the joint line at those feed rates. Bolt the gun onto a cobot and the playing field is level, albeit more costly.

4 – With a 2KW Laser welding machine, you can weld everything from 0.003” s/s foil lap welded onto 0.003” s/s foil on the low end, all the way up to 5/16” s/s full pen on the high end. Find me ANY electrical welder that can cover that range. … I’ll wait.

5 – Some say TIG looks better. Probably because that is what the entire welding community is use to looking at. “Row of dimes” my dad would always say. For all you TIG guys out there, guess what, we can set the laser to ‘pulse mode’ and get “rows of dimes” as well. After market exhaust guys use the Laser welding machine in this mode to simulate/replicate TIG.

6 – Again, people here are saying because the laser has a much smaller heat affected zone (HAZ), that there is “no way” it is a strong as TIG. By that logic, gas welding should be the strongest, right? SMH. The size of the HAZ has essentially ZERO to do with strength. The strength only comes from how much fusion there is at the joint line. Just because you covered the entire flat faces of the 2 boards butted together, doesn’t mean their joint is strong. If you only put glue ON THE ACTUAL EDGES, it will be stronger. Refer to answer 2A. That’s enough for now. If ANYONE has ANY dissenting opinion, PLEASE, PLEASE, PLEASE, POST THEM!!! I’D LOVE TO READ THEM. 100.0% of EVERYTHING I said here is 100.0% .