Welcome back, I’m LaserEd, and I work with lasers.
I’ll be laser-educating for The Metal Magazine and I hope it results in more metal parts being lasered!
First of all, I haven’t had an accident after writing my last article about Laser Safety. I have been busy researching.
Although it is time consuming, I love research. Research is in essence ‘trying new things’. Learning new things takes practice and a healthy dose of trial and error all with the goal of hoping for a breakthrough or a ‘Happy little accident’, to quote Bob Ross. The trouble with research is that too many are striving for a result, a desired outcome. But discovering what doesn’t work is just as valuable as what does work. In fact, if you get the desired outcome on the first try there is more likely an even better solution.
And so the bridge to lasers. Simply put, lasers can do virtually anything cleaning, printing, welding, cutting and sawing, CNC, even polishing. Without soap, ink, metal wire, scissors, a knife, saw, drill or whatever, just the electricity. Just like a Tesla that doesn’t use gearbox oil, differential oil nor benzine/diesel/LPG.
I work with lasers day to day for my job, for this reason you may assume that I’d talk only about the benefits of lasers, but I want to flip the script and let me show you some of the limitations of lasers.
The first time I encountered a disadvantage of lasers was when I laser cut a birdhouse for friends and family. All the pieces fitted perfectly when I assembled one myself and I was proud that I didn’t need glue or screws to keep it all together, just a tight fit. 0% glue, 0% nails, 100% wood, 100% laser.
But after handing them out on a rainy birthday I got complaints that the parts didn’t fit. At least not without any brute force and fear of breaking.
It bothered me, so next week, on a sunny Sunday I tried one more. I hoped to see what went wrong, but when I tried to assemble the birdhouse again every part fitted like a glove. The 3rd and 4th birdhouse fitted just as well and interchanging parts didn’t result in any noticeable difference.
The answer lies in the humidity. I lasered and assembled on an arid day, while it was raining heavily when I handed the other bird boxes out. The laser can cut with such precision and accuracy that even the relative humidity influenced the fit. Wood expands ever so slightly when it absorbs moisture.
The extreme stats of a laser allow melting of metal in order to fuse two pieces together; welding. And let’s be clear, I can’t weld. My grandfather used to call it (freely translated out of Dutch) “Cooking and frying. But mainly frying.”
So a thin piece of titanium would be impossible for me to weld. And yet the picture proves that I pulled it off. No material added, perfect solid weld. And yet, all I did was draw a straight line on the computer, selected the right preset and hit “Laser”.
Now here comes the kicker, I got a call from a large shipyard later that year. They heard we build lasers and that lasers could weld. With a ship containing miles of welds they saw an opportunity and invited me over. During the tour on a ship I noticed gaps up to half an inch and more between panels. I thought it was for wiring but the welder told me he needed to close those up.
A laser can’t bridge-weld that gap without adding material, it can’t create material out of thin air. Any slit needs to be filled up with material from the panels so a laser weld would be impracticable. As material thickness increases so would the amount of energy, time and therefore cost required to weld together thick steel sections by laser
A laser cut is perfectly straight and can be easily welded together, but unless a ship is made from thinner laser cut steel any attempts to laser weld would be futile and could cause further issues to the Heat Affected Zone (HAZ) which may negatively impact on a materials hardness and toughness.
It is easy to see every problem as a nail when your tool is a hammer. I regard it as a sign of strength when one admits there is a better solution out there. Choose the best tool for the job and don’t assume that it is the same job even if you name it the same. The welder is now making yards welding all the panels together and the laser welds small metal tubes (1/2 an inch diameter, wall-thickness 1/10th of an inch) together. Both are working on their strength and doing what the other is not so good at.
I’ll be back with more laser content in the next edition of The Metal Magazine. Until then, keep researching and trying new things. You might be surprised by the results!