You don’t have to trash cast metal parts with small defects. Laser welding can repair them.
Imagine a nice, leisurely day of fishing in your bass boat. As you glide over the glass-like water on the lake, searching for the next school of bass, your boat engine starts to make sounds that spell trouble: cutting out, gurgling, a little smoke. Not good. It stops. You love the silence of the lake, but not when you’re floating without power miles from the dock.
Sometimes, a marine engine breakdown like this is not an actual defect in the mechanical parts of the engine. The heart of the problem is a sealed surface whose cast metal wasn’t perfectly smooth. Water finds its way under the seal, finds the gap in the metal, and water leaks into the engine, causing havoc.
So what does bass fishing have to do with laser welding?
The casing of a boat engine obviously must be watertight – and that requires a perfectly smooth surface on the cast metal parts whose faces meet before being sealed.
At times, due to problems with the casting – the molten metal being too cool, or not under enough pressure for example – a cast engine part may have a slight defect such as a “no fill” area. When the part needs to be perfect, as in the case of marine engines, they can’t be used, which can have a very expensive impact on the production line, which must run like a clock. And when a production line goes down, everyone is out a boatload of money.
A simple solution for the cast metal parts manufacturer is to laser weld defects out of the cast part. This can be done in minutes if a laser welder is on site or sent out to a shop to get it done in as little as 24 hours.
Laser welding is cool.
When casting plastic parts, those with imperfections can easily be re-ground and re-cast. But in the case of cast aluminum, it’s more problematic. Because when you re-heat aluminum to re-melt it, impurities are introduced, which in many cases renders the part unusable for the intended purpose. It takes a lot of work to make the aluminum part usable again.
Instead, laser welding can be used on the imperfection in the cast metal to bring it up to spec. Only the area of the part with the imperfection is welded, and with the low temperature of laser welding compared to TIG welding, the integrity of the metal is maintained.
Unlike traditional welding, laser welding is cool – literally. It won’t change the structure of the metal nearly as much, nor introduce impurities as TIG welding might when it heats the surrounding metal. Laser welding is so cool in fact that the welding technician can handle it with bare hands as soon as it’s done.
Once welded, the part can be quickly machined and made usable. So instead of having to trash the cast aluminum part or shutting down the production line to wait on repairs, it can be laser welded and benched in minutes.
“A major auto brand went into a panic when they discovered small defects in 150 engine blocks that were contracted out for their high-performance brand. They assumed laser welding created a similar heat signature to TIG welding and were concerned that the heat would change the integrity of the engine block to the degree that they would be destroyed. To show them this would not be the case, we recorded a video of a thermocouple attached to the part being welded. The video showed that during the welding process, the temperature of the entire engine block only increased by 3 degrees, posing no problems. Greatly relieved, they gave us the go ahead.”
Laser welding of cast metal parts extends to products you touch every day in your life: mechanical parts of washing machines and kitchen mixers, half of the parts in your car (especially electric cars), gearboxes, hand tools, as well as parts used extensively throughout industry like pump housings, certain kinds of bolts, rotor shafts, engine blocks for trains, and many more.
Our favorite laser welder to weld defects in cast metal parts is the Alflak. Its open, sturdy, flexible design has enough power to get welds done quickly and with precision without having to reposition the welder. You can even put the parts on a conveyor belt underneath it and run the parts as you weld.
See more about Alpha Laser’s Alflak Laser Welder.
We made the video below to show you that a technician can touch the weld point with his bare hands as soon as the weld is finished. How cool is that?