The title might be a play on words, but there’s already a growing use of multi-beam technologies, taking AM processes to another level of productivity, with a number of successful technology platforms that have demonstrated this.
What should now be considered is the types of beam that can be used together, not just more of the same, or more powerful versions of the same. It’s been a long time curiosity of mine to consider mixing and matching laser technologies to take care of the different aspects of the additive manufacturing process. Isn’t it time that others give it some thought as well?
Perhaps they have, and perhaps they’ve always considered that it just doesn’t make sense, or possibly that it’s too difficult to try.
“When there’s only darkness, there’s no such thing as a light that is too dim.”
Thinking outside of the box first. Many of you have seen this type of thing; walking into an event, or disco where lasers are being used to project images onto walls. Could a similar scanning strategy be used to maintain heat in a build, or pre-heat a metal powder bed? Using lower powered lasers to pre-heat, or to maintain a specific temperature over the progression of the build; to add in extra heat when and where it might be required, to relieve internal stresses, prevent distortion, or to aid in the transformation on a metal. The reasons for wanting to try this are many and varied.
Could it even be possible to slowly increase the heat over an entire layer, by repeatedly scanning that slice with ever increasing laser energy to the point that it caused almost simultaneous melting, or sintering over the required area?
So, if any of the above is possible, imagine going further with a type of laser that takes care of a stable border/contour area, and another that does the larger in-fill areas, whilst a third could be synchronously laser re-melting/machining the surface profiles or other critical areas.
What if it were possible to use a bank of pulsed diode lasers, or surface emitting lasers, utilising different wavelengths, and/or combinations of these, used in a single head (much like a multi-nozzle inkjet printhead) to somehow “print” parts?
It would be entirely reasonable to conceive of a multi-head system for simultaneously building with different alloys. A system that could carrying out laser micro-machining, surface modifications (it’s no secret that laser re-melting can enhance corrosion resistance, for instance), or in-line inspection processes. Why not include a system with laser welding to join smaller parts together, and all on the end of clever robotic arms?
In other industries, and in other applications, lasers are used for imaging devices, audio/listening devices, sensors, safety switches, and plain old measurement devices. Imagine what could be achieved if all of this pre-existing knowledge could be combined in an AM machine. Today with ChatGPT and AI, just imagine where AM could go!
The inherent beauty of using lasers is that they can be configured for all sorts of non-contact measurements.
- Laser based optical scanning systems, to accurately measure the 2D contour of a melted layer, or the exact height of a melted layer (sometimes the layer shrinks more than expected, and sometimes it starts to lift more). 3D scanning semi-finished parts whilst still in a machine.
- Laser based thermal analysis systems, used to constantly monitor the build temperature, both at the melt pool and in the previously formed/melted material. Systems with direct feedback to process parameters to ensure unform input energy, an prevent over-heating, or large residual stresses building up.
- Laser based systems for in-line analysis, of process gases (the composition or the pressure) at various stages within an AM machine. On-the-fly powder size measurements in the gas stream, or other part of a powder recirculation system.
Just some of the ideas that could be explored. Nothing too clever, and certainly no detail.
“I don’t know where you get your delusions, laser brain!” – Princess Leia (just love it!)