For basic beam delivery a galvo laser will have just two moving parts with a combined weight of just a few grams. By contrast a plotter mechanism can contain dozens of moving parts weighing several kilograms.
Furthermore, as plotters become larger they are inherently more cumbersome, therefore, when trying to move faster any tolerance in the belts, bearings, etc will be magnified into poorer quality output as the speed increases. For this reason many plotter machines use firmware/software to provide for longer delays as the speed is set faster so that the mechanism can recover from acceleration and deceleration. For small area work such machines never achieve their potential top speed even if the user sets full speed in the software
With galvo technology, having fewer moving parts not only contributes to faster output without any significant loss of quality, it also minimises downtime and unnecessary ownership costs due to wear and tear. It’s almost always the case that galvo lasers are significantly more reliable than their plotter based alternatives.
The optic of a galvo laser will be static (not moving) above the work piece. The beam will be focused through a complex optic called an F-Theta lens. The lens holds the beam in focus over a defined flat field marking area. By interchanging the lens it is possible to vary the available marking area and the size of the focal point (spot).
There are many advantages to this design;
– The lens sits further from the material so it’s possible to engrave inside things like bowls, cylinders, etc
– Contamination is almost non-existent; meaning longer part life and lower maintenance
– For some models it’s possible to engrave the surface of a 3d object at high speed with the focal point following the curve of the surface.