Raster engraving is the standard process of laser engraving. Here, a graphic built from thousands of pixels is engraved line by line, point by point. With vector engraving, however, the graphic consists of curves and lines that are traced one by one, “vector by vector” and engraved simultaneously. Vector engraving is sometimes referred to as “scoring".
For large applications, like filled-in letters, images, stamps and wood engraving, raster engraving is the best-suited method. However, on you're only engraving small, thin lines, you should try using vector engraving - it will be quicker and of higher quality.