Resolution - getting the best out of the Robot ® K600 Laser Engraver

In your Coral files that are exported to the engraver application program, resolution is one of the variables that determine image quality when engraving on the Robot ® K600 Laser Engraver. Resolution is expressed in dots per inch (dpi) and is determined by the number of lines or dots that are engraved for every inch of movement. Each horizontal line is referred to as a raster line. The higher the resolution, the finer the detail that can be achieved. Keep in mind that engraving resolution is only one factor in determining image quality. The quality of the artwork being sent to the laser can have a bigger influence on the look of the final product than the resolution. If low quality artwork is sent to the laser system, even the highest resolution will not improve it. Also keep in mind that image quality is subjective. 300 dpi may be just fine for some images and some customers, while 600 dpi is the absolute minimum for others.

Most importantly, the size and the dpi of the original image are interdependent, and these together with the size of the engraved output image are related. Think of it as - the amount of information in the original image has to be transfered to the engraved output image.

75 - 150 - 200 dpi - These resolution values are typically used for non-production purposes where you want to experiment with image location, or if you want to quickly produce a rough draft.

300 dpi - This resolution can be good for production work where image quality needs to be good, but not great. Many users will use 300 dpi on plastic and other materials that don't require a lot of power in combination with large block lettering. Attempting to produce really fine detail with 300 dpi is not recommended.

400 dpi - This resolution value is ideal for many applications. It combines very good image quality with fast engraving times. Many users like 400 dpi for all of their work.

600 dpi - When really fine detail or overall excellent results are required, most users choose 600 dpi.

There are several things worth noting:

· There are four times as many dots engraved at 600 dpi than there are at 300 dpi - twice as many horizontally and twice as many vertically.
· The gap between the dots is greatly reduced at 600 dpi. At 300 dpi the lesser overlap is responsible for the jagged edges that are visible when engraving at lower resolutions. It's important to remember that while resolution plays a part in producing good image quality, the artwork that is sent to be engraved is just as important. If the artwork that is sent to the laser is poor quality, trying to engrave it at 600 dpi will not improve it. It's always best to start with high resolution images. Poor artwork will probably always look poor at any resolution, while good artwork will look good at any resolution.
· Twice as many dots and twice as many lines at 600 dpi produces a much deeper burn into materials like wood than you would see engraving the same image at 300 dpi. This is important to understand because depth of burn is closely associated with engraving resolution - the higher the resolution, the greater the depth of burn for a given speed.
The relationship between resolution, depth of engraving, speed, power setting and size of image is something that most people figure out with just a little experience.
· Changing resolution does not change the spot size. Resolution only changes the spacing between dots. For most applications, simply increasing the resolution is the preferred method of improving image quality.
· The greater the resolution, the slower the engraving. (Start with 300 dpi)

Power :
We all like the idea of power - (yeh ! - like Tim the Toolman Taylor) However it comes at a price. Not so much the power consumption, but that the power output of a CO2 gas laser tube is proportional to its length. Thus for twice the power the tube needs to twice as long. No problem, except if you want a benchtop unit such as the Robot ® K600 Laser Engraver. That is one of the reasons the power is restricted to 30 Watt. There is a 60W model available, the Robot ® K1200, but it is stand alone, not benchtop, and is designed for making smaller articles such as dies for stamps.

Speed :
Resolution has the greatest effect on speed, so for quality, speed may have to be sacrificed.
And what difference does the power make ? Speed - nothing else, and then not always. Once the unit begins engraving an object, you may go away and do some other work, just like you do on any computer operated machinery.
In fact, for many substrates, such as wood, leather, and most plastics, more power is not an advantage, as it only leads to burning or melting, so the power needs to be restricted.

Overall, the Robot ® K600 Laser Engraver's water cooled 30W CO2 gas laser is an excellent compromise between power, speed, efficiency, cost, reliability and tube replacement cost (the cheapest in the world !).

For more information on rastering For more information on laser engraving