Finding the right laser parameters
Determining laser parameters for optimum engraving results using the grayscale matrix
A perfect engraving result can be achieved only with the right laser parameters. Parameters are always a combination of the following settings:
- Laser power level
- Resolution – dpi / ppi
- Z offset (controlled defocusing)
To be able to rate the engraving result, the desired result must be known in the first place. When talking about perfect engraving results, this usually means:
- Small, thin letters show a sharp engraving pattern and fine details without a “fraying” effect.
- Larger engraved surfaces have an even, smooth surface with intense colors.
- Laser-cut edges are smooth, polished and, in the case of transparent materials, clear.
Material is removed during laser engraving. The engraving should not remove more material than necessary. Too deep engraving is not recommended. If only the required layer is removed, a beautiful, sharp engraving pattern without shadow effects is created.
Engraving and cutting results always depend on the machines used, the individual applications, and the requirements regarding the quality and production speed desired. Therefore, there is no such thing as a perfect parameter set. It may be useful to define different parameter sets for different degrees of fineness. This is easily done by assigning different colors in the graphics. You can then assign different parameters to the individual colors and thus optimize the engraving result.
The Trotec laser software JobControl® comprises parameters for the main product groups of Trotec laser materials. For all JobControl® versions older than 10.5, you can download these here and import them into your JobControl® material database. For each product group, we offer 2 parameter sets: one optimized for speed and one for quality:
- “Quality” parameter sets are recommended in particular for applications with fine details, small font sizes, and high contrast.
- “Speed” parameter sets are recommended for time-optimized applications that tolerate a reduced level of detail.
Depending on the individual application, minor adjustments may be required to increase quality or reduce production time. In order to find the optimal parameters for your application, we recommend adjustments in 10%-steps of laser power, speed, and resolution (DPI).
The appropriate laser parameters can be found with our test matrix. The test matrix consists of 100 rectangles with differing grayscale values. In the printer driver of the JobControl® laser software, using the relief function you can easily determine your suitable parameters with this.
The laser output is automatically adjusted according to the shade. When a 100% black area is engraved, 100% of the selected output can be used. For 80% black, engraving is done at 80% of the selected power, etc. The laser power is linearly proportional to the intensity of black.
How to apply the test matrix:
- Import our template into your graphics application
- Select the “Relief” process in the printer settings of the JobControl® printer driver.
- Select the resolution according to the material you want to test; in our example, we have selected 500 DPI.
The power of your system is 100 watts or greater:
Start with power “P = 80%” and speed “v = 100%”
The power of your system is between 40 and 100 watts:
Here, you set both the power and the speed of the laser machine to 100% (“P = 100%” and “v = 100%”).
The power of your system is 40 watts or less:
Start with power “P = 100%” and speed “v = 50–80%”
Selecting the suitable laser parameters
From the completely engraved matrix, select the desired shade from the 100 parameter settings on your engraving material. Then save this in your JobControl® database. In the example, the selected parameter for P is 80+7, i.e. 87% of the preset P value (power).