How to use z-offset?

A precise laser engraving depends on several factors. Besides the right lens choice, working tables and a corresponding exhaust system, the correct focusing plays a key role. The correct setting of the focus - which means the right distance between the laser head and the material to be engraved - is crucial for a perfect application result.

Defocusing by using the z-offset is an adequate step to optimize engraving and cutting results.

focus setting of laser beam
Z-offset paramters

The z-offset describes the focus setting. If the z-offset is set to zero, it works "in focus," meaning the focus is exactly on the material surface. However, there are also applications in which deliberate defocusing is desired. For example, when engraving large areas on TroLase, we recommend defocusing 2 mm for a consistent engraving result.

laser engraving of large areas
Software setup

The diameter of the laser spot increases, as a result, the intensity per surface unit is reduced, and less heat is induced. Therefore, the possible effect of warping during the engraving of large areas is reduced. Also, due to a larger spot, engraving lines may start to overlap, resulting in more smooth and homogenous engraving surfaces and more lucent colors in the case of 2-ply laminates.

laser engraving laminates
Determination of the engraving and cutting parameters

The value of z-offset heavily depends on the material being processed. For most laminates, a z-offset between 0.5 and 2 mm has been established throughout the industry (reverse materials sometimes request up to 7mm).

JobControl®

z-offset is a standard feature in the material database of JobControl®. It allows us to enter values for a controlled and reproducible defocusing even on individual process color level (benefit of separate settings for engraving and cutting passes).