Optical precision for automated quality control

Machine vision lasers provide structured illumination in measurement and inspection systems for quality control. They project lines or patterns, such as multiple lines or dot grids, onto the inspected objects. A camera captures the projection and software evaluates it.

Z-LASER machine vision lasers are used in a wide range of industries. In the electronics industry, they inspect PCBs and small components. In the tire industry, they measure tire profiles and read DOT codes. In metal processing, they support weld seam inspection. In the food and beverage industry, they measure fill levels and distinguish between food components. You can find an overview of further applications on the page Solutions for Industrial Machine Vision.

For 3D measurement tasks, lasers are usually the better choice, while LED lighting is often sufficient for simpler 2D inspections. An LED illuminates surfaces evenly but, unlike a machine vision laser, does not produce geometrically defined light patterns, which are required for tasks such as profile measurement or contour detection. For more information, see our white paper Laser vs. LED for Machine Vision.

Z-LASER machine vision lasers produce geometrically defined light patterns that can be evaluated precisely. Thanks to robot-guided optical alignment, the laser lines are perfectly straight, sharply focused, and uniformly bright, so measurements are reliable and highly repeatable. Wavelength, output power, fan angle, and interface are configurable and can be adapted to different materials and components. Because inspection is non-contact, the lasers are also suitable for delicate surfaces. An established method for 3D measurement is laser triangulation.

In laser triangulation, the machine vision laser projects a line or a point onto the surface of the inspected object. A camera captures it from a defined angle relative to the light source. When the surface height changes, the laser line shifts in the camera image. The software calculates height and depth information from this offset and creates a high-precision 3D profile of surfaces and edges. Triangulation is non-contact and wear-free, delivers measurement accuracy in the micrometer range, and is suited for high-speed inline processes. When the method uses a line, it is called the light-section method. For more information, read our guide Laser Triangulation in Industrial Inspection.

It depends on the material and the environment. Red lasers (640 or 660 nm) are a good fit for most applications because most camera sensors have a high quantum efficiency in the red spectrum. Near-infrared lasers (760–830 nm) are often used outdoors, where strong ambient light can interfere with the measurement. Blue and green lasers (405–520 nm) offer advantages on (semi-)transparent or highly reflective surfaces such as polished metal and solder joints. They also create visual contrast on glowing materials such as hot steel.

Besides wavelength, three parameters determine which laser fits an application: fan angle, optical configuration, and output power. The fan angle sets the line length at a given working distance. Only the center 80 percent of the line should be used, because optical effects occur at its ends. The optical configuration determines line width and depth of focus. "Extended Line" offers a larger depth of focus and is the first choice for most applications, while "Fine Line" produces very thin lines at the cost of depth of focus. Higher output power allows shorter camera exposure times but also raises the laser class.

The laser class depends on the output power and the fan angle. Z-LASER classifies its lasers in accordance with DIN EN 60825-1. For many applications, an eye-safe laser class (1, 1M, 2, or 2M) is required, which limits the maximum output power. Lasers of class 3R and higher can also be used if the entire system is made eye-safe, for example with covers or safety shut-offs. You can download an overview of the laser classes on the page General and Safety Information.

Yes, Z-LASER offers OEM solutions for machine vision. For example, the ZX series is designed for sensor integration and high-volume OEM production, and the ZXS module is also available as an OEM version with fully integrated electronics. If your custom requirements cannot be met with the standard portfolio, Z-LASER develops a tailor-made solution based on a feasibility study.