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How to Choose the Right Laser Line Generator?

How to Choose the Right Laser Line Generator?

Choosing the right laser line generator is crucial for achieving high precision in measurement and inspection systems. Laser line generators play a significant role in various applications, including alignment, machine vision systems, construction, and process control. In this blog post, we will discuss the key factors to consider when selecting a laser line generator that best suits your needs.

Choosing the Right Laser Line Generator

When it comes to choosing a laser line generator, several important factors should be taken into account to ensure your applications are adequately supported. The following will discuss the key considerations from line geometry to depth of focus

Laser lines are primarily characterized by their length, width, and working distance. The measurement resolution is often determined by the line width and can be limited by laser speckle. A sufficient depth of focus has to be taken into account when measuring objects of variable height.

Product Configurator

Schäfter+Kirchhoff offers thousands of options for laser lines, laser spots and collimated laser beams and it is easy to get confused. The most convenient way to choose the adequate laser line generator is by using the product configurator: After entering a few key specifics e.g. by providing boundaries for key features, the product configurator narrows the search between thousands of available options down to just a few lasers that meet the customer’s specific criteria. These can then be compared easily using the compare button, in order to find relevant differences between the options.

Wavelength and Power

The wavelength and power of the laser line generator should be compatible with your specific application. For instance, diode-based laser modules are available in a range of wavelengths from UV to IR, each with its own impact on visibility and efficiency. Green laser line generators are often used in alignment and machine vision systems due to their good visibility. However, the standard often still is lasers that emit a red line. Blue laser lines offer an advantage as the resulting laser line width is often smaller than for comparable lasers equipped with red laser diodes.

The power of the integrated laser diode determines the laser safety class of the resulting laser system in most cases. Although often, a higher laser power is preferred as the resulting signal intensity is often also higher, please keep in mind that for lasers class 3 and up, specific laser safety measures, like the appointment of a laser safety officer, must be taken.

Laser Line Geometry

Laser lines com in two basic geometries: Laser lines with a fan angle that can produce laser lines with longer line lengths (e.g., the series 13LR), and there are semi-telecentric laser lines (e.g., series 13LT) that produce a line with constant line length. The type of fan angle of the laser can also be decisive in the choice of the laser line. A large fan angle is required for long lines at short distances. A so-called semi-telecentric laser line, with zero fan angle, might be appropriate in case of a glossy surface and a reflection-based measurement technique.

Lines can either have a Gaussian intensity distribution along the laser line, which means that there is significantly lower laser power at the edge of the laser lines. Other laser lines are considered to have an approximately uniform intensity distribution so that there is approximately the same power in the center and at the line edges. The edge intensity gives the intensity in percent compared with the intensity in the center. A typical laser of series 13LR has an edge intensity of about 80%.

Line Width and Depth of Focus

Depending on the type of application you’re working with, you may require a laser line generator with specific line width and depth of focus capabilities. The concept of Micro and Macro lasers comes into play here. Micro Laser Line Generators are designed to produce lines with small line widths. Thin laser lines are often preferred in order to maximize the signal intensity at the sensor and to achieve certain required resolutions. However, thin laser lines also have a comparably small depth of focus, which is specified as the range around the nominal working distance, in which the laser line does not increase by more than a factor of 1.41.

Macro Laser Lines have a larger line width and an extended depth of focus. Within the depth of focus range, the intensity profile across the laser line is approximately Gaussian, and the side lobes caused by diffraction remain below the 13.5% intensity level within the depth of focus range. 

Macro Laser Line Generators like the series 13LTM or series 13LRM generate laser lines with an extended depth of focus and can, e.g., be used for laser triangulation with large height variations.

Working Distance and Line Length

Ensuring that the laser line generator you select is suitable for your specific setup and application needs, also includes line length and working distance. For some lasers like the series 13LR, the working distance can be adjusted by adjusting the focus setting. Beam parameters like line length and line width will increase proportionally to the working distance and a fine-adjustment of the distance between laser and target is recommended for fine-focusing. For lasers of series 13LT, the working distance is fixed and cannot be changed and a fine adjustment of the distance between the laser and target is recommended for fine-focusing to achieve minimal line width.

Laser Line Generators from Schäfter+Kirchhoff

Schäfter+Kirchhoff is known for the durability and long-term stability of its products. All our machine vision lasers are used worldwide for machine vision applications including laser triangulation or laser light sectioning.

Among our notable products are the series 13LR and 13LT laser line generators. The lasers of series 13LR provide laser lines with a fan angle, uniform intensity distribution, and line widths starting at about 40 µm. The laser has integrated electronics for control of the laser output power. The output power can be controlled using the modulation input ports (TTL and analog) or manually using the potentiometer. The lasers optionally also have an RS232 interface, enabling seamless control, data read-out, and critical data storage for maintenance planning purposes.

Moreover, the 13LT series with an optional RS232 interface is a semi-telecentric machine vision laser line with uniform intensity distribution. Lasers of series 13 LT have a constant line length of 15 mm and line widths starting at 12 µm.

Please use the Product Configurator for a quick and efficient way to find suitable solutions.

If you’re ready to purchase, contact us today for a quote.