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glossar_laser_scan_technik_scanpedia

Glossary

SCANpedia - welcome to the SCANLAB GmbH encyclopedia.

Here you'll find explanations and definitions of key technical terms from the fields of optics, scanner technology, laser technology and laser processing.

If you'd like to see a specific new term added to our encyclopedia, then just drop us an email.

Use tags to classify products

C

Calibration Angle

see Angle Terms

Characters per Second

see CPS

Control (and principle of operation)

Scan systems transform lasers into highly flexible processing tools. The range of functionality strongly depends on both the controller and the scan system's servo electronics. The servo electronics in SCANLAB's scan systems not only dynamically positions the laser beam, but also provides status signals. This status information returned by the scan head can be evaluated not just for system monitoring purposes, but also for optimization.

SCANLAB offers a variety of RTC control boards that enable synchronous control of scan systems, lasers and peripheral equipment.

Principle of operation scan system

Scheme of operation for controlling a scan system:

Deflection of the laser beam occurs at the scan mirrors, which are quickly and precisely positioned by galvanometer scanners. SCANLAB's scan heads integrate all components, including electronics, into a compact, sealed housing.

To focus the laser beam, an objective is used at the scan system's beam exit and/or a focusing unit is used at the beam entrance. SCANLAB offers a variety of software for laser process control and vision analysis.

Correction File

A correction file enables compensation of system-specific optical errors.

Barrel and pin-cushion distortion are produced by the arrangement of the mirrors in the scan head and characteristics of the F-Theta objective. This distortion lends itself well to calculation, and can therefore be compensated. A correction file can be used to position the focus of scan heads that employ a variable focus unit (e.g. a varioSCAN) in place of an F-Theta objective. Here, a table is generated that couples the set values in the image field with the control values. Correction files are utilized by the RTC control board before data is sent to the scan head.

The highest precision is attained with a correction file generated by an image field calibration that takes all static errors into account.

CPS

cps (characters per second) is the number of characters/symbols that can be marked in one second.

Marking characters and symbols is a standard application for laser scanners. Because the number of marked characters depends on numerous scanner parameters, a benchmark has emerged for directly comparing marking times. Here, a 1-mm tall single-line typeface is used to mark all 26 Latin letters in both upper and lowercase, as well as the 10 Arabic numerals. The elapsed time is then converted to characters per secondcps.

For setting the scanner's parameters, a tradeoff between writing quality and marking speed is necessary. SCANLAB specifies two possible variants, good quality (faster) and high quality (more precise). The two images below illustrate the differences:

cps quality, SCANLAB

At high quality, no obvious discrepancies should appear, whereas good quality allows minor anomalies such as oscillation and corner-rounding.

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