Laser beam sources are sometimes operated under full load (servicing, special operating modes), without the emitted laser radiation being utilized immediately for a processing task. In these cases > 99% of the radiation must be absorbed. Many beam sources therefore contain a PRIMES absorber.

Laser material processing systems in which the machining process does not completely absorb the laser radiation or the radiation must be “captured” (for example during a workpiece changeover) pose a similar challenge.

PRIMES absorbers are used in these instances as beam dumps. Since laser radiation is mostly not fully absorbed within laser beam diagnostics either (exception: measurement of laser beam power) various special solutions are used, which are either integrated into the diagnostics system or are needed in addition in order to guarantee the safety of people and machinery.

The PRIMES BeamMonitor BM+ is a measuring device for performing beam diagnostics on unfocused, continuous irradiation of CO2 and solid-state lasers with higher outputs.

With the BeamMonitor BM+, the user can quickly and reliably measure the beam parameters, such as the spacial power density distribution. Analyzing and documenting the laser parameters makes it possible to optimize the processing procedure or identify an incorrect beam position or incorrect lens alignment.

In practice, laser beams are “customized” for specific areas of application using telescopes and adaptive lenses. When this happens, the beam diameter as well as the divergence are changed dynamically. This makes it possible to change the focus dimensions or shift the focus position toward the laser beam axis in systems for laser cutting or laser welding. Here the focus is on “penetration” through the material surface and it is “pushed into” the material for the actual cutting process.

During laser welding, dynamic adjustments of the laser beam make it possible to cut with one setting and weld with another.

The BM+ is also suitable for use in the field of quality assurance or laser approval: Deterioration on laser lenses is one of the main causes of problems in laser material processing that can reduce the quality of the processing results considerably.

Diodes and other solid-state lasers are checked in the collimated range and can, for example, be assessed with relatively little effort.

This reference system for raw beam diagnostics of CO2 lasers has been used successfully for a number of years. In fact the PRIMES BeamMonitor-HighQuality (BM-HQ) replaces the typical plexiglass burns used to identify the beam profile or beam symmetry.

The diagnostic device enables quick measurement with high precision. This is guaranteed by a detector with a high dynamic range.

The BM-HQ is the perfect device for analyzing your laser beam. The mechanical scanning system measures the power density of collimated laser beams at full power.

Due to its compact design and light weight, the BM-HQ is ideal for integration into material processing systems and for use in servicing.

The laser beam is scanned point by point with a rotating measuring tip. The mirror mount is also moved in a linear fashion to scan the entire beam profile. In this way, a partial beam is diverted and directed at the detector in each instance.

The incoming signal is digitized and transmitted to the evaluation unit. The 14-bit A/D converter and resolution of up to 256 x 128 pixels employed enable an exact analysis even of small disturbances in the raw beam. The device was designed for use in harsh industrial manufacturing conditions and is adaptable in every spatial orientation.

The PRIMES LaserQualityMonitor LQM+ quickly and automatically characterizes the beam parameters of a beam source. The measuring system is compact, easy to align and can be expanded to meet individual requirements.

Determine Beam Propagations, Analyze Faults
With the LQM+ PRIMES offers an integrated solution for the quick and straightforward analysis of the beam properties of a beam source. The beam propagation of lasers from the UV to NIR range are characterized and certified with this measuring system. Furthermore, errors in the optical structure of resonators of beam imaging systems can easily be analyzed.

The characterization of a collimated laser beam with Rayleigh lengths that are typically ten meters requires a significant measurement effort due to the very long measurement ranges of three to six Rayleigh lengths. This form of measurement is normally impossible for reasons of space. For this reason ISO 11146 recommends, in the alternative, the measurement of a caustic generated by focusing in order to determine the diffraction index M2.

The LQM+ generates this device-internal caustic by focusing the irradiated collimated laser beam. The focused beam is displayed enlarged on the CCD chip via several integrated attenuators and a lens. From the two-dimensional power density distribution measured in this way, the LaserDiagnoseSoftware (LDS) determines the radius, position and orientation of the beam. Through the procedures of this measurement system, and repetition of the measurement at various positions in the device, all parameters necessary for the description of the artificial caustic are determined. The electronic exposure time control of the CCD chip expands the dynamic range of the system. This means that in general it is not necessary to alter the filters during a measurement.

LThe PRIMES HighPower-LaserQualityMonitor (HP-LQM) quickly and automatically characterizes the beam parameters of a beam source. The measuring system is compact, easy to align and can be expanded individually.

Determine Beam Propagations, Analyze Faults
With the HP-LQM, PRIMES offers an integrated solution for quickly and simply analyzing the beam properties of a beam source. In combination with the collimator available from PRIMES, the measuring system determines the beam propagation of fiber lasers and fiber-guided beam sources.

The detailed characterization of fiber-guided laser sources in respect of beam quality, divergence, beam direction and power cannot generally be carried out without a significant effort and the use of several set-ups.

The HP-LQM with collimator collimates the laser beam propagating divergently from the fiber, reduces the power in two adapted water-cooled attenuators, and directs the measurement beam into the LQM. In combination with a PowerLossMonitor, the irradiated laser power can be measured in parallel via the laser power coupled out to the attenuators and the resulting temperature increase in the cooling medium.

The optics installed in the aperture of the HP-LQM focus the incoming collimated beam in the device. The focused beam is displayed enlarged on the CCD chip via several integrated attenuators and a lens. From the two-dimensional power density distribution measured in this way the LaserDiagnosticsSoftware determines the radius, position and orientation of the beam. Through the procedures of this measurement system, and repetition of the measurement at various positions in the device, all parameters necessary for the description of the artificial caustic are determined. The electronic exposure time control of the CCD chip expands the dynamic range of the system. This means that in general it is not necessary to change the filter during measurement.

Laser Mechanisms’ FiberTool™ is a patent pending device that aids in the alignment of standard multimode fibers used with Nd:YAG, Fiber and Disk lasers. Unlike thermal-based systems that have a delayed response between measurements, FiberTool produces a real-time output signal to the user that is a gauge of the alignment quality of the laser energy into the fiber optic’s core.

For a laser system to launch all of its laser energy efficiently through the fiber optic cable and maintain its beam quality, the laser energy must be focused onto only the core of the fiber optic. This focus spot must be smaller than the fiber core’s diameter and not strike the cladding layer around the core. Adjustments of the fiber launch optics in X-Y and Z are made by the laser user to get the laser beam centered on the core and at the correct focus so the optical spot is smaller than the core diameter.

Proper alignment is accomplished by having a real-time measure of the laser energy that is outside the core diameter. Laser manufacture’s feedback signals do not have the resolution necessary for proper alignment and can result in several hundred watts of wasted energy that can heat the external focus head – potentially causing damage to these optics.

FiberTool provides the only true, real-time measure of the laser energy outside the fiber core and allows the laser operator to adjust the fiber launch system while monitoring this signal until a minimum reading is attained. Any time a fiber is removed and replaced, or a new fiber is connected to the laser source, FiberTool should be used to ensure proper fiber alignment and the condition of the laser launch system.

The PRIMES BeamControlSystem (BCS) enables the automatic measurement of the most important laser beam parameters within industrial laser processing lines. Beam power, as well as focal measurements and power density distributions are measured by the system which is shielded, rendering it completely dust-proof.

Features:

• Focal measurement from 0.2 mm to 3 mm
• SPS interface for communications with laser or plant controllers
• Script-controlled automatic measuring sequences
• Monitoring of thresholds for beam parameters
• Electro-pneumatic closing device
• Control and measurement data management via PC
• Fieldbus interface optional for system integration

The PRIMES FocusParameterMonitor (FPM) enables rapid determination of laser beam parameters. The measuring processes are completely controlled from the existing machine programs.

Measure Laser Beams Quickly
The FocusParameterMonitor (FPM) is the first system on the market that allows quick determination of the laser beam parameters in the process zone. Its advantages: It can easily be integrated into the system, and moreover the fieldbus interface (PROFINET, PROFIBUS) provides easy connection to many industrial control systems and networks.

At the beam inlet, an electrical closing device and a protective glass protect the measuring device from contamination. The beam coming from the laser and the processing head is directed into the device via a deflecting mirror.

The beam reaches the measuring components via a beam splitter and a further deflecting mirror. The laser power is measured calorimetrically. For this purpose the laser irradiates the absorber for a defined period. With the help of the known heat capacity, the temperature increase in the test body and the irradiation period, the power is calculated. The camera-based beam analysis unit measures the beam geometry and beam position with a CCD sensor. A fieldbus interface lastly forwards the measurement data data to the system controller. An additional PC is not required.

Specifically for brilliant high power lasers, expanded with a HighBrilliance option: The PRIMES HighPower-MicroSpotMonitor-HighBrilliance (HP-MSM-HB) can determine power density distributions of SM lasers up to 10 kW average power directly in the focal plane.

Measuring Focal Geometries of Multi-kW Lasers
NIR lasers with high beam quality and high average power are increasingly being employed in laser material processing. With these lasers, focal geometries in the range of 20 to several 100 micrometers can be achieved. No known material can resist the resulting power densities up to the GW/cm² range for long. At this radiation level, conventional scanning measurement techniques for analysis are ruled out. PRIMES has expanded the camera-based focus analysis system, the MicroSpotMonitor (MSM) by a HighBrilliance option specifically for finely focussed high-power lasers.

The HighPower-MSM-HighBrilliance determines beam parameters of focused laser beams of multi-kilowatt lasers in the range of 20 micrometres up to a millimetre directly in the process zone – even at full power.

For this purpose, 95% of the laser power is transmitted by a beam splitter through the measurement optic, and absorbed. The remaining five per cent are further attenuated in the measurement optic and destroyed by internal water-cooled absorbers. A part beam with a few milliwatts of power is imaged on the CCD sensor in an enlargement.

The measurement optic was designed for beam powers up to ten kilowatt single-mode. The HighPower-MSM-HighBrilliance is also equipped with a safety circuit that can be connected with the laser and interrupts the laser emission in the event of overheating or device failure. In this way the measuring device is protected from damage.

The HighPower-MSM-HighBrilliance individually measures power density distributions in the focal area of up to 50 measurement planes. The focal caustic is composed of these power distributions. From each individual distribution beam, geometries such as beam position, beam radius and half-axis lengths and also the tilt of the half-axes to the device axis according to the procedure described in standard ISO 11146 (2nd moments and 86 % power inclusion) are determined.

Know everything about your production parameters in less than 3 seconds with the PRIMES ScanFieldMonitor (SFM). The handheld ScanFieldMonitor features an innovative measuring principle tailored specifically for additive manufacturing processes, and its small glass structure and compact design make it perfect for laser beam diagnostics and process optimization.

A piece of glass with a specific measuring structure is what distinguishes the innovation of the PRIMES ScanFieldMonitor (SFM). A photo diode captures the scattered light while scanning the laser beam over this structure and uses this information for fast laser beam characterization. Not only will it tell you the width of the beam on the measuring plane, but it will also allow you to reconstruct the path, position, and length of the beam and determine its speed of movement.

Complex relations such as pincushion distortion, the merging of overlapping scanning fields, and delays in laser activation and deactivation can be analyzed using special measuring schemes. This can be used to synchronize the laser with its scan unit. Using the 3D machine construction platform to move along the z-axis makes it possible to measure the caustic and determine the evenness of the plane. And

The PRIMES FocusMonitor FM+ analyzes and measures laser beam sources in material processing. FM+ determines the beam properties of focused laser beams, in addition to their geometric dimensions, focal position, the beam parameter product and the beam quality factor. The integrated z-axis allows for automatic measuring of entire caustics up to four Rayleigh lengths – facilitating measuring compliance with quality standards.

An update to the original FocusMonitor, the FM+ features new electronics designed to meet current and future requirements for signal processing and a new motherboard with a 16-bit A/D converter. An Ethernet interface allows for fast and secure data exchange with computers or system controllers. The new mechanical design also accommodates upside down installation without additional components.

The FM+ is an opto-mechanically scanning measuring system that scans the laser beam with a special measuring tip. The unit is equipped with a small hole (typically with a diameter of approximately 20 µm) that lets through a small section of the laser beam. Two reflecting mirrors guide this portion of the laser light to a detector selected and configured depending on the laser power and wavelength. This makes it possible to measure the different laser beam sources and systems solely by selecting the optimal measuring tip and corresponding detector. The high orbital velocity of the rotating measuring tip facilitates analysis of high power densities.

A very high signal-to-noise ratio is achieved thanks to the dynamics of the analog-digital converter used. Very low intensities are shown with equal precision next to the high peak intensities. That is one of the requirements for automatically measuring caustics in the area near the focal point over at least four Rayleigh lengths in accordance with ISO 11146.

The FocusMonitor FMW+ is specially designed for analyzing continuous irradiation, even at high beam powers. This universal tool for high-power radiation is the compact version of the proven, globally successful FocusMonitor FM+ with new electronics and an absorber for powers up to 1000 W. With the compact FocusMonitor FMW+, you will know the quality of the laser beam in your processing system and reliably determine the geometric dimensions of the focused laser beam as well as the focal point location in space, the beam parameter product and the beam quality factor M².

The FocusMonitor FMW+ is a mechanically scanning measuring system for measuring focused laser beams with diameters between 100 μm and 3 mm in tight spaces. Unlike the FocusMonitor FM+, the FMW+ does not have its own z-axis. You will therefore have to use the z-axis of the laser system to take caustic measurements.

The device can be used to measure NIR as well as CO2 beams up to 1,000 W laser power. All you need to do is exchange the measuring tip and the corresponding detector. With a maximum size of 8 x 8 mm, the measurement window can be gauged with a resolution of up to 1024 x 1024 pixels.

The PRIMES MicroSpotMonitor (MSM) is the ideal tool for checking, monitoring and approving very finely focused laser beams, such as are used for example in micro-material processing. The MSM automatically measures and analyses the spatial beam distribution all around the focus in various z positions.

The focused laser beam is a significant determinant of the quality of the manufacturing result. In most laser material processing, it constitutes the actual tool. The task of the MSM is to certify and monitor this tool for laser systems which are used in micro-material processing. Through regular measurements, any changes in beam profile, focal position or beam dimensions, among other things, can be identified and logged. The results not only assist failure analysis but also the optimization of a process in microprocessing. The various possibilities for using the MSM provides operators with a wide variety of problem-solving approaches for their applications.

The MicroSpotMonitor determines beam parameters of focused laser beams of lasers with average powers up to 200 W in the range from 20 micrometers up to a millimeter directly in the process zone. The purely air-cooled system images the laser beam, attenuated via various beam splitters and neutral density glass filters, on a CCD sensor. The beam position and beam radius are derived from the beam distribution of a level determined in this way. With the help of the integrated z axis and measurement at various positions of the laser beam, the described beam parameters are determined and recorded.

The measurement optics of the MSM are selected individually, depending on the beam source to be measured. Crucial factors here are the wavelength (248 to 1090 nm) and the enlargement determined by the focal diameter (3:1, 5:1, 15:1).

Developed specifically for microprocessing system, the PRIMES MicroSpotMonitor-Compact (MSM-C) expands the product family of camera-based focus analysis systems by a measuring system that is compact and modular.

Optimized For Microprocessing Plants
The MicroSpotMonitor-Compact (MSM-C) was optimized specifically for restricted installations spaces in microprocessing systems. The dimensions of the camera housing with electronics, attenuation and power absorber are around 230 x 120 x 60 millimeters (L x W x H). The compact device does not have its own movement axes.

The laser beam is enlarged by means of measurement optics, attenuated over two beam splitters and imaged via a deflecting mirror onto a CCD sensor. If necessary, an additional filter can be installed in front of the sensor. The beam geometry and power density distribution are measured by the CCD sensor. The measurement data is transmitted via Ethernet to a PC and evaluated with the PRIMES LaserDiagnoseSoftware. Optionally, the data can be determined internally by the device and transferred via a PROFIBUS interface to the plant controller.