Power Measurement

Power in the Palm of Your Hand.

The PowerMeasuringCube (PWC) is designed for power measurements of solid state lasers. In the processing zone, laser power is one of the key parameters for the result of laser materials processing. A loss of power can lead to serious quality issues of the processed part. This is why laser power must be measured directly in or near the processing zone. The PowerMeasuringCube, as a mobile and compact power probe, enables the determination of laser power directly beneath
the processing head in the processing zone.

The measurement system is designed to monitor laser power in day to day production. The compact design enables the PWC to undertake power measurements even in the smallest of places that usually do not accommodate a measurement device. The PWC is protected against shock and vibration as well as dust by a robust housing. It is also equipped with
an integrated LCD. Operating power is provided via a Lithium cell, which can be charged via a micro-USB port.

The device has an internal ring buffer, which stores the laser 14 measurements, the last of which can be viewed directly
on the display. The ring buffer itself is larger and can be accessed via Bluetooth or the LaserDiagnosticsSoftware (LDS).

Measurement Principle

The absorber of the calorimetric measurement system is irradiated by a laser for a short period of time. The temperature
difference of the absorber between start and finish of the laser pulse is measured. From the temperature rise, the microprocessor based electronics is able to calculate laser power to a high degree of accuracy. An interlock signal is provided in order to turn off the laser beam emission, should the absorber overheat. The usage of this signal is strongly
recommended.

System Parameters

The PowerMeasuringCube measures the incident laser energy and the irradiation time. The calculated laser power has an
accuracy of ± 3%, with a repeatability of ± 1%. The typical working temperature range of the PWC lies between +15 °C
and +40 °C.

System parameters for the Laser:

  • Wavelength: 900 – 1090 nm
  • Power range: 25 – 8000 W (average power)
  • Measurement time = Pulse duration: 0.1 – 2 s

Laser power and irradiation time stand in
direct relationship for the measurement. 

Compact electronic laser power meter.

  • Easy handling
  • High damage threshold
  • 41/2 digit LCD-Display
  • High dynamic due to a 20 bit A/D-converter
  • Battery life time up to > 30.000 measurements
  • High repeatability
  • Different models cover power range from serval watt up to 12 kW

Application

The PocketMonitor is a mobile, easy to use power measuring device, that has been consequently developed for everyday application in production. Emphasis was laid on a compact design and fast, trouble- free use. The electronics is protected against impact shock and dampness by a solid aluminium housing. When it is folded up, the absorber protects the operational elements. Thus a transportation package is not necessary.

Technical description

The microprocessor supported electronics measures the temperature of the absorber and calculates the power of the laser beam with a resolution of one watt. As the resolution is high, measurements can be carried out in a very wide power range with constant accuracy. The big 41/2 digit display optionally indicates the actual power, the maximum power or the temperature. Power is supplied by a built-in lithium cell for approximately 30,000 measurements.

In measuring position (open), the device is 279 mm long. Accuracy of the PocketMonitor is +/- 4 % of the measured value in the range of 10 % to 100 % of the maximum value.

Technical data

  • Power Range: 20 W to 12 kW
  • Display: 41/2 digit LCD-display
  • Resolution: 1 W
  • Dynamics: 20-bit A/D-converter
  • Exposure time: 10 or 20 sec.
  • Battery life span: extremely long, approximately 30,000 measurements
  • Housing: robust aluminium housing (IP65)

Different type

Description Power range Geometry Weight
PocketMonitor 002p 1 W - 20 W plain 530 g
PocketMonitor 01p 5 W - 100 W plain 535 g
PocketMonitor 05p 25 W -500 W plain 560 g
PocketMonitor 30p 150 W - 3.000 W plain 670 g
PocketMonitor 70icu 350 W - 7.000 W inclined 1.110 g
PocketMonitor 120icu 500 W - 12.000 W inclined 1.550 g

Power density often can be as important for the choice of a PocketMonitor model as the maximum laser power is. Especially the PMT 70icu and the PMT 120icu have an outstanding capacity for high power densities. With these two types, even measurements at 5kW/cm2 at 5kW optical power are possible. We will be glad to assist you in your choice of the right PocketMonitor for your application.

Control and presentation

The big 41/2 digit display optionally indicates the actual power, the maximum power or the temperature and short.
The exposure time is 10 or 20 sec.

Compact electronic laser power meter.

Power measurement up to high power densities with cylindrical or plane absorber

  • Power measurement up to high power densities with
    cylindrical or plane absorber

Application

Laser power is the central figure to characterise the laser beam and controls the performance of the material processing directly.
Avoid any uncertainty here!

Technical description

The PRIMES CompactPowerMonitor is measuring the laser power precisely, even for modern beam sources in the multi-kW- range

Due to the integrated display the device can be operated without an additional PC. USB, analogue-out and a safety interlock allows a further integration of the system.
All the water cooled absorbers are designed for long term operation, even with deionized water. Together with the fiber adapter a very high operation safety can be ensured.

CPM  F-10
Highlighting the CPM-F, which provide a large flat absorber, light weight and ultra low rate of back reflection. The calorimetric principle allows various beam dimensions and beam positioning on the absorber, achieving precise diagnostic results always.


CPM F-1
The CPM-1 is a calorimetric power meter operation within 0.1 up to 1.4 kW.Mirroring the relationship to the model CPM-F the reduced all-over-dimensions allow power measurements even in smaller laser processing cells.

CPM F-20  
This „Big Brother“ was reduced in weight as well. The clear aperture of 90 mm allows power measurement far behind the focal plane or measurements of larger beam cross sections e.g. right after a telescope.

CPM C-9
Extended weigth but designed for higher power densities is the conical absorber of the CPM-C. It is equipped with a combination of a conical reflector and a cylindrical absober.

Technical data

   CPM F-10  CPM C-9   CPM F-1  CPM F-20
Power range [kW]  0.5 - 10  0.5 - 9  0.1 - 1.4  1.0 - 20.0
Power density [kW/cm²]  < 1  < 5  < 1  < 1
Wavelength [nm]  800 - 1100  800 - 12000  800 - 1100  800 - 1100
Repeatibility [%]   ± 1.5  ± 1.5  ± 1.5  ± 1.5
Accuracity [%]  ± 3  ± 3  ± 3  ± 3
Time constant [s]   > 10  > 10  > 10  > 10
Flow rate [l/min]   > 5  > 5  > 1  > 10
Clear aperture [mm]  90  55  45  135

Dimensions [mm]
(H x B x T  exc. connectors)

71x180x162 136 x180 x162 71x180x123 113x180x163
Weight [kg]  2.9  4.8  0.9  4.8

Options:

•  Safety transport and shipment box
•  Adapter for direct fiber adaption (LLK-B, LLK-D, QBH)
•  External display
•  Different Interfaces

Fiber adapter

All available fiber adapters enable straight fiber connection to any PRIMES power meter.

For the CompactPowerMonitor CPM F-1, CPM F-10 and CPM F-20 fiber adapters are available for the fiber plugs LLK-B, LLK-D and QBH. Power measurements between fiber connector and focussing optics will be done in a safe environment.

Fiber adapters are also available for PowerMonitor 48 and EC-PowerMonitor.

Calorimetric Power Measurement in the Processing Zone

The PowerMeasuringModule PMM is a new laser power meter to determine the current optical power right in the processing zone.

Application

The PowerMeasuringModule utilize the calori-metric principle. A defined power probe will be irradiated for an accurate time interval.

Technical description

Based on the probe's thermal capacity thermal capacity, temperature rise and exposure cycle, the power will be calculated.

The readings are independent from spot size and spot position. Optional an irradiation time measurement is available. It will increase the reliability of the results.

Technical data

Power range
400 - 8000 W
Wavelength range
780 - 1090 nm
Absorber diameter
49 mm
Max. Beam Diameter
30 mm
Typ. Beam diameter
15 mm - 25 mm
Max. Power Density
1 kW/cm²
Accuracy
± 3 %
Repeatability
± 1 %


Measurement Cycle Time

Exposure + Evaluation
< 15sec
Nominal Measuring Frequence:    
1 cycle / 10 min


Interface (available) ProfiNET
ProfiBUS
Parallel
Dimensions width x depth x height

Closed (mm)
175 x 100 x 93
Opened (mm)
233 x 100 x 230

PowerMonitor

Measuring device to determine the laser power.

  • Calorimetric measuring device with high accuracy and reproducibility
  • A mirror at the beam entrance enables the handling of power densities up to 15 kW/cm2
  • Systems up to 25 kW of laser power and an aperture up to 100 mm are available
  • Integrated LCD-Display
  • A pneumatic shutter protects the entrance mirror

Application

One of the basics of laser material processing is the exact knowlegde of the laser power availible at the work piece. Even in complex processing systems often significant differences betweeen the power at the laser's output window and the power at the work piece occur.Moreover the user gets information about the laser power independent of the display at the laser source:

  • Longterm- stability
  • Precision
  • Reproducebility
  • Short Measuring Time
  • reliable operation even in industrial environement

Technical description

The method is to direct the laser beam with a parabolic mirror into a cylindrical absorber. On its inner surface there is a highly absorbing coating. By this laser power will be absorbed more homogeneously on the surface and any leakage radiation is avoided. This system can be used for highestlaser powers and power densities.

With a high-precision measurement of temperature difference and flow rate of the coolant the power of the absorbed laser beam can be exactly determined.

All parts in the device which get in contact with the cooling water are made of copper or brass. So any corrosion in the coolant circuit because of different chemical potentials will be avoided. A pneumatic shutter is used to close the beam input aperture and to protect the entrance mirror of the PowerMonitor against dust.

Technical data

   PowerMonitor 48
 PowerMonitor 100
Power Range
 300 W - 8 kW
 1 kW - 25 kW
Max. power density
 15 kW/cm2  5 kW/cm2
Reproducibility  1 %
 1 %
Absolute accuracy
 2 %
 2 %
Time constant
 15 cec. bis 99 % of final value
 60 sec. bis 99 % of final value
Water flow rate
 Minimum 5 liter per minute  Minimum 12 liter per minute
Clear aperture
 48 mm
 100 mm
Dimensions (H x L x D)
 125 mm x 242 mm x 400 mm
 210 mm x 330 mm x 540 mm
Weight  15 kg
 50 kg
Fiber adapter  optional  ---

Control and presentation

 For interfacing to a PC the built- in RS485-lnterface (PRIMES priority) is used. The picture shows the graphical user interface. You have the choice for maximum scale value, offset compensation and shutter open / closed. Additionally to the calculated and shown laser power, water input temperature as well as difference between input and outlet temperature and flow rate is displayed. 'Current value' or 'temporeal development' of laser power can be selected.

PowerMonitor

The ElectronicCalibrated-PowerMonitor (EC-PowerMonitor) for beam power measurement conforms the highest industrial standards:

  • State-of-Art power meter with applicability as a reference
    system
  • Long term stability by robust configuration and use of a contactless flowrate sensor
  • Accuracy and reproducibility by use  of high-grade sensors and components
  • Authentic operation in rough operation environment by robust and  rugged  configuration
  • Redundancy of the measuring results  by integrated selftest-function 

Application

One of the most important parameters of laser material processing is the beam power within the process zone.

Due to absorption processes in the beam guidance and the focussing optics, the beam power is reduced.

Practical experience has shown that dirt and deterioration of optical components cause a growing power dissipation within the beam path from time to time. Furthermore, the machining result can be affected negatively.

Due to  the power measurement  in the process zone the user gets information about the beam power at the workpiece. To avoid a reduction of the machining quality, the observation of power dissipation should be done over a longer period of time as well as a punctual accomplishment of maintenance. This can be done by a regular repetition of the power measurement.

The EC-PowerMonitor not only measures the beam power in the process zone, but also possesses an integrated selftest-function.

Thus, the functional capability and the accuracy of the measuring device can be checked any time.

Technical description

The method is to direct the laser beam with a parabolic mirror into a cylindrical absorber. There is an absorbing coating on its inner surface. Thus, the laser power will be absorbed more uniformly on the surface and any radiation leakage is avoided. This system can be used for highest laser powers and power densities.

With a high-precision measurement of the temperature difference and flowrate of the coolant, the power of the absorbed laser beam can be determined exactly.

All parts in the device which get in contact with the cooling water are made of copper or brass to avoid any corrosion in the coolant circuit (due to different chemical potentials).

A pneumatic shutter is used to close the beam input aperture and to protect the entrance mirror of the EC-PowerMonitor against dust. 
An electronic calibration was integrated for self-testing. 
Instead of the laser, a heating element can be used to heat the coolant. This way, two independent systems can be compared for self-test purposes:

1.  The calorimeter that measures the heat flow through the absorber.

2. The amount of electric energy that passed through the heating element.
This redundancy of two independent measuring systems ensures maximum reliability.

 

Technical data

 Power range:  200 W bis 10 kW
 Max. power density:  12 kW/cm²
 Reproducibility:  ± 1 %
 Absolute accuracy:  ± 2 %
 Time constant:  15 sec. 99 % of the final value
 Flow-rate:  min. 5 liters per minute
 Free aperture:  48 mm
 Dimensions (Height x Length x Depth):   205 mm x 242 mm x 400 mm
 Power supply:  24V RS485 only for power measurement
   240 V for selftest-function
 Weight  16 kg

The EC-PowerMonitor is able to show the measured values in different ways:

  • The integrated display shows beam  power, flow-rate and coolant temperature.
  • The values can be displayed and  analysed with the help of the software PMS. The self-testing function enables checking of the functional capacity  and the accuracy of the EC-PowerMonitor. The communication to  the computer can be done via USB or RS485-PRIMES-Bus.
  • In conjunction with a FocusMonitor, it  is possible to transfer the measured values directly into the software LDS.  Furthermore, the values will be used  for absolute power density calculations.
  • An analogue output enables to diplay and to protocol the measured values.

Options

The following options are available:

  • SPS interface for connecting to a system control or laser system
  • Fiber adapter for the direct connection  of a beam guiding fiber
  • A mount for the FocusMonitor

The PowerLossMonitor is a system to measure the power dissipated within water-cooled beam guiding components.

  • Temperature sensors
  • A flow meter
  • The control unit with the electronics
  • Display and interface

Application

The PowerLossMonitor is a system to measure the power dissipated within water-cooled beam guiding components, for instance mirrors.

This is done by measuring the flow-rate of the coolant and the temperature rise between in- and output of the coolant.

Based on these parameters, the dissipated power can be calculated. These readings can be used to supervise the power loss in a beam-guiding system and to determine service intervals for mirrors and similar optical com-ponents.

If there is a sufficient thermal isolation of the mounting of the optics, the measured power directly corresponds to the power dissipation within the optical components.

In standard applications, it is difficult to come to a complete thermal insulation of the optics. Normally, there is always some heat flow between the mounting base and the optics.

This typically leads to a small shift of the zero-level of the measuring value. This zero-level should be subtracted in advance. The software allows for such a zero-level correction.

Technical description

  • LCD display
  • Analog out
  • An RS 485 serial interface to connect to a PC running the PRIMES PowerMonitor Software

A typical result of the PowerLossMonitor within a welding machine is shown below. It indicates the changes of the mirrors of the beam guiding system of the CO2 -laser maschine.

(Voss, Battermann: Qualitiy Assurance through laser beam diagnostics)

Technical data

  • Power supply: 24 Volt, +/-5%, 800 mA
  • Temperature measurement resolution: 0,001K
  • Power measurement resolution: 1 Watt

PRIMES Bus

  • The PRIMES-bus combines power supply and data communication.
  • A 9-pin D-sub plug is used for power supply.
  • In addition, the PRIMES-bus can be used with the RS485/RS232 converter box for serial data communication to a PC.

Control and presentation

The Control Unit is equipped with an LCD display and can be operated independent of a PC.
The display readings are shown for:

  • Input temperature
  • Temperature difference
  • Flow rate of the coolant
  • The recalculated power dissipation

These values can also be displayed on a PC via PRIMES-Bus and the PowerMonitor Software. This requires an RS485 to RS232 converter and the PRIMES PC-Software for the PowerMonitor.


For direct integration into laser processing head of solid-state laser.

The laser power at the process zone is one of the key process control parameters for laser material processing.

An unregistered power drop can cause serious quality problems for the processed part. Therefore the laser power has to be measured at or close to the process zone.

PRIMES offers in cooperation with several suppliers of focussing heads an effective solution for power measurement very close to the process zone.

Application

The PowerMeasuringCassette covers a family of products designed to fit into the slot of the protective window of the focussing head. So the full optical system is used during power measurement.

Stand-alone operation of the systems is for some systems also possible.

Technical description

We have adapted the measuring principle of the PocketMonitor for the Power-MeasuringCassette. The laser is fired for a fixed time period onto the PowerMeasuringCassette. We measure the temperature rise during and after the laser shot. From the temperature rise the incident laser power is determined.

The power-on time can be adapted to the incident power. By this a maximum accuracy can be achived. Please find below some examples which we already realized and are on the market.

To operate the PowerMeasuringCassette with high accuracy it is necessary to detect the temperature of the absober als well as the temperature of the environment. Both ist realized with the Cassette.

The laser on-time has to be set according to the used power range and the time frame which is selected at the Power-MeasuringCassette.

After the laser shot the measuring laser power is displayed after a thermalisation time of a few seconds. Cooling is possible at some systems by compressed air.

The temperatur at the PowerMeasuring-Cassette should not exceed a critical temperature limit. For the control an interlock signal is available. We strongly recommand to use it.

Calibration certificates can be supplied for all PowerMeasuringCassette types on request.

Solutions for the mechanical integration to other focussing heads can be supplied on demand.

Technical data

Power range 400 W - 8000 W
Power density max. 1.5 kW/cm²
Rsolution 1 W
Dynamic 20 Bit
Accuracy 4 % of the measured value
Reproducibility 2 %
Exposure time 100 ms, 300 ms, 1000 ms

 

Control and presentation

Either about the integrated display and control panel or directly with the system control - according to concept of the PowerMeasuringCassette.