Saturday, February 10, 2007

660nm laser diode module is very stable

A 660nm laser diode module with a very high, very stable output power of 70mW and adjustable AR coated glass optics is designed for machine vision applications.

UK optoelectronics device manufacturer and laser diode specialist, Photonic Products, has launched a new 660nm laser diode module with a very high, very stable output power of 70mW and adjustable AR coated glass optics. The 660nm Photon Laser Module, PM806G-GR, incorporates an Opnext HL6548FG high power laser diode (100mW absolute maximum optical output power), with internal monitor photodiode in a 9mm package. An internal monitor photodiode is a unique feature for a laser diode of this power and wavelength which enables the output power of the laser diode module to be accurately stabilised over its operating temperature range of -10 deg C to +50 deg C.

Designed for applications such as machine vision, graphic displays, medical imaging, inspection systems and industrial alignment and positioning, the 660nm laser diode module produces an elliptical output beam of 3.5 x 1.5mm with an output power of 70mW.

Operating voltage is from 3V to 6V DC with a typical operating current of 150mA.

Beam divergence is <0.6 x 0.3mrad and operating temperature range is -10 deg C to +50 deg C.

The module consists of an aluminium housing, laser diode, drive circuit and collimating lens and is stable and reliable.

All Photon Modules can be supplied in various colours, (red, green, blue, black, violet), to assist in wavelength or power identification.

The PMF version modules have a 25mm mounting flange.

Electrical connections are made via external flying leads.

The lens may be adjusted to produce either a collimated beam or focused spot.

The standard lens may be replaced by other optical systems such as line and cross generators.

The Photon range of elliptical beam laser diode modules has been designed as a complete laser diode solution for OEM use.

* About Photonic Products - Photonic Products was established in 1995 and has offices in the UK, USA and Germany.

It is an ISO9001:2000 certified manufacturer of electro-optical sub-assemblies and innovative optoelectronic components based on semiconductor laser diode technology and also a specialist distributor of high performance industrial laser diodes, LEDs and precision optical lenses.

Laser calibration reduces costs, ups accuracy

Laser calibration reduces costs and gives four-fold accuracy improvement for CNC water-jet cutting machine manufacturer, which is experiencing rapid sales growth.

Czech manufacturer PTV, based in Prague, Czech Republic, has experienced a very rapid increase in sales of its CNC water-jet cutting machines. To help manage this growth, the company uses Renishaw's ML10 laser interferometer measurement system and QC10 ballbar, which has reduced manufacturing costs and increased machine accuracy by a factor of four. Precision water cutting has a huge number of applications, and particular advantages over traditional CNC machine tools in processing high specification metals, composites and other media.

Thin, flexible or sensitive materials, such as rubber, plastics and even paper, are especially difficult to 'machine' using traditional methods.

In these cases water cutting offers many of the advantages of laser cutting machines, but at a lower cost.

In the cutting process, the water is compressed to a pressure of over 4000 bar, then directed through specially designed nozzles.

For certain materials and for high-speed grinding, water is mixed with natural garnet abrasive prior to cutting.

PTV manufactures one design of machine, but is able to vary the X and Y dimensions over a large range, according to customer needs.

In effect, every machine is customised - PTV engineers can easily adapt machine components to different requirements, both in initial construction in Prague, and during installation at a customer's site.

* Alignment problems - the PTV machine was designed in 2002, originally with a magnetic linear encoder system and a MEFI CNC control.

Initially there were problems with maintaining the precise separation required between encoder and readhead, particularly over distances greater than 6m.

There were also dynamic problems in achieving the required machine accuracy, due to the lightweight aluminium structures for the X-axis and Y-axis.

PTV therefore sought advice from MEFI, who suggested using a laser interferometer to identify the causes of these inaccuracies.

* Renishaw's solution - PTV searched the Internet and, from a short list of possible systems, reviewed Renishaw's ML10 laser interferometer measurement system.

Explained Jan Kunert, CNC engineer, 'We visited one of our customers, where a Renishaw engineer demonstrated the ML10 system to us'.

'We realised that not only could we use it to identify the dynamic errors, but we could also use it to map errors during machine production'.

'We were only looking for someone to do a one-off study of our machines, as a sub-contract service, but very quickly knew that we had to have a system ourselves'.

'In fact, the system we bought is now used so extensively, both in the factory and during on-site installation, that we intend to buy another.' * Linear accuracy improved from 0.2mm to 0.05mm/m - PTV removed the magnetic linear encoders from the original design, instead taking positional feedback from the rotary encoders integrated onto the drive motors.

These encoders had always been there, but had been thought to provide inaccurate feedback, due to the variable distance and the resulting effects from the twisting of the ball-screw.

This is where the Renishaw ML10 laser interferometer measurement system and Laser10 software proves its worth.

The system's laser optics are mounted onto the structure of the finished machine and readings taken at every 20mm of axis movement.

This is compared to the value provided by the machine's rotary encoder, which is at least always repeatable, to generate a compensation value for that specific position.

The positioning uncertainty on the original design could be up to 0.2mm/m.

Kunert now knows that accuracy is always better than 0.05mm/m and provides customers with a certificate from Renishaw's Laser10 software to prove it.

* Proving quality through international standards - the ML10 laser interferometer measurement system is a reference standard on which PTV relies, using the highly stable wavelength of laser light, to provide performance verification to ISO 230-6 and traceability of the measurements in line with their ISO9001 certified systems.

PTV sees both these factors as crucial in winning new customers, especially in markets where it is unknown.

* Combining Renishaw solutions for maximum efficiency - in addition to the compensation provided by the ML10 laser interferometer for linear positioning, there are a series of other machine characteristics which PTV checks and adjusts through the use of a ten-minute test with a Renishaw QC10 ballbar.

During the test the water cutting machine is instructed to describe a circular path in the X-Y axis, with the QC10 ballbar coupled to the machine on special magnetic mounts.

Any variation from the normal test circle radius is picked up by the ballbar's highly sensitive transducer and data fed back to a PC running Renishaw's Ballbar5 analysis software.

This immediately provides exact error values for 21 different machine characteristics.

* Considerable time-saving - PTV finds that backlash and scale mismatch are two major sources of error, but provided with the exact values from the QC10 ballbar, the engineers can now adjust them immediately.

Jan Kunert estimates that the company used to spend half a day on a machine attempting to find and remove errors.

Now it can be done in 30-40 minutes.

Says Kunert: 'Without the Renishaw ballbar, even if we thought we knew the problem, we were not always right'.

'We often brought in service companies, for example for the motors, to find it was a waste of time'.

'We have one engineer here who is very good at guessing errors, but previously, if he was out sick, or at a customer when we had problems here, we were stuck.' * Rapid increase in business - the future is looking bright for PTV.

After long experience in this field, distributing machines from the USA, it is now selling an increasing number of its own machines.

Its largest customer, V.S.M.P.O.

in Russia, already has six machines and has ordered a special 5-axis machine, which it will use to cut titanium for military and aerospace applications.

Interface connects laser calibration to PC

Interface is designed to connect Renishaw ML10 laser calibration system and EC10 environmental compensator unit to PCs via an industry standard USB connection.

Renishaw's new DX10 interface is designed to connect its market leading ML10 laser calibration system and EC10 environmental compensator unit to PCs via an industry standard USB connection. The DX10 is a reliable high speed communications device, transmitting data at 5kHz to Renishaw's Laser10 software and new QuickView motion analysis software. Suitable for both laptop and desktop PCs, the new DX10 interface avoids the need for PCMCIA or internal PCI interfaces, which are gradually being phased out of mainstream PCs in favour of USB connectivity.

For dual axis data capture from the ML10 laser interferometer, a user can simply use 2 DX10 interfaces which can be plugged into 2 separate USB ports or a separate hub.

Replacing Renishaw's existing PCM20 (PCMCIA) card as the standard system interface, the DX10 unit is compatible with Windows XP and service pack 1 and 2.

The new DX10 interface kit includes a 3m USB cable, DX10 driver and installation CD-ROM.

* Note - Renishaw's ML10 laser interferometer measurement system is used by some of the largest OEMs and end users in industries such as metal cutting, semiconductor processing, flat panel display production and biotechnology.

The ML10's unique properties ensure that the system provides a linear position reading resolution of just 1.24nm, a range of up to 40 m and accuracy better than 1 ppm.

This combination of resolution, accuracy and range makes the laser interferometer an ideal tool for characterising the performance of motion systems, both large and small.

Measuring dynamic movements in machinery alignment

An off-line- to -running fixture combined with a shaft alignment system makes it possible to measure dynamic movements on machines from hot to cold or vice versa.

Dynamic changes in the rotating machinery from an Off Line toRunning condition, needs more attention. There is no such thingas 'identical' machines having identical dynamicmovements. One cannot ignore the possibility of horizontalmovement, assuming growth will be symmetrical and only accountingfor the thermal effects.

Shaft alignment has mostly been carriedout in off-line operating conditions.

However, machine conditionschange from the time they are off line to running under normaloperating conditions.

Some of these changes are due to processforces (fluid pressures, airflow, etc.).

The most notable ofthese changes is the change in the temperature of the machinebearings and supports.

Dynamic changes are difficult tocalculate.

Two 'identical' machines may showdrastically different alignment changes from Off Line to Running.Great care must be taken when calculating the changes in thealignment condition of machines.

Just because two machines appearidentical and serve the same function does not ensure they willexhibit the same operational characteristics.

Several methodshave been used to measure the changes in the shaft alignment oftwo or more machines.

Although widely used, 'hot aligningmachines', only measures changes in the shaft alignment duesolely to the changes in the machines' temperature.Discharge pressure, shaft torque, multiple machines operating inparallel, electrical loading of a generator, etc., can also playan important role in the change of the alignment condition fromOff Line to Running.

The changes will mostly be seen in theHorizontal Plane, but could also affect the Vertical Alignment.

Amachine that operates exposed to large changes in temperaturecould exhibit extreme changes in its shaft alignment as thetemperature changes.

Coupled machines need to be set to coldalignment targets that will reflect the actual changes in theshaft alignment.

This will lead to lower vibration levels,increased mean time between failures, decreased maintenancecosts, and increased production.

Fixturlaser's extensiveresearch into the problems of dynamic movement has resulted in arevolutionary new alignment method.

Fixturlaser L2R off-line- to-running fixture combined with a FixturlaserShaft alignmentsystem makes it possible to measure dynamic movements on machinesfrom hot to cold or vice versa.

Changes in machinery alignmentare mirrored by changes in the alignment of the L2R brackets.

Bymeasuring and documenting the initial position of the bracketsthe actual online changes in the alignment values can be measuredwhen the machine is online under normal operating conditions.Alignment costs are small compared to production loss, shouldcritical machinery fail.

Poor alignment is one of the leadingcontributors to premature rotating machinery failure, often as aresult of too little attention being paid to dynamic movements.Fixturlaser have, through extensive tests, showed that inaddition to cold alignments, the actual dynamic movements ofmachinery need to be considered when aligning.

One man can operate accurate alignment system

Fixturlaser AB, Molndal has developed a new and highly accuratesystem for positioning and aligning machines and production lineinstallations. The new Fixturlaser Level is a laser based'one-man-level' system, which meets high mechanical andaccuracy levelling requirements. The one-man-level makes ahelping hand redundant, since the system consists of a selflevelling, scanning laser transmitter and a high resolutionreceiver.

The laser transmitter, T310, generates a laser planewhich is level or plumb to level.

The laser plane can also belocked to specific receiver values, the receiver then controlsthe transmitter by either IR or cable communication.

This featureis very helpful in unstable environments, e.g when performingmeasurements on-board ship and on high rising constructions, suchas harbour cranes.

The Level can be operated with one or morereceivers and can be fully integrated in the Fixturlaser systemutilising the display unit as a data collector.

All units arepowered by standard batteries or AC-adapter.

The receiver can bepowered by the Display Unit when connected.

Laser scanner unseats templates and save money

US-based Lear Corporation has realised savings of $240,000 injust one seat manufacturing programme by replacing atemplate-based inspection system with a laser scanning one. Using3D Scanners' ModelMaker software, Lear inspects automotiveseats during design and manufacturing. Before, Lear compared asample seat with a series of contoured plastics templates whichshoed the original styling guidelines.

Typically nine templateswere needed for each seat, and the seat had to line up within 6mmunder manual 'GO, NO-GO' inspection.

Total templatecost for a seat programme with 29 seat configurations was some$104,000.

An inspection stand could cost $22,000 and fivedifferent stands would be needed.

Two sets of stands - costing$220,000 - would be needed if a seat style were produced in twodifferent factories.

Lear chose the ModelMaker system, whicheliminated the templates and the stand cost is now $15,000instead of $22,000.

The system is based on a 3D laser sensor, aposition-sensing device on which the sensor is mounted, a PC andsoftware.

The software extracts displays and manipulates thesensor data.

Lear chose the FaroArm with seven degrees of freedomto reach any point in the seat.

In operation, the sensor ispositioned to show a laser light line across the seat, and ismoved across the area to be checked and the data is displayed onthe PC screen.

Laser scanning is much faster than making templatemeasurements, so Lear now scans a number of customer-approvedseats and averages the data to set manufacturing tolerances.Scanning provides real X, Y and Z co-ordinates.

If a seat area isout of tolerance, manufacturing personnel can see exactly howmuch it is in error.

The scanning system is more accurate thanthe template system (gaps between template surfaces and seatareas would have to have been measured manually) and readilywarns of any drift away from the 'mean'.

Also thescanning system is immediately adaptable to seat modifications.

Laser displacement sensor measures problem surface

Laser displacement sensor measures problem surfaces MatsushitaElectric Works has enhanced its range of measurement sensors byintroducing the new SUNX HL-C1 laser measurement system. Usingcharged coupled device (CCD) based technology, the sensor is ableto quickly and precisely inspect surfaces that have historicallyposed problems for analogue based non-contact measurementequipment. Black rubber and specular objects, including glass andwafers, can now be reliably and accurately measured using the newSUNX HL-C1 laser based measurement system.

Suitable applicationsfor the HL-C1 series include measurement of the eccentricity ofsteel shafts, co-planarity of IC pins, thickness measurement ofbrake discs and tyre tread measurement.

Containing an extremelycompact controller, the unit can accept the connection of up totwo measurement sensor heads.

This allows thickness measurementto be carried out easily using built in calculation functions.The sensor heads themselves are available in two styles: one formeasurement of diffuse type surfaces, including black rubber andmachined metal; and the other for specular objects such as glassand highly reflective surfaces.

Both styles offer two measurementranges and are capable of measuring to accuracies of 1micron.Configuration of the controller can be performed using either acompact touch screen console or PC based configuration softwarevia the built in RS232C communications port.

This port can alsobe used to transmit measurement data to a third party device, orthe internal decision-making capability can be utilised andinformation accessed via digital I/O connections.