Optical PV Cell Testing System Provides Non-Destructive Analysis

CRAIC Technologies released the 20/20(TM) UV-visible-NIR microspectrophotometer.  20/20(TM) microspectrophotometer is designed to non-destructively analyze many types of microscopic samples from the deep ultraviolet to the near infrared. Analysis of samples can be done by absorbance, reflectance, luminescence and fluorescence with unparalleled speed and accuracy. The system can also be configured to image microscopic samples in the UV and NIR regions in addition to color imaging.

Applications are numerous and include forensic analysis of trace evidence, vitrinite reflectance of coal and spectral analysis of minerals, measurement of protein crystals, contamination analysis and thin film measurement of semiconductors, hard disks and flat panel displays.

The 20/20(TM) microspectrophotometer integrates an advanced spectrophotometer with a sophisticated UV-visible-NIR range microscope and powerful, easy-to-use software. This flexible instrument is designed to acquire data from microscopic samples by absorbance, reflectance or even luminescence spectroscopy. By including high-resolution digital imaging, the user is also able to use the instrument as a ultraviolet or infrared microscope. Touch screen controls, sophisticated software, calibrated variable apertures and other innovations all point to a new level of sophistication for microanalysis.

www.microspectra.com

Transparent Reciever Provides Pin-Point Alignment

Pinpoint Laser Systems® is introducing the “Transparent” Receiver to the Microgage 2D family. This receiver allows a laser beam to pass clearly through it while making a precise position measurement for aligning machinery and equipment was introduced last fall has since been improved. The receiver is compact and will fit into small places for bore alignment, checking extruder barrels, shaft bearings and much more. Both receivers and the host Laser Microgage 2D are versatile and can be adapted to many industrial measuring and alignment tasks.

The method of operation is simple – a narrow laser beam provides a measuring reference line and these receivers determine the position of a machine or sub-assembly relative to this laser reference beam. These new receivers will operate over distances of 100 feet or more and deliver a measuring precision of 0.0005 inch; ideal for demanding industrial alignment applications. The Laser Microgage system and these newest receiver additions are well suited for lathe and spindle alignment, checking machine tool runout, roll and web alignment, precision bore alignment and much more. The Microgage 2D is easy to use with instructions that show up on the display guiding the operator through their alignment project. Several simple accessories allow for alignment of straightness, runout, parallelism, squareness, roll & web alignment, shaft & bore alignment, flatness measuring and much more.

The 2 Axis Laser Microgage operates on batteries for added convenience and all components are machined of solid aluminum with a hard anodized coating for wear resistance. A sealed push button keypad and large LCD display make the Microgage 2D easy and convenient to use in demanding industrial environments. A serial and USB interface connect to a laptop or PC and link to popular spreadsheets for plotting and analyzing data for maintenance records, customer compliance and other uses. This Microgage system includes a compact carrying case to store the components and is easily carried right out onto the manufacturing floor.

SICK Launches New Bar Code Scanners

SICK today announced the launch of its CLV650 bar code scanners with autofocus technology and the CLV640 bar code scanners with dynamic focus. These new bar code scanners augment SICK’s CLV600 family of flexible and easy-to-use 1D bar code scanners.

With a simple setup process, exceptional reading performance and flexible data handling capabilities, these scanners are ideal for high-performance bar code reading applications in the material handling and logistics markets.

The CLV650 and CLV640 are compact bar code scanners that use proprietary SMART (SICK’s Modular Advanced Recognition Technology) code reconstruction algorithms and high-performance microprocessors, enabling them to read damaged and dirty bar codes. The CLV650’s autofocus feature, distance measurement technology, and expertly engineered optics give it a competitive advantage in applications where space is limited and large depth of field is required. In addition, the CLV640 is a cost-effective option for reading high density codes and for providing increased depth of field in applications requiring an external input to change the focus position.

These bar code scanners feature data handling capabilities to execute a wide variety of user-configurable logic, output data filtering, and sorting functions. Plus, SICK’s easy-to-use SOPAS software helps reduce programming and processing requirements of the host system. An embedded web page can also be configured to provide statistical performance and diagnostic data to remote locations over the Internet using standard browser software.

www.sickusa.com

Optical Testing Device from Yokogawa

Yokogawa has released the AQ2200 multi-application test system, designed for measuring and evaluating a wide range of optical devices and optical transmitters.

The AQ2211 and AQ2212 frame controllers are central to the system and incorporate a variety of measurement functions and applications.

According to the company, remote monitoring and measurement is available via the included USB, Ethernet or GP-IB ports. A macro programming function allows users to build up auto-measurements systems, available for call up at any time.

Remote viewer software for controlling frames and modules is also included.

A variety of measurement modules are available, including: high-stability light sources, wideband tunable light sources, high-speed optical sensors with low PDL and high-resolution variable optical attenuators.

Measurement modules can be inserted or removed without turning off the power.

Testing Provides Roadmap to Intelligent Assembly

“Intelligent assembly” is an approach to quality that shifts the focus from ever-tighter dimensional tolerances to consistent function in the final assembly. It’s based on the use of servo devices and sensors to monitor the assembly operation in real-time, and computer software to determine when the product meets acceptable functional parameters.

Proponents of Intelligent Assembly claim that many components and products could be produced at lower cost with no sacrifice in performance by simply changing the way quality is defined, and adopting intelligent assembly systems. But, the necessary systems aren’t exactly staple items on the shelf of every supplier and that has been one of the factors keeping intelligent assembly from more widespread adoption.

There’s a bit of folk wisdom that says, if the only tool you have is a hammer, it doesn’t take long for everything to start looking like a nail. Since at least the 70’s, manufacturers have been doggedly pursuing “quality” improvements with the only tool available, tighter and tighter tolerances.

Fig. 1-New Promess integrated torque functional test TFT 1/200 is rated at 1 N-m (9 in.-lb) with a maximum rotational speed of 200 RPM in either direction.  TFT systems are used by test equipment builders and end users in a broad range of testing and measuring of torque applications, including automotive steering and drive train component testing and assembly, manual window crank final testing, seat testing, bearing pre-load, and torque-to-turn testing.

But adding extra zeros to a tolerance specification, also adds extra zeros to production costs, and there are limits to how much consumers will pay for “quality” achieved that way. Perhaps it’s time to stop looking for perfection, and start looking for some new tools.

Intelligent assembly systems
An intelligent assembly system gives you a whole new toolbox. Intelligent Assembly is based on the idea that function is the consumer’s ultimate measure of quality. Under that definition it doesn’t matter if the components are perfect, as long as they work properly and deliver acceptable value to the user.

If the assembly system is smart enough to tell the difference between good products and bad products as they are being made, then it’s quite possible to loosen tolerances in the supply chain – or at least stop tightening them. That can be done today using a combination of servo-controlled, instrumented assembly equipment, and sophisticated, real-time computer analysis of the process data.

Custom-engineered Intelligent Assembly systems have been available for more than 20 years. Some use a technology called “signature analysis” to monitor and qualify the assembly process.

What this means is that the assembly system records the force/distance, force/rotation, force/time or other critical relationships of a known good assembly to create a profile or “signature” of the process that produced it. By comparing each subsequent operation to the “signature,” and setting upper and lower tolerance limits, production of good functions or tolerances can be assured without the need for subsequent inspection.

The signature is typically represented as a pair of curves on the system’s display. As long as the results of any individual assembly operation fall within the area between the two curves, the product can be expected to perform as specified.

The exact shape of the signature also provides information about the individual parts being assembled, which can be used as input to control strategies for other processes. For example, parts that are too soft or too hard will produce a distinct change in the signature, as will parts with out-of-tolerance assembly details such as hole or shaft diameters.

The technology has been applied in hundreds of different applications ranging from automotive hood latches, to medical catheters, and including many items traditionally thought of as requiring extremely tight dimensional tolerances.

In the hood latch application, for example, the assembly system cycled the latch while the rivet holding it together was peened. It stopped the peening process when the force required to move the latch reached a specified value. That way, all of the latches produced functioned identically, despite wide variations in rivet dimensions and properties.

Medical catheters have a small diameter metal tube crimped to a larger tube that’s attached to the flexible portion of the catheter. If the crimp fails, the catheter either comes apart or closes off, both of which are unacceptable.

A hydraulic press previously used for the crimping operation produced inconsistent results. It was replaced by an Intelligent Assembly system that provides a 100% effort test certification for every catheter produced, and virtually eliminates crimp failures in the field.

Promess builds Intelligent Assembly systems based on a line of proprietary servo-controlled electromechanical presses; a series of precision torque units; and a line of computer-based controls running Windows(tm)-based software. Other suppliers use similar products, most of which are proprietary as well. Until recently, that meant that anyone wanting to use Intelligent Assembly technology was essentially limited to a custom-engineered system.

Assembly components
The situation is changing, though, as the components required to build intelligent assembly systems become standard, and readily available to end users who want to experiment with the technology before committing to it. Promess, for example, in recent years has made a number of individual components available to customers who wanted to build their own systems. These include a small (1 Nm) torque functional test (TFT) integrated torque-monitoring-and-control systems, Fig 1, and a line of customizable servo-press workstations intended to offer a semi-standard solution for high-precision assembly and test applications, Fig. 2.

Fig. 2-New customizable servo-press workstations offer a semi-standard solution for high-precision assembly and test applications, based on Promess’ electromechanical assembly press (EMAP), intelligent control, and integrated sensor technologies. Typical applications include assembly and testing of springs, check valves, anti-lock brake components, shock absorbers, oxygen sensors, and a broad range of fluid measurements.

The new TFT 1/200 is rated at 1 Nm (9 in.-lb) with a maximum rotational speed of 200 RPM in either direction. Each system consists of a torque module containing a servomotor, encoder, torque transducer, and output shaft plus a Promess EMAC electronic controller/monitor.

The torque module can produce output rotation in either direction, and the integral angular encoder provides shaft-angle feedback to the control. Mechanical overload stops to protect the transducer. The TFT replaces the traditional inline motor/transducer torque-sensing system with a single, fully integrated unit.

The workstations are based on the field-proven Electro-Mechanical Assembly Press (EMAP), with intelligent control, and integrated sensor technologies integrated with Windows-based, icon-driven software. They provide a custom foundation for sophisticated assembly and test systems.

The EMAP, which is also available as a component, consists of a ball-screw driven by a servomotor and equipped with an array of force and position sensors. The unit provides precise monitoring and control of force and position during assembly and test operations. Because the EMAP is servo-driven, the entire system is easily programmed either on or off-line, and easily reconfigured to handle a variety of different parts and/or operations.

Standard workstations are available with press capacities ranging from 40 kN to 120 kN, with larger and smaller sizes available as special orders. Both press to force/position and pull-to-force/position operations are possible with the Promess servo-press workstation. Typical applications include assembly and testing of springs, check valves, antilock brake components, shock absorbers, oxygen sensors, and a broad range of fluid measurements.

Both the TFT and the workstation used the Promess Electro-Mechanical Multiaxis Controller (EMAC). This is an easily programmed, fully integrated, multiaxis motion controller and data-acquisition-and-analysis system that performs the analytical functions using Promess-developed software.

These capabilities deliver the final piece of the intelligent assembly system, providing real-time monitoring and analysis using signature analysis technology. In simple terms, the system records the force/position signature of a known good operation, and then compares subsequent operations to it. The net result is that ability to replicate known good assemblies or processes.

None of this is earthshaking news to those who have been following the development of intelligent assembly technology, but the fact that the necessary components are now available as stand-alone products is something relatively new. The upshot is that these systems are now within reach of more potential users who don’t need a custom-engineered solution, but who can still benefit from the technology.

Promess, Inc.

Automated Gearbox Testing builds in Consistency

Ann Arbor, MI – The U.S. military has demanding requirements for the hardware it needs. Take, for instance, a set of gearboxes built by Excel Gear Inc., Roscoe, Ill, (excelgear.com) for missile launchers on the U.S. Navy’s new DDG1000 series of ships. The gearboxes are drive elements for the servo systems that rotate and elevate the missile launcher. For good servo performance the boxes must meet the Navy’s requirements for stiffness, efficiency, and low backlash.

A prototype was tested using a time consuming manual method. Although satisfactory, the method required careful checking to prevent data entry errors. Requirements for the test system called for high accuracy, elimination of measurement errors, and elimination of data entry errors. The company’s experience automating the test procedures provides a useful design lesson.

After successfully completing the prototypes, Excel Gear president N.K. Chinnusamy, decided the production run needed improved assembly procedures and to automate the test methods. Preload on the bearings was identified as an important factor – too little preload allowed excessive backlash while too much decreases efficiency and generates heat. A measurement accurate enough to size an optimum preload spacer is difficult because before the spacer is in place, the bearing can tip from side to side.

The company manufactured a set of fixtures to prevent bearing tipping and improve the repeatability of the preloads. The fixtures also improved the efficiency of the first production boxes and reduced their backlash from what had been attained in the prototype boxes.

Types of tests

The units called for several tests. For example:

Temperature tests during run-in: The primary sources of heat in the gearbox are seal friction, bearing friction, and oil churning. The heat generated by oil churning distributes throughout the box and dissipates through the case. Seal and bearing friction are concentrated and, if excessive, will cause failure. Temperatures are checked near the bearings on the high-speed shaft, where measurements on the prototype boxes showed the highest temperatures. These areas were also near the seals. Although it isn’t possible to separate the heat generated by the bearings and seals, the seals seem to generate the most heat.

Temperatures were recorded for two hours with the box running at maximum speed. After cooling, the test was repeated with the box running in the opposite direction. In the test, temperatures rose rapidly at first and then at a decreasing rate. While the temperatures do not reach equilibrium, in operation the boxes will not run continuously for two hours, and they will reach top speed only intermittently.

Gear-train stiffness: This characteristic, measured with the output shaft locked, was the ratio of the input-shaft motion to the torque applied, in Nm/rad. Torque was applied using a hydraulic actuator with two opposed cylinders driving two racks against a pinion. The racks are held in the pinion by a bushing. This results in friction force opposite to the direction of motion. Because the friction in the hydraulic actuator would cause measurement inaccuracies, the torque is measured between the actuator and the input shaft using a Dataflex 42/1000 torque transducer. This sensor has a capacity of 1,000 Nm in either direction. Torque is determined by measuring the twist in the transducer shaft using rotary encoders in a differential circuit. An encoder rotor is mounted at each end of the shaft. Because the encoder read heads are mounted to the stationary part of the transducer, there are no slip rings. The A-quad-B output from the transducer is converted to a voltage by an encoder electronic box. The voltage output range is 0 to 10V with a no load value of 5V, and the calibration constant is 0.200 Nm/mV.

Rotary motion was measured using a 2,000 line rotary encoder (resolution of 0.018° ). Because the input shaft extends through the box, the encoder is mounted on the opposite end of the shaft from the hydraulic actuator. When the box is in operation, a brake is mounted on this end of the shaft.

The A-quad-B output from the encoder is converted to a voltage by the programmable encoder-control box. The range and number of volts per degree can be set depending on the amount of rotation to be measured. The output has a range of 0 to10V. For this test, the output was 8.100° per V and the no-rotation voltage was 5V.

Gear train backlash: Some backlash is necessary to provide running clearance for the gears. Too little backlash results in overheating and premature failure, and too much degrades servo performance. Backlash is determined from the data collected for gear train stiffness.

Breakaway torque: For these boxes, it was low and measured manually using a snap-torque wrench. Although automated tests are usually preferred, a few are so simple that the programming required is not justified. This test, for instance, was the only one not automated.

Gearbox power losses over the full range of speeds: Input torque was measured with the gearbox running at a set of speeds both clockwise and counterclockwise. The torque is a nearly linear function of speed with a small component of stiction. This is preferred in a servo system because it contributes to servo loop damping. Because the torque is nearly a linear function of speed, the power-loss curve is nearly parabolic.

Test equipment

Accompanying images show the test equipment and The test hardware table lists a few of its details. The software used, DASYlab, is a graphical programming language. It is programmed by placing block diagrams representing data collection operations on a screen and connecting them with “wires” to control data flow. In the system used here, processed data is written to disk in a tab-separated format suitable for further analysis using Microsoft Excel.

Programming the data collection: The DASYlab block diagram provides an example programming screen. Each block represents an operation on the data such as collecting, scaling, saving to disk, and displaying. This programming method is faster than writing code. For example, the voltage output from the torque transducer, encoder, and thermocouples was connected to the electronic interface box. This box has a built in reference junction for the thermocouples. The device also has digital and analog outputs but these were not used. The interface box scans its inputs and converts from analog to digital values. These are passed to the computer through a USB connection at about 1Hz. This is relatively slow for data acquisition, but more than adequate for these quasistatic tests.

In the DASYlab program, the first box is an input box that “talks” to the hardware and places the input values on its outputs in digital form. Typically this is a special module that works only with particular hardware. Most other boxes do not depend on the type of hardware in the system. The other boxes used are numerical displays, graphical displays, and output boxes to record the data on disk. These boxes have corresponding components on a display screen. This screen can be a virtual instrument, that is, it can look like instruments such as voltmeters, oscilloscopes, and chart recorders. For this test the program converts the inputs to engineering units and displays the values several ways. Digital displays show the current numerical values of inputs.

Another display, an XY-plot, shows rotation on the Y-axis and torque on the X-axis. This feedback gives a preview of results. It can save much time because if something is wrong, such as a broken wire or failed thermocouple, it quickly becomes apparent. The test can be stopped, the problem corrected, and the test resumed. A problem that goes undetected until the data is analyzed wastes the entire test period.

A disadvantage of DASYlab is that this program had to be written with the computer attached to the interface hardware. It would be a great advantage to write the program sitting in front of a desktop computer rather than working in the test area using a laptop.

Details of the analysis

Backlash and Compliance: One advantage of automated data collection is the larger amount of accurate information than can be manually collected in a reasonable period. The additional data gives a better picture of the equipment characteristics than would otherwise be possible. In Backlash and compliance, the red line simulates points collected when the torque was varied from zero to maximum, to minimum, and back to zero three times. (The data shown are not actual values but they are an accurate representation of the type of data collected.) The data showed good consistency and repeatability, which produces confidence in the results. For instance, the blue line shows the curve fitted to the backlash and compliance data. The length of the vertical line at zero-load is reported as backlash. The slope of the lines fitted to the observations is the stiffness. This is a conservative method for determining such values. The normal manual four-point test would have given both lower backlash and compliance numbers. The four-point test uses two torques that are just a little higher than breakaway torque in each direction and two torques that are a quarter to one half of the full load torque.

Converting from manual to automated testing: The first use of an automated system involves debugging because the test system, as well as the tested device, may have problems. An advantage to starting this system was that previous manually collected results were available for reference. Problems with the test system are seen quickly. For the first test, some manual measuring devices were used in parallel with the new test equipment. This either verified the results or showed problems. For example, an incorrect scaling factor was quickly detected and corrected. This illustrates one principle of successful testing: Check the calibration of the test equipment before running the tests.

Peerless Precision in Remote Measurements

By combining the best of two different distance measurement approaches with a super-accurate technology called an optical frequency comb, researchers at the National Institute of Standards and Technology (NIST) have built a laser ranging system that can pinpoint multiple objects with nanometer precision over distances up to 100 kilometers. The novel LIDAR (“light detection and ranging”) system could have applications from precision manufacturing lines on Earth to maintaining networks of satellites in perfect formation, creating a giant space-based platform to search for new planets.

LIDAR transmits light through the air and analyzes the weak reflected signal to measure the distance, or range, to the target. NIST’s new LIDAR, described in Nature Photonics,* has a unique combination of capabilities, including precision, rapid updates from multiple reference points at the same time, and minimal “measurement ambiguity.” The system can update measurements to multiple targets simultaneously every 200 microseconds. Measurement ambiguity in a LIDAR system is due to the fact that, if the target is at long range from the instrument, the system can’t distinguish between two different distances that are multiples of its “ambiguity range.” The new NIST LIDAR has a comfortably large ambiguity range of at least 1.5 meters—large enough to check the coarse distance with widely available technologies such as GPS.

No other ranging system offers this combination of features, according to the new paper. NIST’s LIDAR could enable multiple satellites to maintain tight spacing and pointing while flying in precision formations, acting as a single research instrument in space, the paper states. Formation flying has been proposed as a means to enhance searches for extraterrestrial planets, enable imaging of black holes with multiple X-ray telescopes on different satellites, and support tests of general relativity through measurements of satellite spacing in a gravitational field. The new LIDAR could enable continuous comparisons and feedback of distances to multiple reference points on multiple satellites. There also may be applications in automated manufacturing, where many parts need to fit together with tight tolerances, according to Nate Newbury, the principal investigator.

NIST’s LIDAR design derives its power from combining the best of two different approaches to absolute distance measurements: the time-of-flight method, which offers a large ambiguity range, and interferometry, which is ultraprecise. The LIDAR relies on a pair of optical frequency combs, tools for precisely measuring different colors (or frequencies) of light. The frequency combs used in the LIDAR are based on ultrafast-pulsed fiber lasers, which are potentially smaller and more portable than typical combs that generate laser light from crystals. The two combs operate at slightly different numbers of pulses per second. Pulses from one comb are reflected from a moving target and a stationary reference plane. The second comb serves as precise timer to measure the delay between the reflections returning from the target and from the reference plane. A computer calculates the distance between the target and the reference plane by multiplying the time delay by the speed of light.