Originally Published September 2000

Product Update

New Test Equipment Offers Less Bulk, More Versatility

William Leventon

Test devices are shrinking and providing many new testing capabilities.

Is test equipment on your shopping list? If so, you'll see changes in the ways test functions are packaged. And what you'll see should please any shopper: test devices that are smaller, more affordable, more capable, and easier to use.

"On workbenches, space is always at a premium," says Vladimir Kraz, president of Credence Technologies Inc. (Soquel, CA, USA). With this in mind, Credence and other test equipment manufacturers are developing devices that take up as little room as possible.

One result of these efforts is Credence's EM Aware, a miniature device that measures electrostatic discharge (ESD). In essence, EM Aware is a highly specialized radio tuned to specific properties of ESD events. The device owes its small size mainly to recent advances in wireless communications technology. "Two years ago, we wouldn't have been able to make a product of this size," Kraz says of his unit, which measures 3 x 2.2 x 0.75 in.

According to Kraz, this small unit has several advantages over the hatstand-sized devices usually used to measure ESD. "You can bring it up close to the area you want to monitor," he says. "And it gives you more versatility in installation."

Testers You Can Carry

Unlike their bulkier counterparts, small test devices allow easy movement from one point to another. A product designed with portability in mind is the Rigel 266 electrical safety tester from Seaward Electronic Ltd. (Peterlee, Co. Durham, UK).

This new safety tester is much smaller and lighter than similar devices on the market, according to Paul Millican, a Seaward design engineer who led the Rigel 266 development project. To keep product size to a minimum, Millican and his team grouped many connections that would normally be on the tester itself into a "flying lead" arrangement. The Rigel also features microprocessor-based technology that's more compact than the combination of switching relays and logic circuitry found in larger benchtop testers.

Millican sees a trend toward test systems that are easy to handle. "We've found that most customers like to have lighter-weight, more-portable test equipment," he says.

But buyers beware: smallness has its trade-offs. For example, one of the keys to the Rigel's diminutive design is a tiny transformer that puts some limits on the device's testing capability. Small size can bring other disadvantages as well. "When a device gets smaller, its ability to display information and to provide controls is limited," notes Credence Technologies' Kraz. "On a large box, you can put a big screen and a whole bunch of knobs and buttons."

A safety tester from Seaward Electronic Ltd. combines portability with multitesting functionality.

Kraz considered adding a display to EM Aware that shows the magnitude of ESD events. But in the end, he decided against it. "This would have taken more space and required additional controls," he says. The advantages of supersmall size would have been lost—and the cost of the device would have jumped as well.

The Multitester Option

Besides small size, the Rigel 266 offers another trendy feature: the ability to perform more than one type of test. The Rigel takes the place of two conventional testers, combining leakage-test functions with its appliance-testing capabilities. "It basically means that you don't have to spend money on two testers to check your piece of medical equipment," Millican says.

In the last few years, many test-equipment manufacturers have noticed the advantages of multifunction machines. One of these, Indentec Hardness Testing Machines Ltd. (Stourbridge, W Midlands, UK), now offers a hardness testing machine that takes the place of three standard test devices.

In Europe, medical device manufacturers that perform the three common types of hardness tests—Rockwell, Brinell, and Vickers—must meet new ISO standards. "European companies needing to supply products compliant with these standards need to purchase new machines," says John Piller, Indentec's general manager. "We see this as a window of opportunity for us to supply one machine to do all three tests."

According to Piller, Indentec's three-in-one Universal hardness testing machine offers buyers much lower cost per test function. "Instead of buying three machines, they can buy one machine that does everything at about one and a half times the cost of a single machine," he says.

Besides taking less cash out of your wallet, multitest machines also take up less space than several single-test machines. They also offer a common operator interface for the tests they perform. While three single-test machines would probably have different operator interfaces, Piller notes, the Universal has a single membrane keypad for its three hardness tests.

Test Quality Questions

But what about test quality? Do devices made for a single test perform that test better than multitest machines? Piller concedes the possibility, but insists that Indentec customers have no cause for concern. The Universal is in compliance "with the latest ISO standards," he says. "And if a machine is complying with those, it's as good as it needs to be."

Multitester performance is every bit as good as that of single-test devices, contends Jim Richards, a marketing engineer for QuadTech Inc. (Maynard, MA, USA), whose Guardian 6100 performs five electrical safety tests. Today, says Richards, there's only one reason for buying a single-test unit: if you're doing just one test and want to do it as inexpensively as possible.

As in the development of small devices, microprocessor control plays an important role in the design of multitest units. Under the control of an internal microprocessor, Richards notes, a device like the Guardian 6100 can switch from one test mode to another and perform tests in sequence.

Richards sees several reasons for the emergence of multitest devices. In addition to cost savings (the 6100 costs about half as much as the five separate testers it replaces), the devices offer greater test efficiency. "If you were doing five tests and had to have five test stations, that would take a lot longer," Richards explains. "You have to move a product [to a station], connect it, do a test, then move it to another station, connect it, do another test," and so on. With all the testers combined into one, however, only one test hookup is required, which greatly streamlines the testing process.

Multifunction testers also simplify maintenance. "You only have to calibrate one unit, as opposed to two or three," Richards says. "If you have to take one unit off the production line, it's more efficient than having to take two or three units off the line."

Would you like to find out more about new test equipment and the companies that supply it? Read on, and you'll find descriptions of the products and companies mentioned above, as well as others that may have the solutions to your test problems.

QuadTech Inc.

Designed for fast and easy testing of electronic medical products, a new production safety analyzer can perform five electrical safety tests in accordance with UL, CSA, and IEC standards. According to QuadTech Inc. (Maynard, MA, USA), its Guardian 6100 lets users carry out a number of tests without changing the connection to the device under test.

With its five-tests-in-one capability, the 6100 "streamlines the testing process, eliminating the need for multiple test stations," says Jim Richards, a marketing engineer for QuadTech. "This saves time and, more importantly, reduces test costs."

The Guardian 6100 can perform ac hipot tests from 50 to 5000 V and dc hipot tests from 50 to 6000 V. Current trip levels for the ac and dc hipot testing functions can be programmed over ranges of 1 µA to 40 mA ac and 0.1 µA to 20 mA dc, providing flexibility in testing a wide range of devices.

In addition to these tests, the device performs ground bond tests (which verify the integrity of a product's ground system) to 30 A and takes insulation resistance measurements from 100 k to 50 G. The insulation resistance test calculates and displays a product's insulation resistance value in ohms at any programmed voltage between 50 and 1000 V dc. The instrument's fifth function is taking line and earth leakage measurements from 0.1 µA to 9.999 mA. Earth leakage tests measure the current flowing through a product's line cord ground connector. During these tests, the unit can monitor line voltage, current, or power consumption.

Any combination of these five tests, up to a total of 10, can be run automatically in sequence from a single start command. An overall go/no-go indication is provided based on programmed limits, and any failed measurement results are clearly indicated.

An ISO–9001 certified company, QuadTech offers a variety of testing devices, as well as calibration and repair services. The company has a network of salespeople and distributors who support customers around the world.

Wilco AG

A company has developed a fully automatic, 100% in-line rotary leak tester that inspects ampoules at a speed of 120 per minute. Ampoules with defects of 1 to 2 µm or larger are automatically rejected by the Wilcomat FC/LFC leak tester, supplied by Wilco AG (Wohlen, Switzerland).

Ampoules are transported by a conveying system and a special in-feed handling system to a star wheel. The feeding star positions each ampoule directly below an independent test head, which closes over the sample. Then the samples are subjected to a patent-pending LFC (liquid-filled container) leak test, which consists of drawing vacuum under the flashpoint of the liquid and measuring any vacuum change resulting from a partial pressure increase caused by the steam.

Samples passing the leak test are moved onto the production conveyor belt by an outlet star. Ampoules not meeting the reference standard are guided onto a reject conveyor. Removal of defective ampoules, the reject reference standard, and crucial machine functions are constantly monitored and adjusted to minimize operator errors.

Wilco designs Wilcomat FC/LFC systems that inspect up to 400 ampoules per minute. The company has delivered and installed more than 4000 machines worldwide.

RAM Optical Instrumentation Inc.

New video metrology systems can be used for critical measurement and precise positioning of parts and products during the manufacturing process. "Dimensional tolerance requirements of medical devices require precise measurement capabilities," says Terry Rosene, senior applications engineer for RAM Optical Instrumentation Inc. (Irvine, CA, USA), which manufactures the DataStar 200 and 300 workstations.

The systems feature the manufacturer's Galaxy metrology software package, which allows users to quickly measure parts and analyze critical data. Galaxy includes a suite of 2- and 3-D data-gathering and feature measurement and construction tools. The tools have full-parameter table control and results can be displayed in user-selected colours to maximize best visibility.

The DataStar systems are available in both a workspace-efficient benchtop design and with an optional metrology stage stand. Stages are built on solid granite bases designed to optimize flatness and stability. System electronics are located in a separate, ergonomically designed user console, away from the metrology stage. With vibration and heat away from the stage, test results are both more accurate and more consistent.

Controlled both manually and by software, the patented Optical Video Probe delivers magnifications from 30x to 170x. Magnifications up to 340x are possible with a 2x auxiliary lens.

Part images are displayed on one monitor, while the program is displayed on another. The dual monitor display keeps menus and icons from obstructing the user's view of a part.

Associated Research Inc.

Available in various configurations, a fully automated system provides a turnkey solution for electrical safety compliance testing. Developed by Associated Research Inc. (Lake Forest, IL, USA), the System 9000 includes hardware and software for performing five of the most common safety tests151ac and dc, dielectric withstand, insulation resistance, ground bond, and line leakage151through a single connection.

The System 9000 "is a very flexible and versatile system," says Adam Mikos, international sales manager for Associated Research. The device is designed specifically for manufacturers that must comply with safety agency standards and new EN norms such as the Low Voltage Directive 73/23/EEC and the Medical Devices Directive 93/42/EEC.

The system consists of two instruments. One of these, the Linechek line-leak tester, offers "a switching matrix that allows a manufacturer to automatically switch through the various line-fault conditions," says Mikos. The other instrument can be either the HypotULTRA II 3-in-1 safety analyzer or the Quadchek II 4-in-1 safety analyzer, depending on the customer's requirements. These CE- and TÜV-listed instruments reportedly speed throughput, increase test reliability, and provide a safe testing environment for the operator.

Users can opt for automated testing by installing the company's Autoware custom software package. Data-logging capability for all types of testing is provided through RS-232 or GPIB interfaces.

Founded in 1936, Associated Research sells safety compliance products to companies in many countries. The company's products range from entry-level instrumentation to fully automated systems.

Credence Technologies Inc.

A series of in-process monitors detect and measure electrostatic discharge (ESD) events in a number of environments. Developed by Credence Technologies Inc. (Soquel, CA, USA), EM Aware monitors provide users with information that could help them reduce losses caused by ESD. The devices also inform users of problems with ESD-prevention products and measures.

"EM Aware gives real-time indication of whether ESD preventive measures actually work and how well, indicates if a sensitive component or assembly was exposed to a dangerous level of ESD, and enables manufacturers to control their ESD environment . . . based on facts, not assumptions," says Vladimir Kraz, president of Credence Technologies.

A network of EM Aware monitors gives users a picture of the ESD environment on the production floor and provides information for yield analysis and statistical process control (SPC). "EM Aware can be an integral part of SPC that puts manufacturers in full control of their processes," Kraz says.

Small (3 x 2.2 x 0.75 in.) and unobtrusive, the monitors feature high sensitivity and wide adjustment range, local and remote threshold settings, and audio and visual indication of ESD events. The devices also offer an event "hold" indicator, stand-alone operation, and connectivity to most data acquisition and facility-monitoring systems. Working with built-in or optional remote antennas, the devices can monitor ESD events in tight spots.

"Equipped with EM Aware, medical device manufacturers can react to any ESD-related problem in real time and can allocate their process control dollars to the locations where they have actual ESD problems," says Kraz.

Tantec a/s

Featuring a patented half-angle measuring technique, a manual contact-angle meter uses liquid to determine the wettability of two- and three-dimensional surfaces. The Cam-Plus can be used in R&D labs and on production lines, according to Tantec a/s (Lunderskov, Denmark), which sells the product.

The measurement process begins when a single droplet of liquid is placed on a sample. A light source projects the droplet image onto a screen with a grid and a protractor. The image is measured on the projection screen, which is unique among contact-angle meters, according to Mark Heiman, manager of Tantec's surface measurement product line at its US facility.

Also unique, Heiman notes, is the Cam-Plus's half-angle measurement technique. "While all other contact-angle meters measure the tangent, which can be subjective, the half-angle technique is a much more objective method, using three distinct measurement points," he says.

After a droplet is measured, software converts the contact-angle measurement into a surface-tension measurement. Measurement data are collected and stored for use in statistical process control.

Medical device manufacturers can use the Cam-Plus in a number of ways. For example, many manufacturers change the surface of their parts by adding some type of treatment or coating. By doing so, they change the way a droplet of water reacts on the surface of the part. These manufacturers can use the Cam-Plus to measure the difference between treated and untreated parts.

Manufacturers can also use the device to check the cleanliness of a part. "Different types of contamination on a surface will cause a droplet of water to act differently than it would on a clean part," Heiman explains.

Entela Inc.

A patented vibration machine has been developed specifically for failure mode verification testing (FMVT). Made by Entela Inc. (Grand Rapids, MI, USA), the FMVT machine is a six-axis, pneumatically actuated device capable of activating repeatable failure modes in a wide range of electromechanical components and systems.

With a uniform random frequency range of 2 to 5000 Hz and total displacement of 4 in., the FMVT machine can reveal inherent design weaknesses that may not be detected by traditional testing methods. By subjecting a device to a combination of stress-inducing environments, the machine can produce multiple failure modes in as little as one day.

The machine is suitable for users of various levels of expertise. "The controls are simple, allowing quick setup," notes Alexander Porter, Entela's engineering development manager and the inventor of the FMVT machine. "But a layered menu system allows advanced users to fine-tune the behaviour of the machine."

During a recent test, the machine was able to trigger both mechanical and electrical failure in an ECG unit, Entela reports. Conventional "air hammer" vibration machines normally produce a higher frequency range, which triggers only electrical failure. By producing mechanical failures as well, the FMVT machine provides more data to design engineers and expedites the redesign process, according to the firm.

An international company, Entela provides global conformity assessment services to international and European standards. The company also provides engineering services; failure analysis; and materials, product, and systems testing.

Zwick Testing Machines Ltd.

A machine that performs bending and penetration tests on hypodermic needles is available from Zwick Testing Machines Ltd. (Leominster, Herefordshire, UK). Dubbed the Zwicki, the device is "a high-quality, simple-to-use, low-cost, and space-saving universal testing machine," says Zwick spokesperson Jackie Morris. In addition to hypodermic needles, the machine can be used to test catheters, stents, and other medical devices.

The bending test (to DIN 13097) ensures that the needle has sufficient elasticity and that no permanent deformation occurs during its use. For this test, the needle is loaded up to the defined maximum force. After load removal and a two-minute dwell time, the test determines whether permanent deformation can be measured. The maximum load and support span of the bend test unit depend on the needle's diameter.

The purpose of the penetration test is to ensure that physiological impairment during the phases of an injection (i.e., tapping and total penetration) are kept to a minimum. During the test, a hypodermic needle penetrates a plastic foil, which has characteristics similar to human skin, at a constant speed. Simultaneously, a force versus time curve is produced and evaluated according to specific criteria. The test determines the quality of a needle and makes sure it meets all necessary requirements.

The Zwicki acquires additional capabilities when used with the company's testXpert software. If dwell time at the end of a bending test is required, the software can employ a hysteresis test parameter set. And during penetration tests, it can display curves on a screen that give the operator complete control over relevant curve parameters. Thus, "good or bad" determinations can be made more easily and operator errors minimized.

Indentec Hardness Testing Machines Ltd.

Billed as the first of its kind made in Britain, a hardness testing machine from Indentec Hardness Testing Machines Ltd. (Stourbridge, W Midlands, UK) can be used to perform three traditional test methods. Named the Universal, it is designed to carry out Rockwell, Vickers, and Brinell hardness tests to official standards on loads up to 187.5 kg.

According to Indentec, this three-in-one capability will save manufacturers the trouble and expense of buying extra equipment to meet requirements involving two or more hardness scales. When you buy the Universal, "you're literally getting three testers for the price of one and a bit," says John Piller, general manager of Indentec.

For long-term calibration stability, the bench-mounted Universal employs deadweight technology (rather than load cells) to measure hardness. The standard manually operated model is equipped with a nose-mounted indenter to allow easy access to test areas that might otherwise be difficult to reach.

This basic system can be progressively automated to minimize dependence on operators. The most advanced model offers automatic computer-aided measurement and testing.

Other available upgrades include a built-in measuring microscope, a video camera that takes the place of the standard eyepiece, automatic focus, manual and motorized x-y tables, and software for case-depth determination.

Another Indentec hardness testing machine has been purchased by UK-based Swann-Morton Ltd., a leading manufacturer of surgical blades. The computer-aided Vickers system has been installed in the quality laboratory of Swann-Morton's Sheffield plant, which produces 1.25 million blades a day.

Featuring a video camera that replaces the usual eyepiece, the bench-mounted digital machine performs a number of testing functions ranging from automatic focus and indentation measurement to preprogrammed test sequences. In addition to test results, data identifying specimens by type, production batch, furnace, etc., can be recorded as the tests are carried out.

Seaward Electronic Ltd.

A portable, multipurpose device is designed specifically for electromedical safety testing. A microprocessor-controlled unit, the Rigel 266 tests Class I and Class II equipment during the manufacturing process.

Measuring 310 x 210 x 80 mm, the Rigel weighs only 4 kg—about half the weight of leading competitors, according to Seaward Electronic Ltd. (Peterlee, Co. Durham, UK), which manufactures the device. "The unit has been designed to be highly portable and to give the user the ability to perform quick checks on medical equipment," says Martin Wilson, Seaward's marketing executive.

Besides portability, the Rigel features soft key and rotary switch operation. It also offers a large 7.5 x 10-cm LCD that helps to reduce operator errors.

The Rigel can carry out load, insulation, IEC lead, earth continuity, earth leakage, enclosure leakage, patient leakage, and patient auxiliary current tests. The device offers true rms leakage measurements, automatic testing of single-fault conditions, and 16-A testing capability.

Established in 1982, Seaward Electronic makes test and measurement equipment that helps customers meet the requirements of health and safety legislation. The company has an international network of agents and distributors.