Quality & Testing
The Wide World of Testing

by David Simpson, Contributing Editor

Appliances today are assumed safe, and in most cases, they are. Electrical and gas appliance safety is the result of ever-evolving standards, good design practices, and better testing equipment, among other considerations. But safety is just one area in which today's appliances are tested. Performance, noise, electromagnetic compatibility (EMC), leak detection, part dimensions, energy use, color, and coating thickness are among other test areas.

Equipment producers are playing their part with smarter, easier-to-use equipment. In leak detection, Cincinnati Test Systems (Cleves, OH, U.S.) has a system that simultaneously determines leak location and total leak rate, providing real-time process control. Better yet, the leak location is shown on an on-screen graphic for visual recognition.

Clare Instruments U.S. Inc. (Tampa, FL, U.S.) is phasing out its range of analog safety testing instruments and replacing them with a new product portfolio using the latest digital technology. This will reportedly help manufacturers of electrical and electronic products meet international and product-specific standards. The new range will incorporate a host of new technical features and specifications. Included will be models from entry-level instrumentation through more comprehensive testers for SME manufacturing environments. Specialist instruments are available for more demanding conformance and type testing applications. Advanced PC-controlled instruments have been developed for sophisticated production line testing.

"The system will revolutionize leak testing for many manufacturers because it locates leaks and qualifies the leak integrity of parts simultaneously," says Gary Grebe, the company's marketing director. "This gives them immediate process feedback to improve their manufacturing and save money. They will save capital equipment expenses, floor space, operator time, and scrap production."

Testing Automation

Dwayne Davis, technical service manager at Associated Research, Inc. (Lake Forest, IL, U.S.), says he sees increased use of test automation in the production environment. Automation generally leads to greater efficiency, he feels. "Test stations can be configured to test multiple products," he says. "Automation allows for multiple test setup storage, so that there is greater flexibility in the manufacturing line. Without this capability, the manufacturer would most likely need two separate production lines or have instruments switched in and out in a single line.

The Falcon Leak Test System from Cincinnati Test Systems (Cleves, OH, U.S.) measures the total part leak rate and shows, with an on-screen graphic, the leak location. The system communicates the location and leak rate to the operator and factory network.

"This also results in less time spent programming in tests and setting test parameters," he adds. "An operator, who may be required to perform several safety tests such as a hipot and ground bond, can run these tests much more quickly and often times through a single instrument that only requires a single Device Under Test (DUT) connection. This saves an operator from having to change and manipulate test leads.

"Recording test data can be of significant value in protecting manufacturers in product liability situations," he continues. "Automation also makes it easier to capture, store, and analyze test data. This information can be initially viewed in a graphic or detailed format, stored in an ASCII format, or exported to any database or spreadsheet program. Depending on the requirements of the manufacturer, this can be a great benefit."

He says that if data need to be stored, this is a much better solution than manual recording pass/fail statistics. A manual process of recording data many times will result in a loss of productivity. Manual processes can also result in inaccuracies in the test data. In a busy production environment, distractions can occur. That may cause the recorder to make an unintentional error. These errors are eliminated by the automatic storage of test data. All of these benefits mean increased levels of efficiency that will, in turn, lead to greater throughput.

Reaching Outside

Given the wide variety of testing opportunities, some appliance producers use other companies to perform or supplement some of their non-production testing. This is especially true during product development or to meet product benchmarks.

There are a host of firms that handle non-safety testing for appliance companies. Some of these began in the safety testing areas and have branched out. One example, (see "Speeding 510(k) Approvals") is Underwriters Laboratories' work with two medical appliance companies.

Another medical case history, "Testing to Internal Standards," looks at Intertek's role in assuring performance of a Philips magnetic resonance (MR) camera prior to hospital acceptance. The testing company says it possesses comprehensive expertise in the requirements and regulations pertaining to medical engineering equipment. Besides safety testing and the inspection of heavy installed healthcare equipment, the company works in areas such as EMC, certification, and design reviews.

According to Slaughter Company (Ardmore, OK, U.S.), it is becoming common for more manufacturers to perform ground bond tests as a production tool, despite the fact that the companies are not required to do so. This may be in part because manufacturers see the overall effectiveness of the ground bond test as a production tool. It is also advantageous for them to provide the safest possible product. The ground bond test helps ensure this. A third reason is that it is becoming easier to perform the test. Today's technology allows both the hipot and ground bond tests to be performed through a single connection. This is accomplished through interconnected hipot and ground bond testers. There is no need to have connections removed after performing one test and replaced before performing the other. Therefore, safety can be ensured without sacrificing productivity or throughput.

Emerson Climate Technologies (Sydney, OH, U.S.) is a specialist in commercial refrigeration equipment. Its Design Services Network's testing facility houses equipment that can fully test and evaluate a variety of refrigeration equipment and systems in a range of environmental conditions. A team of Emerson experts tests the performance, quality, and safety of the equipment by utilizing sound chambers, controlled ambient rooms, calorimeters, air-flow tunnels, and more. Expertise ranges from thermal system analysis to fatigue and failure analysis, as well as sound, vibration, and Finite Element Analysis. The company's chemical labs are set up for advanced evaluation of refrigerants, lubricants, and their interactions.

Appliance maker Sub Zero Freezer Company, Inc. (Madison, WI, U.S.) has used Emerson in testing materials used in premium refrigerators. "The appliance company had done theoretical work on the materials, but wanted to validate its work by actual testing," notes Chris Mays, program manager for Emerson. "We conducted two rounds of thermal shock testing, [with] the most recent in mid-2003. Basically, the tests consisted of cyclic thermal shock in ambient temperatures of -20¡F and 140¡F. During the cyclic testing, the materials were analyzed to measure consistency and structural integrity."

"As a first-time customer of Design Services Network, I was very impressed with the quality level of equipment testing they provided," says Shawn Miller, an engineer with Sub-Zero. "The company's testing methods and procedures were organized, the testing was carried out correctly, and projects were completed on schedule."

In the commercial gas appliance area, the Gas Technology Institute (GTI) in Des Plaines, IL, U.S. has had a role in the development of several successful food service products, including the Stellar Sirius boilerless steamer. Details are found in the article, "Sirius Development Work."

• The Wide World of Testing
• Testing to Internal Standards
• Speeding 510(k) Approvals
• Sirius Development Work