issue: December 2002 APPLIANCE Magazine
Quality and Testing
Passing the Test
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by Lisa Bonnema, Managing Editor
As appliance producers strive to meet internal quality goals and standards on a national and international level, they are turning to their testing suppliers to provide the latest in equipment and services to help them pass the ultimate test - that of the consumer.
Instrumented impact testing is one testing category that is still relatively new to the appliance industry, according to testing equipment supplier Instron Corporation. This type of testing allows for simulation of real-life situations such as an actual impact event. Pictured is an impact test of a personal digital assistant (PDA) using Inston's Dynatup Drop Impact System. The system performs tests by simulating the exact velocity and force the small appliance will experience upon being dropped. First, pneumatic grips imitate human fingers. The appliance is then dropped repeatedly in various positions onto a load sensor, and the sensor duplicates various floor surfaces such as wood, bathroom tile, and concrete. The data captured from this test shows how durable the appliance is, and how it will respond to being dropped once or 50 times, the company says.
Appliance makers have much to consider when implementing quality and testing processes into their production lines - compliance with the latest standards, harmonization with their overseas markets, and keeping up with competitors who are one by one making Six Sigma the expectation rather than the exception. Add equipment updates, qualified manpower, and productivity to that list, and it's easy to see how one might forget the reason for it all - the consumer.
In order to keep their focus on the end user, some appliance producers are starting to actually include consumers in their quality and testing processes. "There is a strong trend toward working directly with the consumer in product testing," says Michael Kuntz, director of Global Engineering Services, Whirlpool Corporation. "Engineers are making their test labs 'consumer friendly,' inviting end consumers into their labs for direct consumer opinion," he adds.
"There are also a growing number of tests in consumers' homes," Mr. Kuntz continues. "Data acquisition can be small and easy to hide. Phone connections back to the lab let engineers observe actual usage patterns without disturbing the customer."
Mr. Kuntz also says that testing is starting to go beyond basic performance and life testing. "Testing patterns are also starting to emphasize fail modes under extreme customer usage," he explains. "These tests help ensure customer safety even under the most unusual conditions…and can take the form of either unusual product usage or forced failure analysis."
One testing method that is starting to follow this trend is impact testing, according to Frank Lio, product manager, Instron Corporation (Grove City, PA, U.S.). "Many designers and materials engineers are becoming increasingly aware that the old methods for checking impact resistance (how well their product can take a drop or hit) are just inadequate. The older methods involve simply dropping a ball through a guided tube (a Gardner Test), or even less sophisticated, simply dropping a product from different heights and then inspecting for damage."
Instead, Mr. Lio adds, manufacturers are starting to use simulation of real-life use conditions, keeping in mind the types of situations that can happen in end use. He explains: "What happens when that can of soda falls off the top shelf and hits the refrigerator bottom when the whole appliance is running at a low temperature? The refrigerator must be able to withstand that impact, but plastics exhibit a ductile to brittle behavior. That is, the plastic becomes brittle when the temperature drops. At the same time, the molding process and design is to develop as thin of a 'shell' liner as possible to save material and weight. And would a white plastic shell perform differently than a different colored shell? Additives can change how a material reacts to an impact event and must be identified through testing."
In the end, he adds, the key - and the challenge - is thinking like the consumer. "Quality is not only real, but also perceived," Mr. Lio offers. "A dent on a washer surface may have absolutely no effect on the appliance's operation, but consumers might think otherwise."
Manufacturers continue to face the challenge of incorporating quality and testing into the production process without negatively effecting productivity. "Quality testing continues to be given a high priority when it comes to improving manufacturing processes in the HVAC industry," says Mike Richey, president of HVAC testing equipment supplier Serv-I-Quip, Inc. (Downingtown, PA, U.S.). "Our current business climate has put a greater emphasis on improving productivity in order to maintain or increase profits. Quality is an important part of productivity. The companies that are increasing market share are the companies that are emphasizing quality as an integral part of their productivity goals," he says.
Increased productivity, he adds, often means combining multiple quality tests into a single station and test cycle and using sophisticated testing equipment and processes that allow for faster leak testing cycles, faster refrigerant charging, and automatic tooling connect and disconnect.
Jim Richards of QuadTech (Maynard, MA, U.S.) agrees. "The trend in electrical safety testing of appliances is to do it fast, efficient, and safe," he tells APPLIANCE. "In today's production environment, this implies automation, testers that can be controlled remotely, programmed for repetitive testing, and the data logging of results when necessary."
Dwayne David, technical services manager for Associated Research (Lake Forest, IL, U.S.) says that automated electrical safety testing is a trend his company has been seeing for years. "With automation, customers can set up and run several tests through software and with one connection to the Device Under Test (DUT). This can greatly decrease production test time. In many cases, appliance producers are required to perform hipot tests, ground bond tests, and functional run tests. Now, through automation, a customer can run all these tests through a single setup with a single connection. This allows a customer to test to electrical safety requirements and monitor minimum and maximum readings for voltage, current, watts, power factor, and leakage current all at the same test station," he explains. "This has been a big advantage to some of our consumer appliance makers, who have been able to incorporate electrical safety testing and functional run testing. With this technology and automation they were able to reduce test time, improve test reliability, and increase their throughput by a significant percentage."
According to testing certification company Underwriters Laboratories Inc. (Northbrook, IL, U.S.), updating testing equipment and automating processes are critical in order to keep up with the demands of the appliance industry. "As product development times continue to shorten, there is increasing pressure to reduce testing time," says Ted Hall, UL's chief technology officer. "The major trend is to automate testing processes for appliances, with corresponding benefits in time, accuracy, and portability of testing. PC-based automation systems have resulted in more connectivity and extended use of equipment and chambers for testing."
In response to the growing use of ground bond testing, Slaughter Company (Lake Forest, IL, U.S.) developed the 2630 ground bond tester. The device is the company's first ground bound tester to include microprocessor technology and also features a liquid crystal display, menu driven software, and stored memory locations.
"We have seen more and more companies turn to testing the protective ground circuit of their appliances; therefore, companies are now performing Ground Bond tests as a part of their production line applications," explains Tim Collins, sales coordinator. "This is a trend that we are seeing despite the fact that no agency specifications call for 100-percent production line testing. The Ground Bond test checks the ground system of the Device Under Test (DUT). The purpose is to make sure it can adequately handle the fault current if the product should fail."
One way appliance makers are speeding up the testing phase without sacrificing quality is by working closely with suppliers to merge their quality operations with actual production. "Many customers are integrating their quality testing directly into the point of production to ensure a defect is not passed to the next station," confirms Tom Wagner, senior account manager for Sterling PCU (Dayton, OH, U.S.), a supplier to the commercial refrigeration industry. "For example, by using Nitrogen Burst testing of coils before they are assembled, a customer can eliminate a bad coil being assembled into the product. A helium charge and sniff can indicate a leak in a system before a refrigerant charge is applied. Some customers looking for the next step in quality control are analyzing the viability of Residual Gas Analysis. This method analyzes the signature of gases in a vacuum stream as the product is evacuated. This can help a manufacturer scrutinize their supply chain to verify if there is contamination upstream from their factory."
He adds that in a full-scale production line system, a unit should be required to pass the previous station prior to being processed at the next station.
Italian testing supplier AEA recently developed a new process for on-line quality control of refrigerators. The automatic system is based on thermal imaging of the condenser and the compressor using an IR thermal camera, a PC, and software for the analysis and classification of the captured images. Once the refrigerator arrives in the testing station, a thermal image is taken and is processed in a few seconds. Hotter objects emit more IR energy, and the camera measures these differences as gray levels and displays them in varying colors.
The main advantages of the system, according to AEA, are convenience and extreme time reductions. "Up until now, on-line quality control is based mainly on the measurement of temperatures taken inside a refrigerator for 30-90 minutes. This leads to a very high consumption of energy to cool the refrigerators and of space to store the refrigerators during the testing period," explains Renato Romagnoli, AEA's Home Appliances technical manager. "With the thermal image approach, it is possible to reduce the on-line test time to less than 8 minutes, assuring even a higher level of accuracy in the diagnosis of a defective refrigerator. This is an effective and non-contact method that provides a quick thermal evaluation feasible for a 100-percent on-line quality control of a refrigerator. Moreover, using appropriate Signal Process Techniques, the collected data are analyzed, and the classification (according to a pass or fail quality control strategy) is automatically performed without an operator," he adds.
Traceability is another feature many manufacturers are adding to their processes to validate product quality. "The only way to prove that an appliance or item has been tested properly is through documentation," says John Jansen of Clare Instruments U.S. Inc. (Tampa, FL, U.S.). "With conventional manual recording systems being fraught with potential errors and problems, the most effective way to prove compliance with relevant standards is to use test instrumentation that not only automates the test process, but is also capable of recording the results at the same time. This has led to the development of test instrumentation incorporating memory for storing test results and the capability of communicating with printers directly and/or PC programs."
Clare Instruments' G106 production test system, for example, uses a PC program to create test routines that are then transferred to the test unit. If the test station is on-line (i.e., connected to the PC), the database will be automatically updated with test details while production testing is under way. "This ensures automatic traceability of test details without interfering in any way with the test process or introducing additional work procedures," Mr. Jansen says. "If documentation is required to be shipped with the product, then an automatic print out directly from the test unit after testing is also possible."
An engineer performs an Energy Star ceiling fan test in ETL SEMKO's Cortland, NY, U.S. test facility. The independent testing facility has been testing products using the EPA's Tier I criteria on residential ceiling fans with or without lighting kits since November 2001. Additionally, the company is prepared to test to the guidelines of the upcoming Tier II set of criteria, which have not yet been finalized. This series of tests is expected to include more specific requirements on noise levels, improvements in airflow efficiency, power consumption restrictions, and warranty information.
Leak Testing Advancements
As Peter Palenstyn, market manager for Leak Detection at Varian Vacuum Technologies points out, recent improvements in appliance design have basically mandated improvements in testing processes such as leak detection. "Through our research and discussions with our customers, we have been made aware of the requirement to produce more energy-efficient appliances, while using more environmentally friendly cooling media," he says. "This trend translates in the need for cleaner and more reliable vacuum pumps, gauges with higher accuracy and repeatability, and much more stringent leak detection requirements."
To meet such demands, the company offers its 979 portable helium leak detector. The system features a multi-flow mode vacuum system in which high sensitivity is combined with the ability to start leak testing at quickly achieved pump down pressures. The company's patented MacroTorr high-vacuum turbo pump reportedly allows the 979 to perform quantitative, high-sensitivity testing at high test pressures. Features include helium sensitivity to 10-12 atm-cc/sec range; 1x10-8 std cc/sec testing at pressures < 3 Torr; 1x10-11 std cc/sec testing at pressures < 300 mTorr; and a touch screen interface. It is also operable in evacuation and sniffing modes.
Uson L.P. (Houston, TX, U.S.) says it has designed a breakthrough technology that increases leak testing cycles by at least 50 percent. Released in September, the company's Vector product uses a patent-pending algorithm that actually predicts the pressure response curve during leak testing, explains Jim Rutherford, vice president of Engineering at Uson. "With today's methods you basically have to wait for a period of time for what is known as the adiabatic cooling effect. The current methods are a very accurate way of measuring of the pressure, but are somewhat slow because you have to let everything stabilize out and get onto a linear portion of the curve."
The Vector, he explains, reduces that waiting period, but still gives an accurate measurement. "The breakthrough in technology that we have developed utilizes the adiabatic curve," says Mr. Rutherford. "What we do is record this curve for a part - given the test of the pressure, the volume of the part, and the type of material the part is made of - and then we generate a predictive model for that part."
This is accomplished, he says, through a couple of different mechanisms. "The Vector product has a number of hardware design elements that enable this technology - high-speed sampling, high-precision converters, and a fast microprocessor to do the single processing," Mr. Rutherford explains. "The key, however, is the predictive modeling that we do. It's a very sophisticated multi-variable mathematical formula for being able to derive the model of this pressure response curve."
Vacuum Instrument Corporation (Ronkonkoma, NY, U.S.) recently introduced its Ultra-Sensitive Atmospheric Sampling (USAS) Leak Test System for testing air-conditioning systems and refrigeration components. According to the company, its patented USAS Instrument is the heart of the system, allowing the tester to achieve hard vacuum helium specifications without the vacuum and mass spectrometry components necessary in helium leak detection systems. This factor alone reduces the overall costs of ownership, operation, and maintenance by one-third, the company says.
The system is said to be 10,000 times more sensitive than helium mass spectrometer leak detectors, testing up to 10 parts per trillion SF6. Mixing fans reportedly ensure uniform concentration of test gas, and the gas recovery system is said to achieve an efficiency of 99.8 percent. According to the company, this high level of efficiency permits testing of approximately 15,000 standard components with only 1 lb of SF6 gas; therefore, tracer gas costs are typically 50-percent less than helium.
In order to ensure a quality product, manufacturers must test from the inside out. In an industry where appearance counts, neglecting color or coating quality can prolong shelf life and leave the consumer with the impression of a low-end product.
There are also some major manufacturing disadvantages to overlooking color and coating testing, according to Craig Johnson, assistant general manager, Minolta Corporation, Instrument Systems Division (Ramsey, NY, U.S.). "The need to assure consistency and standardization of products is critical to success and survival. Inconsistent color can often be the 'straw that breaks the camel's back.' A part or product that meets all specifications except for color can result in rejected shipments, delayed production schedules, costly rework, or loss of business," he explains. "Increasingly, color measurement and control instruments and systems are being employed along the supplier chains as an objective and scientific method of inspecting, checking, and evaluating color of incoming materials, in-process work, and outgoing shipments of finished goods."
Cost savings on paint alone might be reason enough for a manufacturer to invest in some form of coating testing, adds John Henderson, design engineer and vice president of DJH Designs, Inc. (Ontario, Canada). He says DJH's Film Thickness Measurement System, for example, can lead to major cost reductions. "The Film Thickness Measurement System is probably paramount because it is a quality control instrument used for your coating thickness. Obviously, you want to make sure that you're able to maintain specifications not only to make sure that you're not under the coating level, but also when you're color matching. If your coating is too high or too low, you typically throw your color match off," he explains.
"For example, an appliance coater that uses on average 8 million liters of paint a year, for every micron of paint it puts down, that's U.S. $1 million a year. We can typically save the company that within the first 3-4 months of running that machine," Mr. Henderson says. "Because they're not having to put excess paint down, they can control the paint process to a tighter tolerance. You have more positive means of checking that your coatings are right. For example, if you're running a 0.7 mil coating thickness, you can run that tolerance much tighter instead of putting on a little bit extra to make sure you meet the requirements."
Elcometer (Rochester Hills, MI, U.S.) offers customers reduced costs by adding flexibility to its product offering. The company's hand-held Elcometer 456 coating thickness instrument comprises a single gauge that uses probes that are able to work on ferrous and non-ferrous metal substrates and on coatings of anywhere from a couple thousandths of an inch all the way up to a half of an inch thick, according to Joe Walker, vice president. "In the past, if a customer wanted to switch from a ferrous to a non-ferrous substrate, he would have to purchase a new gauge. Today we offer dual, ferrous and non-ferrous gauges with the choice of an integral or separate probe option. Additionally, our separate probe gauge can be converted to an integral gauge by using a PINIP™, a plug-in integral probe," he explains.
The 456 also offers a graphical interface menu system that allows the user to calibrate a unit according to a different world standard. "They don't have to go to a reference book if they're out in the field or out on the shop floor, all they have to do is go to that calibration menu and the menu function, and the gauge will talk them through how to follow that standard," Mr. Walker explains. The device also works in 12 different languages.
Keeping track of the constant changes in standards and certification within the appliance industry is a challenge in itself. Whether it is an industry or government mandate or a new certification option, to stay successful, producers need to keep a close eye on the latest in quality standards and certification programs.
Microwave Ovens and Induction Cookers
One appliance segment that will be seeing major changes in the coming months is cooking, specifically microwave ovens and induction cooking devices. As published in the Federal Register in July, the Federal Communications Commission (FCC) has amended the rules of parts 15 and 18 for conducted emissions to harmonize U.S. (domestic) requirements with international standards. In general, the amendment mandates microwave ovens and induction cookers, which were previously only required to comply with FCC radiated emission requirements, to now also comply with conducted emission requirements by July 2004.
According to Nissen Isakov, president, LCR Electronics, Inc. (Norristown, PA, U.S.), the Report and Order, which was released in May, amended the conducted emissions and requirements to coincide with those specified in International CISPR 22 (Information Technology Equipment) and CISPR 11 (Industrial, Scientific and Medical equipment). One aspect of the amendment is that the conducted emission limits, which used to start at 450 kHz, will now be reduced to 150 kHz to harmonize with current European regulations.
Mr. Isakov explains: "These changes will have the most impact on those in the appliance industry involved in the manufacture or import of microwave ovens and induction cooking devices. These products will essentially need to comply with the emissions requirements of the International European harmonized standards, even for use within the U.S."
In order to comply with the new requirements, microwave ovens being sold in the U.S. may need a more comprehensive Electromagnetic Interference (EMI) filter, Mr. Isakov says. Although this may imply an added cost, Mr. Isakov says that the industry should look at the bigger picture. "Today's economy is a global one and this will bring it in line with the rest of the world. It's the overall goal of harmonizing standards," he says.
Energy efficiency continues to be one of the driving forces of new quality standards. As of October 2003, the U.S. Environmental Protection Agency (EPA) will be issuing specifications for Tier II testing of residential ceiling fans for the Energy Star® program. Although the details have not yet been finalized as of press time, several guidelines were given in an Energy Star testing facility guidance manual, Building a Testing Facility and Performing the Solid State Test Method for Energy Star Qualified Ceiling Fans, which was published in September by the EPA.
According to the document, airflow and efficiency requirements have not yet been determined for Tier II, but it has been noted that airflow and efficiency requirements for Tier II may be divided into separate categories by fan diameter if data collected in 2002 indicate clear differences in achievable performance among fans of different sizes. Likewise, the Tier II specification may include consideration of power factor if warranted by product performance and utility request.
The most notable change, however, will be the noise specifications. While Tier I had no specifications, noise will play a large role in the new guidelines. Although the measurements have not yet been announced, Tier II qualifying products will include a standardized label on the product package noting operational noise in dB at each of three operating speeds (low, medium, and high). According to the EPA document, each fan speed will be associated with a minimum airflow in CFM. The final Tier II specification will state a test procedure for measuring fan noise. This specification will need to address, among other things, test chamber size and characteristics, type of measurement equipment, and type of sound being measured. The specification could either measure total sound pressure level (SPL) or attempt to specify the particular harmonics that result from electrical and mechanical fan noise, but are not the product of wind noise from the blades.
According to Jason Prentice, engineer, ETL SEMKO (Cortland, NY, U.S.), a division of Intertek Testing Services, such requirements might be tricky for some companies. "Once this is finalized, it will be imperative that the facility running this particular test verify the product's performance based on what the product is doing, not really any other noise factors that are in the room," he says.
He says that ETL SEMKO is getting fully prepared to be able to test for the new specifications in its ceiling fan testing facility. Hopefully, manufacturers are ready as well. "The Tier II is the next level, the next step," explains Mr. Prentice. "I feel it's going to weed out a lot of those kind of fly-by-night companies, and it's going to make these manufacturers look seriously at their products and determine their viability and if they are performing to par in terms of what standards and what standard operating procedures are available to this type of product," he continues. "For those that do have a hard time meeting those, well, they're going to have to step up and create a better product."
After 3 years of development, The Air-Conditioning and Refrigeration Institute (ARI) announced the initiation of the Indoor Pool Dehumidifiers Certification Program in September. The certification program, based on ARI Standard 910, Indoor Pool Dehumidifiers, covers factory-made residential, commercial, and industrial pool dehumidifiers. According to ARI, the dehumidifiers standard was initially developed for the purpose of establishing definitions, classifications, requirements for testing and rating, minimum data requirements for published ratings, operating requirements, marking and nameplate data, and conformance conditions.
Indoor pool dehumidifiers covered under the standard are those that provide the function of dehumidifying, air circulation, air reheating, and may also provide air cooling, air filtration, pool water heating, and air-to-air heat recovery.
As part of the new certification program, ARI verifies manufacturers' certified performance ratings of industry products in continuous and extensive laboratory testing. Randomly selected units are tested using procedures stipulated in ARI Standard 910 (available on www.ari.org/std/individual/index.html) to verify that they meet the manufacturers' certified published performance ratings. Participation is voluntary and open to members and non-members of ARI.
Looking to the future, it's safe to say that testing practices and standards across the globe will see substantial changes as appliances and their components get smarter.
According to Eli Szamosi, manger of New Business Development, CSA International, this means that companies should start preparing now. "The presence of new technology brings new features, new benefits, easier use, and more convenience, but also creates new challenges and skill demands on both the manufacturer and the testing organizations," Mr. Szamosi says. "To address the changes in technology, certification organizations and standards development organizations are having to enhance their capabilities to be able to properly and adequately create new standards, be aware of any new international standards, as well as test to these requirements."
In addition, he says, when designing new products containing software and microcontrollers, manufacturers now must consider the certification requirements much earlier in the design process in order to develop software that is appropriate, adequate, and meets all certification requirements.
New standards are already in place to deal with smart appliance technologies, Mr. Szamosi says. One such standard, he explains, is UL 1998: 1999 Edition 2, Standard for Safety in Software in Programmable Components. Published in 1999, this software safety standard has been referenced in, among others, CSA International requirement 3.01 U.S. for Portable Fuel Cell Power Systems to address the specific requirements of any safety-related software being used. This has been used by CSA when certifying fuel cells and other "smart" appliances.
Mr. Szamosi explains: "Standard requirements, such as those contained in UL 1998-99 ed. 2, requires that software used in appliances have two major characteristics. First, the software must have been designed and implemented according to a set of procedure requirements. This ensures that the software has been designed and built to a defined level of quality. Appliances are not like household computers where, if a problem occurs, a user can simply re-boot and start over. Software that fails in an appliance can pose serious potential hazards. Secondly, the software has to be designed to act on unsafe conditions, regardless of the situation. The software must be designed, up front, to anticipate potential hazards and situations and how the software will respond so that the product can be placed in a safe operating condition.
Mr. Isakov of LCR Electronics adds that the U.S., as well as other countries around the globe, may also start implementing stricter guidelines in response to EMI and other issues that arise when using advanced communications technologies in appliances. "In Europe, all household appliances, all electrical products, have to comply with stringent EMC regulations. The FCC exempts most of the household appliances," he explains. "What I think is probably going to happen is as smart appliances become more prolific, they will be more susceptible to interference. I believe that eventually all household appliances will have to comply with some form of harmonized, international EMI/EMC standards."
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