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Articles from 1997 In March

Application Digest

Application Digest

Preventing cable failures in cable carriers

Too often, cable carriers that have been carefully designed to meet an application's mechanical variables fail when cable behavior is not considered. Carriersthat are filled beyond 60% of total capacity,or where the cable manufacturer's speci-fications are not factored into the minimum bending radius, regularly result in conduc-tor breakage or twisting, or "corkscrewing," of cables.

Selecting a carrier system that can be easily customized to precise width specifications will maximize cavity opportunity while minimizing applications space interference. Additionally, cables with disparate outer diameters or jacket materials should be isolated from each other to prevent them from rubbing together or twisting. All cables should be clamped at both fixed and driven ends of the carrier.

The installation of vertical dividers is a simple, cost effective method of isolating cables. In applications where space is critical, a combination of vertical and horizontal dividers will create multiple compartments for isolation. Carriers can also be designed with aluminum or plastic interiors that have been custom-bored for a specific layout. These systems provide maximum cable protection, allowing the cables to follow the neutral axis of the carrier.

To contact a KabelSchlepp applications engineer, call 414-354-1994 or fax 414-354-1900.

Oscilloscope clamp: Measurement for all categories

Didier Piaud, R&D Manager Chauvin Arnoux, Paris, France

While the current clamp is an ideal detector for measuring a current without interrupting a circuit, this is not its only function. When it is particularly necessary to ensure the safety of users and to protect their equipment, the current clamp is equally effective as an isolated sensor. It can even enable electrical engineers to make measurements in another more difficult installation category of an industrial type.

A current clamp can be used to form connections according to European standards, particularly with respect to the new Low Voltage Directive. This specifies the conditions for using measuring instruments according to their electrical environment category (the category of installation or overvoltage).

For example, in a workshop containing motors connecting to the mains, the room is classed in Category III (Electrical Engineering). To display a signal from one of these motors, it is necessary for the oscilloscope to also be Category III. The ad-hoc solution is to use a current clamp, such as the E3N clamp. The clamp provides the whole measuring system with the characteristics to meet safety regulations.

By using a clamp, existing instruments can be adapted to meet new safety standards. The total cost of this is much lower than the cost of buying instruments with differential inputs.

To speak with a Chauvin Arnoux applications engineer, call +33 1 44 85 44 86.

Powertrain for the next century

Powertrain for the next century

Stuttgart, Germany-From the outside, it looks like a classic roadster: a low-slung, two-seat, open-bodied vehicle with all the grace and style of its vintage 1950s predecessors. Yet deep inside beats the heart of a "year 2000'' powertrain. It's smart, consumes little fuel, and spits out less emissions. And the transmission thinks for itself. It is, in short, a hybrid vehicle that marries yesterday's style with today's high tech.

Meet the Boxster. Porsche's new roadster has captured the attention of sports car afficionados around the globe. The reason: Its style is more than skin deep. It harks back to its 1950s predecessors not only in outward appearance, but in its engineering cues. Like the classic Porsches of the 1950s, it employs a mid-engine design--that is, the engine lies underneath the middle of the vehicle. And it uses the horizontally opposed engine configuration known as the "boxer," from which it derives its name.

At the same time, however, Porsche engineers have endowed the Boxster powertrain with the best of today's technology. Instead of using air cooling, as the classic horizontally opposed, six-cylinder engines did, it employs water cooling. It also uses a Bosch Motronic M 5.2 electronic engine management system, a variable camshaft timing technique, and a four-valve-per-cylinder design. Together, the new features work hand-in-hand to make the classic horizontally opposed configuration perform up to 1997 standards.

That was critical, because many Porsche enthusiasts would have accepted nothing less than a horizontally opposed six-cylinder. Yet, early boxer engines were never designed for today's environmental concerns. "When the classic roadsters were built, emission controls weren't an issue," notes Wolfgang Sander, manager of dealer service operations for Porsche Cars North America. "Fuel consumption requirements weren't an issue. Air conditioning, power steering, and power brakes weren't available. But when we designed this vehicle from scratch, we took all those matters into account."

Water-cooled mid-engine. Designing the Boxster powertrain to meet today's standards was no easy task. Among the challenges was the development of a water-cooling system for a mid-engine design. Studies showed that the only way to provide heat dissipation under worst-case conditions was to mount the radiator at the front end of the car. But the car's luggage area prevented placement of the radiator in a normal position. Result: Porsche engineers borrowed a solution from the venerable Porsche 959. They split the radiator in half, then placed the two halves in the fenders in front of the wheels.

Water cooling was a key, not only because it cooled the engine more effectively, but because it enabled engineers to employ a four-valve-per-cylinder design. That, in turn, allowed them to center the spark plugs in the combustion chamber for consistent ignition and combustion of the fuel/air mixture. "It makes it much easier to control theflow of gas coming in and the flow of exhaust going out," Sander says. En-gineers say they could not have em-ployed the four-valve-per-cylinder technology in an air-cooled engine.

The engine's fuel injection and ignition are controlled by the Bosch Motronic system. Fuel supply is sequential, through one injector per cylinder, following the engine's firing order.

The Motronic system also plays a role in the operation of Porsche's patented variable valve timing system, known as VarioCam. VarioCam alters camshaft timing to produce greater engine torque. Working in conjunction with the Motronic controller, it advances the timing of the intake cam. The earlier valve timing creates more valve overlap and an earlier closing time than normal, yielding additional torque. The result is a broader, flatter torque curve and lower emissions. At 6,000 rpm, the 2.5 l Boxster engine produces 201 bhp; at 4,500 rpm it cranks out 181 lb-ft of torque. Most importantly, it offers 147 lb-ft or more between 1,750 rpm and 6,500 rpm.

Wheelbase 92.5 in. (2,415 mm) Overall length 115.7 in. (4,340 mm) Overall width 70.1 in. (1,780 mm) Height 50.8 in. (1,290 mm) Ground clearance .1 in. (105 mm)
Manual Tiptronic S0-60 mph 6.7 sec 7.4 sec
0-100 kph 6.9 sec 7.6 sec

ManualCity 19 mpg (12.4 l/100 k) Highway 27 mpg (7.9 l/100 k)

Five gears for Tiptronic. By designing the Boxster from scratch, Porsche engineers also managed to incorporate a better transmission. An optional automatic Tiptronic S transmission now offers five speeds. Introduced in the early 1990s, the Tiptronic uses adaptive shift programs to make logical decisions in choosing the right gear.

The five-speed version of the transmission, however, is a first for Porsche. To accommodate it, engineers expanded the transmission's housing slightly and incorporated an external power transmission shaft inside the housing. The wider housing enabled them to include the extra gear set inside. "The transmission was designed from a clean sheet of paper and never was conceived to be anything but a five-speed," Sander says.

The shorter transmission ratios of the five-speed produce a 0-60 mph acceleration of 6.7 seconds. It moves out from 50 to 75 mph acceleration in fifth gear in 11.4 seconds.

New generation powertrain. The new powertrain may be good enough to satisfy the most hard-core Porsche enthusiasts. Like the first Porsche 356 prototype, designed in the late 1940s, it features the mid-engine configuration. (Production models of the 356 had rear-mounted engines). And, like the classic Porsches of the next generation, it uses the horizontally opposed, six-cylinder engine. "When you look at the basic layout, you see a lot of similarities," Sander says. "But if you compare it part-by-part, you probably won't find two parts that are alike."

Still, those differences may be the key to its success. With lower emissions and better fuel economy, the new powertrain provides Porsche with a map for the future. "This engine represents the beginning of the next generation for Porsche powertrains," concludes Robert F. Carlson, general manager of public relations for Porsche Cars North America. "These are the engines that will carry the company into the next century and beyond."

Jaguar Redefines 'Refined Power'

David J. Bak Senior Technical Editor

Coventry, UK--Heads are turning with Jaguar's new XK8 on the prowl. But even to those enamored with the XKE and XJ8 profiles, the new silhouette looks only vaguely familiar. Less familiar still is the drivetrain: a 4.0 l, 290 hp V-8 coupled to a 5-speed ZF automatic transmission.

Matching the engine's power and torque characteristics calls for a wide gear-ratio spread--specifically 4.5 vs. the previous model year's 3.4. Jaguar achieves this spread with help from a new hydrodynamic, low-inertia torque converter. Instead of a normal fixed lock-up/anti-vibration system, the converter features a controlled-slip lock-up clutch.

This new, electronically controlled design gives partial lock-up in high gears at low speeds. In addition, the lock-up control allows the torque converter to be fully locked, fully open, or in a controlled transition stage for smooth shifting. A high-capacity, high-speed, 32-bit unit controls the three solenoid valves used for gear selection and lock-up control, as well as the combination of five pressure regulator valves.

Adding programmable variable cam phasing (VCP) increases power and low-speed torque. Engine torque is directly proportional to its volumetric efficiency which, in turn, depends on the time at which the inlet valves close. Jaguar's VCP increases torque at low speed by advancing the inlet camshafts to close the inlet valves early. At high speed, VCP achieves maximum power by retarding the inlet camshafts.

Chief components comprise an hydraulic actuator mounted on the end of each inlet camshaft, and a pair of electronically switched oil pressure control valves. Solenoids, activated by the engine control module, switch the valves.

The actuators contain a piston machined with helical splines. The piston acts on a matching set of splines in the actuator housing. When oil pressure is applied to the piston, it advances the inlet cam timing by 30 crank degrees, altering camshaft-to-crankshaft phasing. Removing oil pressure retards the camshaft via a return spring and natural friction. Response between advanced and retarded modes is less than 0.7 seconds.

In Brief: Fastening, Joining, & Assembly

In Brief: Fastening, Joining, & Assembly

The 1500XL automatic dispenser from EFD uses a timed air pulse to make fast and accurate deposits of adhesives, sealants, and lubricants in benchtop assembly operations. According to the company, controlled application eliminates operator guesswork and provides much higher productivity than squeeze bottles, hand syringes, and other manual applicators.

Self-sealing fasteners are designed with a groove under the head to accommodate a rubber O-ring which, when compressed, forms a complete seal. Zago Mfg. says the fasteners can be removed and reused without spoiling the sealing action.

Columbia Marking Tools announces the availability of a compact hot-stamp marker for plastics. The Model 911 is air-operated and can exert marking pressures up to 240 lbs. The marker is specifically designed for applications where space is at a premium. Length is restricted to 5/8 inch.

Tra-Con Inc. claims TRA-CAST 3108 epoxy has excellent flow and wetting properties and exhibits superior adhesion to glass, ceramics, most metals, and plastics. The material is low shrinkage and cures at room temperature with very low exotherm. Fully cured, the material acts as an electrical insulator with good impact and thermal shock resistance.

Allied Devices' AccuStarTM is a Phillips-head precision shoulder screw for close-tolerance applications. Manufactured in magnetic and non-magnetic 303 stainless steel, the screw adapts to diversified environments.

Assembly lines go cordless

Assembly lines go cordless

Towson, MD--Historically, there has been limited acceptance of cordless tools in the world's large assembly plants. Instead, appliance manufacturers, the auto industry, and others have relied almost exclusively on pneumatic assembly tools--primarily for their durability and accurate torque control.

Air tools, however, present problems: Hoses restrict mobility; compressors, oilers, and regulators require constant maintenance; vibration and noise lower productivity. That's why worldwide assembly manufacturers such as Ford and General Motors--in the U.S. as well as Europe--are taking a close look at, and using, a radically new cordless design.

Developed from a blank sheet of paper, the Black & Decker 2920 heavy-duty screwdriver offers the benefits, but not the drawbacks, of traditional pneumatic tools. Specifically, it is the first cordless assembly tool to offer precise torque control. "We had three objectives in designing the tool," explains Project Engineer Craig Schell. "Torque repeatability; no torque drift over time; and insensitivity to joint rate." A rolling-element clutch, he says, proved the key to fulfilling these requirements. Standard clutches call for an input and output cam disc with three interfaces for stability; spring force keeps the discs engaged. Each 120 degrees of rotation brings the clutch from the point of decoupling to the next recoupling point.

Air-tool drawbacks. While the above design works well for an air tool, it can lead to ratcheting, and therefore poor torque accuracy and shorter life for tools driven by electric motors. Simply shutting off the air supply will stop an air motor within 120 degrees of output spindle rotation. An electric motor, however, requires a longer period for speed decay, allowing additional time for secondary torque spikes.

"We're talking about a tool that runs 700,000 to a million cycles per year," Schell points out. "If a tool ratchets seven times before stopping, that's seven million cycles."

Timeline for design JULY 1994--Develop concept for tool
SEPTEMBER 1994--Identify relevant technologies
FEBRUARY 1995--Begin simulation testing and modeling
MAY 1995--Place orders for tooling
JUNE 1995--Begin component testing
JULY 1995--Make prototype units
NOVEMBER 1995--Produce first samples from production tooling
FEBRUARY 1996--Begin global beta site testing
JUNE 1996--Start manufacturing process
JULY 1996--Initial completion of all performance requirements
SEPTEMBER 1996--Begin full production

A rolling-element clutch extends the time allowed to brake the motor. That's because rolling elements move at onehalf the rotational velocity of the input cam disc. Here's how the clutch works:

Each cam disc features three female pockets. When the clutch is engaged, the rolling elements sit in the pockets of both discs. When the clutch disengages, the balls roll up and out of the pockets, forcing the two discs apart. At 240 degrees of rotation, the system recouples.

Since the spindle has enough time to slow down before recoupling, there are no secondary torque spikes higher than the first one. As a result, Schell claims, "we have a single decoupling clutch, rather than a ratcheting clutch." Less torque drift, less wear. Schell also points to another advantage: The rolling elements reduce wear for less torque drift over time and remain insensitive to joint rate. "The beauty of the rolling-element design," he says, "is that one mechanism satisfies all clutch criteria."

The new tool's ability to hold torque, coupled with the advantage of cordless operation, has had an enthusiastic reception by men and women who work on assembly lines.

"The cordless tool performs very well," reports Abba Vice, a trim operator who has worked with GM for 22 years. "It always fastens the screws smoothly on the first try."

Adds Steve Bemiller, a worker on the transportation assembly line at Harley Davidson, "The 2920 is a real timesaver. Because it doesn't vibrate in my hand like an air tool, I can get more pieces finished per hour with less fatigue."

Prototype, prove, improve

Computer modeling and rapid prototyping, says B&D's Group Product Manager Allen Brelsford, proved critical to quick development of the precision torque screwdriver. Starting with the tool's clutch, the company relied on ADAMs software (Advanced Dynamic Analysis of Mechanisms, from Mechanical Dynamics) to program in inertias, set up spring rates, and specify cam profiles.

Proprietary in-house software followed, generating 3-D animation to drive a simulated fastener and evaluate dynamic response of the clutch itself. The program also looks at the transfer of forces from one component to the next, to aid in optimizing design with respect to stress.

Moving back to the gearing, B&D uses TK Solver from Universal Technical Systems, as well as in-house gear simulation packages. "By simulating the gearing," Brelsford notes, "we can evaluate losses within the system, separation forces, and even net shapes for tooth profiles."

As for the motor, "we focus on the efficient use of steel." This, claims Brelsford, lets B&D determine flux density to model the magnetic pathway inside the laminations. Working closely with Johnson Motors, Black & Decker also models commutation losses, EMI, and braking characteristics.

Allegro software from Cadence helps B&D model the assembly tool's electronics package. Working through the system, B&D engineers lay out the circuit diagram with all components in place, input the motor model, and verify response of the circuit itself. Another Cadence package designs the actual pc board and performs thermal modeling.

DYNA 3D--a program originally developed for automotive crash test simulation by Livermore Software Technology Corp.--allows B&D to look at the dynamic inter-relationships of all the subassemblies and how they affect the housing.

"With our old FEA package," explains Ted Mitrou, director of product reliability, "we simply assigned the tool's housing a lump center of gravity for drop simulation. The ability to look at particular bosses at the interface of separate components allows us to generate a more accurate strain plot. "

Once thoroughly modeled, Black & Decker prototypes the new assembly tool using a stereolithography-built housing. SLA, says Project Engineer Schell, lets the company assess manufacturability and place the screwdriver in the field for testing and feedback before final tooling.

"In retrospect," Schell recalls, "the only thing we might have done differently is prototype the molds rather than the housing. Selective laser sintering allows us to make a steel mold useable in production. We can pull out the binder, infiltrate with copper, and be ready to produce parts."

That may be so, but it is hard to imagine improving upon development time for the 2920 screwdriver: Twenty-six months from initial concept to commercial product.

CADKEY 97 expands modeling capabilities

CADKEY 97 expands modeling capabilities

CADKEY 97 for Windows from Baystate Technologies (Marlborough, MA) offers solid modeling capabilities, macro and OLE 2 support, and improved rendering, among other performance enhancements.

The new release extends its solid modeling capabilities by integrating the ACIS(R) kernel. Users can now construct solid primitives; perform Boolean operations; extrude, sweep, or revolve geometry into a solid; and apply constant and variable fillets, chamfers, and blends to solid models. The software also offers 3-D model to 2-D drawing associativity, and permits solid-to-solid, solid-to-wireframe, surface-to-surface, and surface-to-solid trimming operations.

"CADKEY 97's hybrid modeling capability gives designers the freedom to apply the design tool of their choice, from wireframe to surface to solid modeling," says Robert Bean, president and CEO of Baystate.

The software offers ACIS SAT file support and several bi-directional data translators, including DXFTM, DWG, CADL, VRML, and IGES. Metafile output and vector clipboard support are also provided. And the software's Picture It translation utility converts wireframe designs to solid models for mass properties analysis and stereolithography output.

OLE 2.0 server support enables users to embed or link a CADKEY part file image to another Windows application that supports the OLE 2 Container. Macros for recording routine interactions and functions can be stored for playback and editing.

Priced at $1,195, CADKEY 97 is available for Windows 95 and NT 3.5.

Product News

Product News


Flexible beam coupling is smaller than a domestic electrical fuse but provides excellent strength capabilities. Applications include optical measuring, medical science, and microwave communications.

The compact, three-beam coupling measures 6.35 mm in diameter and 14 mm long. It is available with a working torque of 0.4 Nm, or stainless steel with a working torque of 0.5 Nm. The unit is suitable for shafts measuring from 1 to 3.18 mm and has a set-screw fixing.

Hunt Power Drives Ltd., North Yorkshire, England, FAX +44-1423-881376.


Heavy-duty, screw-adjustable 40 Series of lever-action draw latches fulfill a host of sheet-metal fastening applications in the process industries, particularly when quick or frequent connection and disconnection during long service is required to meet the demands of safety, security, and/or high productivity. The rugged fasteners provide strong leverage and an ultimate tensile strength of up to three tons. The fast operation can give substantial time- and cost-saving advantages, while the locking action is positive and secure, providing constant pressure when closed.

Protex Fasteners Ltd., Worcestershire, England, FAX +44 1527-66770.


Powerslide-2 is a bearing-based, guided rodless cylinder. Features include double-row bearings to the majority of sizes and a re-designed carriage plate including plastic blanking plugs for the bearing assembly holes. The largest Poweslide-2, which utilizes a 50-mm-diameter cylinder with a 76-mm slide and 54-mm outside-diameter twin-bearing arrangement, has a load capacity in excess of 4,000N.

Hepco Slide Systems Ltd., Tiverton, England, FAX +44 1884-243500.

Graphics card

WINNER 2000AVI/3D is a multi-purpose graphics accelerator equipped with high-speed VRAM. The card is available in two versions, with either 2 or 4 Mbytes of ultra-fast dual-port EDO-VRAM. Both are suitable for 15- to 20-inch monitors, with which a display of MPEG and AVI sequences is possible, as well as up to 16.7 million colors at resolutions of 1,280 x 1,280 pixels. Microsoft's Direct3D standard, on which 3-D games for Windows 95 are based, is supported by WINNER 2000AVI/3D. S3d, 3DR, BRender, and RenderWare are also fully supported by WINNER 2000AVI/3D.

ELSA GmbH, Aachen, Germany, FAX +49 241-9177-0225.


Ball BushingTM bearing, stocked in interchangeable ISO standard metric sizes, features a twin-track design that increases bearing life. Designers of new equipment can take advantage of the bearing's four-fold increase in load capacity to handle equivalent loads by reducing shaft size to half that needed for the old-style bearing. Optional double-lip integral wipers reduce maintenance by keeping lubricants in and dirt out.

Thomson Industries Inc., Barnstaple, England, FAX +44 1271-334502.


Slimline escap(R) A22 incremental encoders provide three-channel 500-line service in a package diameter of only 22 mm. A custom opto-electronic integrated circuit forms the heart of the units. Resistant to all forms of external disturbance, phase shift between the two quadrature output channels is barely affected by temperature. Encoders with up to 256 lines are also insensitive to motor endfloats of 0.15 mm. This means that expensive preloaded ball bearings are not required in many applications. The escap A22 units have a typical current draw of only 5 mA from its 5V supply. If the motor is known to be stationary, the encoder can be set to a standby mode. In this condition the output line status is retained and the current draw is only 5muA.

Portescap UK Ltd., Ringwood, England, FAX +44 1425-477755.

Air valve

Compact 10, a high-flow four-way pneumatic directional control valve, comes in a compact package and provides fast response time. The valve offers flows up to a Cv of 0.3 in a valve body width of only 10 mm and a weight of 2 oz. Single- and double-solenoid versions, including two- and three-position models, are available in either in-line models or factory-assembled valve banks. Valve banks have electrical connections including two conductor leads, D-sub multi-pin, single-cable connection, and serial link. Operating voltage is 24V dc.

Rexroth Mecman Svenska AB, Stockholm, Sweden, FAX +46 8-7-27-66-32.


SinterstationTM 2500 utilizes the Selective Laser Sintering process. The unit has an expanded build chamber size and optimized chamber dimensions. The chamber is rectangular in shape and represents an increase of more than two times the build volume of the Sinterstation 2000 system. Build chamber dimensions are 380 x 330 x 420 mm. The Sinter station 2500 has been designed in such a way so that existing Sinterstation 2000 customers can easily upgrade their machines to the new larger build volume.

DTM GmbH, Hilden, Germany, FAX +49 2103-52265.


Series muC 2000 programmable converter features two-wire excitation. Other offerings include programmable and isolated analogue output, sensor break detection, and a typical response time of 150 ms. Operating temperature ranges from 0 to 50C, while storage temperature ranges from -20 to 70C. The input, output, and power supply are isolated from one another. The converter is supplied in a black ABS self-extinguishable case.

SFERE, Chassieu, France, FAX +33 4-78-90-83-90.

Current sensors

Compensation current sensors are for current detection in motor-control systems or power-supply units. Units are available for the nominal currents: 50, 100, and 400A.

Vacuumschmelze GmbH, Hanau, Germany, FAX +49 61-81-38-28-60.

Molding compounds

Thermoset sheet-molding compounds provide designers with high modulus, toughness, and flammability advantages for thin-walled electronic-product enclosure applications. EnduronTM consists of thermosetting phenolic resin and high-performance fibers. The compression- and transfer-moldable material is available with carbon, aramid, or fiberglass reinforcement.

Fiberite Inc., Winona, MN, USA.

LM guides

Type RSR-Z is a miniature precision linear motion (LM) guide. The use of resin for some parts of the LM block, particularly the unloaded section of the ball recirculating passage, has resulted in reduction of noise and weight. Other parts of the LM block, as well as the rail and balls, are made in stainless steel, providing resistance to corrosion and making these guides suitable for use in clean rooms. RSR-Z guides are available in four rail widths: 7, 9, 12, and 15 mm. Offered in normal, high, and precision accuracy standards, the guides can support loads in radial, reverse, and lateral directions. The basic radial-load ratings range from 0.88 to 4.41 kN dynamic and 1.37 to 6.57 kN static.

THK Milton Keynes, Milton Keynes, England.


Trim-line swinghandle latch has a shallow profile of 133 x 36 mm. The unit is suitable for construction equipment and small housings often found in advanced electrical equipment technology. The swinghandle can be fitted with a variety of internationally standardized actuator drives and lock cylinders.

DIRAK Konstruktionselemente GmbH & Co. KG, Schwelm, Germany, FAX +49 23-36-8-37-04.

Bellows contacts

Miniature gold-plated bellows contact springs are for flexible interconnections, with diameters ranging from 0.037 to 0.125 inches OD. These contacts come with either a convex-conical or concave-conical tip that allows them to be used in critical interconnection applications where reliability, flexibility, and low force are a must.

Servometer Corp., Cedar Grove, NJ, USA, FAX 001 (201) 785-0756.

Linear encoder

Steel-tape linear encoder, LIDA 105, uses the interferential scanning principle. Using this principle allows for a larger scanning gap resulting in easier, faster, and more reliable installation of the steel tape. Applications include measurement and inspection machines, coordinate-measuring machines, linear-motor applications, pick-and-place machines, robotics assembly and automation processes, and X-Y translation tables. The LIDA 105 allows for a mounting gap of 0.8 mm with tolerance of plus or minus 0.15 mm. The accuracy grade is plus or minus 5mum on a signal period of 40mum.

Heidenhain Corp., Schaumburg, IL, USA, FAX 001 (708) 490-3931.

Rotor production system

3EX rotor production system is for the high-accuracy, high-technology refrigeration compressor industry. This system accommodates advanced manufacturing systems such as automatic tool changing and automatic workpiece clamping. Features include hydrostatic bearings in the workhead for higher stiffness, 130-mm bore spindle in the workhead to allow automatic chucking with rear-mounted actuating mechanism, hydrostatic ways on the cutter-head infeed slide for higher stiffness and better infeed control, and ISO 50 taper on the cutting spindle with automatic clamping for quick and accurate tool change.

Holroyd, Milnrow, England, FAX +44 1706-353350.

Pressure sensors

SchaevitzTM P3000 Series pressure sensors are for applications where very low pressure measurement is required. The Series includes the P3061, P3081, and P3091 for the measurement of either vented gauge, absolute, or wet/dry differential pressures, in a variety of fluid media. The pressure sensing element of the P3000 Series includes an all-welded Ni-Span C capsule that offers low hysteresis and constant-scale factor with temperature variation.

Lucas Control Systems Products, Slough, England, FAX +44-1753-537622.

Ball-screw repair services

Ball-screw repair services range from simple cleaning and rebuilding to a complete regrinding of the shaft and manufacturing of new nut components. The services reduce machine downtime, and all repairs are fully certified and carried out in an ISO 9001- approved factory.

Thomson IBL Co., Barnstaple, England, FAX +44 1271-334501.

Hot isostatic processing

Hot isostatic processing involves subjecting components to simultaneous high temperature and high gas pressure within a specially constructed pressure vessel. The process is used to remove internal porosity from castings, to consolidate powder materials, or to diffuse bond solid or powder material combinations, and is applicable to metals, ceramics, glasses, and composites.

H.I.P Ltd., Chesterfield, England, FAX +44 1246-260889.


Ratchet-Action captive screw has a UL-recognized component listing and meets both UL 1950 and EN 60950 specifications for service access. Both specifications require restricted access to any area of electronic equipment or machinery where a hazardous condition exists. To help protect hazardous areas from accidental or unauthorized entry, the standards require a tool-removable door or cover. The Ratchet-Action screw is tightened by hand, but if a technician tries to loosen the screw by hand, the head of the screw merely ratchets in the opposite direction without disengaging the screw thread. It can only be removed by using a tool such as a slotted, Phillips, or multi-lobe driver.

Southco Inc., Concordville, PA, USA, FAX 001 (610) 459-4012.

Vacuum pumps

Depending on the model chosen, the N 815 and N 828/838 pumps can deliver up to 34 I/min. The mini diaphragm pumps in the units are employed for the clean evacuation and delivery of air and gases, particularly in medical equipment. With oil-free operation, the pumps neither contaminate nor falsify the media they handle.

KNF Neuberger GmbH, Freiburg, Germany, FAX +49 7664-2124.


MicrOringTM seals for miniature applications are available in more than 2,000 sizes with an inside diameter or cross section section ranging from 1.0 mm down to 0.20 mm. The seals are available in a range of materials including Buna-N, EPDM, silicone, Neoprene, Viton(R), and fluorosilicone. Special compounds and materials are also available.

Apple Rubber Products Inc., Lancaster, NY, USA, FAX 001 (716) 684-8302.

Positioning systems

AGS10000 gantry positioning systems feature rare-earth linear brushless servo motors in place of conventional belt or ball-screw drives. The positioning systems harness the acceleration and velocity capabilities of the non-contacting linear motors while eliminating the wear and maintenance issues present with belt or ball-screw drives. To satisfy today's fine lead-pitch electronics component requirements, AGS10000 gantries offer 0.1-micron resolution and highly accurate and repeatable 2-micron placement capability. Applications include laser cutting/welding, dispensing, robotic solder/desolder, and general point-to-point and contoured path automation.

Aerotech Ltd., Nurnberg, Germany, +49 911-521-5235.


StealthTM planetary gearhead is for servo motors. The unit is available in four frame sizes with reduction ratios of 5:1, 10:1, 20:1, 30:1, 50:1, and 100:1. Features include high torque, low backlash, input speeds up to 10,000 rpm, and high stiffness.

Bayside Controls Inc., Port Washington, NY, USA, FAX 001 (516) 484-5496.


(S)PORT II valve features an aluminum-bronze body that eliminates the possibility of corrosion. The unit is an evaporator pressure regulator for the supermarket industry or wherever accurate temperature control and system efficiency are the most important requirements. Advantages include an access fitting that has been relocated from the cartridge for easier usage, and an open-frame housing that allows for a cooler running coil.

Parker Hannifin, Refrigerating Specialities Div., Broadview, IL 60153, FAX 001 (708) 681-6306.

Thermoplastic polymers

Carilon thermoplastic polymers are semi-crystalline engineering thermoplastics suitable for automotive, electrical, industrial, and consumer appliance markets. They mold easily and do not require pre-drying or conditioning after molding. Other features include strong wear and friction characteristics and high resilience. The polymers also retain their properties over a wide range of temperatures and have a low sensitivity to water.

Shell Int'l Chemicals Ltd, London, England, FAX +44 171-934-5186.

Shaft couplings

Injection-molded shaft couplings accept all types of shaft misalignments. Type UJ coupling is suitable for use with rotary switches, variable resistors, small motors, clutch shafts, and other rotary-transmission mechanisms. Bores are available from 1.5 to 12 mm. The one-piece construction guarantees vibration-free, zero-backlash rotation. Type GJ coupling is reinforced with glass-fiber to give it a higher torque capability. The maximum angular displacement is 12 degrees, with parallel displacements from 0.03 to 0.5 mm and torques from 1.8 to 35 kg/cm.

Abssac Ltd., Evesham, England, FAX +44 1386-831500.


Liquid-epoxy encapsulants, underfills, and die-attach adhesives are for chip-on-board, flip-chip, array, and hybrid microelectronics applications. A line of eight encapsulants are for use in consumer, computer, telecommunications, automotive, avionics, and military electronics. For flip-chip packaging three low-viscosity underfill products redistribute stress and strain and protect the die from environmental forces. For use in conjunction with the encapsulants and underfill adhesives, an electrically and thermally conductive die-attach adhesive is formulated for attaching silicon die directly to a substrate.

Loctite Corp., Rocky Hill, CT, USA, FAX 001 (203) 571-5465.

Pressure sensors

Pressure sensor family suits the needs of industrial and severe environment applications. It ranges from moderately priced sensors for factory installation and OEM use to models suitable for sensor and cable immersion or survival at high temperatures. The EPO, S, and XT Series cover a broad range of pressures from 0 to 15 psi through 15,000 psi to meet the varied demands of process control, military, automotive, and aerospace testing; civil engineering; and research and development. The sensors measure both static and dynamic pressures in temperature ranges up to 250C.

Entran Devices Inc., Fairfield, NJ, USA, FAX 001 (201) 227-6865.


GRD relays can be mounted on a DIN rail or panel. They also integrate a heatsink, control-display LED, and protection via varistor and RC into standard size units, all protected by a cover. For temperature-regulation and motor-control applications, the relays are available with dc or ac control, and with synchronous or asynchronous switching.

Crouzet Automatismes SA, Valence, France, FAX +33 04-75-55-98-03.

Motor drive

MaxPlus 12-inch brushless servo motor delivers up to 90 hp, or up to 406.8 Nm of continuous torque for high-production, high-torque applications. The unit comes standard with neodymium-iron-boron magnets made of Magnequench(R) MQ3 magnet material, enhancing the ruggedness of the motor. Other features include resolvers for position and velocity feedback, IP65 sealing for wash-down environments, and MS connector or pipe-thread PCB termination.

Custom Servo Motors Inc., New Ulm, MN, USA, FAX 001 (507) 354-1611.

Membrane keyboard shielding

Membrane keyboard shielding solutions meet all levels of the CE-approval regulations. Shielding within a keyboard is realized by means of printing on a conductive layer within the keyboard that functions as a screen against trough-radiation and capacitive-coupled discharges.

Velleman Switch N.V., Gavere, Belgium, FAX +32 9-384-73-88.


Footswitch design incorporates a novel hinge at the front for improved operating. The Leptron switch has sleek and slender lines and fits snugly into the palm of the hand. Molded in glass-filled nylon for strength and rigidity, the switch is offered in a wide choice of colors and switch actions. A IP67 waterproof version is available.

Herga, Bury, England.


Canted coils energize PTFE seals and provide added performance to low-friction, inert-fluid seals. The seals are specified in medical devices where low friction is needed, such as when the device is manually controlled or run by a low power source. PTFE seals are also specified when the seal must be compatible with bodily fluids and tissues, sterilizing solutions, or where the device must be autoclaved. Sizes run from 0.50 mm on the inside diameter to several meters in diameter. Seal cross sections range from 0.50 to 12.50 mm.

Bal Seal Engineering Europe BV, Amsterdam, The Netherlands, FAX +31 20-625-6018.

Linear bearing

Linear bearing type RN offers an enlarged contact surface of the roller with the guideway, increasing the performance capacity, with unchanged fitting dimensions. Features include reduced susceptibility to cage creep, high rigidity and accuracy, and reduced danger of contamination due to the narrower gap between the individual guides.

W. Schneeberger AG, Roggwil, Switzerland, FAX +41 62-918-41-00.


Hydraulic pull-down clamps and matching mechanical counter-hold clamps are for unobstructed top-surface machining. The clamps feature independent horizontal and vertical movement, achieving lateral clamping forces of 3.9 through 44.0 kN, and pull-down clamping of 1.2 through 14.5 kN. The single-acting, spring-return clamps are for maximum operating pressures of 350 bar. With clamping provided along the entire surface of the jaw face, the clamps effectively hold both high and low sides of the workpiece throughout operation. The compact clamps feature BSPP ports for easy plumbing.

Applied Power GmbH, Dusseldorf, Germany, FAX +49 211-47-14-928.


K1 seal is manufactured from a porous synthetic resin. The material is oil impregnated to further improve lubrication and enhance long-term guide performance. In tests, linear guides equipped with K1 seals achieved lubrication-free running to distances in excess of 25,000 km. Applications include environments where oil-related pollution must be prevented including the food industry, and semi-conductor and medical equipment manufacture.

NSK-RHP Europe Ltd., Clifton, England.


Series F connectors meet the requirements of the demanding motor racing industry and are for both engine-management and data-logging applications. The connectors offer weight and space savings and feature a scoop-proof push-pull self-latching system, color-coded keyway identification, and an integral heatshrink boot adaptor. The units are housed in a rugged aluminum-alloy shell with an anthracite conductive finish and are qualified to withstand rapid temperature changes from -65 to 200C, as well as severe shock and vibrations.

LEMO SA, Ecublens, Switzerland, FAX +41 21-691-16-26.

Thermoplastic bearings

Thermoplastic bearings and assemblies offer flexibility and can be integrated with any number of components such as gears, fixing clips, and housing while still maintaining the rolling element bearing as the central feature. The integration opportunity can provide customers with a ready-made assembly replacing any number of individual components. Free design and prototype services are available.

Sarnatech BNL Ltd., Knaresborough, England, FAX +44 1423-862259.


Inductive product line includes inductive-proximity, magnetic-proximity, and magnetic-cylinder sensors. Inductive-proximity sensors detect metallic objects entering their detection zone. Because their design includes no moving parts or contacts as well as full encapsulation, these sensors function without wear, providing low maintenance and protection against vibration, shock, dust, and dirt. Magnetic proximity sensors offer a sensing distance up to 70 mm and can sense objects through partitioning walls and within pipes. Magnetic-cylinder sensors detect any magnetic ring in the piston through aluminum, brass, or stainless-steel housing walls.

SICK Optic-Electronic Inc., Eden Prairie, MN, USA, FAX 001 (612) 941-9287.


The HFUS Series of hollow-shaft gears includes component sets and units that offer a compact design with an integrated output bearing and a large, central, hollow shaft through the gear. The hollow shaft has a diameter of up to 30% of the unit's outside diameter. The HFUS products are available in nine sizes with torque capacities ranging from 18 to 1,840 Nm.

Harmonic Drive Antriebstechnik GmbH, Limburg/Lahn, Germany, FAX +49 6431-5008-18.


Strain-relief, liquid-tight SKINTOP II connector is UL, CSA, VDE, and SEV certified. The unit consists of three parts: an internal ratchet mechanism; a collet finger, which can accommodate a large range of cords, tubes, and cable diameters; and a neoprene compression gland. The ratchet mechanism allows the cap to be tightened without twisting the cord as it is compressed, pushing the collet fingers together to form a liquid-tight seal with the neoprene compression gland. SKINTOP II is useful for panel, switch, control equipment, and machine-tool applications.

Olflex Wire & Cable Inc., Fairfield, NJ, USA, FAX 001 (201) 575-7178.


FIRG/ISO.A coupling adaptors allow 3/8-, 1/2-, and 3/4-inch flat-face couplings to connect with 3/8- or 1/2-inch ISO.A couplings. Fitted in seconds, the units solve mismatch problems that could otherwise involve many hours of labor. The adaptors are made from heat-treated carbon steel and finished with a chromium-gold passivation process. Nitrile O-rings with PTFE backing rings are fitted as standard.

Holmbury Ltd., Tonbridge, England, FAX +44 1892-870886.


With airtight separation between the pilot and the fluid, Series 110 mini solenoid valves are for applications where the fluid must never come in contact with the electromagnetic part of the valve. These two- or three-ported valves have been created for the control of fluids with high-alkyline or high-acid levels or with oxidizing agents. Stainless-steel internal parts and diaphragms/-discs in EPDM synthetic rubber allow the valves to handle all fluid control needs in food and medical applications.

Asco Joucomatic, Rueil, France, FAX +33 47-51-81-36.

Component molding

The capability to combine the encapsulation of electronic and metal components within injection-molded parts is available. Customer products can be taken from design concept through initial prototypes and into full production. Facilities available include mechanical assembly, plastic injection molding, component insert molding, cold-pour thermoset encapsulation, ultrasonic plastic welding, micro-precision spot welding, and cable termination. Typical products include corotrons, high-voltage transformers, high-voltage connectors, and power-supply assemblies.

Highvol Electronics Ltd., Wimborne, England, FAX +44 1202-861086.

Motor program

A-max dc-motor program provides high performance at an economical cost. Motor housings are precision-made from rolled steel. A reduced-diameter commutator employs more segments and provides longer life. Precious-metal brushes ensure long life and help to minimize power consumption. Snap-on technology allows for greater flexibility in mounting gearheads, encoders, and tachometers. The series includes seven motors from 12 to 40 mm, and versions with precious-metal or graphite brushes, sleeve or ball bearings, and double-ended shafts.

Maxon Interelectric AG, Sachseln, Switzerland, FAX +41 41-666-16-50.


Hall-effect clamps offer high-performance electrical characteristics and a user-friendly design. Digital technology built into the clamps provides automatic dc zero adjust. By simply pressing a key, the user will obtain perfect offset with no further adjustments. The voltage output uses an attached 0.5-mm cord.

Chauvin Arnoux, Paris, France, FAX +33 46-27-73-89.

Air cylinder

EF1 pneumatic cylinder is for international machine requirements. It has a PTFE-impregnated, hard, anodized-aluminum body that provides wear resistance. The repairable cylinder is dimensionally interchangeable with similar compact extruded-aluminum body cylinders. Expected service life is 2,500 kilometers. Models are available in double-acting, single or double rod end, as well as single acting, spring retract or extend.

Bimba Ltd., Peterborough, England, FAX +44 1733-391080.


Millennium bridgehandle is available in 93.5-, 117-, 132-, and 179-mm between centers and can be supplied in two versions, either with a plain bore for use with a socket-cap screw or attached from the underside using a brass-molded insert. Indexable clamping handle is available in four handle lengths: 43, 65, 83, and 104 mm. It comes with a snap-fit cap instead of the usual steel set screw, giving the operator complete electrical insulation as well as a comfortable grip. Both products are produced in a high-impact-resistant glass-filled nylon and are available in a wide range of cadmium-free colors.

RENCOL, Bristol, England, FAX +44 117-950-4550.


Project Engineering System (PEGS) 9.1.1 is an electrical and instrumentation application. At the heart of the program is a flexible data model that allows attributes to be assigned to items, and the ownership hierarchy of these items to be quickly defined. The system can be instructed to recognize panels as sub-components of cabinets or terminal blocks as sub-components of a panel. PEGS 9.1.1 integrates the data between the piping and instrumentation drawings and the electrical and instrumentation diagrams.

CADCENTRE Ltd., Cambridge, England, FAX +44 1223-556666.

Workcell controller

Multi-tasking SRC-310 rack-mount 32-bit robot/workcell controller, capable of running 16 concurrent tasks, is CE Mark certified for sale throughout Europe, as well as ISO 10218 compliant. The unit is capable of powering cartesian, cylindrical, and SCARA robots. The SRC-310 comes standard with one 32-channel optically isolated digital I/O card.

Seiko Instruments USA Inc., Torrance, CA, USA, FAX 001 (310) 517-8158.

Power transmission products

Bison G line includes the 300 DC Series, which matches the parallel shaft gearbox with a continuous duty-rated 180V dc permanent magnet dc motor. The series is rated for torques up to 43.5 Nm, with gear ratios ranging from 5:1 to 245:1. The motors used on these units are rated for up to 0.12 kW.

Power Trans USA, Zeewolde, The Netherlands, FAX +31 36522-2071.

Enclosures are not a commodity product

Enclosures are not a commodity product

Rittal Corporation, established in 1982, is the U.S. daughter company of the world's largest enclosure manufacturer, Rittal-Werk, Germany.

Design News: Do enclosure products, taken as a whole, suffer an image problem?

Wagner: One of the most significant challenges we face as an enclosure manufacturer is countering the perception that our product is a commodity, a box. Unfortunately, this view is somewhat justified, especially in North America. Until the mid-80s, you could compare product catalogs with those going back to the 1950s and see there was literally no change. Some of that negative inertia still lingers.

Q: What changes have been made to alter this perception?

A: Rittal was the first company to introduce the modular approach to enclosure systems, enabling large production runs of standardized products easily modified to customer requirements. There has also been an increasing emphasis on not only the exterior sheet metal, but the enclosure's inside design--the packaging, shielding, and cooling of interior components. For example, a comprehensive chassis system for microprocessor control systems can be designed so that system components, climate control devices, accessories, and enclosure can literally be made for each other.

Q: To what degree is the enclosure manufacturer responsible for such functions as shielding or cooling?

A: Since an enclosure is the ultimate envelope for a final control system, the enclosure manufacturer should be responsible for protecting the system within. A customer does not benefit by integrating a cooling package into a PLC and then placing the unit into an enclosure. It makes more sense to fit the enclosure itself with a complete cooling system. The fact that we sell a fair amount of our climate control solutions to the end user, rather than to the OEM, indicates to me that this is an expertise of ours that design engineers need to be made more aware of.

Q: Has the trend towards bus-based centralized control affected the enclosure business within traditional manufacturing environments?

A: We have observed the tendency to reduce decentralized control logic-- first in Europe, and now the U.S.--with a certain amount of concern. While the trend towards intelligent bus structures and distributed I/O configurations improves efficiency and productivity for our customers, it also reduces the demand for large sheet metal cabinets.

Q: What opportunities do you see compensating for this situation?

A: While we see a slight drop-off in business within the traditional manufacturing sector over the next two to three years, there is strong growth in the electronic and computer peripheral industries. This growth can best be described as the upward migration of formerly simple PC systems into significantly more comprehensive and complex solutions that compete in the mini and mainframe marketplace.

Q: Why is this good for Rittal?

A: The reason this is a positive trend is because manufacturers of PC-based file server structures are known for quick innovation, quick turnaround. Companies like HP and Compaq have a much stronger tendency to utilize standard solutions that exist in the market, and adopt them to their own solution, rather than burden themselves with unnecessary mechanical engineering responsibilities. Additionally, these same companies are looking for manufacturers that can support their solutions on a global basis by offering availability in a just-in-time configuration, the ability to provide local content, as well as compliance with international approvals and certifications.

Q: How can Rittal help with international specifications?

A: Many customers come to us and ask if our enclosure is CE certified. However, the enclosure itself is only a part of the entire system. Our response is to ask, "What is it you wish to put in the enclosure? How is the system laid out?" Once we know the answers to these questions, we can evaluate how the system may be affected by CE regulations. Based on our international resources, Rittal can assist customers with their applications and questions regarding international certifications.

Q: Finally, where is the enclosure industry headed?

A: The emergence of data communications and telecommunications as distinct marketplaces presents us with substantial growth opportunity well into the future.

Dawn of the smart conveyor

Dawn of the smart conveyor

Janesville, WI--Anyone who has ever walked the floors of a large manufacturing operation has seen it: pallets, rolling down a conveyor line, then slamming into one another as they reach a mechanical stop. It's a crude method of material handling, but one that has satisfied manufacturing engineers for generations.

Giddings & Lewis engineer Paul Terpstra, however, wasn't satisfied with that status quo. Terpstra, who works for the company's Assembly Automation group in Janesville, WI, believed conventional conveyor stopping techniques were in-efficient. Increasingly, he noticed that they required considerable maintenance. "When you have that much weight banging into the stops all day long, you create a real maintenance headache," he observes.

Worse, conventional techniques required special clutching mechanisms, which sometimes seized up or needed adjustment. So Terpstra met with other Giddings & Lewis engineers and eventually devised a simple alternative--supplying each of the conveyor's rollers with its own electric drive motor.

Now known as the SmartConveyor, the concept offers users a multitude of advantages--some of which, even Terpstra hadn't foreseen. Because each motor drives a single roller, instead of a team of rollers, it eliminates clutches, belts, and drive chains. As a result, it vastly simplifies maintenance and improves uptime.

It also uses far less energy. When all of the motors are networked to a programmable logic controller, the conveyor operates like a giant inchworm, engaging only those motors in the vicinity of the load, then pushing it forward. In the meantime, the other rollers and their motors lie idle. In tests, the concept has reduced energy use from 25% to 75%. "By transferring power directly from the motor to the roller, you gain efficiency," Terpstra says.

The SmartConveyor concept requires few components: specially designed torque motors and gearheads; drive rollers; proximity switches; a programmable controller; and custom-built "motor blocks." Used in conjunction with networking protocols, such as DeviceNet, it also requires a network cable between motor blocks.

How it works. During operation, SmartConveyor's proximity switches sense the position of the load, then communicate with the controller. The controller activates motors in the area of the load and the rollers push it forward. Afterwards, the rollers stop and a new set of motors is engaged.

Giddings & Lewis engineers designed the system to accurately stop loads, as well as convey them. To accomplish that, SmartConveyor reverses its rollers, thus imparting a stopping force to the load. "If we merely shut off the power to each motor, the pallet will coast, instead of stopping" Terpstra explains. "But by reversing the motors, we can decelerate the pallet and stop it repeatably."

Among the keys to the success of the system were Giddings & Lewis' work with two suppliers: Bodine Electric, Chicago, IL, which provided the torque motors; and Turck, Inc., Plymouth, MN. Early on, Giddings & Lewis engineers teamed with Bodine to develop a motor and gearhead for the project. The engineering team wanted a motor that could operate in a stall condition for prolonged periods while not in use. Bodine provided a torque motor rated at 10 lb-inches for the application, then built a special gearhead, enabling the rollers to operate at a slower speed.

Working with Turck's engineers, Giddings & Lewis also selected a special square proximity switch, Turck's Q26. The Q26's square shape and relatively long sensing distance (about 10 mm) made it a desirable choice for the application, Terpstra says. "The square prox switch mounts right up against the side rail of the SmartConveyor and doesn't need adjustment," he says. "Conventional cylindrical switches would have required a height adjustment."

Turck engineers also designed the motor block, a sealed aluminum housing that contains eight receptacles for the plug-in connection of the motor, proximity switches, and DeviceNet cable. Each straight section of SmartConveyor "track" uses two motor blocks. By communicating with the PLC, the motor blocks help monitor the performance of the motor and prox switches. If, for example, a motor short circuits, the controller knows it immediately.

The SmartConveyor has been used extensively for trimming of engines at General Motors' Flint, MI, V-8 engine plant. Engineers there say that it has dramatically reduced maintenance time and improved throughput by as much as 10%. Similarly, engineers at Ford operated a SmartConveyor test loop for more than a million cycles, saying that it achieved an operating uptime of 99.6%. "Few conveyor lines of any kind have uptimes that high," notes Ken Smerecki, a production superintendent for Ford who was involved in testing the system.

Though Giddings & Lewis plans continued improvement of the system, its engineers say it has met its initial goals. It also minimized part count, simplified the drive train, and reduced downtime. Says Terpstra: "It has already exceeded all of our expectations."

Sensors scout the factory floor

..If an army of electromechanical components constitutes an assembly line or network of manufacturing cells, sensors serve as the advance guard. Constantly on the lookout for indicators critical to the manufacturing process, sensors provide a winning edge in the battle to build things faster, cheaper, better. The following are some of this year's new recruits.
John Lewis, New Technology Editor and David J. Bak, Executive Editor

Proximity sensor stands up to weld slag

Known for their rough environments, welding applications present proximity sensors with a variety of challenges. Allen-Bradley engineers designed the VersaCubeTM inductive proximity sensor with hassles, such as weld-slag build up and weld-field interference, in mind.

Welding applications typically require protective-boot changes every few weeks, increasing downtime and decreasing productivity, according to Kimber Lynn Drake, senior product marketing engineer for Allen-Bradley. "Our proprietary polymer housing material resists weld slag buildup on the sensor enclosure. Boots are disposed of entirely because most weld slag bounces off. Any sticking slag easily wipes away."

In addition, the sensor's internal electronic design alleviates affects from weld-field interference, short-circuits, overload, fast transients, and radio-frequency interference. A patented adjustable-mounting base lets users rotate the sensor head to any of five sensing positions, and helps users limit various sensor styles from their inventory. Multiple-mounting hole patterns simplify retrofits on existing equipment.

Measuring 40 x 40 x 65 mm, the VersaCube offers a sensing range up to 15 mm. Allen-Bradley engineers designed adjustable mini and micro connectors on the VersaCube that enable right-angle mating cables to rotate to almost any position. A rugged die-cast base offers durability, and over-molded grommets, fused to the cable, provide superior cable-strain relief.

U.S. contact: Performark, Tel: (612) 946-7330, FAX: (612) 942-6940, E-mail

European contact: Rockwell Automation/Sprecher + Schuh, Tel: +41-62-837-2121, FAX: +41-62-837-2903.

Sensor exploits single-channel processing

Aromat Corp.'s LM-10 micro-laser sensor is targeted to meet an OEM's growing need for small, cost-effective sensors. Its single-channel processing method (patent pending) employs a single chip to do the work formerly done by two dedicated circuit paths. This reduces size, number of components, cost and weight. Sensor applications include: thickness measurement in paper, lumber, film, and gypsum manufacturing, and electronic applications for board warpage detection.

To maintain a consistent and defined light beam, the LED projects through a transmitter lens. Focused light hits the target's surface, scattering the beam. Some diffused light enters the receiver lens, and is refocused on a position-sensitive diode (PSD).

If the distance to the target changes, so does the position of the refocused spot on the PSD. The LM-10 reads the spot's position, and, using a triangulation method, converts the analog signal to a digital output proportional to the distance from the sensor's face. The 35- x 96- x 55-mm sensor offers three response frequencies: 10Hz, 100Hz, and 1kHz, and provides resolution to 5mu.

U.S. contact: Aromat Corp., Tel: 908/464-3550, Ext. 2086

European contact: Tel: +49-08024-648-0

Pre-programmed sensor detects 5mu movements

Providing resolution to 5mu, Omron Electronics Inc.'s new Z4D-F micro-displacement sensor has a built-in microprocessor. It's available in both analog and digital versions for applications such as presence/absence detection of small parts or solder points, double-feed detection in printers and copiers, and vibration detection.

Integrating the analog output version with Omron's K3TX intelligent signal processors allows digital outputs for monitoring applications. "This scheme is good for applications that have several thresholds requiring voltage variation verification," says Omron's product marketing specialist Nazario Biala.

The Z4D-F04A analog model includes a power alarm indicator that immediately identifies sensing problems. And the Z4D-F04D digital version with ON/OFF output includes a stability/operation indicator and a distance adjuster for precision sensing. It uses a 12- to 24-Vdc plus or minus 10% supply voltage, 10-mV ripple voltage, 35-mA current consumption, and has a 1.5-mm spot diameter at a 4-mm sensing range. Cost: $285.

U.S. and European contact: Omron Electronics Inc., Tel: 314/281-2129, FAX: 314/281-1517

Beam power doubled

.Despite availability of one-touch automatic calibration, many users of fiber-optic sensors prefer trimmer pot designs. Why? Stable detection and the ability to make slight changes in sensitivity.

Keyence Corp.'s FS-M Series FO amplifier gives operators another reason: improved trimmer linearity at longer detecting distances. For example, operating in the FINE mode (standard power) with a Model FU-4F Fiber Unit, the FS-M amplifier obtains specified trimmer linearity to distances of 100 mm. Switching to the TURBO mode (high power) extends that detecting distance to 200 mm.

Three components make this possible: a high-intensity LED, an extra-sensitive photodiode, and proprietary circuitry the company calls "Super EX." Other FS-M features include:

High-speed response. In the FINE mode, 250 microseconds; 500 microseconds, TURBO.

  • Interference prevention. As many as eight units can operate side-by-side.

  • Eight-turn trimmer. "Super EX" circuit ensures linearity between detecting distance and number of trimmer turns, even in TURBO mode.

U.S. contact: Keyence Corporation of America, Tel: 201-930-1400, FAX: 201-930-0088.

European contacts: Keyence United Kingdom, Tel: +44 1908-696900, FAX: +44 1908 6967777.

Keyence Germany: Tel: +39 711 796061, FAX: +39 711 797799

Relative humidity measured

When placed in an air path, the ERH 300 from Elmwood Sensors detects changes in relative humidity--within seconds, without drift. A combination of material and construction accomplishes this measurement task.

The ERH 300 Series Sensor operates by generating a resistive output as a proprietary doping material on the surface of the base alumina absorbs moisture. Output impedance of the thick film changes according to the amount of water vapor present.

Unlike polymer-based humidity sensors, the ceramic-based design does not lose accuracy over time, eliminating the need for recalibration. In addition, it will not clog, and is unaffected by temperature and most gases--the cause for delamination of some polymer-based sensors.

U.S. contact: Elmwood Sensors Inc., Tel: 401-727-1300, FAX: 401-728-5390. 2 European contact: Elmwood Sensors Ltd., Tel: +44 191-258-2821, FAX: +44 191-258-7040

Pressure sensor spurns hostile media

Glass fusing a micro-machined, silicon strain gage to a stainless-steel diaphragm makes this piezo-resistive pressure sensor virtually impervious to most hostile media environments, both physical and electrical. The latter includes radio frequency interference (RFI), electromagnetic interference (EMI), as well as electrical transient problems.

Developed by Measurement Specialties, Inc., the MSP 400 features a diaphragm and pressure port machined from a single piece of high-strength stainless steel. The absence of O-rings, internal welds, or silicone oil-filled cavities means corrosion-, shock-, vibration-, and leak-proof operation. Input pressure simply deflects the diaphragm to generate a directly-proportional change in electrical output.

Good for liquids or gases, the MSP 400 is offered in several pressure ranges from 0-100 psi (7 bar) to 0-10,000 psi (700 bar). Output signal levels of 0.5 to 4.5 VDC (ratiometric), 1.0 to 5.0 VDC (fixed), and 4 to 20 mA (two-wire) are available.

U.S. and European contact: Measurement Specialities Inc., Tel: 201-808-1819, FAX: 201-808-1787.

Hot Spots in Cyberspace

Hot Spots in Cyberspace

Search for patents

Want to find out if there is a patent for an apparatus to generate noise for an electric car? Then head to the new IBM U.S. Patent Search Web Site ( Do a search by typing in "electric car," and you'll get seven hits including Patent 5517173 issued in 1996. The abstract includes in-ventors, assignees, a brief abstract, any references, and claims. Order a copy of the patent right online. The site also offers more than 2 million patents from 1971 through 1996 and full images of nearly 1 million U.S. patents issued since 1987. IBM will be adding images from 1974 to 1986 during 1997. To keep you coming back for more,the site features a Gallery of Obscure Patents that changes on a regular basis.

Autodesk site introduces PartSpec and DesignBlocks

While visiting the Autodesk site( you can browse PartSpec online. There you can review 400,000 predrawn parts and 35,000 materials. You have to download Autodesk's WHIP!TM Plug-In, which enables you to view the PartSpec Online parts drawings stored in Auto-desk's new DWF (drawing web file) format. The plug-in works with Net-scape Navigator 3.0. While on the site, check out the new Design-BlocksTM. The CD-ROM subscription gives you product drawings, details, images, specifications, and technical and performance data.

Job listings for CAD/CAM

Here are several sites where you can shop around your computer-aided-engineering skills. For Pro/Engineer-related job listings, check out And Unigraphics users can visit

Plug into AutoPilot

AutoPilot, sponsored by Reynolds Metals Company (, lets you view a generic 3-D car and select aluminum parts for detailed information. You need Netscape Nav-igator 2.0 and Mac-romedia's Shockwave (downloadable).

Balluff now online

Search the latest product information, distributors, and catalog at Balluff's web site ( Balluff offers sensors for automation. Future plans for the site include enabling users to download technical data sheets in CAD format.

Stay up-to-date with Rapid Prototyping home page

Updated on a weekly basis, the Rapid Prototyping Home Page ( offers listingsof commercial systems, consultants and commercial service providers, research, literature, conferences, and unusual applications and technologies. A couple of must-see sites are the Rapid Prototyping System Selector 3.0 to match the RP system with your needs and a 3-D print-ing process being developed at MIT.

New at

What's the most important tool you use to do your job? Got an impossible problem and need input? Got a beef that you want to get off your chest?Is it easier/faster/more fun collaborating, or is working alone better?How are you ensuring job security?

These are some of the topics available in the Design News discussion forums. Just click on the forums button on the home page and scan through the topics. You may even want to add one of your own. If nothing else, you'll know you're not alone in the design engineering field.

Hot link: Virtual reality gets real

Want to see the latest in the world of virtual reality? Then check out and the top 40 sites of VRML on the Internet. The 10 science and engineering sites include a lunar landing, the physics of sound, and an autogenerated tetrahedron. The sites look best using at least Netscape 3, and you'll have to download VRML 2.0 Browser to view. A little patience is also necessary because it takes a couple of minutes to load the images. Anyone thinking about VRML modeling should look at these sites first to view the technology.

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Engineering News

Engineering News

Manufacturers tout new motor technologies

Munich, Germany--Electric motors have undergone more change in the last ten years than the previous hundred. This is particularly true with ac induction motors. For example, users today can specify vector or inverter drives, as well as the convergence of both systems: sensorless vector control. Other emerging technologies include soft switching techniques and transient-resistant windings.

Computer models take over. Sensorless vector control blurs the distinction between inverter and vector drives. While open-loop inverters are relatively inexpensive, there is no method of feedback from the motor to allow