Wild Heerbrugg: Quality and Innovation
Professional Surveyor Magazine - Nov/Dec 1997
Marc Cheves, LS
Nestled in the northeast corner of Switzerland, in a broad valley where the Rhine River exits the Alps, sits the home of one of the most well known names in surveying instrumentation, Wild Heerbrugg. Wild instruments have been used on every continent and on virtually every type of project involving surveying. Even though Wild has been around since it was founded by Heinrich Wild in 1921, and celebrated its 75th anniversary in 1996, the Wild name has been phased out over time. This was a strategic move on the part of the company to rename itself—the corporate name chosen was Leica—to better reflect the quality of its surveying, microscope and camera products. Here's how it happened: In 1986, Wild Heerbrugg purchased Leitz Wetzlar, a German optics company, with the resulting name Wild Leitz. Leica was the camera division of Leitz and, in fact, the name reflects that association: LEI(tz) CA(mera). Wild Leitz purchased Kern Swiss (another name familiar to surveyors) in 1989. And in 1990 Wild Leitz merged with Cambridge Instruments, an English microscope and optics company started by Charles Darwin's son. As a result of these many business acquisitions by Wild, the company chose to use the name Leica to denote the quality of its many products.
I recently traveled to Heerbrugg for a tour of the factory and spent two days learning that even though the familiar name no longer exists, the famous innovation and quality is very much alive. I was given the opportunity to meet with the product managers for many Leica surveying products. I first met with Dr. Erwin Frei, the general manager of the geodesy business area, who gave me an introduction to the current Leica philosophy. In the past, he said, the approach was to develop new products without sufficient end-user input, but the firm now realizes that each customer is different and has different needs and expectations. To achieve both a local and global touch, Leica relies on software customization to build platforms capable of meeting customers' needs. Dr. Frei mentioned that positioning is a demanding market, and that it is sometimes difficult to communicate quality. More important, he acknowledged that ease-of-use and productivity are not always the same. He echoed the often-heard statement that surveyors can no longer be only involved in data acquisition, but rather must become data managers, specializing in information management. I inquired about surveying in Switzerland, and he said that government regulation has resulted in decreased innovation and a reduction in the amount of competition for cadastral work.
Experienced Tour Guides
After Dr. Frei's introduction to the Leica philosophy, I was given a tour of the production facilities for total stations, digital levels and laser products. My tour included first-hand examples of the world-renowned Swiss manufacturing expertise. Tour guides Karl Zeiske and Alexander Potocnik have each worked for Wild for over 30 years, and served as excellent sources of information not only about Wild but about surveying in general. Zeiske, a professional surveyor with a master's degree, is originally from Berlin, and Potocnik, a master mechanic in the production area, is from South Africa.
The first area we visited was the total station production facility. The cubicles where the initial assembly of the instruments takes place are controlled both for air quality and static electricity. Attention to every detail includes a special machine and process that automatically checks the optics for cleanliness. Each cubicle is a marvel of efficiency, with stacks of lazy-susans for parts. The composite standard-covers are silvery on the inside due to an aluminum coating that prevents stray electronic emissions from interfering with the operation of the instrument. Composite parts are bought from suppliers, and have to meet a tolerance of ±0.2mm. Mechanical parts like the vertical axis have to meet a tolerance of ±0.001mm. Circuit boards are also out-sourced, but board components are installed and assembled in Heerbrugg. One supplier provides all the screws, and all materials are received in what the Swiss call a "pulling" system, or what we would call "just-in-time."
The workforce is not unionized. Each section of the factory has several bulletin boards filled with charts and graphs that plot not only department, division and overall financial performance, but the progress toward achieving quality goals as well. The proximity of such information to the work stations allows each employee to readily determine company performance. Another philosophy that ensures success is the policy of job rotation. Teams are established for each type of equipment. With the skills achieved by rotation, each team member can not only perform the tasks of the other team members, but also work on digital levels or laser equipment, or whatever else is needed. This flexibility serves to prevent layoffs and enhances the company's ability to meet unusual demands.
New Skills Required for Technicians
The total stations are built 20 at a time. An innovative computer program with an automatic QA/QC protocol guides the process and keeps a record of the results of each test. A technician cannot skip a test. While this might seem a bit mistrustful, it actually makes the technicians' jobs easier by guiding them and ensuring that no crucial steps are omitted. As we stood watching a technician run an instrument through the process, Zeiske pointed out the window to a old target array on a hillside across the street, and reminisced about the opto-mechanical days when quality depended more on a technician's eye for assembly and calibration. While sophisticated testing and calibration electronics such as autocollimators and computer-driven assembly processes have changed the technicians' jobs in some respects, the complexity and capability of modern total stations require different skills and knowledge. Figure 1 shows a technician testing and calibrating a total station.
The process takes each instrument through many steps, including a specially designed machine that subjects an instrument to vibration, shaking, and even violent shocks such as would be received by dropping. This step removes tension and backlash, then the instrument is re-calibrated. Newly assembled instruments are placed in an oven for four hours at 123ºF, again to remove tension. Another test in a special environmental chamber checks each instrument for collimation, EDM functionality and overall operation, first at room temperature, next at -4ºF, then at 123ºF and finally again at room temperature.
A new state-of-the-art assembly and calibration facility for TPS1000 instruments features a unique "racetrack" that moves each instrument through the process (see Figure 2). Barely visible in the top center portion of Figure 2 is an in-line shaking and vibration station that accomplishes the same things mentioned above. Each instrument is built by a team. Team leaders are elected by the team members.
Patent Changed Optical Instruments
Our next stop was a room housing a specially designed machine for testing and certifying instruments. Some users, mostly governments, require certification, depending upon the use of the instrument. The Theodolitprüfmaschine (theodolite proofing machine), or TPM, checks instruments for eccentricity. For me to understand this machine, Zeiske had to educate me about modern total stations.
As early as the 17th century, instrument makers recognized that systematic errors result from imperfections in circle graduations. In 1907, Heinrich Wild patented the ingenious idea of using optical means to obtain coincidence from two diametrically opposed circle readings. This angle-reading method determines the mean of the circle readings, and was used until electronic total stations were invented.
In 1983, Wild came out with the T2000, which was a radical departure from the opto-mechanical instruments of the past. The T2000 incorporated a dynamic electronic angle-sensing mechanism that dramatically increased angular accuracy. The horizontal and vertical circles are made of glass imprinted with 1,024 sectors. The sectors alternate between black and clear, and light-emitting diodes are used to shine a light through the circle. Contrary to what seems to make sense opto-mechanically, the circles are driven by motors, and onboard circuitry receives commands from sensors mounted at eight points around the circle (four to send and four to receive). A processor keeps track of the zero-backsight position of the circle, then displays the resultant angle based on where the instrument is pointed. By removing the errors caused by imprecise circle graduations, this technology provides extremely accurate angles. It eliminates one of the most common error sources, that being the reading (and estimating) of angles by eye. It also eliminates the need to advance the circle when observing multiple sets of angles for very precise work. The T2000 helped open the door to the use of electronic data collectors. Data collectors eliminate another common source of error, writing information incorrectly in a field book.
When Wild came out with the T1000 and T1600 instruments, they needed a way to test the angle measurement systems. The Leica system described above is considered to be an absolute system as opposed to an incremental system, which requires initialization before each measurement. In contrast to the T2000, the circles in the T1000 series are static, and are not diametrically scanned. As a result, mechanical eccentricity can cause systematic errors unless corrected. Software can correct for these errors, but only if they are known. Each instrument, after assembly, has a unique amount of eccentricity, and that's where the TPM comes in. Previously, optical instruments were tested by using a rotatable base to advance the circle. Since the absolute encoding system eliminates graduation errors, Wild needed a method of testing that did not involve rotating the base. What they came up with is essentially an instrument-within-an-instrument, whereby a special T2000 is used as an extremely precise (±0.3") reference against which other instruments are compared. The TPM is completely automatic, and once the instrument is placed on the tribrach, it runs the instrument through a 45-minute series of horizontal and vertical tests, then prints out a certificate.
Fully Automated EDM Testing Area
We next visited the EDM testing area (see Figure 3). Using standards traceable to the Swiss Bureau of Standards, the sophisticated facility is fully automated. Once the instrument is installed and its serial number entered, a computer operates a series of prisms to check a wide range of distances. In figure 3, note that the second prism is in its "swung-out" position. By sequentially swinging each prism in and out, each distance is systematically checked to an accuracy of better than ±0.5mm and recorded, along with all the other testing and calibration information for that instrument. It was quite something to watch as the prisms automatically swung in and out. Distances to 120m are checked using this facility, and I found it interesting that the instruments are randomly tested. That is, the cart holding the instruments to be tested holds a mix of every instrument being manufactured, not just, for instance, TPS1000 instruments. The testing scheme fully exercises the testing equipment, putting it through its full range of motion.
Zeiske and Potocnik next took to me to the lens manufacturing part of the factory. Leica uses over 450 types of glass in their instruments, microscopes and cameras. Each type of glass has different properties, depending on its intended use. The smallest lens Leica manufactures is 0.6mm in diameter for use in endoscopes. Endoscopes are tiny instruments used by doctors to view internal organs by inserting the lenses into the body through small incisions. Previous to the invention of endoscopy, large incisions were necessary to allow surgeons to see directly into the body. Optical glass is manufactured in giant ceramic crocks that take two years to cool down at 1ºC per day! The slow cooling process prevents the glass block from fracturing. Potocnik said that because the manufacturing process has such a long lead time, glass consumers have to order very carefully because, once a particular glass is out of stock, it is unobtainable until more is made. Leica manufactures 16 different aerial photogrammetry lenses, each with different properties. Both Zeiske and Potocnik chuckled as we viewed lenses being ground (see Figure 4) because the grinding technology we were watching is hundreds of years old.
We next toured the machining facility and observed the vaunted Swiss manufacturing expertise. I was shown a series of fully automated machining stations that are truly a marvel of modern technology. The five machines accept metal castings from a conveyor belt, and each can automatically select from either 50 or 100 different tool and die bits. These incredibly sophisticated machines use a combination of servo-driven, sensor-driven and ultrasound techniques to sense the 3D position of the casting. The tools drill holes, cut openings and otherwise check tolerances and automatically prepare the castings for the assembly process. Zeiske informed me that the machines cost five million Swiss Francs, which, at the time of purchase, was around $4 million. As an extreme example of productivity gain, they showed me a machine for cleaning castings and removing burrs that does in 20 minutes what used to take 50 people working full-time.
The next phase of my visit involved meeting with the production heads of the various instrument departments. My first meeting was with Dr. Gerhard Bayer, who heads the automatic target recognition (ATR) section. Dr. Bayer explained the ATR concept, and I learned that Leica's approach places a CCD camera inside the telescope to detect the target. Although operating superbly for stationary targets—including geodetic uses—and for moving targets within 500m, it is still being refined for rapidly moving distant targets such as those found in some types of hydrographic surveying. I subsequently learned from Al Pepling (whose review of the ATR can be found on page 46) that he believes for survey uses, the current tracking ability will more than meet our needs. Dr. Bayer indicated that Leica is looking for better-than-centimeter-level accuracy for moving targets. He also said Leica sees a large potential market for ATR in machine-control such as paving machines.
Innovative Manager Rotation Policy
I next received a briefing from product manager Clement Woon, who is responsible for total stations ranging from the TC400N to the TC905. Woon, from Singapore, is on a two-year assignment to Heerbrugg. This innovative policy, used extensively by Leica, allows it to benefit from worldwide experience by "cross-pollinating" managers. Another Leica employee that many Wild customers might know is Chuck Lee. Chuck has worked in tech support out of the Atlanta office for many years, and just began a two-year rotation to Heerbrugg. The picture of the World's Largest Tripod and Instrument (see Figure 5) was taken from Chuck's window at the factory. The picture, because it was taken looking down, does not do justice to the immensity of the local landmark. The HI of the instrument, installed in 1982, is close to seven meters! Chuck e-mailed an interesting story: "The tripod is fully functional. The legs telescope and collapse and the T1010 instrument can be removed. I don't have any information about the tribrach, though. A few months ago there was a big apprentices' competition in St. Gallen [Switzerland]. The tripod and instrument were taken down (with a crane on the truck) and hauled to St. Gallen, where they were set up outside one of the exhibit halls for the duration. (That's how I know the tripod is functional—it had to be to fit into the truck. Un-telescoped, the legs must be close to 7.5 meters long … and they are only half extended!)"
Woon discussed three of the latest total stations, the TC605, TC805 and TC905. The 5", 3" and 2" instruments are available with a laser plummet, as are the TPS1000 series total stations. The laser plummet, mounted in the vertical axis and not the tribrach, provides many benefits over traditional optical plummets, including the ability to check a setup-over-a-point by simply spinning the instrument. Surveyors know that one of the greatest single sources of error is in plummet mis-adjustment. Under excellent conditions, the TC605 will shoot 1,300m to a single prism at ±3mm+3ppm in less than four seconds, and both the TC805 and the TC905 will shoot 2,500m to a single at ±2mm+2ppm in under three seconds. The instruments are economical, easy to use, and provide a wide variety of input/output formats. Leica's DIOR 3002S reflectorless EDM uses a timed-pulse for distance measuring as opposed to the more conventional phase measurement. Pulse measurements are quicker and shoot farther. The DIOR 3002S uses a Class 2 laser. Leica's other time-pulsed EDM, the DI 3000S, uses a class 1 laser.
In Leica's digital level section—where the industry's first digital level was developed—I met with Holger Schade and Felix Schneider. They discussed the newest version, the NA3003 Ver. 3.2. Now available are magnetically damped compensators, which are better than the conventional pneumatically damped ones. The pneumatic option is still available. The first- (NA3003) and second-order (NA2002) levels can achieve a 50 percent increase in productivity and eliminate rod-reading errors and transcription errors. Digital levels operate by comparing a known barcode stored in the instrument with the image gathered by a detector-diode array—much like a CCD camera—inside the instrument. The instruments, which store the data on removable memory in a published ASCII format, provide a variety of leveling routines, including mean and median functions, which help to eliminate systematic error. Because they also gather distances, the levels work well with least-squares adjustments which require distances between shots in addition to differences in elevation.
Erich Baumann is in charge of Leica's SW Fieldlink laptop computing and mapping tool. Running Leica's LISCAD software, the laptop can be combined with a variety of sensors to provide both thematic and survey mapping. I stood at a window with Baumann and used a pair of Leica's Vector binoculars to gather shots on the hillside across the street. The binoculars combine azimuth and laser distance to rapidly gather GIS-quality data. With a few button-pushes, we quickly converted the shots into a contour map. We now have come full circle to the electronic planetable. As shots are made, lines, symbols and contours can be created, thereby allowing the data gatherer to field-check the data before returning to the office.
Laser Instrument Has Many Uses
My final meeting was with Josef Strasser, who heads up the Leica DISTO laser measuring instrument section. First introduced in 1993, the DISTO can be used for a variety of measuring tasks and is more useful because it emits a narrow, visible red beam as opposed to the ultra-wide, invisible beam used by ultrasound devices. Well-suited for interior measurements, the unit can also be fitted with a eyepiece and used to measure wire heights. Three models are available: The first, the DISTO Basic, is accurate to ±5mm and will shoot from one foot to 100 feet without a target. With a target, it will shoot to 300 feet. A unique diagonal base and 90º swivel foot enables the user to stick it into a corner, square it up to a surface or stand it on the floor. A great deal of sophistication has been added, such as the ability to add or subtract a thickness to each measurement. Areas can be computed and added or subtracted from a series of measurements. It has a 10-60 second timer. It uses a Class 2 laser, is priced 15-25 percent less than the original DISTO, and shoots much faster. The DATA DISTO RS232 can be hooked up to any computer capable of supporting RS232 data exchange. The DATA DISTO GSI can be mounted on an electronic theodolite, combining non-contact measurement with accurate angles. The POWER DISTO uses a Class 3A laser and will shoot to 60m, or 140m with a target.
The Death Of An Old Friend
I finished my visit by discussing the venerable Wild T2 with Zeiske. Many surveyors "cut their teeth" on Wild instruments, and for many years a Wild T2 was synonymous with precise work. In fact, many government agencies contracted for work that specified particular angular accuracies, and even though the contracting officers didn't really understand the specification, they knew that a T2 would meet the spec. In my own career, I started with a T16, moved to a T2 in the Army, and returned to a T1 after my tour of duty. Zeiske said the last T2 was manufactured in May of 1996, after a production run of almost 100,000 that started in 1923. We agreed that it was almost like watching an old friend die, but he noted that because of the T2's reliability and stability, they are still in use, most notably in third-world countries. He also noted that, in keeping with the trend of faster and smaller, demand for add-on EDMs is fading. As you can see by examining the sidebar on the next page, Wild has been responsible for many innovations and inventions over the years. There is no sign that this will stop. Those of us who started our careers with Wild will be able to continue with Leica for many years to come.
About the Author
Marc Cheves, LSMarc Cheves was a former editor of the magazine.
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