|Martin Säger, survey engineer at Wolz Nautic: The measurement of the templates clearly saved time.|
Brothers Michael and Andreas Wolz manufactured 5,000 teak boat decks last year, a hand-crafted product with high requirements for quality. Their business, Wolz Nautic, employs 200 people and offers custom-designed and handcrafted decks for customers who expect absolute accuracy and attention to detail for their boats.
Each joint must resemble the other, and the deck’s exterior must be parallel to the glass-fiber reinforced plastic (GRP) on the vessels side. Orders for this deck speciality come from all over Europe. Most of the work is accomplished at the brothers’ workshops in Gaukönigshofen, Germany, but Wolz Nautic employees travel to the respective shipyard at least twice during a project run.
Templates from plywood, which are adapted accurately to the boat, are created during the first on-site appointment. The templates are premilled, based on CAD data of the boat, but the fine tuning must be completed locally because the CAD data usually require precise matching against the actual dimensions of the boat.
The templates are then measured again in the workshops of Wolz Nautic. The teak deck is manufactured in the production hall based on these measurements. The aim is to produce the deck in one piece whenever possible. “Each splice is bad for the visual appearance,” explains Michael Wolz, one of the two managing directors at Wolz. “Therefore we divide the teak deck into as few parts as possible.” The individual components are up to 13.5 m long, which is the maximum size for transporting by truck back to the shipyard. During the second visit to the shipyard, assembly errors such as bubbles and delays on the teak deck are avoided with the help of patented procedures. According to Wolz, these procedures keep complaint ratios from customers extremely low, something quite unusual for the teak-decks industry.
Individual deck components must have an exact accuracy over the deck’s entire length. A difference of two or three millimeters is acceptable, although the brothers aim for less than a millimeter. “With metal this default would not be acceptable, but for wood an accuracy of less than a millimeter is a very demanding resolution,” says Wolz. In addition, the bends must correspond exactly to the original surface, which represents a challenge with wood. For this reason all templates are transported back to the shipyard, even those with errors. Because they react to environmental influences such as humidity and temperature, the templates can falsify the measured values.
Wolz Nautic decided to look for a precise measurement system that could be used instead of the templates to minimize inaccuracy due to the material and also prevent errors. The template procedure is also time-consuming because they must be carefully machined with drills. It takes about one week for the templates to be manufactured and fitted to the boat, another good reason is to replace this traditional procedure. The company wanted a measurement system that could operate flexibly on the boat and that could also measure the deck’s length and transverse curvature to the required accuracy. After a detailed test phase, the API laser tracker was selected. The deciding factors for using the laser tracker were its accuracy and transportability since it is so lightweight.
The laser tracker has been in use at Wolz Nautic since September 2006. To familiarize themselves with the technology and the possibilities of this measurement system, employees continue to premeasure the templates during the early stages. For this production step alone, the company has achieved a time-savings of 60 percent to 70 percent. The laser tracker is used to remove the mass from the boat; the adapted templates are used parallel to the tracker. The laser tracker demonstrates its full capabilities even in the restrained space available on the boat. Larger objects can be measured from the shortest distance. The head of the laser tracker can be swivelled horizontally +/- to 320° and vertically from 80° to 60°, so that the measurement system can be positioned near to the place that needs to be measured.
The 3-D measurement system then calculates the coordinates over both angles. Even several position changes are not an issue, given the laser tracker’s weight of 8.5 kg and head size of 36 cm. The laser tracker’s head system is constructed in such a way that the laser beam is not diverted by a mirror or a light conductor. Systemic measurement inaccuracies due to returning errors are reduced thereby to a minimum. Wolz Natic is particularly pleased with the laser tracker’s compact size and measurement range of 120 m.
Michael Wolz says he is very happy with the laser tracker. “The investment was worthwhile because the measurement system fits our needs. It is portable, rugged, and precise.” Using the laser tracker directly in the shipyards meant an enormous gain in time for Wolz Nautic. In the often chaotic environment of a shipyard, every day of labor that the laser tracker saved has proved extremely valuable for Wolz Nautic. In the past, the craftsmen had to work right up to the project deadline, and delays could be costly. Now within six weeks after the incoming order, a teak deck can be finished to a customer’s satisfaction.
Wolz’s goal is to build in more free time between individual project steps so that the company can work on different projects simultaneously when required, thus saving money and improving efficiency. The possibility of being able to work more flexibly and efficiently using the laser tracker has been a boon for Wolz Nautic.
One reason for the laser tracker’s success at Wolz Nautic has been API’s cooperation. “To buy high-class technology does not automatically mean high-class service,” notes Wolz. “We are, however, completely satisfied with the aftersales service at API.”
If questions or problems arise, Wolz Nautic can rely on API’s telephone hotline. This permanent customer service is an example of the increasing operational level of readiness of API in Europe. During the last 20 years, API has concentrated on developing technology and assigned marketing licenses. In the future, marketing will be be expanded.