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White-Light Interferometry Inspects Pump Components
Heavy duty pumps have to achieve higher and higher performances and are often designed for a pressure of 400 bar and more. If they reach the expected performance depends heavily on the components that are used. Since these components are mainly produced in huge quantities an inspecting system is required that operates precisely and economically. These demands are fulfilled by the white-light interferometer: Within a very short time, it examines the components in regard to form and roughness.
Workpiece surfaces are characterized by several parameters, like flatness, roughness, edges, bearing angle (cone) and roundings. To measure these characteristics with traditional methods, like tactile measurement instruments, is work-intensive and costs a lot of time. The non-contact white-light interferometry is an alternative which is suited best for inline inspection tasks. A major advantage is that samples can have several features automatically tested with one measurement instrument and in only one fixture. In this way, time-consuming sample transfers and fixing procedures are avoided. By using directly the fixture or the transport fixing device for other production processes, the sample table must have a travel of 15 cm or more.
The NewView Technology
For more than 30 years the test equipment manufacturer Zygolot, Darmstadt, Germany, has been engaged with optical metrology, above all with the applications of the white-light interferometry. The NewView measurement technology developed by Zygolot uses white-light interferometry and has become generally accepted for industrial application since the year 2000. Today, about 3,000 NewView instruments are applied in industry worldwide. Many of them are working 24 hours every day seven days each week. In numerous industries where small precision parts are manufactured or required, such as in mechanical engineering, medical technology and other industry branches, the NewView instruments are considered as reference instruments for surface profiling. The white-light interferometer NewView 7300 can be flexibly applied for universal testing tasks. It can automatically realize, analyze, report and document graphically several different measurements.
Precision Parts for Heavy Duty Pumps
The measurement instrument NewView 7300 can be installed right next to a machine, for example a grinding machine.
The operator inspects continuously the quality of the grinded parts - and thus the quality of the manufacturing process. If necessary, he can intervene in the manufacturing process and correct the manufacturing parameters avoiding in this way the production of expensive scrap. Having replaced or adjusted tools, the operator can also examine rapidly whether the machine works in a correct manner or not.
One example for the application of the measurement instrument NewView 7300 is the examination of parts which are used in heavy duty pumps. Such pumps are used in fluid systems, e.g. for the fuel delivery, or hydraulic systems, where they convert mechanical energy into hydraulic energy and transmit it. These systems can be found in industrially used machines and plants as well as in construction engines, passenger cars and utility vehicles. Heavy duty pumps have to achieve higher and higher performances and are often designed for a pressure of 400 bar and more. The proper function of such a pump and the safety of humans and significant material assets depend on the condition of the pump components - above all the pressurized ones. Certain of these components have areas which are set back; upper and lower areas must be parallel to one other. These parts with a diameter of 60-80 mm are manufactured in large volumes of 100,000 and more each month and must adhere to high precision reuirements regarding their form (flatness < 5 µm) and structure (roughness < 1 µm). These characteristics have to be controlled at 100%. In the industrial practice these parts are measured in a transport fixing, which can accept 100 parts. Besides performing a 100% inspection, it is also possible to test automatically each n-th part. Besides various engine components and valves, also components for semiconductor technology, optical lenses of all kinds, components for photovoltaics, components of microlaser systems as well as medical implants and other components for medical technology are typical parts whose surfaces can be tested with the measurement instrument NewView 7300.
Various Measurement Applications
The white-light interferometer NewView 7300 is designed for a wide variety of samples of all materials and shapes with diameters ranging from less than 1 mm up to greater than 130 mm. The system can execute numerous tests, for example the measurement of flatness, roughness, step heights and form deviations. Likewise, areas which are set back, angles, radii, cone angles and cones can be measured. Moreover, grinding structures and wear phenomena can be determined, layer measurements realized and edge effects analyzed. In the case of flatness tolerances a measurement system capability is guaranteed with a part tolerance of 0.5 µm. The NewView 7300 provides also SPC data. The test results are transferred directly into statistics. To make data analysis even easier, the operator can view selectable 3D graphics that enhance the part shape for easy interpretation, documentation and printing. The test results of each inspected piece can be shown three-dimensionally and in color on a monitor or a hard copy resulting in an improved vividness. The measurement instrument NewView 7300 is a modular system. Users can acquire a basic instrument responding to their specific requirements. When further testing tasks are to be added, the system can be extended according to these requirements. The modular system is very versatile. For example there are more than 20 different objectives available. The economic efficiency of the measurement method is still higher because the operator can insert 24 samples into a multi-part pick-up device. Having started the testing procedure, the samples are automatically tested one after the other.
Zygolot is an A-class supplier of companies like Carl Zeiss and Robert Bosch where numerous NewView measurement instruments are already working. Also many small and medium-sized companies already successfully apply the NewView technology and expand their inventory of instruments. The NewView 7300 measurement instrument can be fully integrated into the production process, works with short cycle times and helps to correct production parameters if necessary, avoiding in this way the production of expensive scrap. The operation of the device is simple and safe; the quality of the measurements does not depend on the operator‘s skill. Due to its various characteristics the measurement instrument NewView 7300 is paid for by a rapid return on investment.