The Fraunhofer Institute for Laser Technology ILT has developed an interferometric distance sensor that can precisely measure the geometric features of shafts – for example, camshafts and crankshafts – with sub-micrometer accuracy. The compact » bd-1 « sensor head can be integrated into shaft measuring machines without any difficulty and also measures surface roughness as well as geometric features. Our experts will be demonstrating the sensor live at the Control 2014 trade fair in Stuttgart.
Crankshafts, driveshafts, and camshafts are found in all internal combustion engines. The automotive industry sets extremely high standards on the manufacturing accuracy and surface characteristics of these shafts.
For example, camshafts must work with microsecond precision in controlling valve opening times synchronous to piston movement. Even the tiniest manufacturing errors can greatly impair engine performance, fuel consumption, and the service life of components.
Deviations from the specified roundness or roughness values, for instance, can lead to increased wear, unwanted noises, and malfunctions. Not surprisingly, then, the 100% inspection of shafts on the assembly line calls for measurement technology that is ten times more accurate than values applying to manufacturing technology. Measuring deviations in shape and position requires measurement accuracy in the micrometer range, sometimes even in the range of a few hundred nanometers.
For the most part, shaft measuring machines still use tactile distance sensors and laser triangulation sensors that measure a variety of characteristics such as cam shape, cam lift, base circle radius, roundness, eccentricity, angular position, and straightness of bearing positions. Surface roughness is usually measured separately using perthometers.
» bd-1 « pushes back the limits of measurement technology
Now experts at Fraunhofer ILT have developed the bidirectional optical sensor » bd-1 «, which can measure both the shape and roughness of shafts inline and needs only a fraction of the installation space that triangulation sensors take up. Its name alludes to the fact that the laser beam moves back and forth along a »bidirectional« single path. This does away with adjustment problems, as the transmitter and receiver no longer have to be aligned with each other. In direct comparison with conventional triangulation sensors, » bd-1 « boasts a much lower linearity error value, putting it way ahead of the field.
» bd-1 « can measure all kinds of surfaces – including finely polished, shining, and reflective surfaces, which can be difficult to measure with other optical sensors. It not only measures surfaces positioned at steep angles and drill holes with high aspect ratios; it also records surface roughness while measuring deviations in shape on rotating shafts – eliminating the need for a separate process step and equipment specifically for this purpose.
Precise, rapid inline measurement for quality inspection and process monitoring
» bd-1 « recognizes deviations in shape and the microscopic surface structure of shafts at speeds of several thousand revolutions per minute with an accuracy in the 100-nm range. This is made possible by high-speed data acquisition and processing and distance measurement frequencies of up to 70 kHz in some cases. » bd-1 « thus achieves the precision of interferometric sensors and is faster than conventional absolute-measurement distance sensors. » bd-1 « can be used both for quality inspection on the assembly line and for process monitoring during manufacture.
The sensor also works reliably in rough environments. The window for the beam outlet and inlet has a diameter of < 5 mm and can therefore be effectively protected against dirt by means of an air current.
Fraunhofer ILT developers created the distance sensor primarily for manufacturers of shafts or of high-precision cylinder coordinate measuring machines (CCMMs) for components such as camshafts and crankshafts. » bd-1 « is ideally suited to the 100-percent inline inspection of geometric features in accordance with the requirements of the automotive industry. In field tests, » bd-1 « has already proved how effectively it can measure the thickness of rolled strips and blown films inline, or carry out roundness and distance measurements during the manufacture of turned parts in machine tools.
Visitors to the Control international trade fair for quality assurance in Stuttgart, which is taking place from May 6 to 9, 2014, will have the opportunity to see » bd-1 « in action as it performs live measurements at the joint Fraunhofer booth 1/1502.
Dipl.-Phys. Christian Tulea
Clinical Dioagnostics and Microsurgical Systems Group
Phone +49 241 8906-431
PD Dr. Reinhard Noll
Head of the Competence Area Measurement Technology and EUV Sources
Phone +49 241 8906-138
Fraunhofer Institute for Laser Technology ILT
52074 Aachen, Germany
Petra Nolis | Fraunhofer-Institut
Sensor + Test 2015: Cost-effective production of magnetic sensors
01.04.2015 | Fraunhofer-Institut für Elektronische Nanosysteme ENAS
Hannover Messe 2015: Saving energy with smart façades
01.04.2015 | Fraunhofer Institute for Machine Tools and Forming Technology IWU
Spring is here and ectotherms, or animals dependent on external sources to raise their body temperature, are becoming more active. Recent studies have shown...
Glass-fronted office buildings are some of the biggest energy consumers, and regulating their temperature is a big job. Now a façade element developed by Fraunhofer researchers and designers for glass fronts is to reduce energy consumption by harnessing solar thermal energy. A demonstrator version will be on display at Hannover Messe.
In Germany, buildings account for almost 40 percent of all energy usage. Heating, cooling and ventilating homes, offices and public spaces is expensive – and...
Outstanding chemical, thermal and tribological properties predestine silicon carbide for the production of ceramic components of high volume. A novel method now overcomes the procedural and technical limitations of conventional design methods for the production of components with large differences in wall thickness and demanding undercuts.
Extremely hard as diamond, shrinking-free manufacturing, resistance to chemicals, wear and temperatures up to 1300 °C: Silicon carbide (SiSiC) bundles all...
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
25.03.2015 | Event News
19.03.2015 | Event News
17.03.2015 | Event News
01.04.2015 | Earth Sciences
01.04.2015 | Information Technology
01.04.2015 | Physics and Astronomy