The Fraunhofer Institute for Laser Technology ILT has developed an interferometric distance sensor , the geometric properties of waves , for example, cam or crank can absolutely compete with sub - micrometer accuracy .
The compact sensor head bd -1 slips easily into waves measuring machines integrate and records not only geometric features and surface roughness. On the Control 2014 in Stuttgart Fraunhofer experts lead the sensor from live .
In all internal combustion engines, crankshafts, drive shafts and camshafts are used. The automotive industry has the highest standards of manufacturing accuracy and surface properties of these waves. Thus, for instance roundness or deviate from the default roughness values lead to increased wear , unwanted noise and malfunction. Therefore, waves undergo in the production line of a 100-percent test, the requirements on the accuracy of the measurement technique are ten times higher than those on the accuracy of manufacturing technology. When measuring the shape and position deviations the measurement accuracy in the micrometer range , must sometimes be in the range of a few hundred nanometers.
Currently shaft measuring machines set still a predominantly tactile distance sensors and laser triangulation sensors that measure various characteristics, such as cam profile , cam lift , base circle radius , roundness , eccentricity, angular position and straightness of the bearings. The surface roughness is usually measured separately with Perthometers .
bd -1 overcomes previous limitations of the measurement technique
The Fraunhofer ILT experts have now developed the bi-directional optical sensor bd- 1, which can measure both the shape and the roughness of waves inline. It only requires a fraction of the design space , which is claimed by triangulation . Its name goes back to the concept and bidirectionally means that the laser beam on the same way back and running back . This eliminates adjustment problems , the transmitter and receiver do not need to be aligned. In direct comparison with conventional triangulation has bd- 1 has a much lower linearity error and thus leaves its competition far behind .
bd -1 can measure all types of surfaces , finely polished, shiny and reflective surfaces , their detection with other optical sensors is problematic. Also steep edges or holes with high aspect ratio can be detected with bd -1. In addition, the surface roughness is additionally detected during the measurement of form deviations on rotating shafts , thus eliminating additional process steps for measuring roughness measuring with .
bd- 1 recognizes differences in shape and the microscopic surface structure of wave speeds of several thousand revolutions per minute with an accuracy in the 100 nm range . This is achieved by a high-speed data acquisition and processing , the measurement frequency for individual distance measurements of up to 70 kHz. This reached bd -1 precision interferometric sensors , and is faster than conventional , absolute measuring distance sensors. bd -1 can be used both for quality control in the production line as well as for process monitoring during production.
Even in harsh environments , the sensor operates reliably . The window for the beam entrance Strahlaus and has a diameter of < 5 mm and can therefore be efficiently protected by a flow of air from contamination.
At the International Trade Fair for Quality Assurance , Control , from 6th to 9th May 2014 in Stuttgart , interested visitors can experience live measurements with bd- 1 on the joint Fraunhofer stand 1/1502 .
