The measurements can be started via the encoder pulse of the CMM , thus achieving absolute time-synchronous values . Due to the sensor ’ s intelligent Advanced Surface Compensation feature , stable results are achieved , even on challenging surfaces . With up to 50,000 lx , the sensors are extremely resistant to ambient light and can therefore be used in highly illuminated environments . For signal optimisation , two-stage measurement averaging is available , which enables a smooth signal curve at edges and steps .
Roughness measurement and geometrical inspection
In terms of resolution and measuring rate , confocal chromatic sensors are among the most powerful measuring systems in optical metrology . For example , they are used for highresolution distance measurement on various surfaces and for roughness measurement . The confocal sensor systems from Micro-Epsilon combine state-of-the-art technology and easy integration . The sensors allow a tilt angle of up to ± 30 ° and offer a high numerical aperture . This enables high resolution and small light spots . Curved and structured surfaces can therefore be detected precisely and reliably . In this way , gears or external threads can also be detected . Due to the noncontact measuring principle , the sensor does not affect the target object , which enables wear-free measurements . This is why values can be detected much faster compared to tactile measuring principles . With the confocalDT controllers , measuring rates of up to 70 kHz can be achieved . For measurement in confined spaces , compact sensors , as well as sensors with a 90 ° beam path are available , which can be integrated in the CMM measuring head to save space .
For positioning of the measuring head , optoNCDT 1900 laser sensors measure the distance to the target or baseplate .
3D measurement of complex geometries and rotating components
When measuring large , complex components , the scanCONTROL series of 3D laser scanners from Micro-Epsilon are used . These scan large measurement areas at high resolution and are ideal for use in CMMs due to the low sensor weight . Measurement data acquisition is very fast with measuring rates up to 10 kHz . As a result , a complete 3D point cloud is available , which allows precise evaluation , quality inspection as well as further processing . The scanCONTROL laser scanners are based on the latest GigE Vision and GenICam standards and can therefore be integrated in a wide range of image processing environments . The 3DInspect software is a powerful tool for parameter setting , evaluation and output .
Among other things , laser scanners are used for prototype scanning . The sensor can be guided by a robot arm or integrated in a measuring table . The scanner measures the component while being moved over the component from all sides . Taken from multiple directions , the user obtains a 360 ° image . A software solution transforms it into a complete 3D point cloud within an extremely short time . To enable high-precision measurements , the measurement data must be perfectly synchronised with the measurement position . Conventional sensors are often triggered externally and detect the profile with a time delay that causes inaccurate position data . The scanCONTROL laser scanners from Micro-Epsilon , on the other hand , offer a special CMM trigger for this purpose .
This is a parameter output optimised for CMMs . The sensor can therefore send trigger pulses in the middle of the exposure time and thus assign the profile to an exact measuring position . Fine tuning is also possible , for example , to compensate for run times of the pulse in the cable . As scanCONTROL laser scanners are available with different measuring ranges , both large and small objects can be detected . The captured 3D point clouds can be compared with existing CAD models to make any discrepancies obvious .
Above left , the large aperture angle and the high numerical aperture of confocal chromatic sensors enable high resolution with a small light spot size . Above right , laser scanners are used for 3D measurement of complex geometries and rotating components . For quality assurance of rotary pistons , the piston surface is measured 360 ° and compared with the nominal shape within a narrow tolerance .
For more information on optical sensors for CMMs , please call the Micro-Epsilon sales department on + 44 ( 0 ) 151 355 6070 or email info @ micro-epsilon . co . uk
31