Evolution of Metrology and its Technologies

Since the automotive sector is constantly submitted to pressure to reduce costs and deadlines (which come down to the same thing…), metrology and checking fixtures do not escape this trend. Dimensional metrology and quality control have always been present in the industrial production chain, and in the case of the automotive sector, the demands in that field have always reached the limits of what the latest technology could provide.

Over the past few years, measurement softwares have known a high-speed evolution, with the improvement of data recollection, displaying of files and geometries and software usability, the reduction of training and learning times, the automation of measuring processes through CNC programmes, the automatic calibration of sensors and far more other aspects that have considerably decreased the number of non-productive dead times. Some CAD softwares, like Catia V5R10, have even included a module enabling the direct interconnection with metrology softwares to make off-line programming easier.

On the other hand, CMM machines producers have been improving tridimensional machines to have them used in a closer collaboration with workshops and production sites, as well as with machining, stamping and injection centres, in order to have a real time control and feedback on manufacturing systems in case of having to correct mistakes. In a word: in order to save time, and reduce production scraps and losses of all types.

An initiative called I++DME, carried out by various European vehicle producers (Volvo, Volkswagen, AUDI, Daimler Chrysler et BMW) aims at standardizing the inspection systems in different points of the production chain (in-line metrology), by standardizing the processes and data collections, no matter which technology is used.

Meanwhile, the introduction of sensors and contact-free measuring technologies, called virtual metrology, enables to capture a point cloud with CCD sensors, laser technologies, white light, scan or photogrammetry. The virtual metrology offers new services impossible to carry out with traditional systems, and enables to reach areas inaccessible by CMM. Softwares and equipment have had to be improved a lot to allow doing without difficulty a DSSP, that is, the digital treatment of geometries formed by these point clouds.

Finally, one of the other fields that has known great advances is the portable metrology, through measuring arms or laser-trackers, made by companies such as FARO, Leica, Romer, or GOM as for photogrammetry. These are cable-free systems, with PC connection, tolerances as low as 0.01mm and measuring capacity of up to 14m. These systems can even be combined with one another (Arm+Laser-tracker) and can be connected to contact-free point capture systems.

In all cases, the most important with such a big range of products is to know how to choose the suitable technology for our application. If you choose a technology too advanced, you may risk to pay a price far too high as well as to reveal aspects that would not favour you. On the contrary, if you choose an outdated technology, or one far from the detection capacities you need, you will be investing time and money in a system that will not detect what you need it to detect, or if it will, the results may not have the sufficient precision to take relevant decisions.

Considering this huge panorama, who is able to foresee the future for checking fixtures, that imply an important cost in comparison with all these technologies?

Bellow are some links of products and applications with these new technologies:

http://3shape.com/inspection/_inspection/inspection.htm

http://www.geomagic.com/en/products/qualify/

http://www.metrologicgroup.es/Sp/index.htm