Comparison of advantages and disadvantages between automobile checking fixture and Three-coordinate Measurement
In terms of cost, the cost of automobile checking tool measurement is lower than that of three-coordinate measurement, but in the long run, the cost of Three-coordinate Measurement will be lower than that of automobile checking tool measurement. Vehicle gauge measurement needs to make gauge for all the measuring objects, and it is a one-time investment for the vehicle type. The CMM combined with flexible fixture, although the initial investment is large, and there are certain daily maintenance costs. But in the long run, there is still a price advantage. In terms of cost, CMM has advantages.
In terms of the flexibility of the checking fixture, the automobile checking fixture is a special measuring device for parts/assemblies, without flexibility. Three coordinates combined with flexible fixture can be used to measure almost all parts assembly. Flexibility is very good. Therefore, from the perspective of flexibility, automotive inspection tools are still at a disadvantage.
From the point of view of measurement convenience, the measurement convenience of automobile checking fixture is very good, and the coordination of three coordinates and flexible fixture is poor.
From the point of view of measurement accuracy, the manufacturing accuracy of automobile inspection tools is generally better, that is, +/-0.15 (hole, pin) ~+/-0.2 (surface), with vernier caliper level measuring tools, the measurement accuracy is up to +/-0.1 level. And three coordinates (ordinary level, measurement accuracy can reach +/-0.05). Therefore, it is obvious that the accuracy of the three coordinates is more accurate than that of the automobile gauge.
Because of the high cost of three coordinates, besides the basic investment of equipment, the investment of detection support should also be considered. After all, most parts are flexible and need support to help locate and measure. Although the structure of the test bracket is much simpler than that of the test fixture and the investment is much less, the existing mode of the test bracket is still similar to that of the automobile test fixture. This investment not only increases the cost of three coordinates, but also affects the measurement flexibility to a certain extent.
Vehicle inspection tools can check the following characteristics: key product characteristic inspection, characteristic line inspection, function hole inspection, area detection which is prone to large deformation in assembly process, for sample car assembly, function matching detection in pre-production stage. Especially, the function of matching detection is closer to engineering debugging and vehicle manufacturing, and the three coordinates and flexible bracket are completely incompetent. From the current technical level of our country, it is necessary to use automobile checking tools as automobile measuring tools. Although the development of automobile checking tools in our country has reached a certain level, it has not yet taken the cost into account. At present, automobile inspection tools have become a popular means of inspection.
