Workpiece Profile Of Car Covers

In addition to a few small stamping parts, generally, the dimension datum of the covering is placed in the body coordinate system, except for some characteristic parts of the workpiece (such as hole, flange, etc.), the distance dimension of the adjacent coordinate line is annotated on the graph, and the size value is not given for most of the contour (especially the free surface).Car Covers 

At present, the method of dimensioning by coordinate grid is gradually replaced by CAD data in the 80 's.The CAD data provided by the design department for stamping parts, welding parts and even the body can be used as the dimension basis of the manufacturing mould, welding fixture and inspection tool.Car Covers 

A schematic diagram of a car body coordinate system. The coordinate origin is located at the midpoint of the front axle, and the network line arranged along the X, Y and Z axes passes through the body in 100mm distance to determine all the position points of the vehicle, which can be used to determine the position of each part of the vehicle. Of course, it is also possible to make a tabulation of the size of the coordinate grid previously used.Car Covers

Generally speaking, the inspection elements of the covering and even the body are mainly the position of the workpiece (such as contour, curved surface, etc.) and characteristic parts (such as hole, flange, etc.). The main detection principle and main points of the inspection fixture are described below.Car Covers 

Correct and reasonable positioning of workpiece is the basis of accurate measurement. There are two main ways of locating the Panel on the inspection fixture: to fit the surface position block with the free surface of the workpiece, and then to use the two holes on the workpiece as the locating hole to complete the positioning. One of the two locating holes must be able to limit the position in two directions, can be used cone plug gage (for round hole) or prismatic plug gage (for waist hole) positioning; the other locating hole can only be limited in one direction, can use edge pin, trimming pin (for waist hole) or round pin (for round hole) positioning.Car Covers

When the accuracy of the measured hole is low, can be detected by the line, that is, the workpiece is measured at the bottom of the hole at 1mm interval of the corresponding region of the inspection, the circle diameter (or square side length) of the area should be greater than the measured aperture of 5mm, the contour of the cover is generally irregular, free surface, and other characteristics, Therefore, the main basis of contour detection is the type of inspection fixture, at the same time with other corresponding detection means, such as line comparison, flush ratio, rule inspection, vernier caliper and special handheld measuring tools.Car Covers