Characteristics of automobile body parts
The car body consists of many parts including welding parts and stamping parts. Most car body parts have characteristics such as curved surface, complex structure, irregular shape, large size, heavy weight and others. Because weld pieces accounted for a very large proportion in the parts of the car and has a decisive role on the quality and safety of the car, its accuracy and quality requirements are high. The checking fixture can quickly measure the size of the body parts and find the non-compliance in the body parts. Based on the measurement results the causes of the problem would be quickly analyzed, and then targeted corrective measures are developed. Therefore, the checking fixture which is simple and easy to operate, easy to modify the change, will not cause damage to the parts and suitable for rapid mass inspection of parts.
Design principles of checking fixtures for automobile body parts
Before the manufacture of a good checking fixture, we must develop a good program first. A good checking fixture should have the following characteristics:
(1) should meet the drawings to the integrity of the measure elements. Designers after receiving the task of developing gauges, fully understand positioning and testing requirements on the GD & T drawing, understand the geometric size and tolerance drawings, and design of the gauge without special instructions including all the requirements of the test elements.
(2) should have sufficient measurement accuracy. Checking fixture is not a one-time tool, but a long-term measuring tool, so the designer in the designing time take account of the impact from the gravity of checking fixture, the use of environmental and deformation factors. Designers through the selection of structural design and material to ensure the accuracy and stability.
(3) should have sufficient measurement efficiency. In the design of the checking fixture, in principle, the contents of the checking fixture are required to maintain the same position of the body coordinate system, under special circumstances can be rotated 90 ° or 180 °. The operator's geographical height, operating habits and other factors should also be considered. The purpose of selecting the appropriate location and height of the checking fixture is to maintain the convenience of operation.
(4) should be economical.