First of all, the workpiece should be analyzed with reference to the part drawing, and the design scheme, datum plane, concave and convex condition, detection section and positioning surface of the fixture should be preliminarily drawn up. The geometric dimensions of the fixture should be determined and its two-dimensional schematic diagram should be drawn simply.

Design and modeling directly affect whether the fixture can accurately detect the quality of the workpiece. Because the body panel is mainly a free-form surface, "reverse engineering" is the general method of modeling at present. Reverse engineering is a method to build a prototype model with a specific shape and structure based on the existing workpiece or prototype, using laser scanner to collect data, and through data processing, three-dimensional reconstruction and other processes.

The surface of standard workpiece is scanned by laser scanner, and the feature information of workpiece surface, which is mainly point cloud, is collected, and the point coordinates are converted into volume coordinates.

Surface software is used to process the point information, get the characteristic curve of the workpiece surface and generate the final free-form surface model.

At the same time, the generated prototype model can be detected by the maximum and minimum distances from the point cloud to the surface. At this time, the obtained model is a thin model without thickness. It is particularly important to distinguish whether the model is the inner surface or the outer surface of the workpiece according to the surface scanned by the scanner.

(1) The fixture room is the place where the factory conducts product research and development and product quality inspection. Should be dedicated to special rooms, and shall not engage in other activities. (2) The fixture room shall be managed by special personnel, and the management personnel shall be responsible for it.

(3) The inspection tools (special measuring instruments) and other equipment in the inspection tool room shall be located and stored according to the classification number, with standardized layout, beautiful display, neatness and cleanliness, and well protected against dust, moisture, pressure, extrusion, deformation, heat, sun, magnetism and shock. ?

(4) The recipients of special measuring instruments must go through the registration formalities by management personnel, and the inspection is complete. ?

(5) Take good care of indoor equipment, maintain it regularly and timely, and do a good job in rust prevention, corrosion prevention, insect prevention and mildew prevention, so that inspection tools (special measuring instruments) and other equipment are always in good condition. ?

(6) Establish and improve the system of checking tools (special measuring instruments) and inspection record files, and properly keep the ledger, operating procedures, use register, inspection record forms and other related materials. ?

(7) Operate in strict accordance with the relevant safety regulations, and do a good job in safety precautions such as safe electricity use, fire prevention, anti-theft, anti-virus, explosion prevention and pollution prevention. Collision is prohibited when handling high-pressure vessels. Wires and electrical equipment should be kept dry to prevent leakage and short circuit. Pay attention to close the doors and windows after work and check the water and electricity to ensure the safety of personnel and equipment.