What factors should be considered when designing automobile inspection tools?
Automobile inspection tool is a simple tool used by industrial production enterprises to control various sizes of products (such as aperture, space size, etc.) to improve production efficiency and control quality. It is suitable for mass-produced products, such as automobile parts, to replace professional measurement tools, such as smooth plug gauge, thread plug gauge, outer diameter caliper, etc. So, what factors should be considered when designing automobile inspection tools?
1、 Design concept
Design and manufacture of automobile inspection fixture before inspection fixture design, the concept of inspection fixture design shall be clarified, and the following factors shall be fully considered:
1.1 fully understand GD & T
GD & T is a descriptive document of automobile product design. Product specifications, product positioning datum, key product characteristics (KPC) and product tolerance characteristics will be reflected in GD & T. therefore, * * * fully understands GD & T before fixture design.
1.2 determine product positioning and testing content
Based on the full understanding of the product GD & T, analyze the product positioning datum features, consider the * * * placement position of the product parts, understand the meaning of various tolerances, and determine the test contents that the product parts * * * realize on the inspection fixture and the contents that do not need to be realized or even cannot be realized at all.
1.3 statistics of process control capability (SPC)
Identify whether the product has KPC requirements, CNC precision mold manufacturing, understand the purpose of the inspection tool, correctly understand the requirements of quantitative measurement and qualitative measurement, and ensure the reliability of SPC data acquisition.
1.4 understand requirements and processes
Fully understand the customer’s demand for product inspection tools, learn from previous successful or failed cases, fully understand the customer inspection tool review and approval process, and understand the required documents.
2、 Design principles
The inspection tool shall have sufficient rigidity; It shall have sufficient stability; It shall have sufficient measurement accuracy to ensure vehicle quality; The operation shall be convenient to ensure sufficient measurement efficiency; The structure shall be as simple as possible; It shall have good appearance; It shall have sufficient economy to ensure easy control of vehicle cost; At the same time, it shall be convenient for measurement and calibration.
3、 Key design points of inspection tool for large decorative parts
The inspection of automobile large decorative parts not only has the commonness of automobile parts inspection tools, but also has its own characteristics. Its structure is mainly composed of the following parts: base plate and frame, positioning device, clamping device, measuring device, auxiliary device, etc.
4、 Design and manufacturing steps of automobile inspection tools
Factors to be considered in the design and manufacture of automobile inspection tools and the design process (Fig. 2)
1. Analyze the workpiece with reference to the part drawing, preliminarily formulate the design scheme of the inspection tool, determine the datum plane and concave convex of the inspection tool, detect the section and positioning surface, and simply draw its two-dimensional schematic diagram.
2. Design modeling has a direct impact on whether the inspection tool can accurately detect the workpiece quality. Because the body panel is mainly free-form surface, “physical reverse” is the general method of modeling at present. Reverse is to collect data with a laser scanner according to the existing workpiece or physical prototype, and go through the processes of data processing and three-dimensional reconstruction, A method for constructing a prototype model with a specific shape structure.
3. Scan the standard workpiece surface with a laser scanner, collect the workpiece surface feature information based on point cloud, and convert the point coordinates to the body coordinates.
4. Using surfacer software to process point information, the characteristic curve of workpiece surface is obtained, and the free-form surface model of * * * is generated.
5. At the same time, the generated prototype model can be detected through the small distance from the point cloud to the surface. At this time, the obtained model is a sheet model without thickness. It is necessary to distinguish the model as the inner or outer surface of the workpiece according to the surface scanned by the scanner, which is particularly important for the specific design.
Therefore, in the process of design and manufacturing of automobile inspection tools, in addition to fully considering all aspects of inspection tools, it should also be made according to the actual operation process, and each link of design and manufacturing of automobile inspection tools should be controlled layer by layer, so as to make the structure of automobile inspection tools consistent with the sample.