Checking Fixture
Automotive checking fixture is mainly used for determining and adjusting the accuracy of molds during the production preparation stage, Accurately install the parts on the inspection fixture, and then inspect the surface and periphery of the parts through visual inspection, stop gauges, or calipers.
Automotive Checking Fixture
Automotive checking fixture is an important tool for controlling product quality. An automotive checking fixture is a type of equipment with precise detection techniques. In standardized use, operators must operate the fixture testing correctly according to requirements, to improve product quality, avoid affecting the precision of the checking fixture, and avoid incorrect part inspection data.
Design of Automotive Checking Fixture
There are many design structures for automotive checking fixture. Regarding the design of the bottom plate, its function is to connect each unconnected component on the carchecking fixture into a complete basic component. The basic requirement for precision inspection of automotive checking fixture is to correctly install functional devices, auxiliary equipment, mobile devices, and other platforms. Due to the emergence of more and more new materials and technologies, it is necessary to improve the lightweight production and technology of the bottom plate as much as possible, and enhance the high strength and stiffness of the bottom plate, to facilitate the operation of operators and machine operation, but the requirement is that the total weight must be within 2 tons. The structure of the bottom plate must have the characteristic of stability, as it needs to bear the overall gravity load of the gauge.
The bottom plate plays an important role as a load-bearing structure, the main structure of the mobile device, and an auxiliary measurement benchmark. The width of the bottom plate cannot be less than half of the height, to ensure the stability of the carchecking fixture. The length of the checking fixture cannot be longer than that of the bottom plate. Be able to design various types of vehicle structures, and when designing the base, be sure to pay attention to flexible design.
The checking fixture must have strong stiffness, hardness, and a small thermal stability conductivity coefficient, because the temperature range is relatively large, and the vibration during transportation cannot affect the accuracy of the checking fixture. The design of the base has a significant impact. There should be no paint on the plane and reference plane of the bottom plate to avoid any impact on the use and accuracy of the checking fixture caused by the paint. To avoid collision or deformation of the bottom plane during the movement of the checking fixture, technicians should make a large chamfer on the outer side of the bottom plane of the checking fixture.
The requirements for designing the base plate are as follows：
It has good welding performance and machining performance.
For parts that are symmetrical on the left and right and formed by the same mold at the same time, the checking fixture usually adopts the structural form of separating the mold body and the skeleton part and sharing the base, except for some large parts, such as door panels, wheel guards, etc. The general method used for the bottom plate of the checking fixture is cast aluminum or welded frames. Generally, forged aluminum is used for checking fixture, and attention should be paid to placing standard parts, inspection pins, go/no go gauges, nameplates, and auxiliary devices in the designated space of the bottom plate. The bottom plate of the checking fixture should have the characteristics of easy handling and processability.
The bottom plate has strong load-bearing capacity, good strength, and stiffness. The above characteristics are aimed at minimizing deformation and vibration caused by external forces such as self-gravity during use. The bottom plate should have sufficient wall thickness, and if there are areas with weak stiffness, operators need to promptly increase the reinforcement. Aluminum alloy frame bases are increasingly being used in the industry, which not only effectively increases hardness and strength, but also reduces quality.
It is also important to have good processability and usability, as the bottom plate is generally of large-sized shape. If the requirements for stiffness and strength are met, the mass should be reduced as much as possible, the volume should be reduced, and the operation should be convenient. For the convenience of changing the placement of the checking fixture, the total weight of the checking fixture must be within the range of 3 tons.
It should have good accuracy and dimensional stability. The flatness and roughness of the surface must meet high requirements, as the surface of the bottom plate serves as the installation base or measurement reference. Some factors can affect the detection results, such as the influence of temperature on the thermal stress of the bottom plate, which can damage the dimensional accuracy of the bottom plate and also affect the overall checking fixture. When designing the bottom plate, technicians must choose materials that are not easily subject to shape changes and have a structure that is not resistant to external forces and temperature changes.
Error Adjustment of Automotive Checking Fixture
An automotive checking fixture is composed of multiple parts, and some inevitable factors can have an impact on the checking fixture. No matter which workpiece undergoes some tolerances during processing, it is inevitable that each part will have some errors during the splicing process. The error cannot be too large, because if the error is too large, it will lead to the problem of unqualified assembly, which will cause the carchecking fixture to be unusable.
If manufacturing conditions permit, the manufacturing error of the parts cannot exceed the specified assembly accuracy requirements. During assembly, each qualified part is assembled without adjustment to ensure the precision of the assembly. This method will result in high machining accuracy for the workpiece. The effective way to eliminate assembly errors is to control the dimensional tolerances of each component on the assembly chain.
If there is a high-precision assembly, the main way to directly ensure assembly accuracy is to increase the machining precision of the workpiece. When many related parts affect assembly accuracy, many problems will arise. In this case, the tolerance range of the workpieces is generally widened to ensure that they are produced with good accuracy. Technicians adjust parts that meet the requirements when designing the structure. To achieve the required assembly accuracy during assembly, some parts are usually adjusted to meet this requirement. The adjustment of the workpiece generally has a specified size and a range of size adjustments. There are many design adjustment parts, commonly used including rings, pads, washers, and washers, while the adjustment parts control the assembly size. The purpose is to increase the accuracy of the measuring tool, which has the following main characteristics.
There are many processing methods for parts, including the ability to process according to economic accuracy requirements. In assembly, by adjusting the parts to close the assembly chain, the production requirements for other parts will not be as strict, which effectively improves production efficiency.
It can achieve high assembly accuracy. When adjusting the assembly of parts, the accumulated errors will also be adjusted accordingly due to different situations, to meet the requirements of higher assembly accuracy.
Assembly has the characteristics of easy operation and high efficiency. When assembling, the adjustment parts are already prepared, to able to be replaced at any time according to different actual requirements, reducing the steps of on-site disposal of certain parts; It is not a standard pad that requires simple grinding steps, to meet the standard requirements of actual assembly accuracy.
Standardized Use of Automotive Checking Fixture
When using gauges, operators must follow the standard requirements. Before use, be sure to wear gloves and avoid direct contact with the working surface of the gauge with your hands to prevent any impact. And other tasks, such as repairing parts, cannot be operated on the workbench of the checking fixture. When using a checking fixture, it is important to avoid placing the moving parts of the tool with force and pay attention to handling them gently, otherwise, it may cause damage to the tool and affect normal operation. The following points need to be paid attention to.
To ensure the integrity of the surface of the gauge, it is important not to place other tools on the gauge to avoid causing damage to the surface.
When using checking fixtures, technicians must follow the correct steps for standardized operation. If there is an operation that does not meet the requirements, the consequence is that the equipment will malfunction. In case of a malfunction, please hire professional technicians to repair the equipment. Operators must not heavily hit important components such as the moving device and detection surface of the checking fixture.
Each part of the checking fixture plays a very important role, so no matter which part is indispensable. Unless there are special circumstances, the parts of the checking fixture cannot be disassembled. In case of any problems, report them to the technical personnel responsible for repairing the equipment.
Clean the checking fixture before use to prevent impurities from affecting the accuracy of the checking fixture. The measuring machine surface of the measuring tool should pay special attention to hygiene, and there should be no other impurities.
After using the automotive checking fixture, take out the manufactured workpiece. Then clean the entire checking fixture thoroughly, without any impurities. After confirming that the checking fixture meets the requirements for cleanliness, close the clamping device, place the section sample back in its original position, and return the inspection pin to its original position. Some iron fasteners need to be wiped clean, and to prevent rust, they need to be coated with oil. The main iron fasteners include positioning surfaces and inspection pins.
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