Checking Fixture
The checking fixture can accommodate any number of measuring equipment while fixing the parts to be inspected. Using this tool is of great help in improving the accuracy of the product. The inspection fixture provides proof that the product meets all requirements for safe operation.
Requirements for Automotive Checking Fixture
Automobile checking fixture has multiple requirements. The manufacturing of the fixture testing will select the correct processing technology based on the design of the checking fixture and the requirements of the workpiece. Due to the many precision machining equipment, it provides better assurance for the checking fixture and meets the processing technology of different complex checking fixture workpieces.
Requirements for Assembly Accuracy of Automotive Checking Fixture
The assembly accuracy of checking fixture is to ensure the machining accuracy of automotive checking fixture parts, which is generally determined by designers based on the corresponding checking fixture process technology standards, quality requirements, and production efficiency.
The assembly accuracy of automotive checking fixture includes several aspects, including contact accuracy between components, distance accuracy, mutual position accuracy, relative motion accuracy, and fitting accuracy. The main assembly accuracy requirement is that the positioning device must ensure accurate and reliable positioning. After assembly, the automotive checking fixture must ensure that the parts of the fixture have extremely high accuracy, and the fit of the parts should meet the design standards and uniformity.
The precision of some workpieces is specified as the relationship between the parts that fit together, such as ensuring that the clearance meets technical requirements.
The accuracy of the position of relevant parts, the position of each part must be accurate, for example, the position between each measurement benchmark, positioning hole, detection surface, and positioning surface and detection hole must be within the specified position range.
There are many types of motion accuracy for related components, such as transmission accuracy, circular motion accuracy, and linear motion accuracy, such as the rotational motion of the flipping mechanism, the motion flexibility of the detection pin and guide sleeve, guide rails, and push-pull structures.
The contact accuracy of some stamping molds mainly depends on the consistency of the contact between the opening part and the Cubing part, as well as the flatness and perpendicularity of the assembly surface of each checking fixture part.
Technical Requirements for the Assembly of Automotive Checking Fixture
The technical requirements for fixture assembly mainly include the overall assembly accuracy, size, and shape of the fixture. When technicians assemble checking fixture, they require that the fit and connection between every two parts or adjacent assembly units be accurately positioned according to the technical requirements of the assembly standards determined by the assembly process, to achieve the required fit and position accuracy.
When assembling workpieces, it is necessary to use some soft material fixtures, such as copper bars, aluminum, rubber hammers, etc. Not using soft material fixtures may cause damage to the components. When connecting the bottom plate to the car checking fixture body, bolts are used for fixation, and the depth of bolt insertion must be greater than 20 millimeters.
Under no special circumstances, the bolt rod will not bend or deform, and the connected parts should smoothly contact the bolt head and nut bottom. The connected parts should be uniformly compressed, tightly fitted to each other, and connected firmly. The size deviation of the automotive checking fixture body allows for bottom welding repair, and plug repair is prohibited to avoid unnecessary problems. When installing parts, if there are pinholes, a top rod should be used for initial positioning and then threaded locking. In order not to affect the installation flatness, the installation surface of the parts should not have burrs or debris.
The thread-tightening torque during assembly should be precisely adjusted according to the design specifications. If necessary, the precision structure should be assembled first, to ensure the reliability of the connection structure before formal installation. Before and after assembly, there should be no obvious burrs on the edges of the car checking fixture brackets, models, etc., and sharp corners need to be blunted, otherwise, it may cause injury to operators during use. The installation reference plane must have the characteristics of smoothness, flatness, no rust, and no damage. The head of all screws and the end of cylindrical pins must be lower than the installation plane. Generally, the installation plane should be more than 1 millimeter higher than the head of the screws and the end of the cylindrical pins.
Pay attention to safety and appearance factors. The car checking fixture should protrude from the workbench, and the exposed moving parts should be covered with protective covers to avoid damage to the checking fixture. The technical standards for evaluating the accuracy, quality, and performance of automotive checking fixture are as follows:
By assembling and adjusting, the accuracy of the assembly can fully meet the requirements of the closed ring. The assembled checking fixture can be directly used for precision debugging in three coordinates. The use and performance of the assembled automotive checking fixture ensure that they meet the expected design, reasonable values, and requirements.
Performance Requirements for Automotive Checking Fixture Materials
The process performance of materials is related to their composition and organization, as well as factors such as fixtures, equipment, and appearance. The process technology is influenced by external factors, and the process performance of materials plays an important role in complex processing, production quality, and production efficiency. Due to the variety of workpiece materials used in automotive checking fixture, multi-curved parts generally undergo complex manufacturing processes and therefore must have applicability to various processing techniques. There are many requirements for the processability of checking fixture materials, mainly including heat treatment process performance, welding process performance, cutting process performance, curing process performance, casting process performance, etc.
Heat treatment processability: Most sheet metal checking fixture and welding assembly checking fixture with high hardness requirements have high hardness requirements, while most plastic checking fixture and foam checking fixture do not have high hardness requirements. High hardness can cause scratches and other appearance defects on the surface of plastic parts. A wide quenching temperature range and small quenching deformation are required for metal materials that are prone to wear and tear. The hardenability depends on the carbon content of the steel, while the hardenability mainly depends on the chemical composition, alloy element content, and microstructure before quenching.
Casting process performance: mainly including flowability, solidification characteristics, shrinkage, air absorption, etc. The better the fluidity, the easier it is to cast thin and delicate castings; The smaller the shrinkage, the smaller the deformation of the casting during solidification; The more uniform the chemical composition segregation, the better the performance of various parts of the casting, and the higher the reliability of the casting. Generally, this performance is mainly used for checking fixture materials such as cast aluminum and cast iron.
Cutting process performance: Good machining performance can ensure the quality of the parts, effectively improve the surface quality of the workpiece, and the chip shape convenient to operate or easy to break. Due to the high carbon and high alloy composition of most materials used in automotive checking fixture, the formation of carbides and metallographic structures poses some difficulties in their cold working performance such as cutting and grinding.
Curing process performance: For polymer compounds, such as resins, this is an important process standard for their bonding and curing.
When technicians choose materials for automotive checking fixture, the first step is to pay attention to certain necessary processes that meet the requirements of automotive checking fixture use. Generally, the main use is to utilize the wear resistance, stiffness, hardness, and durability of steel, which can comprehensively reflect the comprehensive performance of automotive checking fixture materials.
Manufacturing Requirements for Automotive Checking Fixture
Long service life. The length of service life is closely related to production efficiency, which directly affects on-site production efficiency and benefits. Due to the repeated use of equipment for process checking of automotive checking fixture or hot-formed workpiece checking fixture, the testing environment is harsh, and the wear of automotive checking fixture parts is large.
Short manufacturing cycle. As new product technologies become increasingly advanced and market competition intensifies, the manufacturing cycle of automotive checking fixture is required to be shorter and shorter. The manufacturing time of an automotive checking fixture is generally determined by the process technology and production management requirements of the checking fixture manufacturing. On the premise of ensuring quality, the manufacturing cycle of checking fixture should be shortened as much as possible to meet production requirements and improve product competitiveness.
Batch production of standard parts. The most commonly used mode for automotive checking fixture is modular assembly, and a large number of standard parts are used in design and manufacturing to save manufacturing time. Therefore, batch production of standard parts is necessary to save time and improve efficiency.
The requirements for the manufacturing of automotive checking fixture are interrelated and interdependent. Improve the manufacturing accuracy and workpiece quality of automotive checking fixture through effective methods. When designing and manufacturing automotive checking fixture, comprehensive consideration should be given to the actual situation. On the premise of ensuring manufacturing accuracy, choose more suitable processes and manufacturing methods to minimize the manufacturing cycle.
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