What is rivet pressing? How is the quality control of rivet pressing carried out?
Pre-Riveting Control
1. Part Inspection
Conduct strict inspections on riveted parts (e.g., rivets, rivet nuts) and workpieces to be joined. Ensure the dimensional accuracy and geometric tolerance of riveted parts meet requirements, with no cracks, burrs, or other defects on their surfaces. For the workpieces, verify that the size and positional accuracy of pre-drilled holes comply with design standards; the hole walls should be smooth, free from oil stains, impurities, and other contaminants.
2. Equipment Debugging
Precisely adjust parameters of the riveting machine (such as pressure and stroke) based on factors like the material and thickness of riveted parts and workpieces. Determine the optimal process parameters through test molding or trial riveting. Conduct regular maintenance on the equipment to ensure its stability and precision.
In-Riveting Control
1. Pressure Monitoring
Real-time monitor pressure changes of the riveting machine during the riveting process. Insufficient pressure may result in loose joints, while excessive pressure can cause excessive deformation or even damage to parts. Use devices like pressure sensors to monitor and record pressure; if the pressure exceeds the set range, stop the machine immediately for adjustment.
2. Positional Accuracy Control
Use positioning jigs or molds to ensure the relative position between riveted parts and workpieces is accurate. Meanwhile, operators must strictly follow operating procedures to ensure the riveting position meets design requirements, avoiding issues such as offset or tilting.
3. Visual Inspection
Continuously check the appearance of parts after riveting, including the shape and size of rivet heads, and the deformation around rivet nuts or screws. If defects are found—such as cracks or flash on rivet heads, or excessive deformation and scratches around riveted parts—promptly analyze the causes and take corrective measures.
Post-Riveting Control
1. Tensile Test
Randomly select a certain proportion of riveted workpieces for tensile testing. Use a tensile testing machine to apply tension to the riveted joint and check whether the maximum tensile force it can withstand meets design requirements. If the tensile test fails, analyze whether the problem lies in rivet material, riveting process, or workpieces, and implement corresponding improvements.
2. Torque Test
For rivet nuts, rivet screws, and similar components, conduct torque testing. Use a torque tester to measure the torque values during tightening and loosening, ensuring the torque falls within the specified range to guarantee connection reliability and usability.
3. Metallographic Analysis
For applications with high riveting quality requirements, perform metallographic analysis. Observe the metallographic structure of the riveted joint to understand the material deformation and microstructural changes during the riveting process. Evaluate whether the riveting quality is satisfactory and check for structural defects.
