In industries with extremely high demands on appearance, such as consumer electronics, high-end home appliances, or automotive trim parts, surface scratches on rivets are unacceptable. This not only affects aesthetics but also serves as a potential initiation point for stress corrosion or fatigue cracks. A comprehensive solution to scratches requires a complete defense system, encompassing mold engineering, motion control, and workshop cleanliness management.
- In-depth Analysis of Scratch Causes
Scratches are essentially caused by the workpiece surface material being “plowed” by microscopic protrusions on the mold surface, or by adhesive wear (galling) occurring between the two under high pressure. Causes include:
Poor mold surface: High roughness, micro-chipping, wear pits, or attached particles on the punch working surface are the most direct causes.
Harmful relative sliding: If the workpiece is not completely fixed during orbital riveting, or if the riveting parameters are inappropriate, instantaneous sliding friction can occur, scratching the surface.
Process impact and overload: Excessive initial contact speed or force can lead to a “hard impact” between the mold and the workpiece, and the instantaneous high pressure can cause micro-welding of the material followed by tearing.
- First Line of Defense: Exquisite Mold Surface Treatment
Mirror-grade polishing: Precision polishing of the mold punch working area to a mirror finish.
Anti-friction coating: For materials prone to scratches or galling, such as aluminum, copper, or stainless steel, it is recommended to use surface coatings on the mold surface, such as PVD, TD, zirconia, or silicon nitride, which can significantly improve surface hardness and smoothness, and reduce the coefficient of friction.
Mold lifecycle management: Establish standard procedures for mold use, cleaning, inspection, and scrapping to prevent the use of defective molds.
- Second Line of Defense: ntelligent Motion Control Riveting Machine with Optimized Parameters
“Soft landing” control: Set an independent, very low “contact speed phase” in the control program to ensure the punch contacts the workpiece at the optimal speed.
Smooth force loading: Program the force to increase smoothly from zero, rather than applying it in a step-wise manner.
Riveting motion trajectory control: For special materials, match the optimal riveting motion parameters to minimize frictional heat and sliding. 4. Systematic Workshop Control
Environment and Cleaning: Maintain a clean working environment to prevent foreign objects from contaminating parts or tools.
First Article Inspection Procedure: After each shift or tool change, perform a rigorous inspection of the first piece using high-intensity LED lights or a magnifying glass.
Conclusion:
Eliminating scratches is a systematic process that embodies the pursuit of excellence in the manufacturing process. Shuntai Technology not only provides the ST-MSF series servo track riveting machines with “soft landing” control functions, but also offers professional mold polishing and coating services, as well as complete process debugging support, ensuring that your products have a flawless surface.