Three Common Polishing Methods For Precision Stamping Dies
There are two main purposes for polishing precision stamping dies. One is to increase the brightness and precision of precision molds. The second is to make the mold easy to demould.
In the polishing process, the coarse oil stone is generally used first, and the surface of the machined mold cavity is roughly polished, and the tool marks of the machine and the tool are polished. Then use a fine oil stone to polish the polishing marks of the rough stone. Then use a fine sandpaper to polish the polished surface of the fine stone. Finally, using a polishing paste or a polishing paste, the final surface of the cavity of the mold is polished and polished to achieve a bright, mirror-like effect.
Precision stamping die mechanical polishing is a polishing method that removes the polished convex portion and obtains a smooth surface by cutting, plastic deformation of the material surface, and the like. Generally, oil stone strips, wool wheels, sandpaper, etc. are used, which are mainly operated by hand. For special parts such as the surface of the rotary body, auxiliary tools such as a turntable can be used, and the method of super-fine polishing can be used for high surface quality requirements.
Ultra-fine grinding and polishing is a special-purpose grinding tool. In the polishing liquid containing abrasive, it is pressed against the machined surface to perform high-speed rotary motion. With this technology, the surface roughness of Ra0.008μm can be achieved, which is the most efficient among various polishing methods. This method is often used in optical lens molds.
Electrolytic polishing of precision stamping dies, that is, by selectively dissolving tiny protruding portions on the surface of the material to make the surface smooth. Compared with chemical polishing, the effect of the cathode reaction can be eliminated, and the effect is better.
The electrochemical polishing process is divided into two steps:
(1) Macroscopic leveling, the dissolved product diffuses into the electrolyte, and the surface roughness of the material decreases by Ra>1 μm.
(2) The low light level is flat, the anodic polarization, and the surface brightness is increased by Ra<1 μm.
3. Ultrasonic polishing
The precision stamping die workpiece is placed in the abrasive suspension and placed in the ultrasonic field together, and the abrasive is ground and polished on the surface of the workpiece by the vibration of the ultrasonic wave. Ultrasonic machining has a small macroscopic force and does not cause deformation of the workpiece, but it is difficult to manufacture and install the tooling.
Ultrasonic processing can be combined with chemical or electrochemical methods. On the basis of solution corrosion and electrolysis, ultrasonic vibration is applied to stir the solution to dissociate the dissolved products on the surface of the workpiece, and the corrosion or electrolyte near the surface is uniform. The cavitation of the ultrasonic wave in the liquid can also inhibit the corrosion process and facilitate surface illuminating.