Mechanical polishing mechanical polishing by cutting, remove the plastic deformation of the material surface the protrusion is polished and smooth surface polishing method, general Whetstone Article wool round, sandpaper, etc., mainly manual, special parts, such as rotating body the surface, you can use the turntable aids, high surface quality requirements can be Superfinishing throwing method. The Superfinishing throwing a special abrasive polishing liquid containing abrasive, pressed in the workpiece is machined surface for high-speed rotary motion. Using this technology can achieve a surface roughness of the Ra0.008μm various polishing method. Optical lens mold often use this method.
Chemical polishing chemical polishing surface micro-projections of some of the more concave part of the material in the chemical medium priority dissolved, resulting in a smooth surface. The main advantage of this method is that no complicated equipment, the complex shape of the workpiece can be polished can be polished simultaneously lot of artifacts, high efficiency. Chemical polishing the core problem is the preparation of the polishing liquid. Chemical polishing to obtain a surface roughness of the general number of 10μm.
The electrolytic polishing electrolytic polishing the basic principle is the same as the chemical polishing, i.e. relying on the the dissolved material surface of the selective minor projecting portion to make the surface smooth. Compared to chemical polishing, can eliminate the impact of the cathodic reaction, the better.
Electrochemical polishing process is divided into two steps:
(1) macro leveling dissolved product diffuses to the electrolyte, the material surface geometry rough decline, Ra> 1μm.
(2) flat anodic polarization shimmer improve surface brightness, Ra of <1μm.
Ultrasonic polishing the workpiece into the abrasive in suspension and placed in the ultrasonic field together, relying oscillation effects of the ultrasonic wave, so that the abrasive on the workpiece surface grinding and polishing. Ultrasonic machining macro force does not cause deformation of the workpiece, but the tooling fabrication and installation more difficult. The ultrasonic processing can be combined with the chemical or electrochemical methods. Solution corrosion, electrolysis based on the ultrasonic vibration is applied to the stirred solution, dissolved product departing from the workpiece surface, uniform near the surface of corrosion or electrolyte; ultrasonic cavitation in a liquid is also capable of inhibiting the corrosion process, conducive bright surface.
Fluid polishing fluid polishing rely on high-speed flow of liquid carry the abrasive scouring workpiece surface to achieve the purpose of polishing. The commonly used methods are: the abrasive jet machining, the liquid jet machining, such as polishing fluid power. And grinding by means of fluid power is driven by a hydraulic reciprocating flow at high speed through the workpiece surface, so that the liquid medium carrying abrasive grains. The media used mainly in the lower pressure downstream of a good special compound (polymer-like substance), the abrasive can be a silicon carbide powder doped abrasive made.
Magnetic polishing magnetic polishing the magnetic abrasives in the magnetic field to form an abrasive brush grinding workpiece machining. This method is high processing efficiency, good quality, easy to control the processing conditions, and good working conditions. The suitable abrasive surface roughness can reach Ra0.1μm.
Polishing the surface as required in the basic methods of mechanical polishing in the plastic mold processing of said polishing and other industries are very different and, strictly speaking, the polishing of the mold should be referred to as mirror-finished. It is not only the polishing itself high demands and high standards in surface flatness, smoothness and geometric accuracy. Surface polished shiny surface can be generally require only. Mirror finish standards into four categories: AO = Ra0.008μm, A1 = Ra0.016μm, A3 = Ra0.032μm, A4 = Ra0.063μm, precise control of the geometry of the part due to the very difficult method of electrolytic polishing, hydrofinish on accuracy chemical polishing, ultrasonic polishing, magnetic polishing method of surface quality and meet the requirements, precision mold mirror finish or mechanical polishing.
Mechanical polishing procedures in order to obtain high-quality polishing effect, the most important thing is to have high-quality Whetstone, ointment polishing sandpaper and diamond grinding tools and supplements. The surface condition after the polishing procedure the selection depends on the pre-processing, such as machining, EDM, grinding and so on.
Mechanical polishing of the following general process:
The rough polishing by milling, EDM, grinding the surface after the process can select the speed at 35 000-40 000 rpm rotation surface polishing machine or ultrasonic grinder polishing. The common method diameter Φ3mm the WA # 400 of the wheels to remove a white spark layer. Then hand whetstone grinding, the strip Oilstone plus kerosene as a lubricant or coolant. Usually the use of the order of # 180 to # 240 to # 320 to # 400 to # 600 to # 800 to # 1000. Many mold manufacturers in order to save time and choose to start from # 400.
2, half of the semi-fine polishing fine polishing sandpaper and kerosene. Sandpaper number is as follows: # 400 to # 600 to # 800 to # 1000 to # 1200 to # 1500. Actually # 1500 sandpaper only suitable for hardened mold steel (52HRC), does not apply to pre-hardened steel, because it may lead to pre-hardened steel surface burns.
3, fine polishing fine polishing using diamond polishing paste. Polished with polishing cloth wheel mixing diamond abrasive powder or abrasive paste, then the usual order of the polishing 9μm (# 1800) ~ 6μm (# 3000) ~ 3μm (# 8000). 9μm diamond polishing paste polishing cloth wheel can be used to remove the # 1200 and # 1500 sandpaper hairy wear scar left. Followed by sticky mat and diamond polishing paste for polishing the order of 1μm (# 14000) 1/2μm (# 60000) to 1/4μm (# 100000).
The polishing process of the precision requirements in the 1μm above (including 1μm) to a clean polished in the mold processing plant can be carried out indoors. If more precision polishing must an absolutely clean space. Dust, smoke, dandruff and saliva foam may have scrapped after a few hours of work to get the high precision polishing surface.
