Details of stainless steel polishing mode

After the metal powder injection molding product is sintered, the surface finish is relatively rough and has slight burr, and there may be small stainless steel powder particles sticking on the surface of the product for various reasons. In order to achieve surface finish (some products even require mirror effect, such as apple's Logo products) and deburring requirements, surface treatment processes such as grinding, polishing and sandblasting are often added.

First of all, what is stainless steel? Stainless steel is a kind of high alloy steel that can resist corrosion in air or chemical corrosive medium. Stainless steel is a kind of steel that has elegant appearance and good corrosion resistance, gives play to the inherent appearance of stainless steel without the surface treatment process such as color plating, and is used in many aspects. It is often called stainless steel. High alloy steels, such as 13 chromium steels and 18- chrome nickel steels, represent performance.

Metallographic analysis shows that stainless steel contains chromium, which forms a very thin chromium film on the outside. In order to maintain the inherent corrosion resistance of stainless steel, steel must contain more than 12% chromium. The new material found that stainless steel is most useful in hospitals or other areas where hygiene is critical, especially after secondary processing and polishing. Generally, a smooth appearance is required in a corrosive environment because a smooth appearance does not readily scale. Dirt deposits can rust or even corrode stainless steel. Stainless steel in food processing, catering, brewing and chemical industry, easy to clean, sometimes even use chemical cleaning agent, not easy to grow bacteria. Stainless steel is comparable to glass and ceramics in this respect!

The following polishing methods are available for stainless steel polishing process introduced by the new materials of dahong:

1. Mechanical polishing

Its advantage is that after processing parts of good leveling, high brightness. The defects of mechanical polishing are high labor intensity, severe pollution, and large and miscellaneous parts can not be processed, its luster can not be consistent, the gloss is not maintained for a long time, easy to be stuffy, rusting. Compare suitable processing simple, medium and small products.

Mechanical polishing is to rely on cutting, material appearance after removing plastic deformation by polishing the convex part of the smooth surface polishing method, commonly used article oil stone, wool wheel, abrasive paper, etc., with manual operation is given priority to, such as special parts of rotors appearance, can be used for tools such as turntable, appearance quality demanding can take over lapping way. Ultra-precision lapping is a special grinding tool. In the lapping liquid containing abrasive materials, the super-precision lapping is pressed on the surface of the workpiece being processed for high speed rotary movement. The metal powder injection molding company USES the technology to reach the roughness of the Ra0.008 exterior, the highest of any type of polishing. This is often used in optical lens molds.

2. Chemical polishing

Its advantages are less investment in processing equipment, large and complex parts can be thrown, speed, high efficiency, good corrosion resistance. The defects of chemical polishing are poor brightness, gas overflow, need ventilation equipment, and difficult heating. Suitable for processing large and complex parts in small batches and small parts with low light requirement.

Chemical polishing is to let the material in the chemical medium surface macroscopically protruding part of the preferential dissolution of concave part, so as to obtain a smooth surface. Dahong new materials found that the important advantage of this polishing method is that it does not require large and complex equipment. It can polish large and complex workpieces, and many workpieces can be polished at the same time, which is of high efficiency. The key problem of chemical polishing is the preparation of polishing liquid. The surface roughness obtained by chemical polishing is generally 10 m.

3. Electrolytic polishing

Its advantage is the mirror luster to maintain long, stable process, pollution less, low cost, corrosion is good. The defects of electrolytic polishing are high pollution resistance, large one-time investment in processing equipment, large and complex parts need tooling and auxiliary electrodes, and large batch production also needs cooling equipment. Guangdong dahong new material suggested that electrolytic polishing is suitable for batch production, which is mainly used in advanced products, export products and products with tolerance. Its processing technology is stable and its operation is relatively simple.

Electrolytic polishing is based on the same principle as chemical polishing, that is, by selectively dissolving the material surface small protruding parts, make the appearance smooth. Compared with chemical polishing, it can remove the influence of cathode reflection, and the effect is better.

The process of electrochemical polishing and chemical polishing is divided into two steps:

（1）Macroscopic levelling solution was dispersed into electrolyte, geometrical roughness of material surface dropped,Ra >, 1, clean m.

（2）Low light flat anode polarization, increased apparent brightness,Ra < 1 cym.

4. Ultrasonic polishing

Ultrasonic polishing put the workpiece into the abrasive suspension and put it together in the ultrasonic field, which depends on the oscillating effect of ultrasonic wave. The macroscopic strength of ultrasonic machining is small, which will not cause deformation of workpiece.

Ultrasonic machining can be combined with chemical or electrochemical methods. Metal powder injection MIM manufacturer found that on the root of solution corrosion and electrolysis, and then applied ultrasonic vibration stirring solution to separate the dissolved product on the surface of the workpiece. The cavitation of ultrasonic wave in liquid can also restrain the corrosion process and facilitate the surface lightening.

5. Fluid polishing

Fluid polishing depends on the high-speed flow of the liquid and its carrying abrasive scour the surface of the workpiece to reach the target of polishing. The common ways of the material finishing are: abrasive, liquid, hydrodynamic grinding, etc. Hydrodynamic grinding is driven by hydraulic pressure, which makes the liquid medium carrying the abrasive to and fro through the workpiece surface in high speed.

It is important that the medium is made of a special compound (polymer-like substance) that flows well at a lower pressure and is blended with an abrasive powder.

6. Magnetic grinding and polishing

Magnetic grinding and polishing is to use magnetic abrasive to form abrasive brush under the action of magnetic field, and to grind and process workpieces.

At present, the most important polishing method for the parts produced by MIM technology is magnetic grinding and mechanical polishing. The polishing in the plastic mold processing is very different from the surface polishing required in other metal powder injection molding industries. Many polishing of the mold can be referred to as mirror finishing. It has high requirements not only for polishing itself but also for surface smoothness, smoothness and geometric accuracy. Surface polishing usually requires only a polished surface.

The standard of mirror processing is divided into four levels: AO=Ra0.008 (mm), A1=Ra0.016 (m), A3=Ra0.032 (m), A4=Ra0.063 (m). As it is difficult to precisely control the geometric accuracy of parts by the methods of electrolytic polishing and fluid polishing, and the surface quality of chemical polishing, ultrasonic polishing and magnetic abrasive polishing cannot meet the requirements, the mirror processing of precision molds is mainly mechanical polishing.

Above are several polishing methods of stainless steel polishing process summarized by new materials of dahong, and more about other contents of metal powder injection molding technology. Welcome to consult the professional team of MIM injection molding technology of new materials of guangdong dahong!