How precise can ultra-precision polishing be?

Promax super polishing technology

For the modern electronics industry, ultra-precision polishing is its soul. Its mission in the modern electronics industry is not only to polish different materials, but also to flatten multiple layers of materials. This kind of “global flattening” helps the silicon wafers at a size of only a few cubic millimeters to form a very large-scale integrated circuit composed of millions of transistors.

Today we will talk about this super-precision polishing process. Usually, we put grinding and polishing together, because the roughness of the parts after these two processes is already very small. First, we need to understand the difference between these two.

Grinding vs Polishing

Grinding is the use of abrasive particles coated or pressed on the grinding tool, through the relative movement of the grinding tool and the workpiece under a certain pressure, to accurately process the parts surface. Grinding can be used to process various metallic and non-metallic materials. The processed surface shapes include flat surfaces, internal and external cylindrical surfaces, conical surfaces, concave and convex spherical surfaces, threads, tooth surfaces and other profiles. The processing accuracy can reach IT5 ～ IT1, and the surface roughness can reach Ra0.63 ～ 0.01 microns.

Polishing is a processing method that uses mechanical, chemical, or electrochemical effects to reduce the roughness of the workpiece surface to obtain a brighter and smoother surface.

The main difference between the two is that the surface finish achieved by polishing is higher than that of grinding. Compared to grinding, which basically uses only mechanical methods to process, polishing can adopt chemical or electrochemical methods. The abrasive particle size used for grinding will be coarser than that used for polishing too.

How important is the ultra-precision polishing process in modern manufacturing? Its application field can directly answer this question: integrated circuit manufacturing as mentioned at the beginning of this article, medical equipment, auto parts, digital accessories, precision molds, aerospace etc.

For the polishing machine, the core device is the "polishing disc" or “belt”. Ultra-precision polishing has extremely strict requirements on the material composition and manufacturing technology of the polishing components in the machine. The components need to not only meet the nano-scale precision of automated operation, but also have an accurate thermal expansion coefficient.

When the polishing machine is in a high-speed running operation, if the thermal expansion causes the polishing disc to be thermally deformed, the flatness and parallelism of the substrate cannot be guaranteed.

Promax Smart super polishing machine adopts nano-finishing technology to overcome the negative effects of regular finishing processes. By high frequency oscillated abrasive belt short stoking on the surface, it removes just the peaks of micro-surface layer. The surface roughness is substantially improved without changing the dimension at the micron level (0.001 mm), improving the friction surface wear resistance. A variety of abrasive belts are available for different requirement of surface parameters, such as Ra, Rz, Rk, Rpk.

If you want to learn more about Promax Super polishing machine, please email sales@promaxsmart.com for more details!