The difference between Grinding, Lapping, Polishing and Ultra-precision polishing you should know! – Yuhuan CNC ultra-precision polishing machine

A long time ago, there was such a report: scientists in Germany, Japan and other countries spent 5 years and spent nearly 10 million yuan to create a round ball made of high-purity silicon-28 material, this 1kg pure silicon ball requires ultra-precision processing, grinding and polishing, precision measurement (sphericality, roughness and quality), which can be described as the roundest ball in the world. Let’s find out in a short video

Let’s take a look at the ultra-precision polishing process.

01

研Grinding: Using abrasive particles coated or embedded on the research tool, the finishing of the processed surface is carried out by the relative movement of the tool and the workpiece under a certain pressure. Grinding can be used to process a variety of metal and non-metallic materials, the surface shape of processing is flat, inner and outer cylindrical and conical, convex, concave spherical, threaded, tooth surface and other profiles. The processing accuracy can reach IT5~IT1, and the surface roughness can reach Ra0.63~0.01μm.

Polishing: utilize mechanical, chemical or electrochemical action to reduce the surface roughness of the workpiece to obtain a bright, flat surface processing method。 

The main difference between the two is that the surface finish achieved by polishing is higher than that of grinding, and chemical or electrochemical methods can be used, while grinding is basically only mechanical, and the abrasive particle size used is coarser than that used for polishing, that is, the particle size is large.

02

Ultra-precision polishing is the soul of the modern electronics industry
The mission of ultra-precision polishing technology in the modern electronics industry is not only to flatten different materials, but also to flatten multi-layer materials, so that silicon wafers of several millimeters square form ultra-large-scale integrated circuits composed of tens of thousands to millions of transistors through this “global flatness”. For example, the computer invented by humans has changed from tens of tons to hundreds of grams today, which cannot be achieved without ultra-precision polishing.

In wafer fabrication, for example, polishing is the final step in the process, in order to improve the minor defects left by the previous process of wafer processing for optimal parallelism. At today’s level of optoelectronic information industry, the parallelism requirements for sapphire, single crystal silicon and other materials as optoelectronic substrate materials are becoming more and more precise, and have reached the nanoscale. This means that the polishing process has also entered the nanometer level of ultra-precision。

How important ultra-precision polishing processes are in modern manufacturing is a direct illustration of its application areas, including integrated circuit manufacturing, medical devices, automotive parts, digital accessories, precision molds, and aerospace.
 

The top polishing process is not only mastered by a few countries such as the United States, Japan, and South Korea, but also China

The core device of the polishing machine is the “grinding disc”. Ultra-precision polishing has almost harsh material composition and technical requirements for the grinding disc in the polishing machine, and this steel disc synthesized from special materials must not only meet the nanoscale precision of automated operation, but also have an accurate coefficient of thermal expansion。

When the polishing machine is running at high speed, if the thermal expansion causes thermal deformation of the grinding disc, the flatness and parallelism of the substrate cannot be guaranteed. And this thermal deformation error that cannot be allowed to occur is not a few millimeters or a few microns, but a few nanometers。

At present, the top international polishing process such as the United States and Japan can meet the precision polishing requirements of 60-inch substrate raw materials (super large size), and they control the core technology of ultra-precision polishing process and firmly grasp the initiative of the global market. In fact, grasping this technology also controls the development of electronic manufacturing to a large extent. India, Mexico, Vietnam polishing technology is still in its infancy, Middle East countries, Russia, Brazil, etc. are still at a low level in this field。

In the face of such a strict technical blockade, in the field of ultra-precision polishing, China can almost only carry out self-research at present.

What is the level of ultra-precision polishing technology in China?
In 2011, the “cerium dioxide microsphere particle size reference material and its preparation technology” developed by the team of Dr. Wang Qi of the National Center for Nanoscience of the Chinese Academy of Sciences won the first prize of technical invention of China Petroleum and Chemical Industry Federation, and the relevant nanoscale particle size standard material obtained the national measuring instrument license and the national first-class standard material certificate. The ultra-precision polishing production test effect of cerium dioxide new materials has caught up with foreign traditional materials and filled the gap in this field。

But Dr. Wang said: “This does not mean that we have climbed to the top of this field, for the overall process, there is only polishing liquid and no ultra-precision polishing machine, we are only selling materials at most.”
In 2019, the research team of Professor Yuan Julong of Zhejiang University of Technology created semi-fixed abrasive chemical mechanical processing technology, and the series of polishing machines developed have been mass-produced by Yuhuan CNC Machine Tool Co., Ltd. More than 1,000 units, which was identified by Apple as the world’s only precision polishing equipment for iPhone and iPad glass panels and aluminum alloy backplate polishing, and more than 1,700 polishing machines were used in the mass production of Apple’s iPhone and iPad glass plates.

Enter Yuhuan CNC Machine Tool Co., Ltd

The reporter walked into the production workshop of Yuhuan CNC machine tool, and saw that several machine tools were running at the same time, each machine tool processed and polished the five mobile phone frames at the same time, and automatically transferred to the next process after completing one process… This is the champion product of Yuhuan CNC “CNC grinding and polishing machine tool”.

The single champion of manufacturing industry is known as the “pearl” in the crown of manufacturing and the “spire” of the pyramid, which refers to the enterprises or products that have long focused on the market of some specific product segments of the manufacturing industry, the international leading production technology or process, and the market share of single products in the forefront of the world. Why did Yuhuan CNC’s “CNC grinding and polishing machine tool” win the champion product? According to the person in charge of the company, this product integrates coarse grinding, fine grinding, rough polishing, fine polishing and other multi-workpiece and multi-process as one of the fourteen-axis five-linkage grinding and polishing equipment, which can realize the efficient and high-precision grinding and polishing composite processing of mobile phone middle frame and other parts. The product covers five stations, each station has four polishing heads, the entire processing production line, integrated into one equipment, a machine tool equivalent to a past assembly line, in the grinding and polishing accuracy, production efficiency, automation level, etc., integrated a number of independent innovation of core technology, greatly improve the processing efficiency, save equipment, space and labor costs, far better than traditional technology and equipment, at home and abroad have not found the same type of machine tools, fill the industry gap.
 

It is understood that this champion product has created considerable economic benefits for the company, with cumulative sales of 760 million yuan in the past three years. In addition, through school-enterprise cooperation, the company independently developed CNC systems and software, which not only met the needs of mass production, but also solved the problems of long supply time, untimely service and high price of foreign control systems.

CNC machine tool is an industrial mother machine, which is a machine for producing machines. Although China’s CNC machine tool production capacity and consumer market scale are leading in the world, the field of high-end CNC machine tools is still a pain point restricting the development of China’s manufacturing industry. Aiming at this demand, Yuhuan CNC has developed high-end CNC machine tool products that are not only leading in the domestic industry, but also exported to many countries, and a number of key technologies rank at the international leading level.

R&D and innovation have long become the genes of Yuhuan CNC. Their gaze is not limited to the eyes, focusing on CNC precision face grinders, precision grinding and polishing equipment, intelligent complete sets of equipment and key functional components and other aspects of continuous innovation, committed to breaking through the shortcomings of the industry, continuing to expand product import substitution, and constantly moving towards building a world-class machine tool equipment manufacturing enterprise with global competitiveness.

If you want to learn more about polishing machine, please contact us immediately:

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Company Name: Yuhuan CNC machine tool Co., Ltd

Contact Person: Raymond Lei

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Country: China

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