Research And Application Status Of Ultra-thin Diamond Cutting Discs

Ultra-thin diamond cutting discs have gradually gained people's attention due to their advantages such as ultra-thin cutting groove width, smooth cutting fracture, low reject rate, and high cutting efficiency.

 

This article summarizes the research progress and application status of the main production methods of ultra-thin diamond cutting discs in the past 10 years, and introduces the preparation methods of ultra-thin diamond cutting discs, including electroplating and curing resin methods. The electroplating method is characterized by its simple equipment, green The advantages of environmental protection and recyclable production have become the most likely preparation method for large-scale industrial application. The article finally pointed out its development direction.

 

Manufacture of diamond ultra-thin cutting discs by resin method is a method that can obtain good shape retention. Generally, thermosetting phenolic resin is used as a binder. Its method is to mix diamond abrasive grains with resin, and then use hot pressing to sinter and heat Grinding is performed after curing, a process that takes hours and is therefore expensive to produce. With the advancement of technology, heat-curable resins are gradually replaced by light-curable resins, which are mainly composed of base polymers (photocrosslinkable polymers), reactive diluents (photopolymerizable monomers), photoinitiators and additives. composition. The most essential difference between it and thermal curing resin is that its curing process is a chemical reaction process caused by absorbing light of appropriate wavelength, and its transformation from liquid to solid is the result of molecular weight increase, not caused by solvent volatilization, so it has rapid curing , pollution-free, and energy-saving advantages, but the restrictive factor is the high price of its raw materials.

Using photocurable resin to manufacture ultra-thin diamond cutting discs, Peng Wei, Gu Taihong, etc. used photocurable resin as a binder to successfully develop an ultra-thin diamond cutting wheel with a thickness of 0.15mm, and completed the cutting test of a single piece. The shape of the grinding wheel after cutting is: 53mm×40mm×0.15mm. Cutting tests were carried out on the samples prepared in the experiment. Through the analysis of experimental data, the final result shows that adding an appropriate amount of SiO2. It can improve the overall performance of the cutting disc, and when the added particle content is 48, the cutting effect of the cutting disc is the best, and the cutting fracture is smoother. According to the analysis, the main cause of this phenomenon is the grinding effect of SiO2 particles on the surface of the groove by the high-density distribution of SiO2 particles on the surface of the original hill and the grinding wheel.

In 2004, based on rapid prototyping technology, Yao Chunyan, Peng Wei, etc. studied the rapid manufacturing technology of ultra-thin diamond cutting grinding wheel sheets using photosensitive resin as a binder, and added Japanese REV whiskers (13μm×70μm) , to improve the mechanical properties of the diamond cutting sheet bond. The Knoop hardness of a single piece is about K1000, while the Knoop hardness of diamond is as high as K7000E. Mix diamond micropowder and whiskers into the prepared photosensitive resin in a quantitative manner, stir evenly, and vacuum to defoam, pour into the thin-cut cutting wheel mold at room temperature, and cure and shape it by ultraviolet radiation. The size of the formed ultra-thin diamond cutting wheel sheet is: 52mm×40mm×0.15mm. Cutting tests of cutting discs with different formulations prove that adding REV whiskers to photosensitive resin cutting discs can enhance the grinding performance of the cutting disc and improve the quality of the cut material after cutting.

Adding SiO2 or whiskers alone to the cutting sheet is limited in improving the performance of the cutting sheet and cannot meet the actual needs. In 2004, Li Chengfu and others used the epoxy resin LC-2800 produced by Showa Polymer Company as a binder. The resin is cured by the irradiation of ultraviolet light to produce ultra-thin cut sheets, and its hardness, strength and wear resistance are improved by adding SiO2 particles and fibers as fillers. The manufacturing method of the dicing sheet is a high-speed spin coating method, that is, first drop the liquid resin on the center of the substrate, and then let the substrate rotate at a high speed, so that the liquid resin diffuses on the substrate to form a thin film, and irradiates with ultraviolet light at the upper 10mm. To make the cured resin solidified, so as to produce ultra-thin cutting blade, the size of the trial blade is 54mm × 40mm × 0.05mm. The cutting comparison experiments of different samples prove that the spin coating method can be used to manufacture ultra-thin diamond cutting sheets, and the addition of granular fillers can improve the hardness, and the fibrous fillers can increase the strength. Carbon fiber has better performance.

 

2.2 Electroplating method

The electroplating method is the process of depositing a thin layer of other metals or alloys on the metal substrate by using the principle of electrolysis. It is a process of using electrolysis to attach a layer of metal film to the surface of metal or other material parts. The particles enter the composite coating through the electrolysis process. Guglielmi believes that the particles entering the composite coating mainly rely on a two-step adsorption mechanism: the first step is that the particles carrying ions and solvent molecular films are adsorbed on the surface of the electrode, which is called weak adsorption. It is in equilibrium with the particles suspended in the bath. Particles in a weakly adsorbed state remove their adsorbed ions and solvated film, and directly contact with the cathode surface to form irreversible electrochemical adsorption, which becomes a strong adsorption step. This is followed by the embedding of strongly adsorbed particles into the coating during the metal electrodeposition process.

In 2000, Liu Dingfu of South China University of Technology introduced a method of using composite plating, which is a process of manufacturing diamond circular saw blades with nickel-cobalt alloy coating as an adhesive. Blade) Use a thin saw blade every 6-7mm to saw a 9mm-long gap along the diameter direction, so that the subsequent diamond particles and the coating as a bonding agent have a similar mechanical mosaic effect, so as to further strengthen the junction between the composite coating and the substrate Force, prolong the service life of the saw blade. The sanding method adopts the sanding method, that is, use a dropper to absorb the hydrophilized diamond particles and evenly spread them on the upward deposition surface, and then slightly vibrate the saw blade so that the diamond particles can be in stable contact with the substrate. After pre-plating, sanding, thickening plating, and bright plating, a good coating is finally obtained. It is finally proved that nickel-cobalt alloy can be used as a binder to obtain a good coating when making diamond tools.

In 2002, Guo Tiefeng and Yang Yanjun proposed that phosphate was first used to prepare chemical conversion coatings. The formula is (g/L): oxalic acid 5, phosphoric acid 15, sodium oxalate 4, disodium phosphate 1O, sodium chlorate 5; operating conditions For: temperature 20 ℃, time 5min. The prepared chemical conversion coating is best with austenitic stainless steel, which has good electrical conductivity, can make the electrodeposition process go smoothly, and prevent the electrodeposition material from being strongly combined with the substrate, so as to facilitate the peeling off of the coating.

For the electrochemical deposition stage, Ni-Co electroplating solution is used. The formula of the plating solution is (g/L): nickel sulfate 220-240, cobalt sulfate 15-30, boric acid 25-35, sodium chloride 10-20, and appropriate amount of patent additives , Diamond powder 5-10. The operating conditions of the experiment are: electroplating temperature 45 ℃ ~ 50 ℃, pH value 4.1 ~ 4.5, Dk = 2A/dm³, air pump stirring, intermittent time 10min. The composite coating is stripped from the substrate by heating, and stamped on a cold stamping machine. For the finished product made in the experiment, the cutting sheet comparison experiment shows that the product can meet the cutting requirements, and the cost is reduced by 1/3.

Zhou Linhua, Xu Jianhong, etc. of the Eighth Research Institute of the Shanghai Nuclear Industry, in a patent filed in 2003, described in detail the method of manufacturing ultra-thin diamond cutting discs. The nickel plate is used as the anode, and the stainless steel is used as the cathode. The electroplating solution is obtained by adding diamond abrasives, boric acid and additives to the mixed solution of hydrated nickel metal salt or hydrated nickel metal salt and other hydrated metal salts. The formula is (g/L): sulfuric acid Nickel 150-300, cobalt sulfate 3-20, boric acid 25-40, nickel chloride 30-60, primary brightener 0.2-2, secondary brightener 0.2-2, lubricant 0.05-1. Electroplating process parameters are: Dk=2A/dm³, pH value 4.1~4.5, temperature 45℃~50℃, diamond density 5~20g/L, time can control the thickness of composite electroplating layer. Put the cathode and anode into the electroplating solution, and after the power is turned on, under the action of electrons, the diamond abrasive and metal ions are uniformly eutectoid on the cathode substrate to obtain a composite electroplating layer. Gently bend the cathode substrate electroplated with the composite layer into an arc shape, the composite electroplating layer is easily separated from the cathode substrate, and finally the separated diamond and nickel-cobalt composite coating is obtained. After three hours of electroplating, a composite coating of 20 μm can be obtained.

Based on different substrates and different stripping methods of composite coatings, in 2009, Liu Jinlong of Dalian University of Technology introduced in detail the method of using aluminum alloy as the substrate for diamond-nickel composite coatings in the article "Experimental Research on Improving the Performance of Composite Electrodeposited Diamond Saws". Preparation, the aluminum alloy substrate is put into the plating tank as the cathode after pre-plating treatment for co-deposition of diamond metal, after obtaining the desired thickness of the coating, it is taken out, electrolyzed in the self-made electrolytic tank, and the substrate is corroded with a suitable electrolyte Dropped to get diamond composite coating. The obtained composite coating was studied on the scratches and blade wear on the silicon wafer and glass. After cutting, the blade remained sharp without warping and other deformations, and the performance met the requirements. He Changyao introduced a method of making ultra-thin diamond cutting discs with coated plastic as the substrate in the patent applied for in 2009.

He chooses coated plastic as the cathode substrate, pre-precipitates a layer of diamond on the surface, and puts in an electrolyte mixed with 18-25 nickel salt, 1-2 sodium salt, 1-3 cobalt and 2-4 acid solution. Among them, the high-purity nickel plate is used as the anode substrate, the temperature is 30 ℃ ~ 40 ℃, and the pH value is 4.2-4.6. The diamond is deposited on the diamond surface of the cathode substrate by electrodeposition to consolidate the diamond, thereby obtaining a thickness of 0.5. 02 ~ 1mm electroplating layer. Then put the cathode substrate with the electroplating layer into the prepared chloroform solution added with 2 ethanol, dissolve the coating plastic, and obtain the diamond-nickel composite coating, and cut it into the required size through post-processing piece.