Papers by Author: Bing Suo Pan

Abstract: To reduce the friction coefficient between impregnated diamond bit and rock, experiments on addition of graphite to the matrix material of bit cutters were conducted. The cutters were made up of diamond contained working layers and binding layers. The friction and wear properties of cutters and binding layers were investigated using a pin-on-disc friction & wear tester with granite as tribopair. The results showed that with addition of graphite, the hardness and friction coefficient of binding layer decreased, but its wear resistance increased; compared to cutters without graphite, those cutters containing graphite had lower wear loss and friction coefficient and their sliding wear process was much steadier, but diamond protrusion was still normal.

Abstract: For machining of hard and brittle materials, iron electrodeposit is a kind of matrix material with potential advantages for manufacture of diamond tools. Aiming at the problem of difficult codeposition of diamond in iron deposit, this paper adopts orthogonal design of experiment to study the effects of solution pH value, cathodic current density, alkylphenol polyoxyethylene (10) ether (OP-10) concentration and ammonium chloride concentration on codeposition of diamond, and then Fe-based diamond bits were fabricated and drilling tests in granite were carried out. The results show that pH value, cathodic current density, OP-10 concentration and ammonium chloride concentration all have statistically significant effect on codeposition of diamond in iron deposit, whose contributions to the variance of the weight of codeposited diamond are 37.45%, 32.05%, 13.13% and 12.38%, respectively. The result of drilling test indicates that Fe-based diamond bit can achieve much higher penetration rate than common Ni-based diamond bit.

Abstract: In precision machining, the uniformity degree of abrasive distribution affects significantly the surface quality. To quantitatively evaluate the uniformity of abrasive distribution, in this paper digital image processing technology was employed to segment the working face images of impregnated diamond tools; mean crowding index was used to classify the pattern of abrasive distribution; fractal dimension determined by gyration radius method was applied to characterize the bulk uniformity of abrasive distribution on face plane; the coefficient of variation of Voronoi cell areas was adopted to describe the local distribution feature of abrasive grits. The results show that mean crowding index, fractal dimension and CV of Voronoi cell areas can characterize the uniformity of abrasive distribution from different points of view, and can be used to quantitatively evaluate the uniformity of abrasive distribution.

Abstract: Formula uniform design method was adopted to study the performance of iron-based matrix with high content of phosphorus and boron. Two forms of regression models on matrix hardness and wear resistance and the optimum matrix formulae were obtained respectively by regression analysis and constrained nonlinear programming using MATLAB. Regression analyses indicate that matrix hardness was mainly affected by the factor of Ni, Co and Fe; matrix hardness and brittleness increased with the increment of P-Fe alloy, but decreased with the increase of 663-Cu. These results can be used as a rough guide for design of highly adaptive diamond bits for different rock formations. After the indoor experiments, diamond bit based on 3# matrix formula was made to perform field drilling tests. The results were that the penetration rate was 1.91m/h and the average diamond bit life was 67.37m.

Abstract: To increase the manufacture efficiency of electroplated diamond tools, a nickel plating solution containing ammonium sulphate and sodium formate was investigated. The effects of concentration of ammonium sulphate, sodium formate and pH value on throwing power, covering power, ability to resist Cu2+ contamination and deposit microhardness were studied. Surface topography of deposits was also observed by SEM. Compared to watts bath, the plating solution studied is advantageous in terms of the performance of plating solution, deposit hardness and diamond bit behavior. Ammonium sulphate can refine deposit crystal grains and result in crystal form change.