抛光瓷砖毕业设计外文文献翻译

1、毕业设计外文资料翻译题 目 POLISHING OF CERAMIC TILES 抛光瓷砖 学 院 材料科学与工程 专 业 复合材料与工程 班 级 复材0802 学 生 窦文杰 学 号 20080103114 指导教师 邵明梁 二一二年三月二十八日MATERIALS AND MANUFACTURING PROCESSES, 17(3), 401413 (2002)POLISHING OF CERAMIC TILESC. Y. Wang,* X. Wei, and H. YuanInstitute of Manufacturing Technology, Guangdong University

2、 ofTechnology, Guangzhou 510090, P.R. ChinaABSTRACTGrinding and polishing are important steps in the production of decorative vitreous ceramic tiles. Different combinations of finishing wheels and polishing wheels are tested to optimize their selection. The results show that the surface glossiness d

3、epends not only on the surface quality before machining, but also on the characteristics of the ceramic tiles as well as the performance of grinding and polishing wheels. The performance of the polishing wheel is the key for a good final surface quality. The surface glossiness after finishing must b

4、e above 208 in order to get higher polishing quality because finishing will limit the maximum surface glossiness by polishing. The optimized combination of grinding and polishing wheels for all the steps will achieve shorter machining times and better surface quality. No obvious relationships are fo

5、und between the hardness of ceramic tiles and surface quality or the wear of grinding wheels; therefore, the hardness of the ceramic tile cannot be used for evaluating its machinability.Key Words: Ceramic tiles; Grinding wheel; Polishing wheelINTRODUCTIONCeramic tiles are the common decoration mater

6、ial for floors and walls ofhotel, office, and family buildings. Nowadays, polished vitreous ceramic tiles are more popular as decoration material than general vitreous ceramic tiles as they can*Corresponding author. HYPERLINK mailto: 401Copyright q 2002 by Marcel Dekker,

7、 Inc. HYPERLINK :/ dekker dekker have a beautiful gloss on different colors. Grinding and polishing of ceramic tilesplay an important role in the surface quality, cost, and productivity of ceramic tilesmanufactured for decoration. The grinding and polishing of ceramic tiles arecarried out in one pas

8、s through polishing production line with many differentgrinding wheels or by multi passes on a polishing machine, where differentgrinding wheels are used.Most factories utilize the grinding methods similar to those used for stonemachining although the machining of stone is different from that of cer

9、amic tiles.Vitreous ceramic tiles are thin, usually 58mm in thickness, and are a sinteredmaterial,which possess high hardness, wear resistance, and brittleness. In general, thesintering process causes surface deformation in the tiles. In themachining process, theceramic tiles are unfixed and put on

10、tables. These characteristics will cause easybreakage and lower surface quality if grinding wheel or grinding parameters areunsuitable. To meet the needs of ceramic tiles machining, the machinery, grindingparameters (pressure, feed speed, etc.), and grinding wheels (type and mesh size ofabrasive, bo

11、nd, structure of grinding wheel, etc.) must be optimized.Previous works have been reported in the field of grinding ceramic andstone1 4. Only a few reports have mentioned ceramic tile machining5 8, wherethe grinding mechanism of ceramic tiles by scratching and grinding was studied. Itwas pointed out

12、 that the grinding mechanism of ceramic tiles is similar to that ofother brittle materials. For vitreous ceramic tiles, removing the plastic deformationgrooves, craters (pores), and cracks are of major concern, which depends on themicro-structure of the ceramic tile, the choice of grinding wheel and

13、 processingparameters, etc. The residual cracks generated during sintering and rough grindingprocesses, as well as thermal impact cracks caused by the transformation of quartzcrystalline phases are the main reasons of tile breakage during processing. Surfaceroughness Ra and glossiness are different

14、measurements of the surface quality. It issuggested that the surface roughness can be used to control the surface quality ofrough grinding and semi-finish grinding processes, and the surface glossiness toassess the quality of finishing and polishing processes. The characteristics of thegrinding whee

15、ls, abrasive mesh size for the different machining steps, machiningtime, pressure, feed, and removing traces of grinding wheels will affect theprocessing of ceramic tiles9.In this paper, based on the study of grinding mechanisms of ceramic tiles, themanufacturing of grinding wheels is discussed. The

16、 actions and optimization ofgrinding and polishing wheels for each step are studied in particular for manualpolishingmachines.GRINDING AND POLISHING WHEELS FOR CERAMIC TILEMACHININGThe machining of ceramic tiles is a volume-production process that usessignificant numbers of grinding wheels. The grin

17、ding and polishing wheels forceramic tile machining are different from those for metals or structural ceramics.In this part, some results about grinding and polishing wheels are introduced forbetter understanding of the processing of ceramic tiles.Grinding and Polishing WheelsCeramic tiles machining

18、 in a manual-polishing machine can be divided intofour stepseach using different grinding wheels. Grinding wheels are marked as2#, 3#, and 4# grinding wheels, and 0# polishing wheel; in practice, 2# and 3#grinding wheels are used for flattening uneven surfaces. Basic requirements ofrough grinding wh

19、eels are long life, high removal rate, and lower price. For 2# and3# grinding wheels, SiC abrasives with mesh #180 (#320) are bonded bymagnesium oxychloride cement (MOC) together with some porous fills,waterproof additive, etc. The MOC is used as a bond because of its low price,simple manufacturing

20、process, and proper performance.The 4# grinding wheel will refine the surface to show the brightness of ceramictile. The GC#600 abrasives and some special polishingmaterials, etc., are bonded byMOC. In order to increase the performance such as elasticity, etc., of the grindingwheel, the bakelite is

21、always added. The 4# grinding wheels must be able to rapidlyeliminate all cutting grooves and increase the surface glossiness of the ceramic tiles.The 0# polishing wheel is used for obtaining final surface glossiness, whichis made of fine Al2O3 abrasives and fill. It is bonded by unsaturated resin.

22、Thepolishing wheels must be able to increase surface glossiness quickly and make theglossy ceramic tile surface permanent.Manufacturing of Magnesium Oxychloride Cement Grinding WheelsAfter the abrasives, the fills and the bond MOC are mixed and poured into themodels for grinding wheels, where the ch

23、emical reaction of MOC will solidify theshape of the grinding wheels. The reaction will stop after 30 days but the hardness ofgrinding wheel is essentially constant after 15 days. During the initial 15-day period,the grinding wheels must be maintained at a suitable humidity and temperature.For MOC g

24、rinding wheels, the structure of grinding wheel, the quality ofabrasives, and the composition of fill will affect their grinding ability. All thefactors related to the chemical reaction of MOC, such as the mole ratio ofMgO/MgCl2, the specific gravity of MgCl2, the temperature and humidity to carethe

25、 cement will also affect the performance of the MOC grinding wheels.Mole Ratio of MgO/MgCl2When MOC is used as the bond for the grinding wheels, hydration reactiontakes place between active MgO and MgCl2, which generates a hardXMgeOHT2YeMgCl2TZH2O phase. Through proper control of the mole ratio ofMg

26、O/MgCl2, a reaction product with stable performance is formed. The bond iscomposed of 5MgeOHT2eMgCl2T8H2O and 3MgeOHT2eMgCl2T8H2O: As theformer is more stable, optimization of the mole ratio of MgO/MgCl2 to producemore 5MgeOHT2eMgCl2T8H2O is required. In general, the ideal range for themole ratio of

27、 MgO/MgCl2 is 46. When the contents of the active MgO andMgCl2 are known, the quantified MgO and MgCl2 can be calculated.Active MgO The content of active MgO must be controlled carefully so that hydrationreaction can be successfully completed with more 5MgeOHT2eMgCl2T8H2O: Ifthe content of active Mg

28、O is too high, the hydration reaction time will be too shortwith a large reaction heat, which increases too quickly. The concentrations of thethermal stress can cause generation of cracks in the grinding wheel. On thecontrary, if the content of active MgO is too low, the reaction does not go tocompl

29、etion and the strength of the grinding wheel is decreased.Fills and AdditivesThe fills and additives play an important role in grinding wheels. Some porous fills must be added to 2# and 3# grinding wheels in order to improve the capacity to contain the grinding chips, and hold sufficient cutting gri

30、t. Waterproof additives such as sulfates can ensure the strength of grinding wheels in processing under water condition. Some fills are very effective in increasing the surface quality of ceramic tile, but the principle is not clear.Manufacturing of Polishing WheelsFine Al2O3 and some soft polishing

31、 materials, such as Fe2O3, Cr2O3, etc., are mixed together with fills. Unsaturated resin is used to bond these powders, where a chemical reaction takes place between the resin and the hardener by means of an activator. The performance of polishing wheels depends on the properties of resin and the co

32、mposition of the polishing wheel. In order to contain the fine chips, which are generated by micro-cutting, some cheap soluble salt can be fed into the coolant. On the surface of the polishing wheel, the salt will leave uniform pores, which not only increase the capacity to contain chips and self-sh

33、arpening of the polishing wheel, but also improves the contact situation between polishing wheel and ceramic tiles.Experimental ProcedureTests were carried out in a special manual grinding machine for ceramictiles. Two grinding wheels were fixed in the grinding disc that was equipped to thegrinding

34、machine. The diameter of grinding disc was 255 mm. The rotating speedof the grinding disc was 580 rpm. The grinding and polishing wheels are isoscelestrapezoid with surface area 31.5 cm2 (the upper edge: 2 cm, base edge: 5 cm,height: 9 cm). The pressure was adjusted by means of the load on the handl

35、e fordifferent grinding procedures. A zigzag path was used as the moving trace for thegrinding disc. To maintain flatness and edge of the ceramic tiles, at least one thirdof the tile must be under the grinding disc. During the grinding process, sufficientwater was poured to both cool and wash the gr

36、inding wheels and the tiles.Four kinds of vitreous ceramic tiles were examined, as shown in Table 1.Two different sizes of ceramic A, A400 (size: 400 400 5mm3T and A500(size: 500 500 5mm3T were tested to understand the effect of the tile size. Forceramic tile B or C, the size was 500 500 5mm3: The p

37、hase composition of thetiles was determined by x-ray diffraction technique. Surface reflection glossinessand surface roughness of the ceramic tiles and the wear of grinding wheels were measured.The grinding and polishing wheels were made in-house. The 2# grindingwheels with abrasives of mesh #150 an

38、d 3# grinding wheels with mesh #320 wereused during rough grinding. Using the ceramic tiles with different surfacetoughness ground by the 2# grinding wheel for 180 sec, the action of the 3#grinding wheels were tested. The ceramic tile was marked as A500-1 (or B500-1,C500-1, A400-1) with higher initi

39、al surface toughness or A500-2 (or B500-2,C500-2, A400-2) with lower initial surface toughness.Two kinds of finishing wheels, 4#A and 4#B were made with the same structure, abrasivity, and process, but different composition of fills and additives. Only in 4#B, a few Al2O3, barium sulfate, and magnes

40、ium stearate were added for higher surface glossiness. The composition of the polishing wheels 0#A and 0#B were different as well. In 0#B, a few white alundum (average diameter 1mm),barium sulfate, and chrome oxide were used as polishing additives, specially. After ground by 4#A (or 4#B) grinding wh

41、eel, the ceramic tiles were polished with 0#A (or 0#B). The processing combinations with 4# grinding wheels and 0#Table 1. Properties of Ceramic TilesCeramic TilesHV0.1CrystallineGrain Size(mm)Mullite(vol.%)Quartz(vol.%)VitreousMass(vol.%)Porosity(vol.%)Pore Size(mm)A400,A500661.010-3032-4015-1835-4

42、03-55-20B500710.610-3032-4010-1335-405-73-50C500614.210-3012-1510-1335-403-55-30polishing wheels were marked as 4#A0#A, 4#A0#B, 4#B0#A, 4#B0#B for each ceramic tile.RESULTS AND DISCUSSIONSEffects of 2# and 3# Grinding WheelsSurface Quality In rough grinding with a 2# grinding wheel, the surface roug

43、hness for all the tiles asymptotically decreases as the grinding time increases, see Fig. 1. The initial asymptote point of this curve represents the optimized rough grinding time, as continued grinding essentially has no effect on the surface roughness. In these tests, the surface roughness curves

44、decrease with grinding time and become smooth at ,120 sec. The final surface quality for different kinds of ceramic tiles is slightly different. In terms of the initial size of the tile, the surface roughness of ceramic tile A400 e 400 5mm3T is lower than that of A500 e500 500 5mm3T: The surface rou

45、ghness of ceramic tile B500 rapidly drops as the grinding time increases. Thus, it is easier to remove surface material from the hardest of thethree kinds of the ceramic tiles (Table 1). However, as the final surface roughness of ceramic tile A500 is the same as that of ceramic tile C500, the hardne

46、ss of theceramic tile does not have a direct relationship with the final surface quality.In the 3# grinding wheel step, all craters and cracks on the surface of ceramic tiles caused by the 2# grinding wheel must be removed. If residual cracks and craters exist, it will be impossible to get a high su

47、rface quality in the next step. The surface roughness obtained by the 2# grinding wheel will also affect the surfaceFigure 1. Surface roughness of several ceramic tiles as a function of grinding time for 2# grindingwheel.quality of next grinding step by the 3# grinding wheel. In Fig. 2, the actions

48、of the 3# grinding wheels are given using the ceramic tiles with different initial Ra, which were ground by the 2# grinding wheel for 180 sec. The curves of surface vs. grinding time rapidly decrease in 60 sec. Asymptotic behavior essentially becomes constant after 60 sec. In general, the larger the

49、 initial surface roughness, the worse the final surface roughness. For example, for ceramic tile B500-1, the initial Ra was 1.53mm, the finial Ra was 0.59mm after being ground by the 3# grinding wheel. When the initial Ra was 2.06mm for ceramic tile B500-2, the finial Ra was 0.67mm.In Ref. 8, we stu

50、died the relations between abrasive mesh size and evaluation indices of surface quality, such as surface roughness and surface glossiness. In rough grinding, the ground surface of ceramic tile shows fracture craters. These craters scatter the light, so that the surface glossiness values are almost c

51、onstant at a low level. It is difficult to improve the surface glossiness afterthese steps. Figure 3 shows the slow increase in surface glossiness with time by means of the 3# grinding wheel. It can be seen that the glossiness of ceramic tile B500-1 is the highest. The surface glossiness of ceramic

52、tile A400-1 is better than that of A500-1 because the effective grinding times per unit area for former is longer than for latter. These trends are similar to those for surface roughness inFig. 2.Wear of Grinding WheelsThe wear of grinding wheels is one of the factors controlling the machining cost.

53、 As shown in Fig. 4, the wear of grinding wheels is proportional to grindingFigure 2. Surface roughness of several ceramic tiles as a function of grinding time for 3# grindingwheel.Figure 3. Surface glossiness of several ceramic tiles as a function of grinding time by 3# grindingwheel.time for both

54、the grinding wheels and the three types of ceramic tiles. The wear rate of the 3# grinding wheel is larger than the 2# grinding wheel. It implies that the wear resistance of the 3# grinding wheel is not as good as 2# for constant grinding time of 180 sec. When the slope of the curve is smaller, life

55、 of thegrinding wheels will be longer. Comparison of the ceramic tiles hardness (Table 1) with the wear resistance behavior in Fig. 4 does not reveal a strong dependency. Therefore, the hardness of the ceramic tile cannot be used to distinguish the machinability. The difference ofFigure 4. Wear of g

56、rinding wheels of several ceramic tiles as a function of grinding time for 2# and3# grinding wheels.initial surface roughness of ceramic tile will affect the wear of grinding wheel. In Fig. 4, the wear of the 3# grinding wheel for ceramic tile B500-1 is smaller than that for ceramic tile B500-2. The

57、 initial surface roughness of the latter is higher than that of the former so that additional grinding time is required to remove the deeper residual craters on the surface. Improvement of the initial surface roughness can be the principal method for obtaining better grinding quality and grinding wh

58、eel life during rough grinding.Effects of 4# Grinding Wheels and 0# Polishing WheelsSurface QualityThe combination and the performance of 4# grinding and 0# polishingwheels show different results for each ceramic tile. The grinding quality vs. grinding (polishing) time curves are presented in Fig. 5

59、, where all the ceramic tiles were previously ground by 2# and 3# grinding wheels to the same surface quality.The surface glossiness is used to assess surface quality because the surface roughness is nearly constant as finishing or polishing time increases8. In this test, the ceramic tile A400 were

60、fast ground by 4#A and 4#B grinding wheels Fig. 5(a). The surface glossiness increased rapidly during the initial 90 sec and then slowly increased. The surface glossiness by grinding wheel 4#B is higher than by 4#A. Afterwards, polishing was done by four different combinations of finishing wheel and