抛光瓷砖毕业设计外文文献翻译.docx

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1、抛光瓷砖毕业设计外文文献翻译 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 学生 学号 指导教师 二一二年三月二十八日 MATERIALS AND MANUFACTURING PROCESSES, 17(3), 401413 (2022) POLISHING OF CERAMIC TILES C. Y. Wang,* X. Wei, and H. Yuan Institute of Manufacturing Technology, Guangdong University ofTechnology, G

2、uangzhou 510090, P.R. China ABSTRACT Grinding 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 depends not onl

3、y 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 be above 208 in

4、 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 found between th

5、e 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 wheel INTRODUCTION Ceramic tiles are the common decoration material for flo

6、ors and walls of hotel, 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. E-mail: cywang 401 Copyright q 2022 by Marcel Dekker, Inc. have a beautiful gloss on differen

7、t colors. Grinding and polishing of ceramic tiles play an important role in the surface quality, cost, and productivity of ceramic tiles manufactured for decoration. The grinding and polishing of ceramic tiles are carried out in one pass through polishing production line with many different grinding

8、 wheels or by multi passes on a polishing machine, where d ifferent grinding wheels are used. Most factories utilize the grinding methods similar to those used for stone machining although the machining of stone is different from that of ceramic tiles. Vitreous ceramic tiles are thin, usually 58mm i

9、n thickness, and are a sintered material,which possess high hardness, wear resistance, and brittleness. In general, the sintering process causes surface deformation in the tiles. In themachining process, the ceramic tiles are unfixed and put on tables. These characteristics will cause easy breakage

10、and lower surface quality if grinding wheel or grinding parameters are unsuitable. To meet the needs of ceramic tiles machining, the machinery, grinding parameters (pressure, feed speed, etc.), and grinding wheels (type and mesh size of abrasive, bond, structure of grinding wheel, etc.) must be opti

11、mized. Previous works have been reported in the field of grinding ceramic and stone1 4. Only a few reports have mentioned ceramic tile machining5 8, where the grinding mechanism of ceramic tiles by scratching and grinding was studied. It was pointed out that the grinding mechanism of ceramic tiles i

12、s similar to that of other brittle materials. For vitreous ceramic tiles, removing the plastic deformation grooves, craters (pores), and cracks are of major concern, which depends on the micro-structure of the ceramic tile, the choice of grinding wheel and processing parameters, etc. The residual cr

13、acks generated during sintering and rough grinding processes, as well as thermal impact cracks caused by the transformation of quartz crystalline phases are the main reasons of tile breakage during processing. Surface roughness Ra and glossiness are different measurements of the surface quality. It

14、is suggested that the surface roughness can be used to control the surface quality of rough grinding and semi-finish grinding processes, and the surface glossiness to assess the quality of finishing and polishing processes. The characteristics of the grinding wheels, abrasive mesh size for the diffe

15、rent machining steps, machining time, pressure, feed, and removing traces of grinding wheels will affect the processing of ceramic tiles9. In this paper, based on the study of grinding mechanisms of ceramic tiles, the manufacturing of grinding wheels is discussed. The actions and optimization of gri

16、nding and polishing wheels for each step are studied in particular for manualpolishing machines. GRINDING AND POLISHING WHEELS FOR CERAMIC TILE MACHINING T he mac hi ni ng of cer ami c t i l e s i s a vol ume-pr oduc t i on pr oc e s s t hat uses significant numbers of grinding wheels. The grinding

17、and polishing wheels for ceramic tile machining are different from those for metals or structural ceramics. In this part, some results about grinding and polishing wheels are intro duced for better understanding of the processing of ceramic tiles. Grinding and Polishing Wheels Ceramic tiles machinin

18、g in a manual-polishing machine can be divided into four stepseach using different grinding wheels. Grinding wheels are marked as 2#, 3#, and 4# grinding wheels, and 0# polishing wheel; in practice, 2# and 3# grinding wheels are used for flattening uneven surfaces. Basic requirements of rough grindi

19、ng wheels are long life, high removal rate, and lower price. For 2# and 3# gr inding wheel s, Si C a brasi ve s wi th me s h #180 (#320)a r e bonde d by m a g n e s i u m o x yc h l o r i d e c e m e n t(M O C)t o g e t h e r w i t h s o m e p o r o u s f i l l s, waterproof additive, etc. The MOC i

20、s used as a bond because of its low price, simple manufacturing process, and proper performance. T he 4# grinding wheel will refine the surface to show the brightness of ceramic tile. The GC#600 abrasives and some special polishingmaterials, etc., are bonded by MOC. In order to increase the performa

21、nce such as elasticity, etc., of the grinding wheel, the bakelite is always added. The 4# grinding wheels must be able to rapidly eliminate all cutting grooves and increase the surface glossiness of the ceramic tiles. The 0# polishing wheel is used for obtaining final surface glossiness, which is ma

22、de of fine Al2O3 abrasives and fill. It is bonded by unsaturated resin. The polishing wheels must be able to increase surface glossiness quickly and make the glossy ceramic tile surface permanent. Manufacturing of Magnesium Oxychloride Cement Grinding Wheels After the abrasives, the fills and the bo

23、nd MOC are mixed and poured into the models for grinding wheels, where the chemical reaction of MOC will solidify the shape of the grinding wheels. The reaction will stop after 30 days but the hardness of grinding wheel is essentially constant after 15 days. During the initial 15-day period, the gri

24、nding wheels must be maintained at a suitable humidity and temperature. For MOC grinding wheels, the structure of grinding wheel, the quality of abrasives, and the composition of fill will affect their grinding ability. All the factors related to the chemical reaction of MOC, such as the mole ratio

25、of MgO/MgCl2, the specific gravity of MgCl2, the temperature and humidity to care the cement will also affect the performance of the MOC grinding wheels. Mole Ratio of MgO/MgCl2 When MOC is used as the bond for the grinding wheels, hydration reaction takes place between active MgO and MgCl2, which g

26、enerates a hard XMg e OH T2Y e MgCl2TZH2O phase. Through proper control of the mole ratio of MgO/MgCl2, a reaction product with stable performance is formed. The bond is composed of 5Mg e OH T2e MgCl2T8H2O and 3Mg e OH T2e MgCl2T8H2O: As the former is more stable, optimization of the mole ratio of M

27、gO/MgCl2 to produce more 5Mg e OH T2e MgCl2T8H2O is required. In general, the ideal range for the mole ratio of MgO/MgCl2 is 46. When the contents of the active MgO and MgCl2 are known, the quantified MgO and MgCl2 can be calculated. Active MgO The content of active MgO must be controlled carefully

28、so that hydration reaction can be successfully completed with more 5Mg e OH T2e MgCl2T8H2O: If the content of active MgO is too high, the hydration reaction time will be too short with a large reaction heat, which increases too quickly. The concentrations of the thermal stress can cause generation o

29、f cracks in the grinding wheel. On the contrary, if the content of active MgO is too low, the reaction does not go to completion and the strength of the grinding wheel is decreased. Fills and Additives The fills and additives play an important role in grinding wheels. Some porous fills must be added

30、 to 2# and 3# grinding wheels in order to improve the capacity to contain the grinding chips, and hold sufficient cutting grit. 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 surfac

31、e quality of ceramic tile, but the principle is not clear. Manufacturing of Polishing Wheels Fine Al2O3 and some soft polishing 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 res

32、in and the hardener by means of an activator. The performance of polishing wheels depends on the properties of resin and the composition 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 surfa

33、ce of the polishing wheel, the salt will leave uniform pores, which not only increase the capacity to contain chips and self-sharpening of the polishing wheel, but also improves the contact situation between polishing wheel and ceramic tiles. Experimental Procedure Tests were carried out in a specia

34、l manual grinding machine for ceramic tiles. Two grinding wheels were fixed in the grinding disc that was equipped to the grinding machine. The diameter of grinding disc was 255 mm. The rotating speed of the grinding disc was 580 rpm. The grinding and polishing wheels are isosceles trapezoid with su

35、rface 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 handle for different grinding procedures. A zigzag path was used as t he moving trace for the grinding disc. To maintain flatness and edge of the ceramic tiles, at least o

36、ne third of the tile must be under the grinding disc. During the grinding process, sufficient water was poured to both cool and wash the grinding wheels an d 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 5mm3

37、T and A500 (size: 500 500 5mm3T were tested to understand the effect of the tile size. For ceramic tile B or C, the size was 500 500 5mm3: The phase composition of the tiles was determined by x-ray diffraction technique. Surface reflection glossiness and surface roughness of the ceramic tiles and th

38、e wear of grinding wheels were measured. The grinding and polishing wheels were made in-house. The 2# grinding wheels with abrasives of mesh #150 and 3# grinding wheels with mesh #320 were used during rough grinding. Using the ceramic tiles with different surface toughness ground by the 2# grinding

39、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 initial 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 mad

40、e with the same structure, abrasivity, and process, but different composition of fills and additives. Only in 4#B, a few Al2O3, barium sulfate, and magnesium 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 w

41、hite alundum (average diameter 1mm), barium sulfate, and chrome oxide were used as polishing additives, specially. After ground by 4#A (or 4#B) grinding wheel, the ceramic tiles were polished with 0#A (or 0#B). The processing combinations with 4# grinding wheels and 0# RESULTS AND DISCUSSIONS Effect

42、s of 2# and 3# Grinding Wheels Surface Quality In rough grinding with a 2# grinding wheel, the surface roughness 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

43、 grinding essentially has no effect on the surface roughness. In these tests, the surface roughness curves 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 su

44、rface roughness of ceramic tile A400 e 400 5mm3T is lower than that of A500 e500 500 5mm3T: The surface roughness of c e r a m i c t i l e B500r a p i d l y d r o p s a s t h e g r i n d i n g t i m e i n c r e a s e s. Thus, it is easier to remove surface material from the hardest of the three kind

45、s 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 hardness 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 su

46、rface 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 surface quality in the next step. The surface roughness obtained by the 2# grinding wheel will also affect the surface Figure 1. Surface roughness of seve

47、ral ceramic tiles as a function of grinding time for 2# grinding wheel. quality of next grinding step by the 3# grinding wheel. In Fig. 2, the actions of the 3# grinding wheels are given using the ceramic tiles with different initial R a, which were ground by the 2# grinding wheel for 180 sec. The c

48、urves of surface vs. grinding time rapidly decrease in 60 sec. Asymptotic behavior essentially becomes constant after 60 sec. In general, the larger the initial surface roughness, the worse the final surface roughness. For example, for ceramic tile B500-1, the initial R a was 1.53mm, the finial R a was 0.59mm after being gro