【机械类毕业论文中英文对照文献翻译】振动镗孔与振动钻孔的研究
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【机械类毕业论文中英文对照文献翻译】振动镗孔与振动钻孔的研究,机械类毕业论文中英文对照文献翻译,机械类,毕业论文,中英文,对照,文献,翻译,振动,镗孔,钻孔,研究
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International Journal of Machine Tools & Manufacture 47 (2007) 133140Study on boring and drilling with vibration cuttingG.-L. Chern?, Jia-Ming LiangDepartment of Mechanical Engineering, National Yunlin University of Science and Technology, 123 University Road, Sector 3, Touliu, Yunlin 640, TaiwanReceived 21 August 2005; received in revised form 22 January 2006; accepted 17 February 2006Available online 18 April 2006AbstractIn this paper, vibration cutting (VC) has been applied to boring and drilling processes using a vibration device we developed. Weanalyzed the effect of vibration in boring by investigating the surface roughness of workpiece with the help of Taguchi method andanalysis of variance (ANOVA). It has been shown that the utilization of VC in boring improves the surface roughness prominently. Theshading-area method we proposed can be employed as a simple and feasible approach for the analysis of burrs in intersecting holes.High-frequency vibration boring can reduce the burr formation in intersecting holes effectively. The experimental results show that theutilization of VC reduces the burrs in intersecting holes noticeably.r 2006 Elsevier Ltd. All rights reserved.Keywords: Vibration cutting; Drilling; Boring; Burr; Intersecting hole1. IntroductionVibration cutting (VC) is a technique in which high orlow frequency of vibration is superimposed to the cuttingtool or the workpiece during a machining operation inorder to achieve better cutting performance. This techniquehad been employed in the precision drilling of wood 1,2and low carbon steel 3. The use of low frequency andultrasonic vibration had been found to be helpful inreducing burr size and prolong tool life in drillingaluminum and glass-fiber reinforced plastics 4,5. Adachiet al. 4 developed an electro-hydraulic servo-system with amaximum frequency of 100Hz to produce a low-frequencyvibration drilling in aluminum and obtained a decrease inburr size of 525%. Onikura et al. 6,7 utilized a piezo-actuator to generate 40KHz of ultrasonic vibration in thedrilling spindle. They found that the use of ultrasonicvibration reduces the friction between chip and rake face,resultingincuttingchipstobethinner,andthenconsiderably reduces the cutting forces. Thus the utilizationof VC decreases the hole oversize, reduces the frictionbetween chip and rake face and improves the surfaceroughness. Chern and Lee 8 proposed a new approach toobtain the desired vibration from the workpiece side.Through extensive experiments with a twist drill size of0.5mm, they found that hole oversize, dislocation of thehole center and surface roughness of the drilled hole innersurface could be improved with the increase of vibrationfrequency and amplitude.Jin and Murakawa 9 had found that the chipping of thecutting tool can be effectively prevented by applyingultrasonicVCandthetoollifecanbeprolongedaccordingly. Takeyama and Kato 5 found that the meanthrust force in drilling can be greatly reduced underultrasonic VC. Drilling chips are thinner and easier toescape from the drilled hole. Burr formation at theentrance and the exit sides is greatly retarded with thelow cutting forces. Thus the overall drilling quality isimproved with the employment of VC.Besides drilling, turning is another field of VC applica-tion. Materials like glass with poor machinability are foundto be machined effectively with the assistance of VC. Themethod of ultrasonic VC had been employed to the turningof machinable glass ceramics 10 and soda-lime glass 11.A surface roughness of 0.03mm in Rmaxwas successfullyobtained in face turning of soda-lime glass by applying VC.Ultra-precision ductile cutting of glass could be achievedby applying ultrasonic vibration in the cutting direction.ARTICLE IN PRESS/locate/ijmactool0890-6955/$-see front matter r 2006 Elsevier Ltd. All rights reserved.doi:10.1016/j.ijmachtools.2006.02.017?Corresponding author. Tel.: +886553426014145;fax: +88655312062.E-mail address: cherngl.tw (G.-L. Chern).In general, the steel cannot be machined by diamondtools due to excessive tool wear. But under ultrasonic VC,diamond turning of stainless steel was realized and anoptical quality mirror of stainless steel with a surfaceroughness of 0.026mm in Rmaxwas obtained 12. Shamotoand Moriwaki 13 proposed an elliptical-vibration-cuttingmethod by introducing synchronized two-directional vi-bration. Hardened die steel could be machined effectivelyin their turning experiments 14 with low cutting force,high quality surface and long tool life.The manufacture of industrial valves often involvesdrilling and boring operations, generating intersectingholes. One major problem caused is the formation of burrsinside the valves. Deburring of intersecting holes is one ofthe most difficult deburring tasks faced by many industries.Many deburring processes are not applicable to mostintersecting-hole cases, especially when small-diameterdrilling is involved. Burrs in intersecting holes may hinderair or liquid flow inside the valve in real application,leading to malfunction or undesirable consequence.In this paper, a vibration-boring device was designed andfabricated. A piezoelectric actuator is utilized on the end ofthe boring bar to generate the desired axial vibration.Surface roughness of the workpiece after boring, withoutand with VC, was investigated. With the help of Taguchimethod, influence and contribution ratio of each machin-ing parameter can be determined. Burr formation inintersecting holes was defined as the region shaded by burrwithin the circular area after drilling and boring. Burr sizewas then measured through an image-processing softwareby calculating the number of black pixels in the capturedimage. Through the experimental results we discussed theeffect of VC on boring and drilling.2. Design and fabrication of vibration-boring deviceThe basic idea of employing VC on the boring operationis schematically illustrated in Fig. 1. Vibration is applied tothe boring bar in the feed direction of the workpiece. Toensure that the boring bar is vibrating in the axial directionof the workpiece, two linear guideways were employed andarranged symmetrically in conjunction with the holdingblocks, as shown in Fig. 2. Piezoelectric actuators had beenutilizedtoproducehigh-frequencyvibrationintheprevious VC researches 68,13,14. Piezoelectric actuatorspossess the characteristics of fine precision, quick responseand large driving force. Thus in this paper we attached apiezoelectric actuator to the end of the boring bar togenerate the desired vibration. Four outwall blocks wereconnected to accommodate the guideways, the holdingblocks and the piezoelectric actuator. The whole vibration-boring device is shown in exploded form in Fig. 3. Photo ofthe device is shown in Fig. 4.The design for this vibration-boring device is based onthe following considerations.1. Due to the space limitation, the device is designed forthe boring bar with a diameter of 12mm and a length of150mm. The boring bar is fastened to the holding block bythe screws in Fig. 4.2. The whole structure must possess enough stiffness towithstand the dynamic loads during the boring operation.Each element of the device is made of stainless steel withhigh strength to provide enough stiffness.ARTICLE IN PRESSFig. 1. Vibration cutting for boring operation.Fig. 2. Linear guideway and holding block.Fig. 3. Vibration-boring device in exploded form.G.-L. Chern, J.-M. Liang / International Journal of Machine Tools & Manufacture 47 (2007) 1331401343. Piezoelectric actuators operate as capacitive loads. Toobtain high-frequency vibration, the power supply mustprovide enough charging currents. In this research, we useda Physik Instrumente (PI) made piezoelectric actuator (PIP-244.10), cooperated with a high power amplifier (PI P-270.02). The maximum frequency of P-244.10 is 16kHz.The output voltage of P-270.02 is from 0 to ?1000V. Itspeak current is 50mA and the maximum average outputcurrent is 13mA.4. The capacities of pushing force and pulling force of P-244.10 are 2000 and 300N, respectively. Obviously, piezo-electric ceramics can withstand high pushing loads but arebrittle and cannot withstand high pulling force. To avoidthe possibility of damage occurred in boring due toexcessivepullingforce,thepiezoelectricactuatorispreloaded by the spring, as shown in Fig. 4, which iscompressed between the outwall block and the holdingblock. The selection of the spring is based on the boringforce involved and the pulling force that can be sustainedby the piezoelectric actuator. Thus a steel spring of 1mm inwire diameter is chosen in this study.3. Experimental equipment and methodThe experimental equipments are described as follows.Engine lathe (Victor-500?1000): to perform boringexperiments. Machining center (MC-1050P, Mitsubishi-520AM controller): for the drilling of intersecting-holeexperiments. Laser displacement meter (Keyence LC-2430): to measure the amplitude of vibration. The samplingrate of this sensor is 50kHz. The resolution is 0.01mm andthe laser beam spot is 12mm. Amplitude of vibration is keptconstant at 2mm throughout the tests.Toolmakers microscope (Olympus-STM): to observethe burrs in intersecting holes. It possesses a maximummagnification of 200 times with a resolution of 0.5mm.Waveform generator (HP-33120A): to provide waveformand frequency for the power amplifier. Surface roughnessmeasuring machine (Talyround, series 2): to measure thesurface roughness of the workpiece after boring.Boring insert: Carbide Depot TPMR221 of 111 clear-ance, P10 tungsten carbide. Boring bar: Carbide DepotS12M-CTFPR11 with a diameter of 12mm. Drill: diameterof 1mm, two flutes, high speed steel (HSS) with anincluded angle of 1181, a helix angle of 301, first relieveangle of 151, and a second relieve angle of 301. Workmaterial: aluminum alloy (Al 6061-T6) tube with insidediameter of 30mm and outside diameter of 40mm. Cuttingfluid: mineral oil.3.1. Vibration-boring experimentsThe experiments were conducted on the engine lathewith the vibration-boring device we developed. There werefour parameters involved in the experiments and thus inthis paper we employed Taguchi method to deal withresponses influenced by multi-variables. Taguchi usedsignal-to-noise (S/N) ratio as the quality characteristicsofthechoiceofparameters.Forsmaller-the-bettercharacteristic, S/N can be expressed asS=N ?10log1nXy2?,where n is the number of experiments and y is the measureddata. The analysis of variance (ANOVA) is then performedto analyze the effect of the process parameters. Based onANOVA, the contribution ratio of each parameter can bepredicted and thus optimal combination of the parameterscan be obtained. Detailed description about how to utilizethe Taguchi method for the planning of experiments can befound in Refs. 15,16 and is not summarized in this paper.Since there are four parameters at three levels each, weused the L9(34) orthogonal array to analyze their effects.The process parameters chosen for the vibration-boringexperiments are: (A) spindle speed, (B) vibration frequency,(C) feed and (D) depth of cut, while the response functionis the surface roughness of the drilled hole inner surface.The range and number of levels of the parameters areselected as given in Table 1. The levels of the parametersare chosen based on the results of our preliminary tests andthe constraints of the engine lathe we employed. Frequencycharacteristics of the vibration-boring device were analyzedin the preliminary tests. Its natural frequency was found tobe around 10kHz. The experimental layout for themachining parameters is shown in Table 2. It is noted thatonly nine experiments are required to study the entiremachining parameters using the L9(34) orthogonal array.ARTICLE IN PRESSFig. 4. Photo of vibration-boring device.Table 1Machining parameters and their levels in vibration-boring experimentsLevelParam.(A) Spindlespeed (rpm)(B) Frequency(kHz)(C) Feed(mm/rev)(D) Depth ofcut (mm)118000.090.04227010.0970.083310140.1050.12G.-L. Chern, J.-M. Liang / International Journal of Machine Tools & Manufacture 47 (2007) 1331401353.2. Intersecting-hole experimentsThe manufacture of industrial valves often involvesdrilling a cylindrical tube and then boring its inner wallsurface, generating intersecting holes. Burr formationinside the valve becomes a bothersome object to be dealtwith. Surface finish of tube workpiece represents the mostimportant machining quality of a boring operation. But forburr formation in intersecting holes, it might not be clearhow to choose a quantitative measurement for the researchanalysis. There are several ways to evaluate the burrformation produced in intersecting holes. The methods ofanalysis are stated as follows.1. Maximum burr height: maximum protrusion of burrfrom the edge of the drilled hole. But if the burr is not quiteuniform in shape, such measured value might not be able torepresent the real scale of burr formation.2. Burr weight: weight of burr directly shows the scale ofburr formation. To measure the burr weight, one has tocarry out deburring first. But collecting all burrs duringdeburring is a very difficult task. Such method of analysiswill be feasible only when a reliable deburring method canbe obtained.3. Burrs shading area: region shaded by burr withinthe circular area of drilling. If the burr in intersecting holesis viewed from the axial direction of the drilling process ithad undergone, an image like shown in Fig. 5 can beobserved. The burrs shading area was then measuredthrough an image-processing software (Matrox Inspector2.2), as shown in Fig. 6. We crop the photo in Fig. 5according to the diameter of the drill, which is 1mm in thisresearch. Now the shading area is measured by countingthe black pixels within the captured image. This providesus a quantitative measurement of burr formation inintersecting holes. Since it is more reliable and feasiblethan the previous two methods, the shading-area approachwe proposed will be employed in the following analysis.The intersecting-hole experiments include two parts: (1)drilling the cylindrical tube workpiece with an HSS drill ofdiameter 1mm; (2) boring the inner wall surface of the tubeARTICLE IN PRESSFig. 5. Photo of burrs in intersecting holes.Fig. 6. Image processing of burrs.Table 2Experimental layout showing levels of machining parameters in vibration-boringNo.Param.ABCD111112122231333421235223162312731328321393321Fig. 7. Photo of vibration-drilling worktable.G.-L. Chern, J.-M. Liang / International Journal of Machine Tools & Manufacture 47 (2007) 133140136workpiece. VC is applied to both drilling and boringoperations with different vibration devices. Vibrationdrilling is carried out by employing the vibration worktablewhich the author had developed 8. Fig. 7 shows the photoof the vibration-drilling worktable used in the first part ofthe intersecting-hole experiments. It provides high-fre-quency vibration in the axial direction, using a piezoelectricactuator (PI P-245.30) coupled by a waveform generator(HP-33120A) and a high power amplifier (PI P-270.02).Two built-in linear guideways are utilized symmetrically toensure un-axial vertical motion of the worktable.After drilling through holes, the tube workpiece wasmachinedbytheboringoperationtocompletetheintersecting-hole experiments. Again, we used Taguchimethod and chose the L9(34) orthogonal array to arrangethe experiments. The process parameters selected are: (A)vibration frequency in boring; (B) vibration frequency indrilling; (C) drilling feed; and (D) spindle speed in drilling,while the response function is the number of pixels of thecaptured image. The range and number of levels of theparameters are selected as listed in Table 3. The parametersare chosen based on our previous study in drilling with VC8, knowing that feed and spindle speed in drilling areimportant in burr formation. The natural frequency of thevibration worktable was found to be around 13kHz. Thelevels of the parameters are chosen based on the results ofour preliminary tests and the constraints of the machinetools we employed. The feed, spindle speed and depth ofcut in boring are kept at constant of 0.09mm/rev, 270rpmand 0.08mm, respectively. The experimental layout for themachining parameters is the same as shown in Table 2 sincethe same orthogonal array is chosen.4. Results and discussions4.1. Vibration-boring experimentsThe objective of the experiments is to optimize theparameters to get better surface roughness in boring withVC. Table 4 shows the actual data measured along withtheir computed S/N ratio. y is the surface roughness (Ra)measured in mm. The response table for mean S/N ratio isshown in Table 5. We can predict the optimal combinationof machining parameters in vibration-boring to be A3(310rpm), B2(1kHz), C2(0.097mm/rev) and D1(0.04mm)by selecting the largest value of S/N ratio for eachparameter.The results of ANOVA for the response function, i.e.surface roughness in vibration boring, are given in Table 6.Contribution ratio of each parameter can be seen in thetable. The contribution ratios of spindle speed (A) anddepth of cut (D) are 17.6% and 2.7%, respectively. It isfound that feed (C) has a dominant effect in vibrationboring, of almost 50% in contribution ratio. This analysisresult is very reasonable since tool mark produced by feedper revolution directly determines the surface roughness ina boring operation.Vibration frequency (B) also has some influence on thesurface roughness, of about 30% in contribution ratio. Inthis study the optimal level of vibration frequency weobtained is B2(1kHz) instead of B3(14kHz). Basicunderstanding is that when frequency is higher, theperformance of VC will be better 7. This is true onlywhen the cutting tool is not damaged by the high-frequencyvibration. Jin and Murakawa 9 pointed out that tool wearis more prominent as frequency increases, as also found byARTICLE IN PRESSTable 3Machining parameters and their levels in intersecting-hole experimentsLevelParam.(A) Frequencyin boring(kHz)(B) Frequencyin drilling(kHz)(C) Drillingfeed (mm/rev)(D) Spindlespeed indrilling (rpm)1000.0210002110.032000314100.043000Table 4Results of vibration-boring experiments and their corresponding S/N ratioNo.ABCDyS/N118000.090.041.494?3.484218010.0970.081.159?1.2853180140.1050.121.601?4.089427000.0970.121.566?3.896527010.1050.041.574?3.9386270140.090.081.435?3.139731000.1050.081.652?4.358831010.090.121.241?1.8769310140.0970.041.130?1.062Table 5Response table for S/N ratio in vibration boringABCD1?2.953?3.913?2.833?2.8282?3.658?2.366?2.081?2.9273?2.432?2.764?4.128?3.287OptimalA3B2C2D1Table 6ANOVA in vibration-boring experimentsParam.Sum ofsquares, SDegree offreedom, fVariance, VContributionratio, P (%)A2.27121.13617.6B3.87021.93529.9C6.43423.21749.8D0.35020.1752.7Total12.9258100G.-L. Chern, J.-M. Liang / International Journal of Machine Tools & Manufacture 47 (2007) 133140137Chern and Lee 8. B3(14kHz) might be more susceptibleto tool wear in vibration-boring, leading to a poor surfaceroughness.To validate the finding of this analysis, confirmingexperiment was conducted with the optimal level of themachining parameters: A3, B2, C2and D1. The measuredsurface roughness of this optimum combination was0.717mm, much lower than the smallest one (1.13mm) inTable 4. It has been shown that machining parameters setat their optimum levels can ensure significant improvementin the surface roughness in vibration boring.To investigate the influence of vibration frequency onsurface finish produced in boring, some additional experi-ments were conducted. Fig. 8 shows the variation ofsurface roughness (Raand Rmax) with respect to differentvibration frequencies. Spindle speed, feed and depth of cutare 270rpm, 0.09mm/rev and 0.04mm, respectively. It isfound that the use of VC in boring does improve thesurface roughness. Fig. 9 shows the photos of machinedsurface after boring, without and with VC. The differenceis quite obvious. In Fig. 9(a) we observed clear tool marksand obtained Raof 1.19mm without VC. Whereas Raof0.73mm was produced with VC of 1kHz and the toolmarks were almost not distinguishable. Since vibration isimposed in the axial direction, it levels off the tool markand produces a better surface finish.4.2. Intersecting-hole experimentsBefore discussing the experimental results, burr forma-tion in intersecting holes should be studied first. It isproduced by drilling and the following boring operations.Before a drilling process is completed, burr formationinitiates due to the lack of material support where the drillexits the workpiece. These uncut materials near the exitside are pushed out and rotated by the bending moment(M) caused from the axial motion of the drill, as shown inFig. 10(a). Eventually, burrs are created at the exit edge ofthe drilled hole, as shown in Fig. 10(b).During the following boring operation, some of thoseburrs produced by the previous drilling process will be bentto form the final burrs in intersecting holes, as shown inFig. 11(a). Burrs in region I are most prominent since thedrilling burrs in this area form a very large angle withrespect to the cutting velocity, V. This angle formedbetween the workpiece edge and the cutting velocity hadbeen called in-plane exit angle and found to be asignificant factor in burr formation 17. Those drillingburrs in region I are easy to rotate with the advancement ofthe boring tool. Burrs in region III are very few since thefeed motion of the boring tool tends to push them aroundand to be cut away. Fig. 11(b) shows the photo of burrs inintersecting holes.The objective of the intersecting-hole experiments is tooptimize the parameters to get minimum burrs with VC.Table 7 shows the measured number (y) of black pixels ofthe captured image, using Matrox Inspector 2.2 as in Fig.6, along with their computed S/N ratio. The response tablefor mean S/N ratio is shown in Table 8. The optimalcombination of machining parameters is A3(14kHz inboring), B3(10kHz in drilling), C1(0.02mm/rev) and D3(3000rpm).The results of ANOVA for the response function, i.e.black pixels of the captured image, are given in Table 9. Itis found that frequency in boring (A) has a dominant effectof 71.7% in contribution ratio. The optimal level of A isthe largest one, 14kHz. This means that the high-frequencyvibrationboringcanreducetheburrformationinintersecting holes. It is noted that the vibration in the axialdirection creates rapid impact on the drilling burrs, causingtheir breaking off during the boring operation. Thus burrformation is retarded.To validate the finding of the analysis, confirmingexperiment was conducted with the optimal level of themachining parameters: A3, B3, C1and D3. As expected, themeasured number of pixels was 43,606, much lower thanARTICLE IN PRESSFig. 9. Photos of machined surface in boring (270rpm, 0.09mm/rev, 0.04mm): (a) without VC; (b) with VC of 1kHz.00.511.50Hz100Hz1kHz14kHzfrequencyRa (m)0510Rmax (m)Fig. 8. Variation of surface roughness vs. vibration frequency (270rpm,0.09mm/rev, 0.04mm).G.-L. Chern, J.-M. Liang / International Journal of Machine Tools & Manufacture 47 (2007) 133140138those data in Table 7. Fig. 12 shows the photos of burrs inintersecting holes, without and with VC. Spindle speed andfeed in drilling are 2000rpm and 0.03mm/rev, respectively.The number of pixels in Fig. 12(a) without VC is 152,162while such number drops to only 52,973 in Fig. 12(b) with100Hz in drilling and 14kHz in boring. It has been shownthat the utilization of VC reduces the burrs in intersectingholes noticeably.5. Conclusions1. In this paper, vibration cutting has been applied toboring and drilling processes by the vibration devices wedeveloped. In the vibration-boring experiments, it has beenshown that the use of VC improves the surface roughnessprominently. Feed has a dominant effect of almost 50% incontribution ratio, while frequency also has influence onthe surface roughness of about 30% in contribution ratiobased on the Taguchi method and ANOVA. The machin-ing parameters set at their optimum levels can ensuresignificantimprovementinthesurfaceroughnessinvibration boring.2. The shading-area method we proposed can beemployed as a simple and feasible approach for analysisof burrs in intersecting holes. In intersecting-hole experi-ments, we found that high-frequency vibration boring canreduce the burr formation effectively. It has been shownthat the utilization of VC reduces the burrs in intersectingholes noticeably.AcknowledgementsThe authors would like to thank the National ScienceCouncil in Taiwan ROC for financially supporting thisresearch under contract no. NSC-90-2212-E-224-004.References1 J. Kumabe, T. Sabuzawa, Study on the precision drilling of wood (1streport)profile analysis of drilled hole, Journal of JSPE 37 (2) (1971)98104 (in Japanese).ARTICLE IN PRESSmaterialdrillMMmaterialdrillburr(a)(b)Fig. 10. Burr formation in drilling.Fig. 11. Burr formation in boring after drilling.Table 7Results of intersecting-hole experiments and their corresponding S/N ratioNo.ABCDyS/N1000.021000105,056?100.432010.032000185,198?105.3530100.043000114,025?101.144100.033000117,045?101.375110.041000167,115?104.4661100.02200090,910?99.1771400.04200069,759?96.8781410.02300060,664?95.66914100.03100056,003?94.96Table 8Response table for S/N ratio in intersecting-hole experimentsABCD1?102.307?99.556?98.420?99.9512?101.667?101.824?100.561?100.4663?95.832?98.425?100.824?99.389OptimalA3B3C1D3Table 9ANOVA in intersecting-hole experimentsParam.Sum ofsquares, SDegree offreedom, fVariance, VContributionratio, P (%)A76.388238.19471.7B17.97128.98516.9C10.43625
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