Surface Roughness in High Feed Turning with Wiper Insert

Transcription

1 Key Egieeig Mateials Vols (008) pp olie at (008) Tas Tech Publicatios, Switzelad Olie available sice 008/Ma/07 Suface Roughess i High Feed Tuig with Wipe Iset Zhaqiag Liu 1,a, Peg Zhag 1,b, Peg Guo 1,c ad Xig Ai 1,d 1 School of Mechaical Egieeig, Shadog Uivesity, Chia a melius@sdu.edu.c; b zp816004@163.com; c galic1984@hotmail.com; d aixig@sdu.edu.c Keywods: Suface oughess, Wipe iset, High feed tuig, Mild steel Abstact. Suface oughess i a tuig opeatio is affected by a geat umbe of factos. Two of the most impotat factos ae feed ate ad the size of the coe adius. Suface oughess ca be oughly detemied to icease with the squae of the feed ate ad decease with iceased size of the coe adius. Howeve, wipe iset geometies chaged this elatioship with the capability to geeate good suface oughess at elatively highe feeds by tasfeig small pat of the oud iset edges ito the staight cuttig edges of the poited iset. The piciple of how wipe isets behave diffeet fom covetioal isets as to the effects o the suface oughess is exploed i this pape. Expeimetal study of the suface oughess poduced i the tuig of hadeed mild steels usig coated cabide tools with both covetioal ad wipe isets is coducted. The test esults pove the effectiveess of the wipe isets i povidig excellet suface oughess. The esults also suggest that the use of the wipe iset is a effective way that sigificatly iceases cuttig efficiecy without chagig the machied suface oughess i high feed tuig opeatios. Itoductio Machiig opeatios ae utilized i view of the bette suface oughess that could be achieved by it compaed to othe maufactuig opeatios. Thus it is impotat to kow what could be the effective suface oughess that ca be achieved i a machiig opeatio. The suface oughess i a tuig opeatio is affected by a geat umbe of factos such as: (1) the geomety of the cuttig tool; () the cuttig pocess paametes, such as speed, feed ate ad depth of cut; (3) applicatio of cuttig fluids o ot; (4) wokpiece ad tool mateials chaacteistics; (5) igidity of the machie tool ad the cosequet vibatios [1]. The majo two of the above impotat factos ae feed ate ad the size of the tool ose adius. Suface oughess ca be oughly detemied to icease with the squae of the feed ate ad decease with iceased size of the tool ose adius. A lage feed will give pooe suface oughess but shote cuttig times while a lage ose adius will geeate a bette suface oughess ad povide moe stegth. Howeve, a excessively lage ose adius ca lead to vibatio tedecies, usatisfactoy chipbeakig ad shote tool-life because of isufficiet cuttig edge egagemet [, 3]. Theefoe, the size of the iset ose adius ad the feed may be limited i a pactical opeatio. To upset this elatioship to achieve a bette suface oughess at a highe feed, the wipe techology fo the idexable iset ose-adius has bee developed [4]. The wipe isets ae a ecet developmet i edge pepaatios, which is desiged with modified ose adii with lage coes o flatte foms ito the staight mio cuttig edge to wipe the suface smooth. The coe o flatte fom of the wipe iset idicates that it takes off moe mateial with the back of the iset as it cuts (wipes). As a ule of thumb, the suface fiish poduced by the wipe iset is twice as good as it would be with the covetioal iset fo a give feed ate. Alteately, the feed ate ca be appoximately doubled while maitaiig a simila suface fiish [5, 6]. Howeve, little wok has bee doe to theoetically evaluate the mechaism of the wipe isets effect o the suface oughess. The emaide of the pape is ogaized as follows. Sectio theoetically exploes the wipe geomety effects o suface oughess, while Sectio 3 gives a expeimetal study of the wipe geomety effects o suface oughess poduced i the tuig of hadeed mild steel. Fially, coclusios will be peseted i Sectio 4. All ights eseved. No pat of cotets of this pape may be epoduced o tasmitted i ay fom o by ay meas without the witte pemissio of the publishe: Tas Tech Publicatios Ltd, Switzelad, (ID: /05/08,16:15:06)

2 Key Egieeig Mateials Vols Wipe Iset Effect o Theoetical Suface Roughess Ude ideal coditios the elevet tool cuttig pat pofile will be epoduced o the compoet to fom the machied suface which will exhibit the chaacteistic feed maks. A gaphical epesetatio of the feed mak is show i Fig.1 fo covetioal iset ad wipe iset. It is oted that the cusp aeas ae epoduced o the tued suafce by the tuig isets. The theoetical suface oughess ca be expessed i tems of stadad idices such as the peak to valley height R t (R tw ad R tc fo wipe iset ad covetioal iset, espectively). The peak to valley height R t is depedet o the tool ose adius, the mio cuttig edge agle κ, ad the feed ate f. It is appaet that R tc will additioally be depedet o the modified ose aius fo wipe iset. I :1 w Rtw Rtc Feed mak with covetioal iset fw I fc A w B κ Feed mak with wipe iset Rtw Rtc f Covetioal iset Wipe iset Fig.1 Feed maks fo covetioal iset ad wipe iset I Fig.1, poit A is the itesectio betwee covetioal iset ose ad staight mio cuttig edge, while poit B is the itesectio betwee wipe ose ad staight mio cuttig edge. f c ad f w ae the feed ates whe the majo cuttig edge tasveses the poits A ad B, espectively. Fom the geomety of Fig.1, f c siκ (1) f w wsiκ + -[ w (1 cosκ () )] Deivatio of the peak to valley height R t equies classificatio of the feed maks ito thee cases depedig o the feed ate f applied i tuig opeatios small feed, tasitioal feed, ad lage feed. The elatioships amog peak to valley heights R tw as well as R tc, tool ose adius, the mio cuttig edge agle κ, the applied feed ate f, ad the wipe ose aius w ae give as follows fo these thee cases with wipe iset ad covetioal iset,espectively. Case of small feed (f c > f ): ( ) + w ( w ) f (fo wipe iset) (3) R tc f - (fo covetioal iset). (4) 4

3 408 Advaces i Machiig & Maufactuig Techology IX Case of tasitioal feed (f c < f < f w ): ( ) + w ( w ) f (fo wipe iset). (5) R + f (fo covetioal iset). (6) tc ( Rtc) ( Rtc) taκ + siκ siκ cosκ Case of lage feed (f > f w ): R ( R ) ( R )taκ + w w tw tw + w tw ( fo wipe iset). (7) siκ siκ cosκ I the case of lage feed, the elatioship amog peak to valley heights R tc with covetioal iset, tool ose adius, the mio cuttig edge agle κ, ad the applied feed ate f is the same as i the case of tasitioal feed, which ca also be expessed usig Eq. (6). f Tuig Tests fo Iset Geomety Effect o Suface Roughess Tuig Expeimet Setup. The wokpiece mateial was 45# mild steel (0.45% cabide) bastock with a hadess of 30 HRC 35 HRC. The Keametal coated cabide gade KC9110 (MT-CVD-TiCN/Al O 3 /TiN, Fig.) with covetioal iset geomety CNMG10408FN ad wipe iset geomety CNMG10408FW wee used. The coe adius was 0.8 mm fo both iset types. The wipe adius w was 5 mm fo the wipe iset. The toolholde PCLNR00K1 was selected. The mio cuttig edge agle was 5 as show i Fig.3. κ Fig. Keametal coated cabide tool Fig.3 Keametal toolholde PCLNR00K1 Tests wee coducted at six feed ates 0.1, 0., 0.3, 0.4, 0.5, ad 0.6 mm/. These feeds wee i lie with those coveig small ad tasitioal feed ate cases that affect the peak to valley height. Each test was epeated thee times. All tests wee pefomed at fixed cuttig speed 170 m/mi ad depth of cut 0.5 mm. I ode to measue the peak-to-valley oughess of the tued pats, a suface pofile teste with a esolutio of ±8μm/1m was employed. Compaisos fo Theoetical ad Expeimetal Results of Suface Roughess. Fo these selected toolholde ad iset geometies, f c ad f w ae mm ad mm by calculatig with Eq. 1 ad Eq., epepectively. Fig.4 shows that the feed ate affects the theoetical suface oughess R t fo the selected tool geometies ad cuttig coditios. The values of R t ae diectly calculated usig Eq. 3 ~ Eq. 7, depedig o the iset type ad feed ate f applied. Both iset types peset the same ted of suface oughess iceasig with the feed ate. It is oted, fo example, that the tued suface oughess μm at feed ate of 0.3 mm/ with covetioal iset is moe tha twofold of the suface oughess 4.6 μm with wipe iset. Fo the suface oughess 8. μm, the feed ate equied is 0.3 mm/ fo covetioal iset, while 0.4 mm/ fo wipe iset.

4 Key Egieeig Mateials Vols Fig.4 Feed ate effect o theoetical suface oughess (a)with wipe iset (b) With covetioal iset Fig.5 Measued suface pofile fo the tued wokpiece at the feed ate 0.mm/ Feed ate f (mm/) Fig.6 Measued values of suface oughess fo tuig with covetioal ad wipe isets Fig.5 shows the measued suface pofile fo the tued wokpiece with covetioal iset ad wipe iset at the feed ate 0.mm/, espectively. The compaiso betwee the tued suface oughess obtaied usig the wipe isets ad those obtaied with covetioal isets at all six tested feed ates is show i Fig.6. These test esults pove the effectiveess of the theoetical aalysis esults ad the wipe isets i povidig excellet suface oughess. I paticula, tuig usig the wipe isets with a doubled feed ate with espect to the covetioal oes povides machied suface with lowe oughess values.

5 410 Advaces i Machiig & Maufactuig Techology IX Coclusios The coclusios of this study ca be summaized as follows: Without chagig cuttig coditios, up to two-times bette suface oughess was achieved with wipe iset i tuig opeatios. I this ivestigatio this fact was poved though theoetical aalysis ad expeimetal study whe tuig mild steel with covetioal isets ad wipe isets, espectively. Fo example, keepig the same feed ate of 0.3 mm/ i Fig.6, the suface oughess R tc 15.5 μm was achieved whe tuig with covetioal iset, while suface oughess R tw 9.95 μm was obtaied with wipe iset. Without sacificig fiish equiemets, oe ca double the feed ates to obtai the same suface oughess. Fo the suface oughess 9 μm i Fig.6, the feed ate equied was 0.17 mm/ fo covetioal iset, while 0.8 mm/ was fo wipe iset. Both usig covetioal iset ad wipe iset peseted the same ted of suface oughess iceasig with the feed ate. Ackowledgemets This poject is suppoted by Natioal Natual Sciece Foudatio of Chia (506751), Excellet Postdoctoal Foudatio of Shadog Povice ( ), ad the Pogam fo New Cetuy Excellet Talets i Uivesity (NCET ). Specifically, the authos thak M. Joe, Xiao Yag of Keametal (Chia) Co. Ltd. fo his cotibutio of wipe isets i this study. Refeeces [1] P.N. Rao: Maufactuig Techology Metal Cuttig & Machie Tools (McGew-Hill Compaies Ic., USA 000). [] W. Gzesik ad T. Waat: It. J. of Machie Tools & Maufactuig, Vol.46 (006), pp [3] Y.K. Chou ad H. Sog: J. of Mateials Pocessig Techology, Vol.148 (004), pp.59. [4] [5] G.D.S. Galoppi, M.S. Filho ad G.F. Batalha: J. of Mateials Pocessig Techology, Vol.179 (006), pp.146. [6] A.M. de Souza, J.W.F. Sales, S.C. Satosc ad et al: It. J. of Machie Tools & Maufactuig, Vol.45 (005), pp.335.