THE EFFECT OF THE DIFFERENT CUTTING TOOLS ON THE MICRO-GEOMETRICAL SURFACE OF ENGINEERING PLASTICS

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1 Dy of eserh 2010 Februry 10 Lbo Soete, Ghent University, Belgium THE EFFECT OF THE DIFFEENT CUTTING TOOLS ON THE MICO-GEOMETICAL SUFACE OF ENGINEEING PLASTICS Gbriell Frks ** ** Bánki Donát Fulty of Mehnil nd Sfety Engineering, Institute of Mteril Siene nd Mnufturing Engineering, Universits Budensis Gábor Klásk * * Institute for Mehnil Engineering Tehnology, Fulty of Mehnil Engineering, Sent István University Abstrt We would like to present in this rtile the results of the mirogeometril study of the engineering polymer surfes nd the pplied utting tools. We ompre the effets of different tehnologil prmeters (utting speed, utting feed, depth of ut) hving on the mirogeometril hrteristis (, ) nd we summrise the results nd onlusions from the prtil engineering life. Keywords Engineering plstis, prmeters of utting, utting tools, prmeters of the surfes roughness. 1. INTODUCTION In the mhining irumstnes nd dt should be hosen in the utting proess so tht the work piee mhined is in ordne with the ury to gge, geometril trueness nd surfe qulity given by design engineer. Severl reserhers delt with the utting of metls nd the study of effet of utting fetures [1]. The im of my reserh work is minly the nlysis of the roughness prmeters of utting surfes in se of different irumstnes. Other importnt tsk is the elbortion of surfe plnning riterions in ordne with the expeted funtionl behviour. The most importnt spet ws tht the results of tests would be useful for the tehnil prtie. Tht s why we hose severl thermoplsti polymers whih re importnt in the tehnil prtie but their behviour isn t known in se of utting. 2. EXPEIMENT OF CUTTING The tehnil literture provides utting prmeters generlly [2,3,4,5]. Cutting speed n be verge nd high rte between 200 nd 600 m/min. Feed rte n be low nd verge rte is between 5 nd 0,4 mm. The optiml utting prmeters re not extly determined for ertin polymers with regrd to surfe roughness. We performed the utting tests in the mhine shop of the Institute by NCT EUOTUN 12B CNC ontrolled HSC lthe. We fixed the work piees into the huk. The turning ws mde with 80 mm length nd 40 mm dimeter. We hose severl polymers in ordne with tehnil pplition: PA6, POMC, PET, PEEK. We ut the work piees lwys without ooling with different prmeters given below: - utting speed, v [m/min]: utting feed, f [mm/rev.]: 5 8 0,12 0,16 0,2 0,25 0,315 0,4 - depth of ut, [mm]: 0,5 - prmeters of workpieses: ø40x80 mm, - we don t used ooling. We used three different tools for experiment. Figure 1. ontins the prmeters of tools. 102 Copyright 2010 by Lbo Soete

2 Dy of eserh 2010 Februry 10 Lbo Soete, Ghent University, Belgium prmeters κ r ε r α λ s 0 0 r ε 0.4 mm 0.4 mm r n 14,1 ± 5,6 μm 6,75 ± 0,96 μm (tool) 1,29 ± 0,15 μm 0,58 ± 3 μm (tool) 6,43 ± 0,62 μm 2,66 ± 0,18 μm Figure 1. Edge-geometry of A, B tools Before utting I mesured the edge rdius (r n ) nd the edge of roughness (r ε ) of the tools s well s the rithmeti men devition of the roughness profile ( ) nd the mximum height of roughness profile ( ) of tools. In se of A tool the vlue of r n hs got lrge stndrd devition nd roughness prmeters differed differing. It ws typil of B tool the smll edge rdius (r n ) nd the little surfe roughness (, ) with smll stndrd devition in this wy it ws the better qulity tool. 3. STUDY OF MICOGEOMETY During mhining typil mirogeometril unevenness is rousing on the surfe whih depends on pplied tehnologil prmeters, geometril fetures of tool nd mhinig irumstnes. egrding miro-geometri hrteristis, the roughness nd wviness prmeters re pplied whih hve been worked out for dedes nd re still subjet of reserh t present, nd provide informtion bout divergenes nd hrteristis of the surfe. Severl mesuring proesses hve evolved for the exmintion of surfe texture by tody. 2D Stylus instruments re generlly used for mesuring nd evlution; however, there is n inresing demnd for 3D topogrphi snning in order to lern more bout the hrteristis of surfe texture (rndom, periodil, isotropi, nisotropi, et.) nd its stereosopi position [6,7]. The exmintions were performed on surfes with Perthometer-Conept type stylus snning instruments. The surfes were evluted on n evlution length (LM=4 mm) omplying with the ISO stndrd with the stndrd filter (LC=0.8 mm) nd one grde smller filter (LC=0.25 mm). Considering the possibilities of mesuring tehniques during the tests, the following dt were tken: unfiltered profile (P), filtered roughness profiles (), s well s 8 roughness (), 4 wviness (W) nd 5 unfiltered (P) prmeters. 2 figures were inluded in the preise omprison, whih re lso generlly used in industril prtie: prmeters of height (, P, t, P t ), one sping prmeter ( sm, P sm ), nd two hrteristis of shpe ( sk,p sk, dq,p dq ). 103 Copyright 2010 by Lbo Soete

3 oughness, [μm] oughness, [μm] oughness, [μm] oughness, [μm] oughness, [μm] oughness, [μm] oughness, [μm] oughness, [μm] Dy of eserh 2010 Februry 10 Lbo Soete, Ghent University, Belgium PA 6, - f - v, "A" tool ,10 0,15 0,20 0,25 0,30 0,35 0,40 PET, - f - v, "A" tool PA 6, - f - v, "B" tool ,10 0,15 0,20 0,25 0,30 0,35 0,40 PET, - f - v, "B" tool ,10 0,15 0,20 0,25 0,30 0,35 0, ,100 0,150 0,200 0,250 0,300 0,350 0,400 POM C, - f - v, "A" tool POM C, - f - v, "B" tool ,10 0,15 0,20 0,25 0,30 0,35 0, ,10 0,15 0,20 0,25 0,30 0,35 0,40 PEEK, - f - v, "A" tool PEEK, - f - v, "B" tool ,10 0,15 0,20 0,25 0,30 0,35 0, ,10 0,15 0,20 0,25 0,30 0,35 0,40 Figure 2. The results of in se of A, B tools 104 Copyright 2010 by Lbo Soete

4 Dy of eserh 2010 Februry 10 Lbo Soete, Ghent University, Belgium The results of mesurements represent the grphs were inlude the Figure 2. in se of polymide 6 (PA 6). It n be see tht the results of is more different in se of A tool like the other two tools. The behviour of the polymer studied by different utting speed nd by the sme utting feed is stble the vlue of rithmetil men devition of the ssessed profile is bout onstnt. The results of is better in se of B tool, so it hs lrger ngle of tool (ε r =55 ). This is true the ll studied polymers (PET, POM C, PEEK) s well. 3. STUDY OF THE THEOETICAL OUGHNESS ( E ) WITH DOE (DESIGN OF EXPEIMENTS) I hve plnned nd rried out the tests with method of the Design of Experiments. I hve modelled nd vlues mesured with power funtions. The prmeters in the ftoril test pln were: - (rithmetil men devition of the ssessed profile) [μm] - (mximum height of profile) [μm] The ftors: - v (utting speed) [m/min] - f (utting feed) [mm/rev.] The two prmeters of surfe roughness nd the utting dt ftors set n be given with the following funtion: C v f x 1 x 2 [μm] I rried it out with Minitb14 sttistil softwre the regression funtion exmintion. I hve deided with the help of progrm the oeffiient of individul models nd exponents (C, x 1, x 2 ), the vlues of the stndrd devition (s) nd the orreltion (). 3.1 STUDY OF THE CUTTING TOOL A We exeuted the utting tests with A tool t first. The funtions write down the mesuring results with smll stndrd devition (s= 54-0,16) nd reltively lrge orreltion (= 0,877-0,983). It s exponents of vribles signifint in se of A tool. Inresing utting speed uses deresing of the roughness in the domin exmined. Speed is hving effet on the surfe roughness (x 1 = from -03 to -0,316). The utting feed hs lmost liner onnetion with, vlues (x 2 = 1,2-1,68), it hs smller effet on the mesuring results s the Burer-formul shows tht. This experiene is reverse with the mesurement outomes, whih t his steels fshioning by mhine tool our well versed in our try efforts. Polymide 6 (PA6) Model s Model s 0,292 1,46 0,111 0, ,8 93 v 93 0, v 0,316 1,2 631 v 0,106 0, , v 0,105 0,953 Poly(etylen-tereftlt) (PET) Model s Model s 08 1,6 0,1606 0, , v 52 0, v 26 1, v 0,154 0,877 0,105 1, v 74 0,98 Poly(oxi-metylen) (POMC) Model s Model s 03 1,68 50 v 77 0, ,1 110 v 35 0, , v 76 0, , v 60 0, Copyright 2010 by Lbo Soete

5 Dy of eserh 2010 Februry 10 Lbo Soete, Ghent University, Belgium Poly(eter-eterketon) PEEK Model s Model s 48 1, , ,6 42 v 0,110 0,95 63 v f 89 1, v 54 0,983 Figure 3. esults of DoE in se of polymers studied 62 1, v 0,128 0, STUDY OF THE CUTTING TOOL B We rried out the utting tests with B tool for the seond time. The exponents of vribles re not signifint in se of B tool beuse the effet of the utting speed less thn stndrd devition of vlues mesured. The vlues of stndrd re between (s= 35-0,128) nd the orreltion is lrger thn in se of A tool (= 0,923-0,997). Cutting speed is shows lmost muh smller effet of the B tool (x 1 = from -02 to 62), the utting feed hs qudrti onnetion with the roughness (x 2 = 1,47 2,1), so better this suits better to the theoretil formul used t turning with regulr egde-geometril tool. Aording to results found in the mirogeometril study the line of the theoretil roughness ( e ) follows the line of the roughness mesured ( mximum height of profile) in the domin studied. 4. SUMMAY OF ESULTS The behviour of the polymer studied by different utting speed nd by the sme utting feed is stble. Tht is different from wht we hve experiened with steel. The result of (rithmetil men devition of the ssessed profile) is under 2 μm by low utting feed nd by the utting speed used [8,9]. Overll the effet on the roughness hrteristis of the utting speed exmined t plstis n be observed. This experiene is ontrditory with those mesuring results, whih we hve experiened in our tests t utting steels. EFEENCES [1] dr. Plásti K., B. - Cifr, Á.: Forgásolt felületek mikrogeometriáj és mikrotopográfiáj. Gyártóesköök, sersámok, sersámgépek, 2002/2. p [2] dr. Klásk Gábor: Műski műnygok gépéseti lpji, M-Sop. Sopron, old. [3] dr. Fües Lásló, dr. Kelemen Andorné: Műski műnygok sebkönyve. Műski Könyvkidó. Budpest, old. [4] Mehmet Sgdi, Friedrih Dubbert: Spnende Berbeitung von Kunststoffen. Bildshirmpresenttion, LBK, FSM-02, [5] George Southrd: High Performne Thermoplstis. Mterils, properties nd pplitions. The IAPD Edution Committee (Module 5), 2001 [6] Kovás K., Plásti Kovás B.: Műski felületek mikrotopográfiájánk jellemése háromdimeniós prméterekkel. I. A háromdimeniós topográfii prméterek áttekintése. Gépgyártástehnológi, 1999/ p. [7] K.J. Stout, P.J. Sullivn, W.P. Dong, E. Minsh, N. Luo, T. Mthi, H. Zhouro: The Development of Methods for the Chrteristion of oughness in Three Dimensions, Commission of the Europen Communities, [8] Frks, G. Plásti, K. B.: Forgásolt műski műnygok felületi simság, Gépgyártás, XLVI évfolym, sám, p HU ISSN [9] Frks, G.: A megmunkálási körülmények htás felületi mikrogeometriár műski műnygok estergáláskor, Gyártóesköök, sersámok, sersámgépek, XII. évfolym, sám, p ISSN , ISSN Copyright 2010 by Lbo Soete