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egime, the contact behaviour is governed bycontact between asperities where no lubricantfluid film can remain [2]. To prevent realcontacts between roll and strip at asperitieslocations, additives react with surfaces to form aprotective film. The friction reducer additives arethe polar ones and they get desorbed from acritical temperature estimated at about 100°C[2].o No clear influence of forward slip on frictioncoefficient is observed• Iron fines residues:After pass one, iron fines are measured only on roll.After pass two, they are measured both on URTspecimen and roll. The quantities of iron finesresidues collected for each configuration test arerepresented on Fig. 3.b:o The quantity of iron fines measured decreaseswith temperature contrary to friction coefficient.As previously observed (Fig. 3.a), a highercontact temperature causes a higher frictioncoefficient which favours the wrenching ofasperities: a high amount of iron fine residuesshould be found [1] contrary to what has beenobserved and measured (Fig. 3.b). As aconsequence, the high temperature conditionsimply that more wrenched particles must adhere(directly or indirectly) on strip or roll and cannotbe collected.o No clear influence of forward slip on thequantity of iron fine residues is observeda) b)Fig. 3. Results for each test configuration (a) Mean computedCoulomb coefficient (b) Total iron fine residues collected onroll and strip6. CONCLUSIONS AND PERSPECTIVESTo better understand cold rolling contact behaviour anew methodology was created and recentlyoptimised to simulate mechanical, thermal andlubrication contact conditions. It has enabled topoint out that:o friction increases with temperature because ofthe desorption of polar additiveso quantity of iron fines residues decreases withtemperature. It means that adhesive wear andtransfer layer formation is favoured by a hightemperature.o friction increases with the number of the passbecause of the decrease of the contact ratioDespite these interesting conclusions, importantquestions remain: What are the nature and the realimpact of the transfer layer? What is the pertinenceof the current industrial measurement of iron finespollution? Finally, what are the behaviour and therole of the lubricant additives?ACKNOWLEDGEMENTSThe present research work has been supported by Myriad, aCORUS group company, the CNRS, the European Community,the Association Nationale de la Recherche Technique, theConseil Régional du Nord Pas de Calais. The authors gratefullyacknowledge the support of these institutions.REFERENCES[1] R. Deltombe, M. Dubar, A. Dubois, L. Dubar, A newmethodology to analyse iron fines during steel cold rollingprocesses, Wear 254 (2003) 211-221[2] P. Montmitonnet, Tribologie du laminage à froid de tôles,Revue de la Métallurgie Paris, N°2 (2001), 125-130[3] S. Matysiak, S. Konieczny, A. Yevtushenko, Distribution offriction heat during cold rolling of metals by using compositerolls, Numerical Heat Transfer, Part A, 34: 719-729 (1998)[4] A.K. Tieu, P.B. Kosasih, A. Godbole, A thermal analysis ofstrip-rolling in mixed film lubrication with O/W emulsions,Tribology International 39 (2006) 1591-1600[5] A. Boutonnet, Etude de la résistance thermique de contactà l’interface de solides déformables en frottement : applicationaux procédés de forgeage, Thèse INSA de Lyon, 1998[6] J. Molimard, Etude expérimentale du régime delubrification en film mince – Applications aux fluides delaminage, Thèse INSA de Lyon (1999)[7] O. U. Khan, A. Jamal, G. M. Arshed, A. F. M. Arif, S. M.Zubair, Thermal analysis of a cold rolling process – Anumerical approach, Numerical Heat Transfer, Part A, 46:613-632 (2004)[8] N. Letalleur, Influence de la géométrie des aspérités dansun contact hydrodynamique ultramince. Effets locaux etcomportements moyen, Thèse INSA de Lyon (2000)[9] A.D. Bugg, A. Shirizly, J.G. Lenard, The use of emulsionsduring cold rolling of steel strips,, The second Europeanrolling conference rolling , VASTERAS Suède, (2000)[10] K. Dick, J. G. Lenard, The effect of roll roughness andlubricant viscosity on the loads on the mill during cold rollingof steel strips, Materials Processing Technology 168 (2005) 16-24
Metrology of the burr amount - correlation with blanking operationparameters (blanked material – wear of the punch)H. Makich 1 , L. Carpentier 1 , G. Monteil 1 , X. Roizard 1 , J. Chambert 2 , P. Picart 21 LMS – ENSMM, 26 Chemin de l’Epitaphe 25000 Besançon, FranceURL: www.lms.ens2m.fre-mail:hamid.makich@ens2m.fr; Luc.Carpentier@ens2m.fr;guy.monteil@ens2m.fr; xavier.roizard@ens2m.fr2 Institut FEMTO-ST – DMARC, 24 Chemin de l’Epitaphe 25000 Besançon, FranceURL: www.femto-st.fre-mail: jchamber@univ-fcomte.fr; philippe.picart@univ-fcomte.frABSTRACT: Blanking burr and punch wear are two phenomena closely linked. This leads to consider burr asthe best criterion for regrinding or renewing tools. Thus, in order to control the quality and cost in blankingprocess, it is necessary to measure with the best accuracy the amount of burr and wear punch. To do this, amethod for measuring the volume of burr was developed. This method is based on the use of 3Dtopographical images. On the other hand, punch wear was calculated by combination of a mathematicalmodel to the geometric shape of punch. This model gives the geometry variations of the punch, depending onthe number of press storks. At the end, the aim of this study is to identify a relationship between burr andpunch wearKey words: Blanking, Burr amount, Punch wear, Cut edge profile, Worn geometry1 INTRODUCTIONIn the blanking industry, the punch wear has asignificant impact on production. In particular,important wear causes a wrong geometry of the cutpieces, which can lead to a rejection of products.Among other defects, the apparition of burr is themost incapacitating in the use of the blanking piece.So, in order to overcome this problem, industrialsregrind their tools after a number of press storks. Butthis operation has a negative consequence on costs.In fact, the production stopping for regrindingpunches creates substantial losses for the industry.Thus, it is important to control aspects of theblanking operation leading to the appearance of burr.To do this, it is necessary to have in advance areliable way to measure the quantity of burr. In thispaper, we present an original method for thequantification of the volume of burr. Moreover, afirst approximation of the burr amount with the levelof wear and the cutting materiel is also presented.2 BLANKING BURRamount, the cutting pieces can be unusable.Fig. 1.Geometry of the cutting edge.HR : Roll-over depth.HS : Sheared edge.HF : Fracture depth.Hb : Burr height.φ : Fracture angle.Given the important issues related to the appearanceof blanking burr, a lot of work has been undertakento explain the appearance. Most of this work wasdevoted to the study of the influence of blankingconditions (clearance, radius, etc...) (Fig. 2), on theappearance of burr.The burr occurs on the cutting edge of pieces (fig.1),this presence is one of the most serious limitations ofthe blanking process. Indeed, beyond a certain burr
Page 1 and 2: Development of a friction modelling
Page 3: The evolution of heat flux transmit
Page 6 and 7: 2.2 Toolkit and specimen geometryFi
Page 8 and 9: In general, the friction coefficien
Page 10 and 11: determining a relative movement bet
Page 12 and 13: force needed to move the pin (frict
Page 14 and 15: and specimens are parts of actual i
Page 16 and 17: 4.3 Effect of lubricant particle si
Page 18 and 19: 2 EXPERIMENTAL2.1 PSCT set-up and p
Page 20 and 21: found here only in a low strain rat
Page 22 and 23: pieces are scaled by the same scali
Page 24 and 25: the experimental one shows nearly n
Page 26 and 27: 2 NUMERICAL TOOL2.1 General descrip
Page 28 and 29: much better when rotating velocity
Page 30 and 31: transfer across the roll-strip inte
Page 34 and 35: eJ / 2βD pD mr pJ / 2PunchFig. 2.G
Page 36 and 37: number of profiles, which has the a
Page 38 and 39: In spite of the predominance, galli
Page 40 and 41: other hand, it has not been observe
Page 42 and 43: corresponds to the minimum energy s
Page 44 and 45: 10.90.80.70.60.50.40.30.20.100 5 10
Page 46 and 47: 2 EXPERIMENTAL PROCEDURETwo lubrica
Page 48 and 49: can be described using the followin
Page 50 and 51: through an arc cathodic equipment.
Page 52 and 53: To verify the absence of coating in
Page 54 and 55: angle, and m 0 the constant frictio
Page 56 and 57: 4 NUMERICAL MODELLING4.1 Upsetting
Page 58 and 59: indenter. T-shape compression, a ne
Page 60: Tangential force / Normal force0.35

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