单点增量成形过程中成形性的研究现状【中文2787字】【PDF+中文WORD】

单点增量成形过程中成形性的研究现状【中文2787字】【PDF+中文WORD】,中文2787字,PDF+中文WORD,单点,增量,成形,过程,研究,现状,中文,2787,PDF,WORD ReviewFormability in single point incremental forming:A comparativeanalysis of the state of the artTegan McAnultya,*,Jack Jeswietb,Matthew DoolanaaResearch School of Engineering,Australian National University,North Road,Canberra 2601,AustraliabDepartment of Mechanical and Materials Engineering,Queens University,Kingston,ON,CanadaContentsIntroduction.000Material parameters.000Tool parameters.000Toolpath parameters.000Geometry.000Experimental parameters.000This work.000Research question.000Hypothesis.000Method.000Results and discussion.000Material thickness.000Tool diameter.000Tool type.000Step down.000Feed rate.000Spindle speed.000Spindle rotation direction.000Interactions.000CIRP Journal of Manufacturing Science and Technology xxx(2016)xxxxxxA R T I C L E I N F OArticle history:Available online xxxKeywords:Single point incremental formingSPIFFormabilityQuantitative reviewToolsProcess parametersA B S T R A C TSingle point incremental forming(SPIF)has higher formability limits than other sheet metal formingprocesses including stamping,and is therefore a desirable method of forming sheet metal components.To take advantage of this high formability it is necessary to understand how to maximise the limitsthrough manipulation of parameters,increasing the likelihood of component success.In this paper,a systematic quantitative literature review was undertaken analysing experiments andresults from 35 papers that studied the effect of process parameters on formability in SPIF.Collectiveresults are presented regarding material thickness,tool diameter,tool shape and type,step down,feedrate,spindle speed and rotation direction,and some parameter interactions.The analysis providesevidence to support the hypothesis of an ideal operating range for each parameter and interdependencyof parameters.A lack of focus in the literature on parameter interactions was found.A framework forimportant experimental parameters is proposed based on the review.Statement of originality:Quantitative analysis of research presented in the literature about parametereffects on formability in SPIF.?2016*Corresponding author.E-mail address:tegan.mcanultyanu.edu.au(T.McAnulty).G ModelCIRPJ-381;No.of Pages 12Please cite this article in press as:McAnulty,T.,et al.,Formability in single point incremental forming:A comparative analysis of thestate of the art.CIRP Journal of Manufacturing Science and Technology(2016),http:/dx.doi.org/10.1016/j.cirpj.2016.07.003Contents lists available at ScienceDirectCIRP Journal of Manufacturing Science and Technologyjou r nal h o mep age:w ww.els evier.co m/lo c ate/c irp jhttp:/dx.doi.org/10.1016/j.cirpj.2016.07.0031755-5817/?2016Feed rate spindle speed interaction.000Tool diameter material thickness interaction.000Tool diameter step down interaction.000Step down material thickness interaction.000Parameter comparison.000SPIF parameters in the literature.000Final discussion.000Differing conclusions among papers.000Process mechanics.000Future directions in SPIF.000Conclusion.000Acknowledgements.000References.000IntroductionSingle point incremental forming(SPIF)is a method ofmanufacturing components from sheets of material,with theadvantage of little to no customised tooling and otherwise genericsetup 1.This makes it ideal for producing sheet metal prototypecomponents before investing in a stamping mould,or for one-offcustomised components.SPIF is a type of incremental sheet forming(ISF),a class ofprocesses which includes spinning and shear forming 2.SPIF hasthe advantage over a method such as spinning of being able to formasymmetric shapes.In the 2005 paper,Jeswiet et al.3 succeededin bringing all the current knowledge at that time and synthesisingit into a comprehensive review of the progress and state of the artof asymmetric ISF processes.The decade of research since thencalls for an updated review of the progress and understanding ofSPIF,including incremental forming of polymer sheets firstexplored in 2008 4.This paper comprises a review of literature on single pointincremental forming,specifically to present the process param-eters that influence the formability of the material during forming.Organising the results of this investigation will assist in creatingstraightforward parameter guidelines and instructions useful forfuture research and manufacturing real components with SPIF.While commercial and industrial SPIF components have beenmade in the past,they can be so complex that trial and errorbecomes the most feasible development technique,as using FEA(finite element analysis)would be too computationally expensive.Therefore,a significant challenge is how to develop it into anindustrial process using methods more sophisticated than trial anderror.The aim of this literature review is to collect relevant data fromexperimental papers and draw conclusions on maximising theformability of the material used in SPIF.The other aspects of SPIFthat are not systematically covered in this review are formingforces,surface quality,geometric accuracy,and resultant materialproperties.Formability is most commonly quantified by finding themaximum wall angle(Fmax)to which the material can be formedbefore failure occurs 5,with respect to the horizontal plane.Typically a simple shape,such as a cone or pyramid,is used todetermine this maximum wall angle.Multiple parts can be formed,each one with a steeper wall angle than the previous,until a partbreaks 6.Another option is a shape where the wall angle changes fromshallow to steep,for example the variable wall angle conicalfrustum(VWACF)reported in 2007 by Hussain et al.7.If this partis used,only one test is needed to determine the wall angle wherefailure occurs.In the same paper,Hussain et al.7 compared theVWACF results and results from straight-wall tests and found thelatter overestimated Fmaxby less than 4%due to its higherstiffness.Therefore,if the exact wall angle at fracture is required forstraight wall parts,the VWACF results should be further testedwith conical or pyramidal frustums.Any formability test,however,if it is repeated accurately,should give consistent results such thatthe general effect of a process parameter can be determined.Thegeneral effect,further explained in Results and discussionsection,provides the data that is analysed in this literature review.Material parametersMany different materials have been used in SPIF,including avariety of metals 3,polymer sheets 4,and other sheet materialssuch as sandwich panels 8,with a wide range of formabilityamong them.This review will not examine formability limits ofspecific materials but will instead list them in the parameteranalyses to allow comparison between experiments with the samematerial,for example PVC or AA3003-O.Material type can be seenas the base upon which all other parameters are selected.The thickness of the undeformed material blank is an importantparameter and has significant effects on the SPIF process and finalpart,especially the force needed to deform the sheet whichincreases with increasing thickness 9.Sheet thickness is also afactor in the sine law equation for shear forming,where the finalthickness(tf)of a part can be calculated from the initial thickness(ti)and the wall angle from horizontal(F).The equation istf=ti*sin(90?F)and has been shown to be accurate for SPIFparts formed in a single pass 10.The absolute values of thickness are not important in thisreview,as unique material properties mean a 2 mm sheet of onematerial performs differently to a 2 mm sheet of a differentmaterial 3.Only the general effect of increasing or decreasing thethickness of the undeformed blank has been studied.Tool parametersThe tool or punch used in SPIF to deform the sheet hastraditionally been one of two types.Firstly,a solid hemisphericaltool 2,and secondly,a tool with a ball bearing in a socket,allowing it to roll freely over the sheet 6.As progress in SPIF andincremental forming in general developed,the types of toolsexpanded to include flat-ended and other shaped tools 11.Fig.1shows the dimensions used to describe 3 main types of tools.TheHemis phericalFlat-e ndedRrRBall bearingRFig.1.The main types of tools used in SPIF.T.McAnulty et al./CIRP Journal of Manufacturing Science and Technology xxx(2016)xxxxxx2G ModelCIRPJ-381;No.of Pages 12Please cite this article in press as:McAnulty,T.,et al.,Formability in single point incremental forming:A comparative analysis of thestate of the art.CIRP Journal of Manufacturing Science and Technology(2016),http:/dx.doi.org/10.1016/j.cirpj.2016.07.003advantages of one type of tool over another have been a consistentarea of research for some time,for example Kim and Park 12 andmore recently Cawley et al.13.Tool diameter and tool type aretwo parameters studied in this literature review.The size and end-shape of the tool influence the mechanisms ofthe forming process.The size and shape of the area of contactbetween the tool and sheet can affect process aspects such asgenerated friction 14,observed forces 15,and pressure 16.The tools can be made from different materials,and theinteraction between the tool material,blank material and lubrica-tion influence the friction conditions seen during the process17.Currently there have been no published journal papersexamining the effect of different tool materials on formability inSPIF,therefore it is not able to be included in this literature review.Toolpath parametersThe toolpath used in SPIF can be the equivalent of a machiningoperation such as Z-level finishing,though the tool does not cut thematerial.The motion of the tool is defined by the same parametersused in machining operations.Feed rate is the velocity of the tool asit moves over the sheet,typically defined in mm/min.Step down ishow far the tool presses into the sheet with each circuit.Spindlespeed is how fast the tool spins,specified in rotations per minute(rpm).Toolpath parameters influence the generated friction by themovement and rotation of the tool 18,and the feed rate and stepdown define the deformation rate of the material.The relative rotation directions of the tool and toolpathdetermine the milling mode;either conventional or climb milling,to use the standard machining terms.If the tool and the toolpathare both moving clockwise or counterclockwise,it is conventionalmilling,and if they are rotating in different directions,it is climbmilling.Climb milling is the most commonly used mode in SPIF,asthe friction is reduced by the tool effectively rolling over the sheetas it forms 19.While cutting tools typically rotate in a clockwisedirection,and therefore specifying toolpath direction might beenough for the reader to assume which milling mode is being used,it is not as thorough as defining conventional or climb(rolling)milling as the utilised machining mode.GeometryThe shape of the incrementally formed part affects the strainsand therefore the formability of the material.The geometry is anaspect which is not covered in this literature review due to thecomplexity of analysing the many different shapes and dimensionsused across the studied papers.In manufacturing a practical component,a draft angle analysiscan be performed on the CAD model of the part to highlight whichwalls are steeper than a specified angle.Using the maximum wallangle for that material in the analysis will show whether there areany sections which may be too steep to form in a single SPIF pass.Ifthere are no sections steeper than the permitted angle,it is likelythat the part will succeed 20.The curvature of the part,fromstraight walls to tight curves,affects the types of strains(plane,biaxial)developed during the process.For example strains from aconical frustum with 100 mm radius compared to the edge of apyramidal frustum with 10 mm radius,as presented in Filice et al.21 and Fratini et al.22.Experimental parametersSince the process was first developed,research has beenconducted into modifications of the basic SPIF process.Forexample,many different methods of heating the workpiece havebeen explored.Duflou et al.23 in 2007 used a laser to improveFmaxof TiAl6V4 sheets by more than 208.The same Titanium alloywas heated up to 400 8C with band heaters installed in the blankholder in Palumbo and Brandizzi 24,and an improvement informability was observed.The use of electric current through thetool and the sheet has been explored in recent years,also applied toTiAl6V4 25 and other materials such as AA6061-T6 26 withresulting formability improvements.As this literature reviewstudies process parameters for basic SPIF,parameters relevant tohot SPIF and electric SPIF are not examined.This workResearch questionWhat does the literature say about the effects of SPIF processparameters on formability?HypothesisEach parameter has an optimal operating range which is afunction of other parameters.They are interdependent in variouscombinations.MethodThis literature review is undertaken as a systematic quantita-tive literature review.This type of literature review is defined inPickering and Byrne 27.The process has been tested by multiplestudents and researchers,and produces repeatable and highquality results.This technique is highly applicable to the area of SPIF parametersdue to the quantitative nature of the data input,and as will be seenin the tabulated results,allows effective comparisons of parametervalues between multiple papers.The selected parameters that havebeen studied in this review are universal to every single pass SPIFprocess,and more specialised processes such as applying electriccurrent or external heat are not addressed.Many SPIF papers have been published in the area offormability,however the inclusion criteria highlighted below areused to select a high quality collection of papers that are a goodrepresentation of the wider field.Details of the process steps as they relate to this literaturereview are shown below.Topic.Formability in single point incremental forming.Research question.What does the literature say about the effects of processparameters on formability and techniques for improving form-ability?Is there consistency between conclusions?What materials,parameter values and test shapes were used forthe SPIF formability tests?Keywords searched.SPIF/single point incremental formingISF/incremental sheet formingISMF/incremental sheet metal formingSpifabilityFormabilityForming limitFLD,FLCMaximum strainWall angleParameter interactionDatabases searched.ScopusScience DirectT.McAnulty et al./CIRP Journal of Manufacturing Science and Technology xxx(2016)xxxxxx 3G ModelCIRPJ-381;No.of Pages 12Please cite this article in press as:McAnulty,T.,et al.,Formability in single point incremental forming:A comparative analysis of thestate of the art.CIRP Journal of Manufacturing Science and Technology(2016),http:/dx.doi.org/10.1016/j.cirpj.2016.07.003ProQuestWeb of ScienceCriteria for inclusion of papers.Published journal articleOriginal researchNot a review paperVaries SPIF process parametersUses standard SPIF,not multi-pass,electro SPIF,externallyheated etc.Presents results on formability limits for single pass SPIFCategories.Summary of the categories which were used in the literaturedatabase:Bibliographic informationValues of process parametersMaterial usedExperimental setupTest geometryType of analysisResults of analysisMost effective combination of parametersResults and discussionThe following results explain the main factor effects presentedin the papers from this literature review.Four conclusions arediscussed with respect to the effect of the factor on formability;specifically how the variation of that parameter increases theformability.These conclusions are:1 Increasing the value of the parameter causes an increase informability,2 Decreasing the value of the parameter causes an increase informability,3 The parameter has no effect on formability,or4 The value of the parameter should be optimised to obtain thegreatest increase in formability.An analysis on key parameter interactions is presented after theresults of the main factor effects.For this review,there were 35 papers found which fulfilled therequirements outlined in the method.In the data tables the papers are referenced,for ease ofunderstanding,by the name of the first author,the year,and thenumerical reference which will allow for clear differentiationbetween papers with the same first author and year of publication.For example,Hussain,2011 28 and Hussain,2010 29.Ifinformation about a parameter was not stated in the paper,it isnoted as N/A in the results tables.After the results of each parameter are presented,a discussion iscarried out for that parameter.Finally,the cumulative results arediscussed in Final discussion section.Material thicknessA total of 15 papers from this literature review varied thematerial thickness to determine the effect on formability in SPIF.Ofthese,the majority(10)found the formability to increase withthicker sheets.The results are graphically represented in Fig.2 anddetails are given in Table 1.Out of the papers which tested variation of material thickness,only Bagudanch et al.37 noted more than one repeat of each test.It is important to repeat tests when results are close together todetermine significance,as in Fang et al.41 where results wereonly 0.5 mm apart.They measured the failure depth of a 1 mmsheet as 36 mm,and the failure depth of the 2.5 mm sheet as35.5 mm.As these two thicknesses are significantly different,itmay have provided more insight to also test a mid-point betweenthe two,for example 1.5 or 2 mm thickness.It may be the case thata peak in formability was present rather than formabilitydecreasing with thickness.Hussain et al.28 examined the influence of the tool radius(R):thickness(t)ratio on failure,which can be said to precludeformability.The material is tested at two thicknesses,0.7 and2.6 mm,which is quite a large range the largest differencebetween two successive thicknesses.They conclude that optimi-sation of R:t ratio is needed to maximise the success of parts.PVC was tested in 5 papers 31,34,33,37,40 and the majorityconcluded that an increase in sheet thickness improved theformability of the material.On the other hand,Franzen et al.40found a slight trend towards increased formability with the thinnersheet.However,the uncertainty in the experiment requires greaterwork to definitively compare the results against those from theother polymer papers.Fig.2.Material thickness conclusions.Table 1Material thickness:summary of papers.Papers Material ThicknessmmTestrepeatsConclusion:Increase material thickness to increase formabilityJeswiet,2002 10 AA3003-O 0.8,1.3,2.1 N/AJeswiet,2005 5 AA3003-O 1.21aN/AAA5754-O 1.02bN/AHam,2006 30 AA3003-O 0.81,1.2,2.1 N/AMartins,2009 31 PA,PC,PE,POM,PVC 2,3 N/AManco,2010 32 AA6082-T6 1,2 1Silva,2010 33 PVC 2,3 N/AMarques,2012 34 PA,PC,PET,PVC 2,3 N/AShanmuganatan,2013 35 AA3003-O 1,1.25 N/AGolabi,2014 36 SS304 0.5,0.7 N/ABagudanch,2015 37 PVC 1.5,2 3Conclusion:Optimise material thickness to increase formabilityHam,2007 38 AA5182 0.93,1,1.5 N/AAA5754 0.93,1,1.45 N/AAA6451 0.8,0.9,1.545 N/AHussain,2011 28 AA1060 0.7,2.6 N/AHussain,2013 39 AA2024-O 0.9,1.4,1.95,3 2Conclusion:Decrease material thickness to increase formabilityFranzen,2009 40 PVC 2,3 N/AFang,2014 41 AA1100 1,2.5,4 1aFmax=8.5t0+60.7.bFmax=3.3t0+58.3.T.McAnulty et al./CIRP Journal of Manufacturing Science and Technology xxx(2016)xxxxxx4G ModelCIRPJ-381;No.of Pages 12Please cite this article in press as:McAnulty,T.,et al.,Formability in single point incremental forming:A comparative analysis of thestate of the art.CIRP Journal of Manufacturing Science and Technology(2016),http:/dx.doi.org/10.1016/j.cirpj.2016.07.003Thickness optimisation.Any kind of non-linear trend in formability is not observable inpapers with only two levels of material thickness,and will thereforebe categorised in either Increase or Decrease.For example,Jeswietand Young 5 plotted a linear trend of thickness against maximumwall angle.The equation for this trend is