Ncej -Machining Deformation ntawm Aluminium Vaj nyob rau hauv Natural State
Nature of Post-Kev tshem tawm Deformation
Thaum lub tsev nyob aluminium raug tshem tawm los ntawm CNC machining chaw thiab muab tso rau hauv nws lub ntuj unconstrained lub xeev, qhov kev hloov pauv tshwm sim vim qhov kev tso tawm ntawm residual stresses thiab tsis muaj clamping rog uas tswj kev sib npaug thaum lub sij hawm machining. Qhov kev deformation no txawv ntawm hauv - txheej txheem deflection vim tias nws tshwm sim tsuas yog tom qab ib feem tsis muaj kev txwv, feem ntau pom thaum kuaj zaum kawg es tsis yog thaum lub sij hawm machining. Qhov loj tuaj yeem muaj los ntawm cov micrometers tsis txaus ntseeg hauv cov tuab, qhov sib luag mus rau ntau millimeters ntawm warping hauv nyias -walled lossis asymmetric geometries, muaj peev xwm ua rau qhov tseeb ntawm qhov ua siab ntev txawm tias txaus siab rau hauv - cov txheej txheem ntsuas.
Residual Stress Release Mechanisms
Residual stresses originates los ntawm ntau qhov chaw thoob plaws hauv lub manufacturing saw. Cov khoom siv raw nws tus kheej muaj kev ntxhov siab los ntawm casting, extrusion, lossis dov txheej txheem. Thaum tshav kub kub-kho tempers xws li T6 qhia quenching stresses uas nyob twj ywm hauv cov khoom matrix. Kev ua haujlwm machining tshem tawm cov txheej txheem kev ntxhov siab, ua rau cov qauv seem rov qab mus rau qhov sib npaug tshiab. Kev tshem tawm cov khoom sib sib zog nqus los ntawm ib sab ntawm lub tsev tsim cov kev ntxhov siab asymmetric redistribution uas ua rau bending los yog twisting.
Asymmetric machining yog qhov teeb meem tshwj xeeb. Thaum lub hnab ris, tav, lossis lub qhov rais yog machined feem ntau los ntawm ib lub ntsej muag thaum lub ntsej muag rov qab tseem zoo li qub, qhov sib txawv ntawm qhov kev ntxhov siab tso tawm ua rau ib feem hneev rau sab ntau dua. Cov nyhuv no intensifies nrog nce cov khoom tshem tawm piv thiab txo phab ntsa thickness.
Thermal Equilibration Effects
Thaum lub sij hawm machining, cov cua kub hauv zos los ntawm kev txiav txiav ua kom kub gradients thoob plaws lub tsev. Thaum clamped, lub fixture txwv thermal expansion, khaws elastic strain zog. Thaum tshem tawm thiab raug rau qhov chaw nyob ib puag ncig, qhov chaw txias tsis yog -ib txwm thiab lub zog khaws cia tau ploj mus los ntawm qhov hloov pauv. Cov ntu nyias txias sai dua li cov ntu tuab, tsim kom muaj qhov sib txawv ntawm qhov sib txawv uas cuam tshuam cov duab geometry tag nrho.
Kev hloov ntawm lub tshuab ib puag ncig mus rau ambient tej yam kev mob kuj pab. Cov cuab yeej siv tshuab feem ntau ua haujlwm ntawm qhov kub siab vim yog cov cua sov spindle thiab cov tshuab ua kom txias. Ib feem ntsuas kub ntawm lub tshuab yuav tshwm sim tau tab sis kev cog lus kom qis dua tom qab txias. Hloov pauv, yog tias qhov ntsuas kub ntawm qhov ntsuas kub qis dua ambient, qhov yuav nthuav dav tom qab tshem tawm.
Clamping Force Tso
Elastic deformation induced los ntawm clamping quab yuam thaum lub sij hawm machining sawv cev rau cov khoom siv zog khaws cia. Thaum cov clamps raug tso tawm, lub zog no tsav qhov mus rau nws cov duab tsis muaj kev ntxhov siab. Rau cov vaj tsev nyob nrog cov phab ntsa nyias, txawm tias nruab nrab clamping siab tsim cov elastic deflection tseem ceeb uas zoo siab thaum tso tawm. Nta machined thaum lub phab ntsa yog elastically deflected ua misaligned los yog tawm ntawm txoj hauj lwm nyob rau hauv lub xeev dawb.
Lub caij nplooj ntoos hlav no-Cov nyhuv rov qab yog qhov tshwj xeeb tshaj yog nyob rau hauv cov vaj tsev uas tsis muaj kev txhawb nqa loj los yog cov seem cantilevered. Lub tiaj tiaj phaj clamped ntawm cov npoo thiab machined nyob rau hauv qhov chaw yuav pom lub hauv paus doming los yog phaj tom qab tso tawm nyob ntawm seb qhov clamping ua rau sab saud lossis downward deflection.
Khoom siv -Cov yam ntxwv tshwj xeeb
Aluminium alloys sib txawv muaj qhov sib txawv ntawm qhov sib txawv rau tom qab-machining deformation. High -lub zog tshav kub- kho tau cov alloys xws li 7075-T6 thiab 2024-T351 muaj cov kev ntxhov siab ntau heev los ntawm kev kho thiab kev laus, ua rau lawv muaj kev cuam tshuam rau warping. Lub 6061-T6 temper, thaum ruaj khov dua 7-series alloys, tseem tau txais txiaj ntsig los ntawm kev ntxhov siab-txo T651 mob rau kev siv precision. Cam khwb cia hlau zoo li A380 los yog ADC12 tam sim no cov kev cov nyom ntxiv los ntawm porosity thiab inhomogeneous microstructure uas tsim cov kev nyuaj siab nyob rau hauv lub cheeb tsam thiab unpredictable distortion qauv.
Ua hauj lwm- hardening alloys nyob rau hauv 5-series xws li 5052 los yog 5083 sau strain hardening thaum lub sij hawm machining, uas yuav ua rau lub caij nplooj ntoos hlav-rov qab cwj pwm raws li cov hardened txheej. Ntshiab aluminium thiab 1-series alloys muaj lub zog tsis tshua muaj zog tab sis siab ductility, tso cai rau rov qab zoo dua tom qab clamping tso tawm.
Geometric Influences
Cov qauv geometry profoundly cuam tshuam tom qab- tshem tawm deformation. Cov phab ntsa nyias hauv qab 3 millimeters thickness tsis muaj rigidity los tiv thaiv kev ntxhov siab -tsav distortion. Cov chaw tiaj tus loj nrog qhov ntev ntev - mus rau - thickness piv qhia cov qos yaj ywm classic - nti warping. Cov hnab tshos sib sib zog nqus nrog cov plag tsev nyias nyias thiab cov tav nyias nyias tsim cov ntsiab lus kev ntxhov siab uas qhov kev sib txawv pib. Asymmetric designs nrog cov ntaub ntawv concentrated ntawm ib sab lawm distort mus rau sab sib dua.
Qhov piv ntawm machined ntim rau cov khoom ntim uas tseem tshuav yog ib qho txiaj ntsig kwv yees. Thaum qhov piv txwv no tshaj li ntawm 50 feem pua, tom qab-machining deformation txaus ntshai yuav nce ntxiv. Cov vaj tsev nrog cov phab ntsa tuab tuab thiab cov khoom siv sib xyaw ua kom pom tau zoo dua qhov kev ruaj ntseg zoo dua li cov kev hloov pauv sai.
Mitigation Los ntawm Txheej Txheem Tsim
Kev ntxhov siab ua ntej ua tiav machining sawv cev yog qhov kev tiv thaiv zoo tshaj plaws. Rau wrought alloys, qhia txog kev ntxhov siab -relieved tempers xws li T651 lossis T7351 es tsis yog tus qauv T6 txo cov kev ntxhov siab seem los ntawm 50 mus rau 80 feem pua. Thaum muaj kev ntxhov siab- cov khoom siv tau yooj yim tsis muaj, qhov kev ntxhov siab nruab nrab- kev kho cua sov ntawm kev ntxhib los mos tuaj yeem ua tiav, feem ntau suav nrog cua sov mus rau 250 txog 350 degrees Celsius rau 2 mus rau 4 teev tom qab los ntawm kev tswj kom txias.
Rough machining yuav tsum tshem tawm cov khoom ntawm cov khoom thaum tawm hauv cov khoom tiav ntawm 0.3 txog 0.5 millimeter. Qhov roughing theem no tso cai rau thawj zaug kev ntxhov siab tso tawm. Tom qab roughing, lub sij hawm so unclamped ntawm 15 mus rau 30 feeb tso cai rau ib nrab kev ntxhov siab sib npaug ua ntej ua tiav machining. Ua tiav cov haujlwm tom qab ntawd tshuab qhov kawg ntawm qhov kawg nrog qhov kev qhia txog kev ntxhov siab tsawg kawg nkaus.
Balanced machining sequences uas alternate khoom tshem tawm ntawm lub ntsej muag tawm tsam pab tswj symmetry. Tsis yog ua kom tiav tag nrho cov yam ntxwv ntawm ib lub ntsej muag ua ntej flipping ib feem, kev sib npaug ntawm kev tshem tawm ntawm ob sab ua rau muaj kev ntxhov siab ntau dua nyob rau hauv cov txheej txheem.
Fixture thiab Clamping Considerations
Qhov tsawg kawg nkaus clamping quab yuam thaum lub sij hawm ua tiav machining txo qhov loj ntawm elastic deflection uas rov qab los tom qab tso tawm. Lub tshuab nqus tsev ua hauj lwm, conformable fixtures, los yog yam tsawg kawg nkaus - quab yuam hydraulic clamping yuav tsum tau ua hauj lwm kom tiav pass. Clamping ntawm cov yam ntxwv nruj es tsis yog cov phab ntsa nyias tiv thaiv kev sib txawv hauv zos.
Rau cov vaj tse tseem ceeb, machining ib pawg pilot thiab ntsuas tom qab- tso tawm deformation muab cov ntaub ntawv rau kev kwv yees them nyiaj. Yog tias cov qauv deformation zoo ib yam raug txheeb xyuas, txhob txwm ua hauv - txheej txheem distortion tuaj yeem qhia los ntawm kev hloov kho clamping lossis parameter manipulation kom cov ntu tuaj yeem ua siab ntev thaum tso tawm.
Tom qab -Machining Stabilization Treatments
Tom qab machining, kev kho kom ruaj khov tuaj yeem txo qhov kev hloov pauv tsis tu ncua. Artificial aging nyob rau hauv nruab nrab kub accelerates kev nyuaj siab so tsis muaj kev cuam tshuam rau txhua yam khoom. Rau 6061, cua sov mus rau 175 degrees Celsius rau 8 teev muab kev ntxhov siab zoo li lub lis piam ntawm kev laus ntawm ntuj nyob rau hauv chav tsev kub.
Kev vibration kev ntxhov siab siv cov kev tswj xyuas resonant vibration rau 15 mus rau 30 feeb tuaj yeem txo cov kev ntxhov siab seem los ntawm 30 mus rau 60 feem pua tsis muaj thermal raug, ua rau nws haum rau qhov chaw nrog nruj qhov ntev ntev qhov kev kho cua sov yuav muaj kev cuam tshuam. Kev txhaj tshuaj peening qhia txog compressive deg stresses uas tiv thaiv tensile machining stresses, txhim kho qhov seem stability rau qaug zog- vaj tse tseem ceeb.
Kev ntsuas ntsuas
Kev ntsuam xyuas qhov tseeb ntawm kev tshaj tawm - tshem tawm deformation yuav tsum tau ntsuas lub sij hawm thiab cov txheej txheem. Cov khoom yuav tsum tau tso cai rau thermally sib npaug rau qhov chaw kuaj xyuas yam tsawg kawg 4 teev ua ntej qhov ntsuas qhov ntsuas. Kev ntsuas cov khoom siv yuav tsum txhawb nqa ib feem ntawm cov ntsiab lus sib cuag tsawg kawg kom tsis txhob muaj kev cuam tshuam ntuj tsim thaum lub sijhawm tshuaj xyuas.
Sib piv qhov ntev ntsuas nyob rau hauv lub xeev clamped piv rau lub xeev dawb quantifies caij nplooj ntoos hlav -rov qab magnitude. Cov ntaub ntawv no yuav tsum tau sau tseg rau kev txhim kho cov txheej txheem thiab kev kwv yees nyiaj txiag. Rau qhov chaw tsim khoom, cov txheej txheem kev txheeb cais tswj kev taug qab ntawm kev tshaj tawm - qhov ntev tshem tawm txheeb xyuas qhov drift hauv cov txheej txheem machining ua ntej tawm - ntawm - cov khoom tshwj xeeb raug tsim.
Xaus
Tom qab-machining deformation ntawm aluminium vaj tse nyob rau hauv lawv lub xeev ntuj yog ib qho kev sib tw uas tshwm sim los ntawm kev cuam tshuam ntawm residual stresses, thermal keeb kwm, clamping mechanics, thiab cov khoom siv. Tsis zoo li hauv - txheej txheem deflection uas tuaj yeem pom thiab them nyiaj rau lub sijhawm tiag tiag, kev tshaj tawm - tshem tawm distortion qhia nws tus kheej tsuas yog tom qab machining tiav, ua kev tiv thaiv los ntawm cov txheej txheem tsim khoom tseem ceeb. Kev tswj kom zoo yuav tsum tau xaiv cov khoom siv nrog cov kev kub ntxhov uas tsim nyog, cov tswv yim ua haujlwm sib npaug, txo qis clamping quab yuam, thiab kev kho kom ruaj khov thaum tsim nyog. Rau cov ntawv thov precision, kev nqis peev hauv kev ntxhov siab-relived cov ntaub ntawv thiab kev kho cua sov nruab nrab yog pheej yig dua li rework lossis seem ntawm distorted tiav lawm.
