CNC MachiningAcrylic ntau lawmPaub meej
Peb tau khiav PMMA los ntawm CNC tshuab rau ntau tshaj kaum xyoo tam sim no. Dab tsi hauv qab no tsis yog phau ntawv piav qhia- nws yog cov ntawv sau los ntawm ntau pua qhov kev tsim khoom, sau rau cov kws tsim khoom thiab cov neeg tsim khoom uas yuav tsum nkag siab tias qhov tshwm sim tiag tiag thaum acrylic ntsib carbide.
Cast los yog extruded? Qhov no yog qhov uas txhua qhov kev sib tham yuav tsum pib, tab sis nws tsis tshua muaj.
Ob yam khoom zoo ib yam ntawm daim ntawv. Ob leeg yog PMMA, ob lub tshuab ntawm tib lub cuab yeej, ob daim ntawv spec sau cov khoom siv tshuab zoo sib xws. Nyob rau hauv pem teb khw, lawv coj zoo li txawv hom nkaus. Cam khwb cia acrylic tsim fluffy nti spirals uas eject huv si los ntawm tej cheeb tsam -zoo li zoo li machining 6061 txhuas. Extruded Tshuag muab rau koj stringy, gummy ribbons uas qhwv ib ncig ntawm lub cuab tam shank thiab fuse rov qab mus rau lub workpiece. Cov kev ntxhov siab sab hauv kaw rau hauv cov ntawv extruded thaum lub sij hawm tsim khoom kuj tsim teeb meem hauv qab: crazing uas tshwm nyob rau lub lis piam tom qab sib dhos, tshwj xeeb tshaj yog nyob ib ncig ntawm hnyav- cov pob qij txha.
Peb cov qauv kev pom zoo rau kev tso saib thiab cov khoom siv kho qhov muag yog cov khoom siv pov tseg, txawm tias 20-30% tus nqi hwm. Qhov laj thawj yog lej yooj yim- lub sij hawm voj voog nrawm dua, tsawg dua tsis lees paub, tsis muaj kev hu rov qab rau kev ntxhov siab tawg. Rau cov nqi-tsav cov ntawv thov uas tsis tas yuav muaj qhov meej meej meej, extruded tuaj yeem ua haujlwm. Tab sis txoj kev machining hloov pauv tag nrho: spindle ceev poob qis dua 4,000 RPM, pub tus nqi nce ntxiv kom thawb cov chips tawm ua ntej lawv yaj, thiab tom qab kev ua haujlwm anneal yuav tsum tau ua es tsis yog xaiv.
Kev qhia ceev ceev thaum cov ntaub ntawv pov thawj tsis ploj: kev sim hlawv. Cam khwb cia acrylic crackles thiab haus luam yeeb yam tsis muaj dej. Extruded melts ntsiag to thiab tsim cov tee dej. Crude, tab sis nws ua haujlwm.
Kev Tswj Kub Kub
Lub iav hloov pauv kub ntawm PMMA nyob ib puag ncig 105-116℃nyob ntawm kev tsim. Tus lej ntawd tseem ceeb tsawg dua qhov koj xav. Qhov kev ua haujlwm zoo tshaj plaws yog qis dua - nyob ib ncig ntawm 70℃- thiab hla nws hloov txhua yam txog seb cov khoom teb li cas rau kev txiav.
Kev tshawb fawb luam tawm hauvPolymers(pmc.ncbi.nlm.nih.gov) taug qab nti tsim tawm tsam qhov kub thiab txias. Hauv qab 70 degree, PMMA puas huv si hauv hom nkig. Tshaj li qhov pib, cov khoom nkag mus rau hauv lub xeev viscoelastic- nws softens, smears, thiab deforms es tsis shearing. Burrs daim ntawv. Nto zoo degrades. Chips fuse rov qab mus rau qhov chaw.
|
Lub Hom Phiaj Machining |
Spindle Ceev |
Pub tus nqi |
Qhov tob ntawm Txiav |
|---|---|---|---|
|
Yam tsawg kawg nkaus roughness |
8,000-12,000 RPM |
0.1-0.15mm / hniav |
0.5 hli |
|
Kev tshem tawm siab tshaj plaws |
15,000-18,000 RPM |
0.15-0.2 hli / hniav |
1.0 hli |
|
Sib npaug |
10,000-15,000 RPM |
0.12-0.18mm / hniav |
0.8mm ib |
Qhov yuam kev feem ntau yog txo tus nqi noj kom zoo dua. Nrog rau cov khoom siv feem ntau, kev pub qeeb qeeb txhais tau tias zoo dua qhov chaw zoo. Acrylic inverts no logic. Kev pub qeeb qeeb txhais tau hais tias lub cuab yeej nyob hauv qhov txiav, kev sib txhuam cov cua sov, cov khoom siv softens, cov cuab yeej rubs es tsis txhob txiav. Cov khoom tuaj tawm pos huab. Peb cov neeg ua haujlwm kawm thaum ntxov: thaum tsis ntseeg, thawb cov khoom noj, tsis poob.
Cov cua txias yog compressed cua, tsis yog kua. Qee cov dej- cov kua dej ua kua ua kua ua rau muaj kev ntxhov siab tawg hauv PMMA yog tias cov seem tseem tshuav. Thermal shock los ntawm cov kua dej txias los tsoo sov acrylic ua rau muaj kev ntxhov siab sab hauv. Huab cua qeeb qeeb kom txias tab sis tshem tawm ob qho kev pheej hmoo.
Tooling Notes
Tib -flute O-geometry kawg mills. Qhov no yog acrylic machining tus qauv thiab tau ntau xyoo. Lub geometry-ib ntu txiav, loj nti gullet, siab zoo rake (10-}15 degree), siab clearance-ua kom cov ntug ntse thiab cov chips txav.
Nov yog qee yam tsis txaus ntseeg uas peb pib tso tawm thaum hnov nws los ntawm tus kws kho tshuab ntawm Practical Machinist forums (practicalmachinist.com): hnav siab -ceev steel qee zaum ua kom zoo dua qhov tiav dua li ntse carbide. Qhov kev piav qhia, thaj, yog qhov dulled ntug burnishes es txiav. Peb khiav kev xeem. Cov txiaj ntsig tau sib xyaw, tab sis ntawm qhov kawg dhau mus rau qhov tsis yog - qhov chaw kho qhov muag, muaj qee yam rau nws.
Txheej mob ntau dua li nws pab ntawm acrylic. TiN, TiAlN, txawm li cas los xij - txheej ntxiv microns rau ntawm ntug, ua rau lub cuab yeej dulling zoo. Rau cov ntaub ntawv nyuaj uas hnav tsis kam tseem ceeb, coatings ua rau kev nkag siab. Rau cov yas mos, liab qab carbide lossis HSS nrog polished ntug outperforms coated xaiv.
Khaub thuas kauv rau lub tshuab nqus tsev cov ntxhuav thiab cov kab xev nplaum- tiv thaiv nqa. Upcut kauv rau mechanical clamping -zoo dua nti khiav tawm. Cov cuab yeej xaiv ua raws li kev ua haujlwm, tsis yog cov khoom siv.
Kev xaiv Deg tiav
Machining ib leeg yuav tsis tsim kho qhov muag pom tseeb. Txawm tias optimized tsis cia pom cov cuab yeej cim nyob rau hauv lub Ra 1.6-3.2 μm ntau yam. Nkag mus rau iav zoo li pob tshab yuav tsum tau ua haujlwm thib ob.
Mechanical polishing yog qhov kev xaiv tswj. Standard grit progression: 320, 600, 1000, 2000, ces buffing log nrog compound. Ua haujlwm- hnyav heev. Zoo ib yam. Muaj kev nyab xeeb rau qhov chaw uas yuav pom rov ua dua tshiab.
Nplaim polishing yog nrawm dua thiab ua kom pom tseeb tshwj xeeb ntawm ntug-tab sis. Qhov "tab sis" tseem ceeb. Cov txheej txheem qhia txog kev ntxhov siab ntawm qhov chaw uas tuaj yeem tshwm sim tau ntau lub lis piam lossis ntau hli tom qab, tshwj xeeb yog tias qhov chaw tiv tauj nrog cawv- cov tshuaj ntxuav tes. Peb muaj ib pawg ntawm cov khoom txee tsim cov kab plaub hau tawg yim lub lis piam tom qab xa khoom. Cov hauv paus hauv paus ua rau cov nplaim taws- polished npoo ua ke nrog cov tshuaj ntxuav ethanol uas cov neeg siv khoom kawg siv. Txoj haujlwm ntawd tau qhia peb kom paub meej txog kev tshaj tawm - ua cov lus pom zoo hauv cov ntaub ntawv.
Vapor polishing nrog dichloromethane (DCM) ua haujlwm zoo geometries zoo. Kwv yees li 3 vib nas this lub sij hawm raug, tsim nyog qhov cua yuav tsum tau. Qhov tshwm sim yog 93%+ lub teeb kis tau tus mob- piv rau polished cam khwb cia ntawv. Cov txheej txheem yog tswj kom txaus uas peb tuaj yeem qhia nws rau kev tsim khoom, tsis yog cov qauv tsim xwb.
Tolerance Reality
| Chav kawm | Tus nqi | Daim ntawv thov |
|---|---|---|
| Txuj | ± 0.10 hli | General Cheebtsam |
| Zoo | ± 0.05 hli | Mating nto |
| Precision | ± 0.02 hli | Optical fixtures |
Cov lej no sawv cev rau qhov ua tau, tsis yog qhov tsis siv neeg. Lub limiting yam yog thermal stability thiab fixturing.
PMMA lub thermal expansion coefficient txhais tau hais tias ib feem machined ntawm 28℃ntsuas txawv ntawm 20 degree. Rau kev ua haujlwm precision, peb theem khoom nyob rau hauv lub khw thaum hmo ntuj ua ntej kev txiav txim zaum kawg, tom qab ntawd txheeb xyuas qhov ntev tom qab qhov sib npaug ntawm qhov sib npaug. Phab ntsa tuab kuj muaj feem xyuam rau cov kev ua tau zoo - hauv qab 0.8 hli, nyias ntu flex nyob rau hauv kev txiav quab yuam thiab qhov sib xws ntawm qhov sib xws.
Lub aerospace sector qhia tau dab tsi ua tau nrog acrylic machining ntawm qhov tseeb kawg. DATRON tau sau ib qhov project rau Aero-Tec (datron.com) machining tub rog-qib cam khwb cia acrylic rau cockpit instrumentation- hmo- tsis pom kev- siv tau cov teeb pom kev zoo uas xav tau ob qho tib si nruj thiab qhov pom tseeb. Ib leeg-crystal pob zeb diamond tooling, kev nyab xeeb- tswj machining ib puag ncig, txuas ntxiv polishing raws tu qauv. Lub peev xwm ntawd muaj nyob. Feem ntau cov zaub thiab cov ntawv thov kev lag luam tsis xav tau nws, tab sis kev nkag siab ntawm sab sauv pab txhawb qhov kev cia siab tiag tiag rau txhua qhov project.
Failure Modes Tsim Nyog Paub
Ntug chipping feem ntau qhia cov cuab yeej npub lossis tsis ncaj ncees lawm geometry. Tib -flute carbide nrog lub siab rake ces daws feem ntau.
Melting los yog gumming txhais tau tias pub qeeb dhau, nrawm dhau, lossis ob qho tib si. Nce pub ua ntej txo RPM- counterintuitive tab sis yog.
Tshaj tawm -kev sib sau ua ke yog kev ntxhov siab- cuam tshuam. Ob leeg los ntawm machining parameters, nplaim polishing, los yog ob qho tib si - tso tawm thaum cov kuab tshuaj tiv tauj rau qhov chaw nyuaj siab thaum sib txuas. Kev tiv thaiv yog annealing ntawm 80℃ua ntej cov kuab tshuaj, nrog rau lub sij hawm cua sov scaled rau cov khoom thickness (kwv yees li 1 teev ib hli) thiab txias npaum li cas nyob rau hauv qab no 50℃F ib teev.
Cov ntawv sau los ntawm peb lub Hoobkas
Cov kev txwv thiab cov txheej txheem tau piav qhia ntawm no qhia txog kev coj ua ntawm Ouke Display qhov chaw tsim khoom. Rau cov khoom siv acrylic hauv cov khw muag khoom, cov rooj sib tham, thiab cov ntawv thov kev lag luam, peb tuaj yeem hais raws li cov duab kos nrog kev hloov pauv hauv 2-3 lub lis piam rau ntau lawm.
Kev xaiv cov khoom siv thiab kev ua tiav tiav yog tsim nyog los tham txog thaum ntxov. Lub nplaim taws- polished ntug duab zoo nkauj tab sis yuav tsis muaj sia nyob ntau xyoo ntawm kev muag khoom tuav. Mechanical polishing raug nqi ntau dua hauv lub sijhawm ua haujlwm tab sis tsim cov txiaj ntsig zoo dua. Cov kev sib pauv no cuam tshuam rau ob qho tib si ncua sij hawm thiab pob nyiaj siv - zoo dua los hais txog lawv thaum lub sij hawm tshaj tawm tshaj li lub sij hawm soj ntsuam zoo.
Kev tshuaj xyuas engineering muaj rau cov haujlwm uas kam rau ua, qhov yuav tsum tau kho qhov muag, lossis cov txheej txheem sib dhos xav tau cov tswv yim ua ntej pib tsim khoom.
Ouke Display ua haujlwm puv -kev pabcuam acrylic fabrication chaw hauv Shenzhen nrog rau hauv -lub tsev CNC machining, polishing, thiab sib dhos. ISO- tau lees paub kev tswj hwm zoo, muaj peev xwm rau cov qauv los ntawm cov khoom ntim ntau lawm.
