Taw qhia
Nyob rau hauv lub ntiaj teb no ntawm cov ntaub ntawv yas, shrinkage yog ib tug inevitable kev muaj tiag uas txhua yam khoom tsim thiab pwm tsim yuav tsum sib cav nrog.Pwm shrinkagehais txog kev cog lus ntawm cov yas molding raws li nws txias thiab solidifies tom qab txhaj tshuaj. Qhov tshwm sim no cuam tshuam ncaj qha rau qhov tseeb qhov tseeb, qhov zoo, thiab qhov kawg, kev ua haujlwm ntawm cov khoom kawg. Kev nkag siab txog tus cwj pwm shrinkage ntawm cov khoom sib txawv tsis yog tsuas yog kev paub txuj ci xwb - nws yog lub hauv paus ntawm kev tsim pwm zoo thiab kev tsim khoom.
Kab lus no muab kev sib piv zoo ntawm cov nqi shrinkage ntawm peb cov khoom siv feem ntau:ABS, PC / ABS Alloy, thiabAcrylic Composite Sheet. Thaum thawj ob yog cov ntaub ntawv homogeneous nrog cov kev xav tau ntawm qhov shrinkage ntau yam, acrylic composite sheet nthuav tawm cov kev sib tw tshwj xeeb vim nws cov qauv multilayer. Txawm hais tias koj tab tom tsim cov khoom siv hauv tsheb, cov khoom siv hluav taws xob siv hluav taws xob, lossis cov vaj huam sib luag zoo nkauj, kev nkag siab txog qhov sib txawv no yuav pab koj txiav txim siab xaiv cov khoom siv thiab tsis txhob raug nqi ua yuam kev.
Plastic Shrinkage yog dab tsi?
Ua ntej dhia mus rau hauv cov khoom siv- cov ntaub ntawv tshwj xeeb, nws yog qhov tseem ceeb kom nkag siab tias qhov shrinkage txhais li cas hauv cov ntsiab lus ntawm kev ua cov yas.
Yas molding shrinkageyog qhov contraction ntawm ib feem yas raws li nws txias tom qab txhaj tshuaj. Feem ntau cov shrinkage tshwm sim nyob rau hauv pwm thaum lub sij hawm txias, tab sis ib co txuas ntxiv tom qab ejection raws li ib feem mus txog ambient kub thiab stabilizes nws cov ntsiab lus noo noo. Qhov kev cog lus no tuaj yeem txuas ntxiv, txawm tias me ntsis, rau ntau teev lossis txawm hnub tom qab tsim khoom.
Tus nqi shrinkage txawv nyob ntawm ntau yam:
Hom khoom: Amorphous vs. crystalline polymers coj txawv txawv
Cov xwm txheej ua haujlwm: Lub sij hawm voj voog, qhov kub thiab txias, kev txhaj tshuaj siab, thiab cov cua txias
Pwm tsim: Qhov chaw ntawm lub rooj vag, cua txias channel layout, thiab qhov cua
Ntu geometry: Phab ntsa thickness, zoo li complexity, thiab ntws kev taw qhia
Rau cov khoom siv amorphous xws li ABS, PC, thiab lawv cov khoom sib xyaw, qhov shrinkage yuav qis dua thiab zoo ib yam piv rau semi-cov ntaub ntawv crystalline xws li PP lossis PA . Qhov no ua rau lawv nyiam cov kev xaiv rau cov ntawv thov uas xav tau qhov kev ruaj ntseg.
Shrinkage Rate Sib piv ntawm ib nrais muag
Cov lus hauv qab no qhia txog tus nqi shrinkage ib txwm rau peb cov ntaub ntawv uas peb tab tom tshuaj xyuas:
| Khoom siv | Hom Shrinkage Rate | Cov ntaub ntawv Source Notes |
|---|---|---|
| ABS(Acrylonitrile-Butadiene-Styrene) | 0.4% - 0.7% | General - qib hom phiaj |
| PC / ABS Alloy(Polycarbonate / ABS Blend) | 0.5% - 0.7% | Tus nqi ib ncig ntawm 0.5-0.7% |
| Acrylic Composite Sheet(PMMA + ABS laminate) | Tsis muaj ib tus nqi ruaj khov | Multilayer qauv nrog cov txheej txheem sib txawv |
Tam sim no, cia peb tshuaj xyuas txhua yam khoom kom ntxaws.
1. ABS (Acrylonitrile-Butadiene-Styrene)
Khoom Txheej txheem cej luam
ABS yog ib qho ntawm feem ntau siv engineering thermoplastics, khoom plig rau nws zoo heev toughness, rigidity, thiab processability. Raws li ib qho amorphous polymer, ABS muaj qhov zoo ntawm qhov ruaj khov thiab kev coj tus cwj pwm shrinkage.
Shrinkage yam ntxwv
Tus nqi shrinkage tus nqi rau dav dav - lub hom phiaj ABS yog los ntawm0.4% txog 0.7%. Txawm li cas los xij, tiag tiag - cov ntawv thov hauv ntiaj teb qhia tias tus nqi no tuaj yeem sib txawv raws li cov qauv tsim thiab kev ua haujlwm. Cov kws tshaj lij pwm tsim qauv feem ntau kho cov nqi shrinkage raws li cov khoom siv tshwj xeeb:
Tswv yim ABS shrinkage piv txwv los ntawm kev lag luam:
|
Yam khoom |
Qhov tseeb Shrinkage siv |
|---|---|
| Lub tshuab luam ntawv vaj tse, automotive audio panels | 0.45% |
| DVD ntsej muag (500 × 35 × 30mm) | 0.35% |
| Cov xov tooj ntawm tes, cov khoom siv kho mob, cov khoom siv hauv tsev | 0.5% |
| Cov keyboard keycaps | 0.3% |
| IML (hauv -mould labeling) vaj tse | 0.3% |
| LCD bezels | 0.35% |
Cov yam ntxwv cuam tshuam rau ABS Shrinkage
Kev hloov pauv cuam tshuam: Siab- cov qhab nias cuam tshuam tuaj yeem pom qhov sib txawv me ntsis
Kev taw qhia ntws: Shrinkage tuaj yeem sib txawv ntawm laminar (nrog ntws) thiab transverse (tawm tsam ntws) cov lus qhia
Phab ntsa thickness: Thicker seem txias qeeb qeeb thiab yuav ntsws ntau dua
Fillers thiab reinforcements: Cov iav fiber ntau- txhawb nqa ABS tuaj yeem muaj qhov shrinkage tsawg li0.1-0.2%
2. PC/ABS Alloy
Khoom Txheej txheem cej luam
PC/ABS alloy yog ib qho kev sib xyaw ntawm polycarbonate thiab ABS uas sib txuas cov khoom zoo tshaj plaws ntawm ob qho khoom siv: lub tshav kub tsis kam, lub zog ua haujlwm, thiab qhov ruaj khov ntawm PC nrog kev ua haujlwm yooj yim thiab qis -kub los ntawm ABS. Qhov kev sib xyaw no yog siv dav hauv tsheb sab hauv, hluav taws xob vaj tsev, thiab cov khoom siv hauv tsev.
Shrinkage yam ntxwv
PC/ABS alloy exhibits shrinkage feem ntau nyob rau hauv ntau yam ntawm0.5% txog 0.7%, nrog ntau qhov chaw hais0.5%raws li tus nqi siv tau zoo. Cov khoom yog paub txog nwstsawg shrinkage thiab tsawg warpage, pab txhawb rau qhov zoo tshaj plaws qhov tseeb.
Cov ntsiab lus tseem ceeb:
Txheem PC / ABS:0.5% - 0.7%
Flame-retardant PC/ABS:0.3% - 0.6%
20% iav fiber ntau- txhawb PC/ABS:0.2% - 0.3%
Vim li cas PC/ABS muaj kev ruaj ntseg
Qhov sib ntxiv ntawm PC rau ABS hloov cov cwj pwm shrinkage. PC nws tus kheej muaj tus nqi shrinkage nyob ib ncig ntawm0.5-0.7%, thiab thaum sib xyaw nrog ABS, lub alloy tuav qhov qis -shrinkage yam ntxwv thaum txhim kho qhov kub thiab txias deflection. Kev tshawb fawb qhia tau hais tias cov iav hloov pauv kub ntawm qhov sib xyaw ua ke nce nrog cov ntsiab lus PC, txhim kho qhov ruaj khov ntawm qhov kub siab.
Kev txiav txim siab ua
PC / ABS feem ntau yuav tsum tau ziab ua ntej ua haujlwm (piv txwv li, 2-4 teev ntawm 180℃F / 82 degree)
Pom zoo pwm qhov kub thiab txias ntawm66℃rau 93 degree
Cov khoom siv amorphous xwm pab txhawb nqa kev sib txawv ntawm qhov sib txawv
3. Acrylic Composite Sheet (PMMA + ABS)
Khoom Txheej txheem cej luam
Acrylic composite sheet, tseem hu uaacrylic -coated ABSlos yogPMMA/ABS laminate, yog cov khoom siv ntau txheej uas muaj acrylic (PMMA) txheej sab saum toj sib koom ua ke rau ABS substrate txheej. Qhov kev tsim kho no ua ke nrog cov khoom zoo tshaj plaws ntawm acrylic-gloss, weatherability, thiab khawb tsis kam-nrog toughness thiab formability ntawm ABS.
Shrinkage Challenge
Tsis zoo li cov ntaub ntawv homogeneous,acrylic composite ntawv tsis muaj ib qho, ruaj shrinkage tus nqi. Qhov no yog vim nws muaj ob yam khoom sib txawv uas muaj peev xwm sib txawv shrinkage cwj pwm:
| Txheej | Khoom siv | Hom Shrinkage Range |
|---|---|---|
| Sab saum toj txheej | PMMA (Acrylic) | 0.3% - 0.8% |
| Base txheej | ABS | 0.4% - 0.7% |
Kev txhawj xeeb tseem ceeb nrog cov qauv sib xyaw
1. Kev sib tsoo tsis sib haum
Qhov kev sib tw tseem ceeb nrog cov nplooj ntawv acrylic composite yog tias ob txheej txheej shrink ntawm tus nqi sib txawv thaum lub caij txias. Thaum lawv qhov shrinkage sib tshooj sib tshooj, qhov sib txawv ntawm qhov shrinkage tiag tiag -txawm yog vim qib khoom, kev ua haujlwm, lossis ib feem geometry- tsiminternal stresses ntawm txheej txheej interface.
2. Kev pheej hmoo ntawm delamination
Yog tias qhov sib txawv shrinkage tshaj qhov nplaum nplaum lub zog ntawm cov khaubncaws sab nraud povtseg, qhov tshwm sim tuaj yeem yogdelamination-Kev sib cais ntawm cov txheej acrylic los ntawm ABS substrate. Qhov kev pheej hmoo no tshwj xeeb yog mob ntawm:
Ntug thiab txiav nto
Cov cheeb tsam raug kub caij tsheb kauj vab
Sib sib zog nqus- cheeb tsam kos los yog tsim loj heev
3. Kub rhiab heev
Cov coefficient ntawm thermal expansion txawv ntawm PMMA thiab ABS. Thaum cov ntawv sib xyaw muaj qhov sib txawv ntawm qhov kub thiab txias thaum lub sijhawm ua haujlwm lossis thaum kawg - siv, qhov sib txawv ntawm qhov sib txawv thiab kev cog lus tuaj yeem ua rau muaj kev ntxhov siab ntxiv rau cov kab ntawv cog lus, uas ua rau lub sijhawm ntev - tsis ua haujlwm.
Cov kev cuam tshuam
Rau cov ntawv thov uas xav tau cov nplooj ntawv acrylic composite, cov rooj shrinkage txheem tsis txaus. Designers yuav tsum:
Nrog rau cov chaw muag khoom rau cov ntaub ntawv tshwj xeeb ntawmthermal cycling kev ua tau zoo
Thov cov ntaub ntawv xeem rau ntawmtxheej adhesion zogtom qab tsim
Xav txog qhovkawg- siv qhov kub thiab txiasthiab nws cov kev cuam tshuam rau qhov seem stability
Ntsuam xyuas lwm cov ntaub ntawv xws li huab cua ASA lossis PMMA alloys rau cov ntawv thov tseem ceeb
Cov ntsiab lus sib piv
| Parameter | ABS | PC / ABS Alloy | Acrylic Composite Sheet |
|---|---|---|---|
| Hom khoom | Homogeneous amorphous | Homogeneous amorphous sib tov | Multilayer laminate |
| Hom Shrinkage | 0.4-0.7% | 0.5-0.7% | Txheej - nyob ntawm |
| Shrinkage Predictability | Siab | Siab | Tsawg (nyob ntawm txheej txheej) |
| Risk ntawm Warpage | Tsawg | Tsawg heev | Nruab Nrab (vim muaj kev ntxhov siab sib txawv) |
| Delamination Risk | Tsis muaj | Tsis muaj | Tam sim no yog tias cov khaubncaws sab nraud povtseg tsis sib xws |
| Dimensional Stability | Zoo | Zoo heev | Zoo, tab sis nrog caveats |
Factors cuam tshuam Shrinkage hla txhua yam khoom
Txawm hais tias xaiv cov khoom siv, ntau yam universal cuam tshuam rau qhov kawg ntawm qhov ntev:
1. Kev ua tsis tau
Kev tshawb fawb qhia tau hais tias rau ABS cov ntaub ntawv, kev ua tsis tau muaj feem cuam tshuam rau shrinkage nyob rau hauv cov nram qab no kev txiav txim ntawm qhov tseem ceeb:
Lub sijhawm txhaj tshuaj(feem ntau influential)
Melt kub
Tuav lub siab thiab lub sijhawm(siab dua txo shrinkage)
Pwm kub(Qhov kub siab dua tuaj yeem ua rau shrinkage vim qeeb qeeb)
2. Tshooj Tsim
Phab ntsa thickness variations: Tsis yog-cov tuab tuab ua rau qhov sib txawv ntawm qhov txias thiab qhov sib txawv
Ntws ntev: Kev khiav ntev ntev tuaj yeem ua rau kev taw qhia thiab anisotropic shrinkage
Ribs thiab bosses: Cov yam ntxwv no tsim cov kev hloov loj hauv zos uas cuam tshuam rau cov nqi cua txias
3. Cov tshuaj ntxiv thiab cov tshuaj ntxiv
iav fibers: Ua kom txo qis qis thiab ua rau nws ntau dua anisotropic (ntau sib txawv hauv kev sib txawv ntawm cov lus qhia kev hloov pauv)
Pigments: Qee cov tshuaj pleev xim ua haujlwm ua cov tshuaj nucleating, uas tuaj yeem hloov pauv qhov shrinkage
Cov ntsiab lus rov siv dua: Cov khoom siv rov ua dua tuaj yeem muaj qhov sib txawv shrinkage ntau dua li cov khoom siv nkauj xwb
Cov lus pom zoo
Thaum xaiv ABS
General - lub hom phiaj vaj tse thiab enclosures
Cov khoom yuav tsum tau muaj kev cuam tshuam zoo zog thiab nto tiav
Cov ntawv thov uas tuaj yeem kwv yees tau, zoo - nkag siab txog qhov yuav tsum tau ua
Thaum xaiv PC / ABS Alloy
Automotive sab hauv Cheebtsam (dashboard qhov chaw, trim)
Daim ntawv thov yuav tsum tau kub siab dua li ABS ib leeg
Parts xav tau superior dimensional stability thiab tsis muaj warpage
Cov khoom siv hluav taws xob hauv tsev thiab cov khoom siv hauv tsev
Thaum twg los xav txog Acrylic Composite Sheet
Daim ntawv thov yuav tsum muaj siab -gloss, weatherable nto
Kho kom zoo nkauj panels thiab nameplates
Cov xwm txheej uas tom qab-moulding painting yog undesirable
Ceev faj: Zam rau qhov chaw uas muaj qhov sib txawv ntawm qhov kub thiab txias los yog yuav tsum tau ua kom nruj nruj ntawm daim ntawv tuab
Mould Design Guidelines
Rau cov cuab yeej precision, xav txog cov kev coj ua zoo tshaj plaws no:
Tham nrog cov neeg muab khoom siv: Ib txwm tau txais cov ntaub ntawv tshwj xeeb rau cov qib uas koj siv
Xav txog anisotropic shrinkage: For large parts (>300mm), shrinkage yuav txawv ntawm X, Y, thiab Z axes
Prototype thaum ua tau: Rau qhov loj me, sim pwm nrog tus sawv cev geometry ua ntej cog lus rau kev tsim khoom
Tus account rau kev tshaj tawm -molding hloov: Cov khoom yuav txuas ntxiv me ntsis rau cov xuab moos lossis hnub tom qab ejection
Xaus
Kev nkag siab txog qhov shrinkage tus nqi yog qhov tseem ceeb rau kev ua tiav cov khoom yas tsim thiab ua pwm. ThaumABSthiabPC / ABS alloymuab kev kwv yees, qis qis qis hauv 0.4-0.7% ntau,acrylic composite nplooj ntawvtam sim no cov kev sib tw tshwj xeeb vim lawv cov kev tsim kho multilayer. Lub peev xwm rau qhov sib txawv shrinkage ntawm cov khaubncaws sab nraud povtseg qhia txog kev pheej hmoo ntawm kev ntxhov siab thiab delamination uas yuav tsum tau ua tib zoo soj ntsuam.
Rau cov ntawv thov xav tau qhov siab tshaj plaws qhov tseeb thiab ntev - lub sij hawm ruaj khov, PC/ABS alloy feem ntau muab qhov sib npaug zoo tshaj plaws ntawm cov khoom. Rau tus nqi- siv tau dav dav- lub hom phiaj kev siv, ABS tseem yog cov neeg ua haujlwm txhim khu kev qha. Thiab rau cov xwm txheej tshwj xeeb uas qhov kev zoo nkauj ntawm qhov chaw ua kom pom tseeb qhov nyuaj, cov nplooj ntawv acrylic sib xyaw tuaj yeem xa cov txiaj ntsig zoo nkauj - muab lawv cov kev txwv yog hwm thiab tsim nyog rau.
Nco ntsoov tias tag nrho cov ntawv luam tawm shrinkage tus nqi yog cov txheej txheem, tsis lav. Qhov kawg qhov ntev ntawm txhua qhov molded yog nyob ntawm kev sib cuam tshuam ntawm cov khoom, tsim, thiab txheej txheem. Thaum precision teeb meem, txheeb xyuas nrog koj tus neeg muab khoom thiab siv tau los ntawm kev tsim qauv.