Dab tsi yog qhov siab tshaj plaws ua haujlwm kub rau Aluminium vs. Stainless Steel Heating Platens?

Aluminium tsis tuaj yeem siv rau lub tshav kub platen uas yuav tsum tau ua tiav 300 C. Nws yuav twist thiab deform txawm tias me ntsis nias quab yuam. Yog tias koj thawb mus rau qhov kub ntau dua, nws yog ib qho tseem ceeb kom paub qhov kub ntawm qab nthab ntawm cov khoom siv platen. Cov cua kub platens yog siv rau laminating, composite curing, iav forming thiab kub nias. Lub teb yog dominated los ntawm ob cov ntaub ntawv, txhuas (lub teeb, conductive thiab pheej yig) thiab stainless hlau (muaj zog, ruaj thiab kub resistant). Qhov ntawd yog qhov tseem ceeb ntawm kev xaiv qhov kub ntawm lawv. Paub txog qhov siab tshaj plaws qhov kub thiab txias txwv rau aluminium stainless steel platens lav lub platen muaj peev xwm txhawb nqa qhov kub thiab txias thiab cov khoom siv kho tshuab tso rau ntawm nws thaum ua haujlwm.

Aluminium Platens Qhov Nruab Nrab -Tshav Kub Ua Haujlwm
Txhuas muaj cov thermal conductivity siab (200–250 W / m·K rau alloys xws li 6061) uas ua rau kom kub ceev - nce thiab kub zoo homogeneity. Nws kuj yog qhov hnyav thiab yooj yim machined rau hauv intricate designs nrog embedded rhaub raws los yog thermocouple qhov dej. Tab sis aluminium's Achilles pob taws yog qhov poob ntawm lub zog ntawm qhov kub siab.

Kub thiab Mechanical Behavior txwv
Rau feem ntau cov txhuas alloys, xws li 6061-T6, qhov nrov tshaj plaws platen-qib alloy, qhov siab tshaj plaws kev ruaj ntseg ua haujlwm kub yog li 200℃(392℃F). Tshaj li qhov pib no, cov khoom siv pib ua kom tiav; cov nag lossis daus hardened microstructure maj mam dissolves thiab cov alloy poob nws temper. Raws li qhov tshwm sim, muaj qhov poob qis hauv qhov kev tawm dag zog thiab qhov tawv nqaij . 6061 txhuas ntawm 250 C muaj tsawg dua 50% ntawm nws chav tsev kub yield zog Thaum xovxwm muaj zog tsawg li 1-2 MPa (kwv yees 150-300 psi), lub platen tuaj yeem deformed mus tas li (sagging, bowing lossis tsim kev sib cuag depressions).

Hauv kev xyaum, aluminium platens tsis tshua muaj kev ua haujlwm hauv cov ntawv thov kev thauj khoom siab tshaj 180 degree. Qee cov qauv tsim yuav mus rau 220℃yog tias xav tau ib lub phaj me me (piv txwv li kev sib cuag cua sov yam tsis muaj kev quab yuam sab nraud) tab sis tseem muaj lub sijhawm hloov pauv.

Qhov sib txawv ntawm PTFE txheej
PTFE (polytetrafluoroethylene) yog siv los ua txheej txheej ntawm ntau lub tshuab cua sov aluminium kom muab qhov tsis yog - nplaum tso tawm. PTFE tuaj yeem siv tsis tu ncua ntawm qhov kub txog li 500℃F (260 degree). Aluminium substrate tsis muaj sia nyob ntawm 260 degree. PTFE txheej tau pom muaj sia nyob ntawm ib qho txhuas substrate ntawm 260 degree. Tsis muaj teeb meem ntau npaum li cas cov txheej txheem tuaj yeem siv tau, tag nrho cov txheej txheem muaj lub qab nthab nyuaj, raws li tau hais los ntawm qhov ntsuas kub ntawm cov khoom ntawm platen. Yog tias qhov kub siab tshaj 200℃steel yuav tsum tau txawm tias cov txheej txheem xav tau qhov tsis yog - nplaum nplaum (steel tuaj yeem coated nrog PTFE ib yam nkaus, tab sis kev ua raws li qhov nyuaj dua).

Thermal Expansion ntawm Aluminium
Aluminium muaj cov coefficient siab ntawm thermal expansion (nyob ib ncig ntawm 23 x 10^-6 / C rau 6061). Aluminium platen 300 hli ntev, rhuab los ntawm 20 mus rau 200 degree, expands ib ncig ntawm 1.2 hli. Qhov kev nthuav dav no yuav tsum tau them nyiaj siv cov mounting slots, qhia cov ntsia hlau lossis cov khoom sib txuas yooj yim. Kev ua tsis tiav rau kev txhim kho thermal tuaj yeem ua rau buckling lossis puas lub tshuab cua sov.

Stainless Hlau Platens: Lub Siab Kub Ua Haujlwm
Rau platen kub tshaj 250 degree, stainless hlau yog nyiam, tshwj xeeb tshaj yog cov austenitic qib 304 thiab 316. Hlau khaws cia ntau ntawm nws cov neeg kho tshuab zoo mus txog thiab tshaj 400 C. tshaj qhov ntawd, qhov kev txwv yog nyob ntawm cov alloy thiab qhov tso cai kev ntxhov siab.

Kev txwv kub rau cov qib sawv cev
Cov Khoom Siv Ua Haujlwm Zoo Tshaj Plaws Kub Kub (nruam) Cov Lus Cim
Aluminium 6061-T6 200℃(392℃F) Lub zog txo qis dua 180℃Aluminium 7075-T6 130℃(266℃F) Tsawg kub txwv vim muaj teeb meem corrosion
Stainless hlau 304 800℃(1472℃F) Tswv yim platen txwv ~ 500℃vim muaj cua sov thiab rwb thaiv tsev txwv
Stainless hlau 316 800℃(1,472℃F) Zoo ib yam li 304; Cov tshuaj chloride zoo dua
Stainless hlau 430 (ferritic) 750℃(1382℃F) Tsawg nqi, tsawg formable
Tool Steel H13 550℃(1022℃F) Hardened, hnav-resistant; kub stamping
Rau cov cua sov platens qhov ua tau zoo tshaj plaws kub zoo rau cov hlau tsis muaj steel feem ntau tsis txwv los ntawm cov hlau nws tus kheej, tab sis los ntawm cov khoom cua sov, rwb thaiv tsev thiab cov khoom siv thermocouple. Stainless hlau phaj tuaj yeem ua haujlwm ruaj ntseg ntawm qhov kub ntawm 400-500℃(750-930℃F) thaum nruab nrog cov cua sov sab hauv (xws li cov ntxhia hauv-cov khoom siv insulated hlau-sheathed) thiab cov rwb thaiv tsev kub (xws li ceramic fiber lossis mica). Qee qhov tshwj xeeb iav tsim platens siv Inconel clad cua sov thiab cov rwb thaiv tsev ua haujlwm siab kom ncav cuag 650 degree.

Lub zog tuav ntawm qhov kub thiab txias
AISI 304 stainless hlau khaws cia ib ncig ntawm 70% ntawm nws chav tsev kub yield zog ntawm 500 degree. Nyob rau hauv lwm yam lus, ib tug platen ua rau ib tug xovxwm quab yuam ntawm 50 tonnes ntawm ambient kub tseem yuav tswj tau ib ncig ntawm 35 tonnes ntawm 500 degree. Aluminium, los ntawm qhov sib piv, khaws cia tsuas yog 10-20% ntawm nws lub zog ntawm 250 degree. Hlau yog cov khoom nyiam ntawm qhov kub siab tshaj 250℃vim nws tsis nkag los yog anneal nyob rau hauv ib txwm muaj xovxwm presses.

Thermal conductivity Puzzle
Thawj qhov kev txwv ntawm stainless hlau yog nws cov thermal conductivity tsis zoo. Hom 304 steel, uas muaj chav sov thermal conductivity ntawm kwv yees li 15 W / m·K, muaj cov thermal conductivity txog li 18 W / m·K ntawm 500 degree. Qhov no yog nyob ib ncig ntawm 10 mus rau 12 npaug tsawg dua li ntawm aluminium. Raws li qhov tshwm sim:

Txhawm rau tshem tawm cov kab mob khaub thuas cua sov cov ntsiab lus yuav tsum tau muab tso rau ze dua ua ke (xws li . 30-50 hli qhov sib nrug ntawm 80-100 hli rau txhuas).

Thermal gradients thoob plaws lub platen siv sij hawm ntev dua kom sib npaug, yog li cov cua sov yuav tsum tau ua tib zoo tsim thiab platen lub cev ua kom tuab dua los faib cov cua sov.

Ramp up lub sij hawm ntev npaum li cas rau tib lub tshuab cua sov.

Ntau qhov kub siab stainless hlau platens yog drilled sab hauv rau lub tshuab cua sov los yog cam khwb cia hauv cov cua sov kom them thiab lawv yuav muaj ntau qhov chaw ua cua sov nrog cov neeg tswj xyuas.

Lwm yam khoom siv
Thermal Expansion ntawm
Stainless hlau nthuav dav ntawm ib ncig ntawm 17 × 10⁻⁶ /℃(qib 304), uas yog tsawg dua aluminium tab sis tseem ceeb heev. Lub 300 hli steel platen rhuab mus rau 500℃yuav nthuav dav li ntawm 2.4 hli (los ntawm 20 degree). Qhov no yuav tsum tau them nyiaj los ntawm kev hloov pauv hloov pauv lossis kev txhawb nqa zawv zawg. Kev nthuav dav ntawm steel platens thiab steel xovxwm thav duab tsis txawv heev tab sis yog tias cov hlau platen tau teeb tsa rau hauv ib qho txhuas thav duab (tsis tshua muaj ua) kev npaj ceev faj yog tsim nyog.

Kev tiv thaiv corrosion
Txhuas thiab stainless hlau ob leeg muaj qhov zoo corrosion kuj nyob rau hauv ntau qhov chaw, tab sis stainless hlau yog zoo dua nyob rau hauv lub xub ntiag ntawm noo noo, tshuaj los yog kub oxidation. Aluminium muaj txheej txheej oxide uas tiv thaiv cov hlau tab sis txheej txheej tuaj yeem ua rau tsis muaj zog hauv qhov kub thiab txias lossis acidic / alkaline ib puag ncig. Stainless hlau yog qhov kev xaiv zoo tshaj plaws rau cov zaub mov -kev tiv tauj, kev kho mob lossis tshuaj txheej txheem platens, tshwj xeeb tshaj yog thaum siv cov tshuaj ntxuav.

Machinability thiab nqi
Aluminium yog pheej yig (txog 3-5 zaug pheej yig dua 304 stainless los ntawm ntim) thiab ntau yooj yim rau kev ua. Me me tswj tau aluminium chips. Gummy ua hauj lwm-hardening stainless hlau xav tau kev txiav qeeb qeeb thiab cov cuab yeej ruaj khov dua. Qhov no txhais tau tias cov qauv thiab kev cai platens ua pheej yig dua hauv txhuas - tsuav yog qhov kub thiab txias yuav tsum nyob hauv nws qhov txwv.

Platens nrog txheej thiab kub tsis sib haum
PTFE or fluoropolymer coatings are typically used when a non-stick surface is required (e.g. for curing epoxy prepregs or moulding thermoplastics). The highest continuous temperature of these coatings is 260–290 °C for ordinary grades (some high performance fluoropolymers approach 300 °C). A PTFE coated aluminium platen can not be utilised over 200°C since the aluminium fails first. A stainless steel platen with PTFE coating may be utilised up to the limit of the coating (260°C) however the steel is over specified for that temperature. Permanent PTFE coatings are not used in applications requiring both high temperature (>250℃) thiab tsis yog - nplaum nto; Hauv cov ntawv thov no lwm cov txheej txheem tso tawm yog ua haujlwm (silicone coated tso tawm nplooj ntawv lossis liab qab hlau nrog cov tshuaj tsuag tso tawm).

Cov txheej txheem xaiv tswv yim
Qhov kub siab tshaj Platen yuav tsum tau nyeem
Txog li 150℃Aluminium 6061 (tsim nyog, ceev cov tshuaj tiv thaiv thermal)
150℃txog 200℃Aluminium 6061 nrog load derating; stainless hlau yog muaj zog nias quab yuam yuav tsum tau
200℃-250℃Stainless hlau (304 lossis 316) - txhuas yog qhov txaus ntshai
Stainless hlau (304, 316, 430) 250℃txog 500 degree
Tshaj 500 deg CSpecial heaters (Inconel sheated) los yog ceramic platens, stainless hlau
Abstract
Aluminium vs. stainless hlau xaiv rau lub cua sov platen yog qhov teeb meem kub tiag tiag. Aluminium yog qhov zoo rau thaj tsam 200 ° C rau cua sov ceev, siab homogeneity, tsis tshua muaj nqi, thiab yooj yim machinability. Tab sis ntawm qhov kub no nws softens thiab deforms nyob rau hauv kev ntxhov siab.