PTFE ay-tɛmpracha fabrik nɔ gɛt fiks kɔfishin fɔ tɛmal ɛkspɛnshɔn (CTE). Nɔ lɛk mɛtal ɔ sɔlid plastic, in ɛkspɛnshɔn bihayvya de jɔyn fɔ afɛkt bay di fayv glas bays fabrik, PTFE lod kɔntinyu, wef strɔkchɔ, ɛn ɔpreshɔn tɛmpracha rɛnj.
Dis kɔmplisiti kin mek bɔku tɛm prɔblɛm dɛn we dɛn nɔ bin de ɛkspɛkt: bɔku bɔku kɔnvaysɔ bɛlt dɛn, gasket dɛn we dɔn rɔtin, layers dɛn we dɔn delaminated, ɔ layna dɛn we dɛn dɔn wɔp. Ɔndastand ɛn disayn fɔ thermal expansion impɔtant fɔ rilibul lɔng tɛm pefɔmɛns.
Aokai PTFE dɔn analayz tɛmal ɛkspɛnshɔn bihayvya akɔs bɔku aplikeshɔn dɛn. Dis gayd de ɛksplen di tipik CTE valyu dɛn ɛn gi siks prɛktikal sɔlvishɔn fɔ avɔyd fɔlt dɛn we gɛt fɔ du wit ɛkspɛnshɔn.
Tipik Kɔfishin fɔ Tɛmral Ɛkspɛnshɔn – No Yu Nɔmba dɛn
1. Pure PTFE rɛfrɛns CTE
Pure PTFE gɛt ay linya kɔfishin fɔ tɛmal ɛkspɛnshɔn: roughly 10×10−5/°C (100–200 ppm/°C) na rum tɛmpracha, wit nɔ-layn vɛryushɔn as tɛmpracha de shift.
krichכl not: PTFE de כndago kristalin fεz transishכn dεm na arawnd 19°C εn 30°C , we de lid to wan abrupt vכlyum chenj fכ 1%–2% . Dis kwaliti nid spɛshal atɛnshɔn fɔ prɛsishɔn aplikeshɔn dɛn. 1 mita lכng pure PTFE film kin gro bay 1-2 cm jכs bay we i pas tru rum tεmprachכ.
2. PTFE ay-tεmpratura fabrik (fayba glas sabstεrayt) – tipik CTE rεnj
Fayba glas insɛf gɛt wan ɔlta-lɔ CTE we na lɛk. 5×10−6/°C (5 ppm/°C) , we de sav as rigid fremwok fɔ ristrikt PTFE ɛkspɛnshɔn ɛn drastikli ridyus di in-plɛyn tɛmal ɛkspɛnshɔn fɔ finish fabrik. Bɔt di strɔkchɔ we dɛn wev stil de mek di tin dɛn we dɛn dɔn mek, bɔku pas di klos we dɛn mek wit fayv glas we nɔ gɛt wan bɔt.
We
Tipik CTE we dɛn kin yuz
Valyu
Warp (we lɔng wan) .
3×10− – 5×10−/°C
30–50 ppm/°C
Weft (krɔs-krɔs) .
4×10−5 – 6×10−/°C
40–60 ppm/°C
Ekspɛnshɔn along di tiknɛs dairekshɔn na mɔ signifyant bikɔs ɔf di ay prɔpɔshɔn fɔ PTFE rɛsin. Fɔ injinɛri prɔpɔz, na in-plan dimɛnshɔnal chenj dɛn nɔmɔ dɛn kin jɔs put fɔs.
Disain Strukchɔral Kliarens fɔ Tɛmal Ɛlɔngeshɔn
1. Fri ɛkspɛnshɔn edj dɛn
We yu yuz am as gasket, thermal insulation mat, ɔ slayding surface, avɔyd fɔ ful-ɔp ɔl di 4 say dɛn. Rizav at le wan ɔ tu fri edj fɔ alaw fɔ mek di tɛmal strɛch ɛn kɔntrakshɔn we nɔ gɛt ɛnitin fɔ stɔp am.
2. Elongated mawntin ol dɛn
If yu nid fɔ fast bolt, mek ol dɛn big ɔ adopt lɔng ol dɛn we gɛt slot. Nɔ tayt di bolt dɛn ful wan; ad gasket fɔ rizɔv smɔl smɔl slaydin alawɛns. Dis de alaw di matirial fɔ expand ɛn kɔntrakt witout strɛs kɔnsɛntreshɔn na di bolt pɔynt dɛn.
3. Segmɛnt layn
Fɔ instɔleshɔn na big eria, split di klos insay sɛpret panɛl dɛn wit 3–5 mm ɛkspɛnshɔn jɔyn bitwin di pis dɛn, mɔ along di lɔng-ways dairekshɔn. dis de mek di bכklin nכ de kumulativ εkspכnshכn akɔdin to lכng span dεm.
Avɔyd Rapid Tɛmal Sayklin Akɔs Faz Transishɔn Kritikal Tɛmpratura
PTFE de sofa dramatik volyum fluktueshכn nia rum tεmprachכ – spεshal wan na 19°C εn 30°C fεz transishכn pכynt dεm. If di ikwipmɛnt kin chenj bɔku tɛm bitwin kol stɔrɔj ɛn ambiɛnt tɛmpracha, nɔ tɛnsi di PTFE klos tu tayt.
We dɛn instɔl am na lɔw tɛmpracha yet dɛn de wok ɔnda ay ɔt, di klos go lɔng (ɛgz., 1 mita klos kin strɛch sɔm milimita we dɛn ɔt am frɔm 25°C to 200°C).
Krio rul: Nɔ ɛva tɛnsi PTFE fabrik tayt wan na rum tɛmpracha ɛn afta dat ɔt am – ɛkspɛnshɔn go mek ripɛl. Nɔ ɛva tɛnsi am tayt pan ay tɛmpracha ɛn afta dat i kol am – shrinkage go tear ɔ ova strɛs di matirial.
Anti-Buckling Dizayn fɔ Ɔvalap ɛn Jɔyn
Ɔvalap along di ɛkspɛnshɔn dairekshɔn , ɛn mek shɔ se di ɔvalap wit pas di maksimal prɛdikted ɛlɔngeshɔn.
Fɔ siŋ sim , lɛf lɔs alawɛns pan stich trɛd dɛn. If dɛn bon am wit ay-tɛmpracha adeziv, pik ɛlastik glu fɔ mek i nɔ te we di ɛkspɛnshɔn kɔfishin dɛn we nɔ mach kin mek.
Instɔl kɔntrawɛt ɔ spring-lod ɔtomɛtik tɛnsiɔn fɔ absɔb di fabrik rilaks we di tɛmpracha ay ɛn shrink we di tɛmpracha smɔl. Nɔ ɛva tay di bɛlt ɔva-tayt ɔnda ay ɔt – dis go mek i ɔvalod we kol kɔntrakshɔn. Di bɛlt tɛnsiɔn fɔ sɛt na di lɔs ɛkspɛkt ɔpreshɔn tɛmpracha.
2. Rilis layna ɛn ayzolayshɔn shit dɛn
Le flat witout pre-tɛnshɔn. Sikyuɔr layt wan bay sɛlf-weit ɔ smɔl prɛs strip dɛn na wan singl dairekshɔn fɔ mek yu nɔ gɛt pɔrmɛnt kris we di tɛmal ɛkspɛnshɔn kin mek.
