melaetsa

Polasetiki ente bōpa Shrinkage

Polasetiki ente bōpa shrinkage ke e 'ngoe ea litšobotsi ha lintho tse bonahalang mocheso marotholi. Sekhahla sa ente bōpa shrankage hlokahala ho fumana hore na litekanyo ho qetela workpiece. Boleng bo bontša palo ea khutsufatso eo sethala sa mosebetsi se se bonts'ang kamora hore se tlosoe hlobo ebe se pholisoa ho 23C nako ea lihora tse 48.

Shrinkage e khethoa ke equation e latelang:

S = (Lm-Lf) / Lf * 100%

moo S e leng sekhahla sa hlobo sa shrinkage, Lr litekanyo tsa ho qetela tsa mosebetsi (ka. kapa mm), le Lm litekanyo tsa hlobo ea hlobo (ka kapa mm). Mofuta le tlhophiso ea thepa ea polasetiki e na le boleng bo fapaneng ba shrinkage. The shrinkage e ka angoa ke mefuta e mengata e joalo ka matla a pholileng a mosebetsi oa mosebetsi, ente le likhatello tsa bolulo. Ho eketsoa ha li-filler le li-reinforcements, tse kang fiber ea khalase kapa ho tlatsa diminerale, ho ka fokotsa ho fokotseha.

Ho fokotseha ha lihlahisoa tsa polasetiki kamora ho sebetsoa ho atile, empa li-polymeri tsa kristale le tsa amorphous li ikhula ka tsela e fapaneng. Lisebelisoa tsohle tsa polasetiki lia fokotseha kamora ho sebetsoa feela ka lebaka la khatello ea tsona le khatello ea mocheso ha li ntse li pholile ho tloha mochesong oa ho e lokisa.

Lisebelisoa tsa amorphous li fokotsehile hanyane. Ha thepa amorphous pholile nakong ea mohato tsidifatso ea thulaganyou e ente bōpa, ba retun ho plymer tenyetseheng. Liketane tsa polymer tse etsang thepa ea amorphous ha li na mokhoa o ikhethang. Mehlala ea thepa ea amorphous ke polycarbonate, ABS le polystyrene.

Lisebelisoa tsa ho lla li na le sebaka se hlalositsoeng sa kristale e qhibilihisang Liketane tsa polymeri lia ipopa ka tatellano ea limolek'hule. Libaka tsena tse laetsoeng ke likristale tse thehoang ha polima e pholile ho tloha boemong ba eona bo qhibilihisitsoeng. Bakeng sa lisebelisoa tsa polima ea semicrystalline, sebopeho le keketseho ea ho paka liketane tsa limolek'hule libakeng tsena tsa kristale. injectio bōpa shrinkage bakeng sa semicrystalline thepa e phahameng ho feta bakeng sa thepa amorphous. Mehlala ea lisebelisoa tsa kristale ke nylon, polypropylene le polyethylene, e thathamisang lisebelisoa tse 'maloa tsa polasetiki, tse nang le amorphous le semicrystalline, le hlobo ea tsona ea hlobo.

Shrinkage bakeng sa thermoplastics /%
lintho tse bonahalang hlobo shrinkage lintho tse bonahalang  hlobo shrinkage lintho tse bonahalang hlobo shrinkage
ABS 0.4-0.7 polycarbonate 0.5-0.7 PPO 0.5-0.7
Acrylic 0.2-1.0 PC-ABS 0.5-0.7 polystyrene 0.4-0.8
ABS-nylon 1.0-1.2 EA-PC-PBT 0.8-1.0 Polysulfone 0.1-0.3
Acetal 2.0-3.5 PC-PET 0.8-1.0 PBT 1.7-2.3
Nylon 6 0.7-1.5 Nhua polyethylene 1.0-3.0 PET 1.7-2.3
Nylon 6,6 1.0-2.5 Polypropylene 0.8-3.0 TPO 1.2-1.6
PEI 0.5-0.7        

Phetoho e feto-fetohang ea shrinkage e bolela hore ho sebetsana le mamello e ka fumanoang bakeng sa li-polymeri tsa amorphous li betere haholo ho feta tsa li-polymeri tsa kristale, hobane li-crystallites li na le lipakete tse laetsoeng le tse betere tsa liketane tsa polymer, phetoho ea mohato e eketsa ho fokotseha haholo. Empa ka li-plastiki tse amorphous, sena ke sona feela ntlha mme se baloa habonolo.

Bakeng sa li-polymeri tsa amorphous, litekanyetso tsa shrinkage ha li tlase feela, empa shrinkage ka boeona e potlakile ho etsahala. Bakeng sa polima e tloaelehileng ea amorphous joalo ka PMMA, shrinkage e tla ba ka tatellano ea 1-5mm / m. Sena se bakoa ke ho phola ho tloha ho 150 (mocheso oa ho qhibiliha) ho isa 23C (mocheso oa kamore) mme e ka amana le coefficient ea thermal expando.


Nako ea poso: Sep-19-2020