momona

ʻO ka Shrinkage hoʻoheheʻe lula

ʻO ka hoʻoheheʻe palakiko ka hoʻowahāwahā ʻia kekahi o nā waiwai ke kulu ka mahana wela. Pono ka helu o ka hoʻoheheʻe ʻana i ka hoʻoheheʻe ʻia i ka hoʻoholo ʻana i nā ʻāpana hana hope loa. Hōʻike ka waiwai i ka nui o ka hōʻemi a kahi mea hana e hōʻike ai ma hope o ka lawe ʻia ʻana mai ka popopo a laila hoʻomaʻalili ʻia ma 23C no kahi manawa o 48 mau hola.

Hoʻoholo ʻia ka Shrinkage e ka hoʻohālikelike aʻe

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

kahi o ka nui o ka huina shrinkage punahelu, Lr ka nui o ka hana (i. a i ole mm), a me Lm ke ana o ka hakahaka (i a i mm). ʻO ke ʻano a me ka hoʻonohonoho ʻana o nā mea ea i ka waiwai loli o ka shrinkage. Hiki ke hoʻopili ʻia ka shrinkage e kekahi mau loli e like me ka mānoanoa o ka workpiece mānoanoa, kaomi a me nā kaomi noho. ʻO ka hoʻohui ʻana o nā mea hoʻopihapiha a me nā hoʻoikaika ʻana, e like me ka fiber glass a i ʻole ka mea hoʻopiha mineral, hiki ke hōʻemi i ka shrinkage

Hoʻopiʻi ka Shrinkage o nā huahana plastics ma hope o ka hana ʻana, akā ʻokoʻa ka crystalline a me nā polymers amorphous. Kūleʻa nā mea hana Plastics āpau ma hope o ka hana maʻalahi ʻana ma muli o ka hopena o kā lākou compressibility a me ka hoʻohaʻahaʻa wela e hoʻomaʻalili mai ka mahana hana.

ʻO nā mea amorphous he haʻahaʻa haʻahaʻa. Ke hoʻomaʻalili nā mea amorphous i ka manawa hōʻoluʻolu o ke kaʻina hana hoʻoheheʻe, hoʻi lākou i kahi plymer paʻa. ʻO nā kaulahao polymer e hana i nā mea amorphous ʻaʻohe kikoʻī kikoʻī. ʻO nā laʻana pf amorphous mea he polycarbonate, ABS, a me polystyrene.

Hana ʻia nā mea crystalling i kahi kiko hoʻoheheʻe crystalline Hoʻonohonoho nā kaulahao polymer iā lākou iho i kauoha ʻia i ka hoʻonohonoho ʻana o ka mole. ʻO kēia mau wahi i kauoha ʻia he mau aniani ke ʻano ke anuanu ka polymer mai kona moku hoʻoheheʻe ʻia. No nā mea semicrystalline polymer, ka hoʻokumu a me ka hoʻonui ʻana o ka hoʻopaʻa ʻana o nā kaulahao mole i kēia mau wahi crystalline. ʻoi aku ka kiʻekiʻe o ka hoʻoheheʻe injectio no nā mea semicrystalline ma mua o nā mea amorphous. ʻO nā laʻana o nā mea crystalline he nylon, polypropylene, a me polyethylene. Ke papa inoa nei i kahi helu o nā mea ea, nā amorphous a me nā semicrystalline, a me kā lākou punahelu shrinkage.

Shrinkage no thermoplastics /%
mea hoʻoheheʻe puna mea  hoʻoheheʻe puna mea hoʻoheheʻe puna
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 PC-PBT 0.8-1.0 Polysulfone 0.1-0.3
Acetal 2.0-3.5 PC-Hānai Ā Huhu 0.8-1.0 PBT 1.7-2.3
Naelona 6 0.7-1.5 ʻO Polyethylene 1.0-3.0 Hānai Ā Huhu 1.7-2.3
Naelona 6,6 1.0-2.5 Polipropylene 0.8-3.0 TPO 1.2-1.6
PEI 0.5-0.7        

ʻO ka hopena o ka hopena shrinkage ʻoi aku ka maikaʻi o ka hana ʻana i nā tolerances i hiki ke kiʻi ʻia no nā polymers amorphous ma mua o nā mea no nā polymine crystalline, no ka mea, ʻoi aku ka nui o ke kauoha a me ka maikaʻi o ka ʻūlū ʻana o nā kaulahao polymer i ka crystallites, hoʻonui ka hoʻololi i ka wā liʻiliʻi. Akā me nā plastics amorphous, ʻo kēia wale nō ka mea a helu maʻalahi ʻia.

No nā polymers amorphous, ʻaʻole haʻahaʻa wale nā ​​kumukūʻai shrinkage, akā wikiwiki e hana. No kahi polymer amorphous maʻamau e like me PMMA, aia ka shrinkage ma ke ʻano o 1-5mm / m. Loaʻa kēia i ka hōʻoluʻolu mai ma kahi o 150 (ke ana wela o ka hoʻoheheʻe) a 23C (ke ana wela o ka lumi) a hiki ke pili i ka coefficient o ka thermal expo.


Ka manawa Post: Sep-19-2020