jekiseni molding process inofurira zvinhu

Mu jekiseni kuumba nzira zvepurasitiki, thermoplastics, nekuda kwekushanduka kwevhoriyamu kunokonzerwa nekristalllization, kushushikana kwakasimba kwemukati, kushushikana kukuru kwakasara kwakaomeswa nechando muchikamu chepurasitiki, yakasimba molecular orientation uye zvimwe zvinhu, saka zvichienzaniswa thermoset plastiki, shrinkage rate yakakura. The shrinkage rate yakafara uye directionality iri pachena. Pamusoro pe, iyo shrinkage mushure mekuumbwa, annealing kana humidity kurapwa kazhinji yakakura kupfuura iyo thermosetting mapurasitiki.

Apo chikamu chepurasitiki chinoumbwa, iyo yakanyungudutswa inobata nepamusoro pegomba uye dhiri rekunze rinobva ratonhodzwa kuita goko rakadzika-density rakasimba.. Nekuda kwehurombo hwekupisa conductivity yepurasitiki, chikamu chemukati chechikamu chepurasitiki chinotonhodzwa zvishoma nezvishoma kuita dhizaini yakasimba-yakasimba ine shrinkage yakakura.. Naizvozvo, kukora kwemadziro, kunonoka kutonhora, uye yakakwirira-density layer ukobvu huchadzikira zvakanyanya. Pamusoro pe, kuvapo kana kusavapo kwekuisa uye marongerwo uye uwandu hwekuisa zvinokanganisa zvakananga kutungamira kwekuyerera kwezvinhu, density distribution uye shrinkage resistance. Naizvozvo, maitiro ezvikamu zvepurasitiki ane simba guru pane shrinkage uye kutungamira.

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Zvinhu zvakadai sefomu, saizi, uye kugoverwa kweiyo feed inlet inokanganisa zvakananga kutungamira kwekuyerera kwezvinhu, density distribution, kudzvinyirira kuchengetedza uye kuderera mhedzisiro uye kuumba nguva. Yakananga yekudyisa madoko uye madhishi ekudyisa ane mahombe-zvikamu (kunyanya dzakakora muchinjiko) kuva nekuderera kushoma asi kukuru kunanga, uye mapfupi ekudyisa madoko ane hupamhi hupfupi uye kureba ane kushomeka kwekutungamira. Idzo dziri padyo nekudya kunopinza kana kuenderana negwara rekuyerera kwezvinhu zvichaderera zvakanyanya.

Molding mamiriro: high mold tembiricha, kunonoka kutonhora kwezvinhu zvakanyungudutswa, high density uye shrinkage yakakura, kunyanya kune crystalline zvinhu, nekuda kwekristallinity yakakura uye shanduko huru yevhoriyamu, saka kuderera kwakanyanya. Iyo mold tembiricha yekugovera inoenderana zvakare nemukati uye kunze kutonhora uye density kufanana kwechikamu chepurasitiki, iyo inobata zvakananga ukuru uye kutungamirirwa kwe shrinkage yechikamu chimwe nechimwe. Pamusoro pe, kubata kudzvanywa uye nguva zvakare zvine simba guru pakusunga, uye kukonana kuri kudiki asi kutungamira kwakakura kana kudzvanywa kuri pamusoro uye nguva yakareba.

Iyo jekiseni pressure yakanyanya, the melt viscosity musiyano idiki, iyo interlayer shear stress idiki, uye elastic rebound mushure mekudhirowa yakakura, saka iyo shrinkage inogonawo kuderedzwa nehuwandu hwakakodzera. Tembiricha yezvinhu yakakwira, iyo shrinkage yakakura, asi nzira yacho idiki. Naizvozvo, kugadzirisa iyo mold tembiricha, kumanikidzwa, jekiseni kumhanya uye nguva yekutonhora panguva yekuumbwa inogonawo kuchinja zvakakodzera shrinkage yechikamu chepurasitiki.

Paunenge uchigadzira mold, maererano nekuderera kwemhando dzakasiyana-siyana dzepurasitiki, kukora kwemadziro uye chimiro chechikamu chepurasitiki, ukuru uye kugoverwa kweiyo inlet fomu, iyo shrinkage rate yechikamu chimwe nechimwe chechikamu chepurasitiki inotarirwa maererano neruzivo, uye ipapo saizi yegomba inoverengerwa. Kune yakakwirira-chaiyo zvikamu zvepurasitiki uye kana zvakaoma kubata shrinkage rate, nzira dzinotevera dzinofanira kazhinji kushandiswa kugadzira mold:

①Muyedzo mold inosarudza fomu, saizi uye kuumbwa mamiriro eiyo gating system.

②Zvikamu zvepurasitiki zvichagadziriswa mushure-zvinogadziriswa kuti zvione shanduko yehukuru (kuyerwa kunofanira kuva 24 maawa mushure mekugadzirisa.

③ Gadzirisa mold zvinoenderana neiyo chaiyo shrinkage.

④ Edzazve mold uye shandura zvakakodzera mamiriro ekuita kuti agadzirise zvishoma kukosha kwe shrinkage kuti isangane nezvinodiwa zvechikamu chepurasitiki..

Iyo fluidity ye thermoplastics inogona kuwanzo kuongororwa kubva munhevedzano yema indexes senge molecular uremu., melt index, Archimedes spiral kuyerera kureba, inooneka viscosity uye kuyerera ratio (process urefu / epurasitiki chikamu madziro ukobvu).

Diki molecular uremu, yakafara molecular uremu kugovera, kushata kwema molecular structure nguva dzose, high melt index, kureba kutenderera kuyerera kureba, yakaderera inooneka viscosity, high flow ratio, mvura yakanaka, mapurasitiki ane zita rechigadzirwa chimwe chete anofanira kutarisa mirairo yavo kuti vaone kana fluidity yavo ichishanda Pakuumba jekiseni. Maererano ne mold design zvinodiwa, iyo fluidity yemapurasitiki anowanzo shandiswa anogona kukamurwa zvakakamurwa kuita zvikamu zvitatu:

①Zvakanaka fluidity PA, Kuti udzivise kusvibiswa kwezvinhu zvakasvibirira uye kuvapo kwezvinhu zvekare kana kusvibiswa mumashure escrew uye accessories., PS, PP, CA, poly(4) methylpentene:

②Polystyrene akatevedzana resin ine yepakati fluidity (zvakadai seABS, polycarbonate), PMMA, POM, polyphenylene ether;

③Kusanaya zvakanaka kwemvura: PC, yakaoma PVC, polyphenylene ether, polycarbonate, polyarylsulfone, fluoroplastics.

Iyo fluidity yemapurasitiki akasiyana zvakare inoshanduka nekuda kweakasiyana ekuumba zvinhu. Zvinhu zvikuru zvinofurira ndezvinotevera:

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①Kupisa kwepamusoro kwezvinhu kunowedzera mvura, asi mapurasitiki akasiyana ane misiyano yawo, zvakadai sePS (kunyanya avo vane high impact resistance uye yakakwirira MFR kukosha), PP, PA, PMMA, yakagadziridzwa polystyrene (zvakadai seABS, polycarbonate) The fluidity of, PC, CA nemamwe mapurasitiki anosiyana zvakanyanya nekupisa. ZvePE uye POM, kuwedzera tembiricha kana kudzikira hakuna zvazvinoita pakuyerera kwavo. Naizvozvo, iyo yekutanga inofanirwa kugadzirisa tembiricha panguva yekuumbwa kudzora fluidity.

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② Sezvo kumanikidzwa kwejekiseni kuumba kunowedzera, iyo yakanyungudutswa inokwanisa kuveura kukuru uye kunyorova, kunyanya PE nePOM zvinonyanya kunzwa, saka iyo jekiseni pressure inofanirwa kugadziridzwa kudzora fluidity panguva yekuumbwa.

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③Chimiro, saizi, layout, kutonhora system dhizaini, kuyerera kupikisa kwezvinhu zvakanyungudutswa (zvakadai sepamusoro pekupedzisira, ukobvu hwechikamu chechiteshi, chimiro chemhango, iyo exhaust system) uye zvimwe zvinhu zve mold structure casting system zvinokanganisa zvakananga zvinhu zvakanyungudutswa mumhango Iyo chaiyo fluidity mukati, kana iyo yakanyungudutswa yakasimudzirwa kudzikisa tembiricha uye kuwedzera fluidity kuramba, iyo fluidity ichaderera.

Paunenge uchigadzira mold, chimiro chinonzwisisika chinofanira kusarudzwa maererano nekuyerera kwepurasitiki inoshandiswa. Panguva yekuumba, tembiricha yezvinhu, mold tembiricha, saka iyo yese jekiseni molding process Yekugadzirwa kwezvinhu mbishi, jekiseni kumhanya uye zvimwe zvinhu zvinogona zvakare kudzorwa kugadzirisa zvakakodzera mamiriro ekuzadza kuti asangane nezvinodiwa zvekuumba.

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Crystalline thermoplastics inogona kukamurwa kuita crystalline mapurasitiki uye asiri-crystalline (inozivikanwawo seamorphous) mapurasitiki maererano nekusavapo kwavo kwekristallisation panguva yekumisikidza. Iyo inonzi crystallization phenomenon inoreva chokwadi chekuti kana ipurasitiki yachinja kubva payakanyungudutswa kuenda kune condensation state., mamorekuru anofamba akazvimirira uye ari zvachose mune kusagadzikana. Mamorekuru anomira kufamba akasununguka, dzvanya nzvimbo yakagadziriswa zvishoma, uye kuva nekatsika kekuita kuti hurongwa hwemamorekuru huve muenzaniso wenguva dzose. Chiitiko ichi.

Maitiro ekutaridzika ekutonga aya maviri marudzi epurasitiki anogona kutariswa nekujeka kweiyo gobvu-yakavakirwa madziro epurasitiki zvikamu.. Kazhinji, crystalline zvinhu zviri opaque kana translucent (zvakadai sePOM, Nekuti iyo IC tray ine huremu huremu), uye amorphous zvinhu zviri pachena (zvakadai sePMMA, Nekuti iyo IC tray ine huremu huremu). Asi pane zvisizvo. Semuyenzaniso, poly(4) methylpentene ipurasitiki ine crystalline asi ine kujeka kwakanyanya, uye ABS chinhu amorphous asi kwete pachena.

Paunenge uchigadzira mold uye kusarudza jekiseni molding michina, teerera kune zvinotevera zvinodiwa uye zvidziviriro zvecrystalline mapurasitiki:

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① Kupisa kwakawanda kunodiwa kuti tembiricha yemidziyo ikwire kusvika kune tembiricha yekuumbwa, uye midziyo ine hombe plasticizing kugona kunodiwa. To

②Inoburitsa huwandu hukuru hwekupisa panguva yekutonhora kumashure uye inoda kutonhodzwa zvakakwana.

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③Musiyano chaiwo wegiravhiti pakati penzvimbo yakanyungudutswa nenzvimbo yakasimba yakakura, the molding shrinkage yakakura, uye shrinkage uye pores zvinowanzoitika.

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④ Kukurumidza kutonhora, low crystallinity, kuderera kudiki uye kujeka kwepamusoro. Iyo crystallinity inoenderana nemadziro emadziro echikamu chepurasitiki, uye ukobvu hwemadziro hunononoka kutonhora, iyo crystallinity yakakwirira, iyo shrinkage yakakura, uye zvinhu zvenyama zvakanaka. Naizvozvo, iyo mold tembiricha yezvinhu zvecrystalline inofanira kudzorwa sezvinodiwa.

⑤Yakakosha anisotropy uye kushushikana kukuru kwemukati. Mamorekuru asina kucheneswa mushure mekudhirowa ane tsika yekuramba achipenya, vari musimba kusaenzana kwesimba, uye vane tarisiro ye deformation uye warpage. ⑥ The crystallization tembiricha renji yakamanikana, uye iyo isina kunyungudutswa inokwanisa kubaiwa muforoma kana kuvharira chiteshi chekudya.

Heat senitivity inoreva maitiro emamwe mapurasitiki ekunyanya kunzwira kupisa. Kana ichipisa pakupisa kwakanyanya kwenguva yakareba kana chikamu chechiteshi chekudya chiri chidiki, kana kugera kwacho kwakakura, tembiricha yemidziyo inowedzera uye hunhu hwekubvisa ruvara, kudzikisira, uye kuora kunoitika. Purasitiki inonzi ipurasitiki inonzwa kupisa.

Zvakadai zvakaoma PVC, polyvinylidene chloride, vinyl acetate copolymer, POM, polychlorotrifluoroethylene, nezvimwewo. Mapurasitiki anopisa-sensitive anogadzira monomers, magasi, zvakaonda uye zvimwe zvinobva-zvigadzirwa panguva yekuora. Kugadzirira uye kuomeswa kwezvinhu zvakasvibirira Sezvo chero tsvina muIC tray inogona kukanganisa plastiki yeIC tray., mamwe magasi ekuora ane anogumbura, zvinoparadza kana zvine chepfu pamuviri wemunhu, Nekuti iyo IC tray ine huremu huremu, uye zviumbu. Naizvozvo, kutarisisa kunofanirwa kubhadharwa kune kugadzira mold, jekiseni molding muchina kusarudzwa uye kuumba. Screw injection molding machine inofanira kushandiswa. Chikamu chekudira system chinofanira kunge chakakura. Iyo mold uye dhiramu zvinofanirwa kuve chrome-plated. Panofanira kunge pasina kumira kwekona. The kuumba tembiricha inofanira kunyatsodzorwa. Stabilizer, kuderedza kushanda kwayo kusinganzwisisi kupisa.

Vamwe mapurasitiki (Kuti udzivise kusvibiswa kwezvinhu zvakasvibirira uye kuvapo kwezvinhu zvekare kana kusvibiswa mumashure escrew uye accessories.) kunyange iine mvura shoma, asi ivo vanozoora pasi pekupisa kwakanyanya uye kudzvinyirira kwakanyanya. Iyi pfuma inonzi easy hydrolysis, iyo inofanira kupiswa uye kuomeswa mberi.

Kana uine chero mibvunzo papolycarbonate,plz sunungukai kutibvunza,tichakupa yakanakisa sevhisi!

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