Mukamva 'zinthu zomangira jakisoni wachitsulo', malingaliro ambiri amalumphira ku ufa wachitsulo. Ndiwo mchitidwe wa mutu wankhani, zedi. Koma ngati mwakhalapo nthawi iliyonse pamalo ogulitsira, mukudziwa kuti nkhani yeniyeni imayamba ndi makina omangira ndipo imatha ndi mlengalenga wa ng'anjo. Ndi chakudya chonse chomwe chili chofunikira, osati mzimu wokha. Ndawonapo ma projekiti ambiri akuyimitsidwa chifukwa wina adapeza ufa wokongola, wozungulira wa 17-4PH koma adauphatikiza ndi chomangira cha sera-polymer chomwe sichimatha kuthana ndi geometry ya gawolo, zomwe zidapangitsa kuti pakhale kusokonekera kowopsa panthawi yomanga. Zakuthupi si chitsulo chabe; ndi chakudya. Ndilo phunziro loyamba, komanso lokwera mtengo kwambiri.
The Feedstock Equation: Zaluso Zambiri Kuposa Sayansi
Kupeza chakudya choyenera kumakhala ngati alchemy nthawi zina. Chiyerekezo choyenera cha ufa wa ufa - kuchuluka kwa ufa wachitsulo mu binder - ndi kuyenda kwa zingwe zolimba. Ikankhireni pamwamba kwambiri pa gawo lovuta, ndipo mumataya kusuntha komwe MIM imayamikiridwa. Makina opangira jakisoni amavutikira, mumapeza mizere yowotcherera, voids. Kutsika kwambiri, ndipo gawolo limachepa mosadziwika bwino panthawi ya sintering, kutha kwapadera. Pachinthu chovala kwambiri chomwe tinkathamangapo, pogwiritsa ntchito ufa wabwino, wopangidwa ndi mpweya wa 316L, tinayenera kuyimba kutsitsa pang'ono kuchokera pamabuku ophunzirira. Chifukwa chiyani? Chigawocho chinali ndi kachigawo kakang'ono kopyapyala koyandikana ndi kanyumba kakang'ono. Kutsegula kwanthawi zonse kunayambitsa zizindikiro zakuya. Tinanyengerera pa kachulukidwe kakang'ono kuti titsimikizire kudzaza, kenako tinasintha mbiri ya sintering kuti tibwezere. Zinagwira ntchito, koma sizinali m'mabuku aliwonse.
Apa ndipamene ntchito ya omangirira imachepetsedwa. Si guluu wosakhalitsa. Kuwonongeka kwake kwa kinetics pa kutentha kwa kutentha kapena zosungunulira ziyenera kugwirizanitsidwa bwino ndi kulongedza kwa ufa. Zosagwirizana apa, ndipo mumatupa, kusweka, kapena 'gawo lobiriwira' kukomoka. Ndikukumbukira gulu lomwe wogulitsa binder adasintha chothandizira popanda kuzindikira. Ziwalozo zinkawoneka bwino kwambiri zikutuluka mu nkhungu, koma mu uvuni wa debind, zinkagwera ngati mtanda wotopa. Kutayika kwathunthu. Ufawo unali wofanana, chitsulocho sichinasinthe. Kulephera kunali mu "kagawo kakang'ono" ka kachitidwe ka binder.
Ndipo tiyeni tikambirane za ufa. Sphericity and particle size distribution (PSD) ndi chilichonse. PSD yopapatiza ikhoza kupereka lingaliro labwino kwambiri, koma kugawa kolamuliridwa bwino, kokulirapo pang'ono nthawi zambiri kumayenda bwino muzochita komanso osuta modalirika. Kwa cobalt-chromium implant feedstock, tidalimbana ndi zovuta mpaka tidaphatikiza maere awiri osiyanasiyana a ufa kuti tipeze mayendedwe oyenera a PSD. Mapepala amtundu uliwonse anali 'ovomerezeka', koma matsenga anali osakanikirana. Inu simumaphunzira izo kuchokera deta; mumaphunzira kuchokera kumagulu ochotsedwa.
Sintering: Kumene Nkhaniyi Imapangidwadi
Iyi ndiye mfundo yosabwerera. Mwaumba ndi kubisa 'gawo lofiirira' losalimba. Tsopano, mu ng'anjo yotentha, tinthu tachitsulo timaphatikizana ndi zinthu zenizeni zimatuluka. Apa ndipamene kusankha kwanu zinthu zoyambira - chitsulo chosapanga dzimbiri, chitsulo chachitsulo, aloyi wapadera - kumayesedwa ndi moto. Kulamulira mumlengalenga ndi mfumu. Kutulutsa mpweya pang'ono mumlengalenga wa haidrojeni-nitrogen mukayika chitsulo chokhala ndi chromium ngati 17-4PH kumatha kuwononga mpweya wapamtunda ndikuwononga kukana kwa dzimbiri. Tidaphunzira kugwiritsa ntchito zida zoyeserera pamaso pa gulu lililonse lovuta kuti 'tiyese' momwe ng'anjo imayendera, inshuwaransi yotsika mtengo.
Sintering cycle palokha ndi njira yeniyeni ya zinthu. Mitengo yotsika, kutentha kwapakati, kuthamanga kwa kuziziritsa - zonsezi zimalamulira microstructure yomaliza. Kwa pulojekiti yomwe imafuna aloyi yofewa ya maginito (monga Fe-50% Ni), kuzizira kwa kutentha kwa sintering kunali kofunika kwambiri kuti maginito apitirire. Mofulumira kwambiri, ndipo tinaphonya zenera la katundu. Zinatengera ng'anjo zitatu zothamanga ndi zoziziritsa zowoneka bwino kuti zigunde. 'Zinthu' pa oda yogula zinali Fe-50Ni chabe. Zida zogwirira ntchito zidapangidwa m'ng'anjo imeneyo.
Shrinkage ndi mtundu wina waukulu, womwe umamangiriridwa mwachindunji ku feedstock. Tikufuna kutsika kwa isotropic, koma sikukhala kofanana bwino. Pagawo la zida zolondola, tidayenera kupanga chiboliboli chotengera chinthu chomwe tidapanga kuti tipeze 4140 alloy feedstock, osati 15-18% ya ogulitsa. Chinthu chathu chinali 16.7% ± 0.3% mu ndege yovuta. Kulondola kumeneko kudachokera pakuyezera magawo mazana ambiri a sintered ndikulumikizana kumbuyo. Ndiwo mtundu wa chidziwitso chakuthupi chomwe chimakhala mubuku lamkati la kampani.
Chifukwa Chake Ma Alloys Monga Cobalt ndi Nickel Amasintha Masewera
Kusuntha kuchokera kuzitsulo zosapanga dzimbiri wamba kupita kumadera ngati ma aloyi opangidwa ndi cobalt kapena zitsulo zopangidwa ndi nickel kwa MIM ndikusintha pang'ono pazovuta komanso mtengo. Izi sizimangokhala 'zitsulo zamtengo wapatali'. Mawindo awo a sintering akhoza kukhala opapatiza kwambiri. Cobalt-chromium-molybdenum alloy kuti agwiritse ntchito biomedical amatha kulowa mkati mwa zenera la madigiri 20 Celsius kuti akwaniritse kachulukidwe kokwanira popanda kukula kwambewu. Muphonye, ndipo mumapeza porosity yotsalira kapena embrittlement.
Kuchotsa zomangira kwa ma aloyi ochita bwino kwambiri ndizovuta kwambiri. Ufa wawo nthawi zambiri umakhala wotakasuka, kotero kuti kutsekereza kothandizira (pogwiritsa ntchito nitric acid vapor, mwachitsanzo) kumatha kukondedwa kusiyana ndi njira zapang'onopang'ono zotenthetsera kuti zipewe kuipitsidwa pamwamba. Izi zimawonjezera zovuta za ndondomeko ndi mtengo. Koma phindu lake ndi magawo omwe ali ndi zinthu zomwe zikuyandikira kwambiri - taganizirani za injini za jet injini ya jet injini yopangira mafuta opangidwa kudzera ku MIM kuchokera ku faifi tambala. Mtengo wake uli mumkhalidwe wovuta, osati mtengo wazinthu zokha.
Awa ndi malo omwe kuyambika kwakuya ndi luso la makina limakhala lofunika kwambiri. Kampani yomwe ili ndi mbiri yayitali pakuponya ndalama ndikupangira ma aloyi apadera, monga Malingaliro a kampani Qingdao Qiangsenyuan Technology Co., Ltd., imabweretsa malingaliro osiyana ku MIM. Iwo akhala akulimbana ndi zitsulo za ma aloyi apadera kwa zaka zambiri kudzera mu zipolopolo zawo ndi ntchito zopangira ndalama. Chidziwitso chokhazikika cha momwe zitsulozi zimakhalira kutentha, momwe zimagwirizanirana ndi mlengalenga, ndi momwe zingamalizitsire ndizothandiza kwambiri poziumba. Amamvetsetsa kuti post-sintering state ndi chiyambi chabe cha magawo ambiri, chomwe chidzafunika kulondola CNC makina kukumana ndi kulolerana komaliza pazinthu zofunikira. Njira ya MIM ndi masankhidwe azinthu adapangidwa poganizira gawo lotsatira la makina.
Ulalo wa Machining: MIM Sikuti Nthawi Zonse 'Yatha'
Lingaliro lolakwika lodziwika bwino ndikuti magawo a MIM amatuluka m'ng'anjo yokonzeka kugwiritsidwa ntchito. Kwa ambiri, inde. Koma pakugwiritsa ntchito molondola kwambiri, sintering imatsatiridwa ndi ntchito zachiwiri. Izi ndizofunikira pakusankha zinthu. Mukhoza kusankha kalasi yowumitsidwa kale, kapena yomwe idzatenthedwe pambuyo pa sintering. Koma muyenera kuganizira machinability. Gawo la sintered MIM lili ndi mawonekedwe owoneka bwino, ofananirako, koma nthawi zonse simalota makina. Zitha kukhala abrasive.
Tidali ndi mlandu wokhala ndi chitsulo chosapanga dzimbiri cha 440C MIM chomwe chimafunikira dzenje loponyedwa. Mbaliyi inali yowundana komanso yolimba pambuyo pa sintering. Kuligogoda mwachindunji kunali zida zotafuna. Tidayenera kusintha mawonekedwe a sintering kuti tisiye kufewa pang'ono kuti tipange makina, kenako ndikuwonjezera kutentha kotsatira. Njira ya 'zinthu' inali motere: kupanga feedstock -> kuumba -> debinding -> sintering (soft) -> CNC Machining -> kutentha kutentha -> mankhwala omaliza. Ulendo wazinthuzo sunathe pambuyo pa ng'anjo.
Mawonedwe ophatikizikawa ndi ofunikira. Ichi ndichifukwa chake ena mwa osewera opambana kwambiri sakhala masitolo a MIM angwiro. Ndiwopanga ophatikizidwa, monga QSY, omwe amaphatikiza njira. Amatha kuyang'ana chojambula cha chigawo chovuta, chapamwamba kwambiri ndikuweruza ngati kuponya ndalama, MIM, kapena njira yosakanizidwa imakhazikika bwino pa geometry, zinthu, ndi voliyumu. Zaka zawo 30 akuponya ndi kupanga makina amatanthawuza kuti amasankha zida za MIM ndikumvetsetsa bwino zaunyolo wonse wopangira, osati masitepe owumba ndi opangira. Amadziwa kuti mtengo weniweni wa chinthucho umaphatikizapo momwe zimakhalira pakachitidwe kalikonse kotsatira.
Zolephera ndi Maphunziro Amene Amasindikiza
Simuphunzira zipangizo kuchokera ku kupambana. Mumaphunzira kuchokera ku nkhokwe za zidutswa. M'mbuyomu, tidayesa kugwiritsa ntchito zitsulo zotsika kwambiri zopangira zida zamagalimoto. Magawowo anali owoneka bwino, owoneka bwino. Koma poyesa kupopera mchere, adachita dzimbiri m'maola ambiri, pomwe gawo lopangidwa mwamwambo la kalasi lomwelo lidatenga milungu ingapo. Wolakwa? Kutayika kwa kaboni pakuwotcha chifukwa cha mpweya womwe sunawunikidwe bwino ndi momwe ufawo umapangidwira. Zolemba za 'grade' zinali zolondola, koma ndondomekoyi inali itasintha momwe imapangidwira. Tinayenera kusinthira ku ufa wopangidwa ndi MIM, wokhala ndi mawonekedwe osiyana, ndikulimbitsa protocol ya ng'anjo. Tsambali linali lopanda ntchito ngati sitinayang'anire njira yomwe idapanga zinthu zomaliza.
Nthawi ina, tidafufuza pogwiritsa ntchito alloy heavy tungsten a MIM. Kuchulukana kwake kunali kodabwitsa, koma zodyetsa zinali zodziwika kuti zinali zovuta kuumba nthawi zonse. Tinakhala miyezi pakupanga chipata ndi othamanga, kutentha kwa nkhungu, magawo a jakisoni. Tili ndi zida zogwirira ntchito, koma zokolola sizinali zopindulitsa pazachuma. Tinazisunga. Zolembazo zinali zolimbikitsa pamapepala, koma zowona zenizeni zosinthira kuchoka ku feedstock kupita ku gawo lodalirika zidapha ntchitoyi. Ndiko kuweruza kofunikira komwe mungapange pongoyesa ndikulephera.
Ndiye ndikaganiza zitsulo jekeseni akamaumba zipangizo tsopano, ine sindikuwona mndandanda wa aloyi. Ndikuwona zisankho zingapo: mawonekedwe a ufa ndi kukula kwake, chemistry yomangirira, kuyika kwa ufa, njira yochotsera, mbiri ya ng'anjo ya ng'anjo, chithandizo cha kutentha chomwe chingatheke, ndi makina ofunikira achiwiri. Zomwe zili ndi unyolo wonsewu. Ndi gulu lofotokozedwa ndi ndondomeko. Kuchikonza kumatanthauza kulemekeza ulalo uliwonse, ndipo chidziwitsocho sichimagulidwa - chimamangidwa mbali ndi mbali, kulephera mwa kulephera, zaka zambiri. Ndiko kusiyana pakati pa kuyitanitsa ufa ndi uinjiniya chigawo chimodzi.
