Timagwiritsa ntchito ma cookies kuti tiwongolere zomwe mukukumana nazo. Mukapitiliza kusakatula tsamba lino, mukuvomereza kugwiritsa ntchito ma cookies. Zambiri Zowonjezera.
Kupanga zinthu zowonjezera (AM) kumaphatikizapo kupanga zinthu za 3D, gawo limodzi lochepa kwambiri panthawi imodzi, zomwe zimapangitsa kuti zikhale zodula kuposa kukonza kwachikhalidwe. Komabe, gawo laling'ono chabe la ufa limalumikizidwa ku gawolo panthawi yopangira. Zotsalazo sizimasakanikirana, kotero zimatha kugwiritsidwanso ntchito. Mosiyana ndi zimenezi, ngati chinthucho chapangidwa mwanjira yakale, nthawi zambiri chimafunika kugaya ndi kupangira kuti chichotse zinthuzo.
Katundu wa ufawo ndiye amene amaika malire a makinawo ndipo ayenera kuganiziridwa poyamba. Mtengo wa AM sungakhale wotsika mtengo poganizira kuti ufa wosasungunukawo ndi wodetsedwa ndipo sungabwezeretsedwenso. Kuwonongeka kwa ufa kumabweretsa zochitika ziwiri: kusintha kwa mankhwala a chinthucho ndi kusintha kwa mphamvu za makina monga mawonekedwe ake ndi kugawa kwa tinthu.
Choyamba, ntchito yaikulu ndikupanga zinthu zolimba zokhala ndi alloys oyera, kotero tiyenera kupewa kuipitsidwa kwa ufa, mwachitsanzo, ndi ma oxides kapena nitrides. Pachinthu chomalizachi, magawo awa amagwirizanitsidwa ndi kusinthasintha ndi kufalikira. Chifukwa chake, kusintha kulikonse kwa mawonekedwe a ufa kungayambitse kufalikira kosagwirizana kwa chinthucho.
Deta yochokera m'mabuku aposachedwa ikusonyeza kuti ma flowmeter akale sangathe kupereka chidziwitso chokwanira chokhudza kufalikira kwa ufa mu AM kutengera bedi la ufa. Ponena za mawonekedwe a zinthu zopangira (kapena ufa), pali njira zingapo zoyezera pamsika zomwe zingakwaniritse izi. Mkhalidwe wa kupsinjika ndi gawo la kuyenda kwa ufa ziyenera kukhala zofanana pakukhazikitsa koyezera komanso mu ndondomekoyi. Kupezeka kwa katundu wopanikizika sikugwirizana ndi kuyenda kwaulere pamwamba komwe kumagwiritsidwa ntchito muzipangizo za IM mu zoyesa za shear ndi rheometers akale.
GranuTools yapanga njira yogwirira ntchito yofotokozera ufa wa AM. Cholinga chathu chachikulu ndikupatsa geometry iliyonse chida cholondola choyezera njira, ndipo njira yogwirira ntchito iyi imagwiritsidwa ntchito kumvetsetsa ndikutsatira kusintha kwa ubwino wa ufa m'njira zosiyanasiyana zosindikizira. Ma aluminiyamu angapo okhazikika (AlSi10Mg) adasankhidwa nthawi zosiyanasiyana pa kutentha kosiyanasiyana (kuyambira 100 mpaka 200 °C).
Kuwonongeka kwa kutentha kumatha kulamulidwa pofufuza momwe ufa ungasonkhanitsire mphamvu yamagetsi. Ufawo unasanthulidwa kuti uzitha kuyenda bwino (GranuDrum instrument), packing kinetics (GranuPack instrument) ndi electrostatic behavior (GranuCharge instrument). Kuyeza kwa cohesion ndi packing kinetics ndi koyenera kutsatira ubwino wa ufa.
Ufa wosavuta kugwiritsa ntchito umawonetsa zizindikiro zochepa zogwirizana, pomwe ufa wokhala ndi mphamvu zodzaza mwachangu umapanga zida zamakaniko zokhala ndi ma porosity ochepa poyerekeza ndi zinthu zovuta kudzaza.
Pambuyo pa miyezi ingapo yosungidwa mu labotale yathu, ufa wa aluminiyamu atatu okhala ndi kukula kosiyana kwa tinthu (AlSi10Mg) ndi chitsanzo chimodzi cha chitsulo chosapanga dzimbiri cha 316L adasankhidwa, pano amatchedwa zitsanzo A, B ndi C. Katundu wa zitsanzozo akhoza kusiyana ndi opanga ena. Kugawa kwa tinthu ta zitsanzo kunayesedwa ndi kusanthula kwa laser diffraction/ISO 13320.
Popeza amayang'anira magawo a makina, kaye kufunika kwa ufa kuyenera kuganiziridwa, ndipo ngati ufa wosasungunuka ukuonedwa kuti ndi wodetsedwa komanso wosagwiritsidwanso ntchito, ndiye kuti kupanga zowonjezera sikotsika mtengo monga momwe munthu angayembekezere. Chifukwa chake, magawo atatu adzafufuzidwa: kuyenda kwa ufa, mphamvu zopakira ndi ma electrostatics.
Kufalikira kumagwirizana ndi kufanana ndi "kusalala" kwa ufa pambuyo pa ntchito yobwezeretsanso utoto. Izi ndizofunikira kwambiri chifukwa malo osalala ndi osavuta kusindikiza ndipo amatha kufufuzidwa ndi chida cha GranuDrum chokhala ndi muyeso wa index yomatira.
Popeza ma pores ndi malo ofooka mu chinthu, amatha kubweretsa ming'alu. Mphamvu yodzaza ndi chinthu ndiye chinthu chachiwiri chofunikira chifukwa ufa wodzaza mwachangu umapereka ma porosity ochepa. Khalidweli limayesedwa ndi GranuPack yokhala ndi n1/2.
Kupezeka kwa magetsi mu ufa kumapanga mphamvu zogwirizana zomwe zimapangitsa kuti ma agglomerate apangidwe. GranuCharge imayesa kuthekera kwa ufa kupanga magetsi amagetsi akakhudzana ndi zinthu zina panthawi yoyenda.
Pakukonza, GranuCharge imatha kulosera kuwonongeka kwa kayendedwe ka madzi, mwachitsanzo, popanga wosanjikiza mu AM. Motero, miyeso yomwe yapezeka imakhala yogwirizana kwambiri ndi momwe pamwamba pa tirigu ulili (kusungunuka, kuipitsidwa ndi kuuma). Kukalamba kwa ufa wobwezeretsedwa kumatha kuwerengedwa molondola (± 0.5 nC).
GranuDrum ndi njira yoyezera kuyenda kwa ufa yokonzedwa bwino kutengera mfundo yozungulira ya ng'oma. Hafu ya chitsanzo cha ufa imakhala mu silinda yopingasa yokhala ndi makoma am'mbali owonekera bwino. Ng'oma imazungulira mozungulira mzere wake pa liwiro la 2 mpaka 60 rpm, ndipo kamera ya CCD imatenga zithunzi (kuyambira zithunzi 30 mpaka 100 pa sekondi imodzi). Mawonekedwe a mpweya/ufa amadziwika pachithunzi chilichonse pogwiritsa ntchito njira yodziwira m'mphepete.
Werengerani malo apakati a mawonekedwe ndi kusinthasintha kozungulira malo apakati awa. Pa liwiro lililonse lozungulira, ngodya ya flow angle (kapena "dynamic angle of repose") αf imawerengedwa kuchokera ku malo apakati a mawonekedwe, ndipo dynamic cohesion factor σf yogwirizana ndi intergrain bonding imasanthulidwa kuchokera ku kusintha kwa mawonekedwe.
Ngodya ya kayendedwe ka madzi imakhudzidwa ndi zinthu zingapo: kukangana, mawonekedwe ndi mgwirizano pakati pa tinthu tating'onoting'ono (van der Waals, mphamvu zamagetsi ndi ma capillary). Ufa wogwirizana umabweretsa kuyenda kosalekeza, pomwe ufa wosakhuthala umabweretsa kuyenda kosalekeza. Mitengo yotsika ya ngodya ya kayendedwe ka madzi αf imagwirizana ndi kuyenda bwino. Chizindikiro cholumikizira champhamvu pafupi ndi zero chikugwirizana ndi ufa wosagwirizanitsa, kotero pamene kulumikiza kwa ufa kukuwonjezeka, chizindikiro cholumikizira chimawonjezeka moyenerera.
GranuDrum imakulolani kuyeza ngodya yoyamba ya chipale chofewa ndi mpweya wa ufa panthawi yoyenda, komanso kuyeza index yolumikizira σf ndi ngodya yoyenda αf kutengera liwiro lozungulira.
Kuchuluka kwa ufa, kuchuluka kwa ufa, ndi kuchuluka kwa ufa wa GranuPack (komwe kumadziwikanso kuti "mayeso opopera") ndi abwino kwambiri pofotokozera ufa chifukwa cha kusavuta kwawo komanso liwiro lawo. Kuchuluka kwa ufa ndi kuthekera kowonjezera kuchuluka kwake ndi zinthu zofunika kwambiri pakusunga, kunyamula, kusonkhana, ndi zina zotero. Njira zomwe zalimbikitsidwa zafotokozedwa mu Pharmacopoeia.
Mayeso osavuta awa ali ndi zovuta zitatu zazikulu. Muyeso umadalira wogwiritsa ntchito, ndipo njira yodzazira imakhudza kuchuluka koyambirira kwa ufa. Kuyeza kuchuluka konse kungayambitse zolakwika zazikulu mu zotsatira. Chifukwa cha kuphweka kwa kuyeseraku, sitinaganizire za mphamvu ya kukanikizana pakati pa miyeso yoyambirira ndi yomaliza.
Khalidwe la ufa womwe umalowetsedwa mu chotulutsira chopitilira linasanthulidwa pogwiritsa ntchito zida zodziyimira pawokha. Yesani molondola Hausner coefficient Hr, initial density ρ(0) ndi final density ρ(n) mutatha kudina kwa n.
Chiwerengero cha matepi nthawi zambiri chimakhala chokhazikika pa n=500. GranuPack ndi muyeso wokhazikika komanso wapamwamba woyezera kuchuluka kwa matepi kutengera kafukufuku waposachedwa.
Ma index ena angagwiritsidwe ntchito, koma saperekedwa pano. Ufawo umayikidwa mu chubu chachitsulo kudzera mu njira yokhazikika yodziwikiratu. Kuchulukitsa kwa parameter ya dynamic n1/2 ndi kuchuluka kwakukulu kwa ρ(∞) kwachotsedwa pa compaction curve.
Silinda yopepuka yokhala ndi dzenje imakhala pamwamba pa bedi la ufa kuti isunge mulingo wa ufa/mpweya panthawi yoponderezedwa. Chubu chokhala ndi chitsanzo cha ufa chimakwera kufika kutalika kokhazikika ΔZ ndipo chimagwa momasuka pamtunda womwe nthawi zambiri umakhala wokhazikika pa ΔZ = 1 mm kapena ΔZ = 3 mm, womwe umayesedwa wokha mutakhudza chilichonse. Werengani kuchuluka kwa V kwa mulu kuchokera kutalika.
Kuchulukana ndi chiŵerengero cha kulemera kwa m ndi voliyumu ya wosanjikiza wa ufa V. Kulemera kwa ufa wa m kumadziwika, kuchuluka kwa ρ kumayikidwa pambuyo pa kugwedezeka kulikonse.
Hausner coefficient Hr imagwirizana ndi compaction factor ndipo imasanthulidwa pogwiritsa ntchito equation Hr = ρ(500) / ρ(0), pomwe ρ(0) ndiye kuchuluka koyambirira kwa bulk ndipo ρ(500) ndiye kuyenda kowerengedwa pambuyo pa ma cycle 500. Kuchuluka kwa madzi. Mukagwiritsa ntchito njira ya GranuPack, zotsatira zake zimatha kubwerezedwanso pogwiritsa ntchito ufa wochepa (nthawi zambiri 35 ml).
Makhalidwe a ufa ndi makhalidwe a zinthu zomwe chipangizocho chimapangidwira ndi magawo ofunikira. Pa nthawi yoyenda, ma electrostatic charges amapangidwa mkati mwa ufa chifukwa cha triboelectric effect, yomwe ndi kusinthana kwa ma charges pamene zinthu ziwiri zolimba zikumana.
Ufa ukalowa mkati mwa chipangizocho, mphamvu ya triboelectric imachitika pa kukhudzana pakati pa tinthu tating'onoting'ono ndi pa kukhudzana pakati pa tinthu tating'onoting'ono ndi chipangizocho.
Ikakhudzana ndi chinthu chomwe chasankhidwa, GranuCharge imayesa yokha kuchuluka kwa mphamvu zamagetsi zomwe zimapangidwa mkati mwa ufa panthawi yoyenda. Chitsanzo cha ufa chimayenderera mkati mwa chubu cha V chogwedezeka ndikugwera mu kapu ya Faraday yolumikizidwa ndi electrometer yomwe imayesa mphamvu yomwe yapezeka pamene ufawo ukuyenda mkati mwa chubu cha V. Kuti mupeze zotsatira zobwerezabwereza, gwiritsani ntchito chipangizo chozungulira kapena chogwedezeka kuti mupereke machubu a V pafupipafupi.
Mphamvu ya triboelectric imapangitsa chinthu chimodzi kukhala ndi ma elekitironi pamwamba pake motero chimakhala ndi mphamvu yoipa, pomwe chinthu china chimataya ma elekitironi motero chimakhala ndi mphamvu yabwino. Zipangizo zina zimapeza ma elekitironi mosavuta kuposa zina, ndipo mofananamo, zipangizo zina zimataya ma elekitironi mosavuta.
Zinthu zomwe zimakhala zoipa komanso zomwe zimakhala zabwino zimadalira kuchuluka kwa zinthu zomwe zikugwiritsidwa ntchito kuti zipeze kapena kutaya ma elekitironi. Pofuna kuyimira izi, mndandanda wa ma triboelectric womwe wawonetsedwa mu Table 1 unapangidwa. Zinthu zomwe zili ndi njira yabwino yopezera ma elekitironi ndi zina zomwe zili ndi njira yabwino yopezera ma elekitironi zalembedwa, ndipo njira zomwe sizikuwonetsa njira iliyonse yopezera ma elekitironi zalembedwa pakati pa tebulo.
Kumbali inayi, tebuloli limangopereka chidziwitso cha momwe zinthu zimayendera pakusintha kwa mphamvu yamagetsi, kotero GranuCharge idapangidwa kuti ipereke manambala olondola a momwe ufa umasinthira mphamvu yamagetsi.
Kuyesa kangapo kunachitika kuti afufuze kutentha komwe kwawonongeka. Zitsanzozo zinayikidwa pa 200°C kwa ola limodzi kapena awiri. Kenako ufawo unafufuzidwa nthawi yomweyo ndi GranuDrum (dzina lotentha). Kenako ufawo unayikidwa mu chidebe mpaka utafika kutentha kozungulira kenako unafufuzidwa pogwiritsa ntchito GranuDrum, GranuPack ndi GranuCharge (kutanthauza "ozizira").
Zitsanzo zosaphika zinafufuzidwa pogwiritsa ntchito GranuPack, GranuDrum ndi GranuCharge pa chinyezi/kutentha komweko kwa chipinda chimodzi (monga 35.0 ± 1.5% RH ndi kutentha kwa 21.0 ± 1.0 °C).
Chizindikiro cha cohesion chimawerengera kuyenda kwa ufa ndipo chimagwirizana ndi kusintha kwa malo olumikizirana (ufa/mpweya), komwe ndi mphamvu zitatu zokha zolumikizirana (van der Waals, capillary ndi electrostatic force). Asanayambe kuyesa, chinyezi cha mpweya (RH, %) ndi kutentha (°C) zinalembedwa. Kenako ufawo unathiridwa mu ng'oma, ndipo kuyesako kunayamba.
Tinatsimikiza kuti zinthuzi sizingagwirizane kwambiri tikaganizira za thixotropic. Chochititsa chidwi n'chakuti, kupsinjika kwa kutentha kunasintha momwe ufa wa zitsanzo A ndi B umagwirira ntchito kuyambira pakukhuthala kwa shear mpaka kuchepetsedwa kwa shear. Kumbali ina, Zitsanzo C ndi SS 316L sizinakhudzidwe ndi kutentha ndipo zinangosonyeza kukhuthala kwa shear. Ufa uliwonse unali ndi kufalikira bwino (monga chizindikiro chochepa cha cohesion) pambuyo potenthetsa ndi kuziziritsa.
Kutentha kumadaliranso dera lenileni la tinthu tating'onoting'ono. Kutentha kwa zinthuzo kukakwera kwambiri, kutentha kumakhala kwakukulu (monga ???225°?=250?.?-1.?-1) ndi ???316?. 225°?=19?.?-1.?-1) Tinthu tating'onoting'ono tikakhala tating'ono, kutentha kumakhala kwakukulu. Ufa wa aluminiyamu ndi wabwino kwambiri pakugwiritsa ntchito kutentha kwambiri chifukwa cha kufalikira kwawo, ndipo ngakhale zitsanzo zoziziritsidwa zimakhala ndi kuyenda bwino kuposa ufa woyambirira.
Pa kuyesa kulikonse kwa GranuPack, kulemera kwa ufa kunalembedwa mayeso aliwonse asanayambe, ndipo chitsanzocho chinagundidwa ka 500 ndi pafupipafupi ya 1 Hz ndi kugwa kwaulere kwa 1 mm mu selo yoyezera (mphamvu ya impact ∝). Chitsanzocho chimaperekedwa mu selo yoyezera malinga ndi malangizo a pulogalamu yodziyimira payokha. Kenako miyesoyo inabwerezedwa kawiri kuti iwone ngati ingathe kubwerezedwanso ndipo anafufuza kusiyana kwapakati ndi kokhazikika.
Pambuyo poti kusanthula kwa GranuPack kwatha, kuchuluka kwa bulk density koyambirira (ρ(0)), kuchuluka kwa bulk density komaliza (pa ma taps angapo, n = 500, mwachitsanzo ρ(500)), Hausner ratio/Carr index (Hr/Cr) ndi magawo awiri olembetsa (n1/2 ndi τ) okhudzana ndi compaction kinetics. Kuchuluka kwabwino kwambiri ρ(∞) kwawonetsedwanso (onani Appendix 1). Gome ili pansipa likusintha deta yoyesera.
Zithunzi 6 ndi 7 zikuwonetsa curve yonse yokhazikika (kuchuluka kwa zinthu poyerekeza ndi kuchuluka kwa zotsatira) ndi chiŵerengero cha n1/2/Hausner parameter. Mipiringidzo yolakwika yowerengedwa pogwiritsa ntchito avareji ikuwonetsedwa pa curve iliyonse, ndipo kupotoka kokhazikika kunawerengedwa poyesa kubwerezabwereza.
Chopangidwa ndi chitsulo chosapanga dzimbiri cha 316L chinali cholemera kwambiri (ρ(0) = 4.554 g/mL). Ponena za kuchuluka kwa kupopera, SS 316L ikadali ufa wolemera kwambiri (ρ(n) = 5.044 g/mL), kutsatiridwa ndi Chitsanzo A (ρ(n) = 1.668 g/mL), kutsatiridwa ndi Chitsanzo B (ρ(n) = 1.668 g/ml). /ml) (n) = 1.645 g/ml). Chitsanzo C chinali chotsika kwambiri (ρ(n) = 1.581 g/mL). Malinga ndi kuchuluka kwa ufa woyamba, tikuwona kuti chitsanzo A ndicho chopepuka kwambiri, ndipo poganizira zolakwika (1.380 g / ml), zitsanzo B ndi C zili ndi mtengo wofanana.
Pamene ufa ukutenthedwa, chiŵerengero chake cha Hausner chimachepa, ndipo izi zimachitika kokha ndi zitsanzo za B, C, ndi SS 316L. Pa chitsanzo A, sizinatheke kuchita chifukwa cha kukula kwa mipiringidzo yolakwika. Pa n1/2, njira yowunikira mizere ndi yovuta kwambiri. Pa chitsanzo A ndi SS 316L, mtengo wa n1/2 unachepa patatha maola awiri pa 200°C, pomwe pa ufa B ndi C unawonjezeka pambuyo pa kutentha.
Chodyetsa chogwedezeka chinagwiritsidwa ntchito pa kuyesa kulikonse kwa GranuCharge (onani Chithunzi 8). Gwiritsani ntchito chubu chachitsulo chosapanga dzimbiri cha 316L. Miyeso inabwerezedwa katatu kuti muwone momwe mungapangirenso. Kulemera kwa chinthu chomwe chinagwiritsidwa ntchito pa muyeso uliwonse kunali pafupifupi 40 ml ndipo palibe ufa womwe unapezekanso pambuyo poyesa.
Kuyesera kusanachitike, kulemera kwa ufa (mp, g), chinyezi cha mpweya (RH, %), ndi kutentha (°C) zinalembedwa. Poyamba kuyesa, kuchuluka kwa mphamvu ya ufa woyamba (q0 mu µC/kg) kunayesedwa poika ufawo mu kapu ya Faraday. Pomaliza, kuchuluka kwa mphamvu ya ufa kunakhazikika ndipo kuchuluka kwa mphamvu yomaliza (qf, µC/kg) ndi Δq (Δq = qf – q0) kumapeto kwa kuyesako kunawerengedwa.
Deta ya GranuCharge yaiwisi ikuwonetsedwa mu Table 2 ndi Chithunzi 9 (σ ndi kusiyana kwa muyezo komwe kwawerengedwa kuchokera ku zotsatira za mayeso obwerezabwereza), ndipo zotsatira zake zikuwonetsedwa ngati histogram (q0 ndi Δq zokha ndi zomwe zawonetsedwa). SS 316L ili ndi mphamvu yotsika kwambiri yoyambira; izi zitha kukhala chifukwa chakuti mankhwalawa ali ndi PSD yapamwamba kwambiri. Ponena za kuyika koyamba kwa ufa wa aluminiyamu woyambira, palibe mfundo zomwe zingaganizidwe chifukwa cha kukula kwa zolakwikazo.
Pambuyo pokhudzana ndi chitoliro chachitsulo chosapanga dzimbiri cha 316L, chitsanzo A chinalandira mphamvu zochepa kwambiri, pomwe ufa B ndi C unawonetsa njira yofanana, ngati ufa wa SS 316L unapakidwa pa SS 316L, mphamvu ya mphamvu yofanana ndi 0 inapezeka (onani mndandanda wa triboelectric). Chogulitsa B chimakadali ndi mphamvu yochulukirapo kuposa A. Pa chitsanzo C, njirayo ikupitirira (chaji yoyambirira yabwino ndi chaji yomaliza pambuyo potuluka), koma chiwerengero cha mphamvu chimawonjezeka pambuyo powonongeka kwa kutentha.
Pambuyo pa maola awiri a kutentha kwa thupi pa 200 °C, khalidwe la ufa limakhala losangalatsa kwambiri. Mu zitsanzo A ndi B, mphamvu yoyambirira inachepa ndipo mphamvu yomaliza inasintha kuchoka pa negative kupita pa positive. Ufa wa SS 316L unali ndi mphamvu yoyambirira yapamwamba kwambiri ndipo kusintha kwa mphamvu yake ya mphamvu kunakhala kwabwino koma kunakhalabe kotsika (monga 0.033 nC/g).
Tinafufuza momwe kutentha kumakhudzira machitidwe ophatikizana a aluminiyamu (AlSi10Mg) ndi ufa wachitsulo chosapanga dzimbiri wa 316L, pomwe ufa woyambirira unasanthulidwa patatha maola awiri pa 200°C mumlengalenga.
Kugwiritsa ntchito ufa pa kutentha kokwera kungathandize kuti zinthu ziziyenda bwino, zomwe zimawoneka kuti ndizofunikira kwambiri pa ufa wokhala ndi malo enieni komanso zinthu zomwe zimakhala ndi kutentha kwambiri. GranuDrum idagwiritsidwa ntchito poyesa kayendedwe ka madzi, GranuPack idagwiritsidwa ntchito poyesa kulongedza kwamphamvu, ndipo GranuCharge idagwiritsidwa ntchito poyesa mphamvu ya ufa wokhudzana ndi chitoliro chachitsulo chosapanga dzimbiri cha 316L.
Zotsatirazi zinapezeka pogwiritsa ntchito GranuPack, zomwe zinawonetsa kusintha kwa Hausner coefficient pa ufa uliwonse (kupatula chitsanzo A, chifukwa cha kukula kwa zolakwika) pambuyo pa njira yotenthetsera kutentha. Palibe njira yomveka bwino yomwe inapezeka pa parameter yopakira (n1/2) chifukwa zinthu zina zinawonetsa kuwonjezeka kwa liwiro lopakira pomwe zina zinali ndi zotsatira zosiyana (monga Zitsanzo B ndi C).