1.1Umthelela we-HPMC ekuphrintekeni kwemishini yokuphrinta ye-3D
1.1.1Umthelela we-HPMC ekuxhumekeni kwezinsimbi zokuphrinta ze-3D
Iqembu elingenalutho i-M-H0 ngaphandle kwe-HPMC kanye namaqembu okuhlola anokuqukethwe kwe-HPMC okungu-0.05%, 0.10%, 0.20%, no-0.30% avunyelwe ukuma isikhathi esihlukene, bese kuhlolwa uketshezi.Kungabonakala ukuthi ukufakwa kwe-HPMC Kuzonciphisa kakhulu uketshezi lodaka;lapho okuqukethwe kwe-HPMC kukhuphuka kancane kancane kusuka ku-0% kuya ku-0.30%, i-fluidity yokuqala yodaka iyancipha ukusuka ku-243 mm kuya ku-206, 191, 167, no-160 mm, ngokulandelana.I-HPMC iyi-polymer ephezulu yamangqamuzana.Bangakwazi ukugoqana ukuze benze isakhiwo senethiwekhi, futhi ukuhlangana kwe-cement slurry kungandiswa yizingxenye ezihlanganisayo ezifana ne-Ca (OH) 2. Ngokwe-macroscopically, ukuhlangana kodaka kuyathuthukiswa.Ngokunwetshwa kwesikhathi sokuma, izinga le-hydration lodaka liyakhula.ukwanda, i-fluidity elahlekile ngokuhamba kwesikhathi.I-fluidity yeqembu elingenalutho i-M-H0 ngaphandle kwe-HPMC yehle ngokushesha.Eqenjini lokuhlola elino-0.05%, 0.10%, 0.20% kanye no-0.30% HPMC, izinga lokuncipha kwe-fluidity lehla ngokuhamba kwesikhathi, futhi uketshezi lodaka ngemva kokuma imizuzu engu-60 kwaba ngu-180, 177, 164, no-155 mm, ngokulandelana. .I-fluidity ingu-87.3%, 92.7%, 98.2%, 96.8%.Ukufakwa kwe-HPMC kungathuthukisa kakhulu ikhono lokugcinwa kwe-mortar fluidity, okubangelwa ukuhlanganiswa kwe-HPMC nama-molecule amanzi;ngakolunye uhlangothi, i-HPMC ingakha ifilimu efanayo Inesakhiwo senethiwekhi futhi igoqa usimende, okunciphisa ngokuphumelelayo ukuguquguquka kwamanzi odongeni futhi kunomsebenzi othile wokugcina amanzi.Kuyaphawuleka ukuthi lapho okuqukethwe kwe-HPMC kungu-0.20%, ikhono lokugcinwa kwe-motar fluidity lifinyelela ezingeni eliphakeme kakhulu.
Ubumanzi bodaka lokuphrinta lwe-3D oluxutshwe namanani ahlukene e-HPMC ngu-160~206 mm.Ngenxa yamapharamitha ephrinta ahlukene, ububanzi obunconyiwe bobumanzi obutholwe abacwaningi abahlukene buhlukile, obufana no-150~190 mm, 160~170 mm.Kusuka kumfanekiso wesi-3, kungase kubonakale ngendlela enembile Kungabonakala ukuthi uketshezi lwe-3D printing mortar exutshwe ne-HPMC ngokuvamile kungaphakathi kwebanga elinconyiwe, ikakhulukazi uma okuqukethwe kwe-HPMC kungu-0.20%, ukugcwala kodaka phakathi kwemizuzu engama-60 kungaphakathi. ububanzi obunconyiwe, obunelisa uketshezi olufanele nokusimama.Ngakho-ke, nakuba i-fluidity yodaka ngenani elifanele le-HPMC incishisiwe, okuholela ekwehleni kokukhishwa, kusenakho ukukhululeka okuhle, okungaphakathi kwebanga elinconywayo.
1.1.2Umthelela we-HPMC ekuqineni kwezisindo zokuphrinta ze-3D
Esimeni sokungasisebenzisi isifanekiso, usayizi wezinga lokugcinwa komumo ngaphansi kwesisindo somuntu siqu uncike ekucindezelweni kwesivuno sento, ehlobene nokuhlangana kwangaphakathi phakathi kwe-slurry ne-aggregate.Ukugcinwa komumo wezinsimbi zokuphrinta ze-3D ezinokuqukethwe okuhlukile kwe-HPMC kunikezwa.Izinga loshintsho ngesikhathi sokuma.Ngemva kokwengeza i-HPMC, izinga lokugcinwa komumo wodaka liyathuthukiswa, ikakhulukazi esigabeni sokuqala nokuma imizuzu engama-20.Kodwa-ke, ngokwelulwa kwesikhathi sokuma, umthelela wokuthuthukiswa kwe-HPMC kuzinga lokugcinwa komumo wodaka kancane kancane waba buthaka, okwakubangelwa ikakhulukazi Izinga lokugcinwa likhuphuka kakhulu.Ngemuva kokuma imizuzu engama-60, u-0.20% kuphela kanye no-0.30% we-HPMC ongathuthukisa izinga lokugcinwa komumo wodaka.
Imiphumela yokuhlolwa kokumelana nokungenwa kodaka lokunyathelisa lwe-3D olunokuqukethwe okuhlukile kwe-HPMC kukhonjiswe kuMfanekiso 5. Kungabonakala kuMfanekiso 5 ukuthi ukumelana nokungena ngokuvamile kuyanda ngokwandiswa kwesikhathi sokuma, okubangelwa ikakhulukazi ukugeleza i-slurry ngesikhathi senqubo ye-cement hydration.Kancane kancane yashintsha yaba ukuqina okuqinile;emizuzwini engu-80 yokuqala, ukufakwa kwe-HPMC kwandisa ukumelana nokungena, futhi ngokunyuka kokuqukethwe kwe-HPMC, ukumelana nokungena kwanda.Okukhulu ukumelana nokungena, ukuguqulwa kwezinto ngenxa yomthwalo osetshenzisiwe Ukumelana okukhulu kwe-HPMC, okubonisa ukuthi i-HPMC ingathuthukisa ukugxila kokuqala kodaka lokunyathelisa lwe-3D.Njengoba izibopho ze-hydroxyl ne-ether ochungechungeni lwe-polymer ye-HPMC zihlanganiswa kalula namanzi ngokusebenzisa izibopho ze-hydrogen, okuholela ekuncipheni kancane kancane kwamanzi amahhala kanye nokuxhumana phakathi kwezinhlayiya zanda, amandla okungqubuzana ayanda, ngakho ukumelana nokungena kokuqala kuba kukhudlwana.Ngemva kokuma imizuzu engu-80, ngenxa ye-hydration kasimende, ukumelana nokungena kweqembu elingenalutho ngaphandle kwe-HPMC kwanda ngokushesha, kuyilapho ukumelana nokungena kweqembu lokuhlola nge-HPMC kwanda Izinga alizange lishintshe kakhulu kuze kube yimizuzu eyi-160 yokuma.Ngokusho kukaChen et al., lokhu ikakhulukazi ngoba i-HPMC yakha ifilimu evikelayo ezungeze izinhlayiya zikasimende, okwandisa isikhathi sokumisa;Pourchez et al.kucatshangelwa ukuthi lokhu ikakhulukazi kubangelwa ifayibha Imikhiqizo yokuwohloka kwe-ether elula (njenge-carboxylates) noma amaqembu e-methoxyl angabambezela ukugeleza kukasimende ngokuhlehlisa ukwakheka kwe-Ca(OH)2.Kuyaphawuleka ukuthi, ukuze kuvinjelwe ukuthuthukiswa kokumelana nokungena ukuthi kungathinteki ukuhwamuka kwamanzi ebusweni bomfanekiso, Lokhu kuhlola kwenziwa ngaphansi kwezimo ezifanayo zokushisa kanye nomswakama.Sekukonke, i-HPMC ingathuthukisa ngempumelelo ukusndeleleka kodaka lokuphrinta lwe-3D esigabeni sokuqala, ibambezele ukuhlangana, futhi yelule isikhathi sokuphrinta sodaka lokuphrinta lwe-3D.
Inhlangano ye-3D printing mortar (ubude obungu-200 mm × ububanzi 20 mm × ukujiya kongqimba obungu-8 mm): Iqembu elingenalutho ngaphandle kwe-HPMC lalikhubazeke kakhulu, lawa futhi laba nezinkinga zokopha lapho kunyatheliswa ungqimba lwesikhombisa;Udaka lweqembu le-M-H0.20 linokuqina okuhle.Ngemva kokunyathelisa izendlalelo ezingu-13, ububanzi bonqenqema obungaphezulu bungu-16.58 mm, ububanzi bonqenqema obuphansi bungu-19.65 mm, kanti isilinganiso esivela phezulu kuya phansi (isilinganiso sobubanzi bonqenqema olungaphezulu kuya kobubanzi bonqenqema olungezansi) singu-0.84.Ukuchezuka kwe-Dimensional kuncane.Ngakho-ke, kuqinisekiswe ngokuphrinta ukuthi ukufakwa kwe-HPMC kungathuthukisa kakhulu ukuphrinta kodaka.I-Mortar fluidity ine-extrudability enhle ne-stackability ku-160 ~ 170 mm;izinga lokugcinwa komumo lingaphansi kuka-70 % likhubazekile kakhulu futhi alikwazi ukuhlangabezana nezimfuneko zokuphrinta.
1.2Ithonya le-HPMC kuzakhiwo ze-rheological ze-3D printing mortars
I-viscosity esobala ye-pulp ehlanzekile ngaphansi kokuqukethwe okuhlukile kwe-HPMC kunikezwa: ngokukhuphuka kwezinga lokugunda, ukubonakala kwe-viscosity okumsulwa kuyancipha, futhi ukwenzeka kokugunda kwe-shear kungaphansi kokuqukethwe okuphezulu kwe-HPMC.Kusobala kakhulu.Iketango lamangqamuzana le-HPMC liphazamisekile futhi libonisa i-viscosity ephakeme ngenani eliphansi lokugunda;kodwa ngezinga eliphezulu lokugunda, ama-molecule e-HPMC ahamba ngokuhambisana futhi ahleleke eduze kwendlela yokugunda, okwenza ama-molecule abe lula ukushelela, ngakho ithebula I-viscosity ebonakalayo ye-slurry iphansi ngokuqhathaniswa.Uma izinga lokugunda likhulu kuno-5.0 s-1, i-viscosity ebonakalayo ye-P-H0 eqenjini elingenalutho ngokuyisisekelo izinzile phakathi kwama-5 Pa;kuyilapho i-viscosity ebonakalayo ye-slurry ikhula ngemva kokuba i-HPMC yengezwe, futhi ixutshwa ne-HPMC.Ukwengezwa kwe-HPMC kwandisa ukungqubuzana kwangaphakathi phakathi kwezinhlayiya zikasimende, okwandisa i-viscosity ebonakalayo yokunamathisela, futhi ukusebenza kwe-macroscopic ukuthi ukukhishwa kwe-3D printing mortar kuncipha.
Ubuhlobo phakathi kokucindezeleka kwe-shear kanye nesilinganiso se-shear se-slurry ehlanzekile ekuhlolweni kwe-rheological kwabhalwa, futhi imodeli ye-Bingham yasetshenziselwa ukulingana nemiphumela.Imiphumela iboniswa kuMfanekiso 8 kanye neThebula 3. Lapho okuqukethwe kwe-HPMC kungu-0.30%, izinga lokugunda ngesikhathi sokuhlolwa lalilikhulu kuno-32.5 Uma i-viscosity ye-slurry idlula ububanzi bethuluzi ku-s-1, idatha ehambisanayo. amaphuzu awakwazi ukuqoqwa.Ngokuvamile, indawo evalwe amajika akhuphukayo nawayo esigabeni esizinzile (10.0~50.0 s-1) isetshenziselwa ukubonisa i-thixotropy ye-slurry [21, 33].Thixotropy ibhekisela endaweni lapho i-slurry inoketshezi olukhulu ngaphansi kwesenzo sokugunda ngamandla kwangaphandle, futhi ingabuyela esimweni sayo sasekuqaleni ngemva kokukhanselwa kwesenzo sokugunda.I-thixotropy efanelekile ibaluleke kakhulu ekuphrinteni kodaka.Kungabonakala ku-Figure 8 ukuthi indawo ye-thixotropic yeqembu elingenalutho ngaphandle kwe-HPMC yayiyi-116.55 Pa / s kuphela;ngemva kokwengeza i-0.10% ye-HPMC, indawo ye-thixotropic ye-net paste yanda kakhulu ku-1 800.38 Pa / s;Ngokukhula kwe-, indawo ye-thixotropic yokunamathisela yehla, kodwa yayisephakeme izikhathi ezingu-10 kuneqembu elingenalutho.Ngokombono we-thixotropy, ukufakwa kwe-HPMC kwathuthukisa kakhulu ukuphrinta kodaka.
Ukuze udaka lugcine isimo salo ngemva kokukhishwa futhi lukwazi ukumelana nomthwalo wesendlalelo esikhishwe kamuva, udaka ludinga ukuba nokucindezeleka kwesivuno esiphezulu.Kungabonakala kuThebula 3 ukuthi ingcindezi yesivuno τ0 ye-net slurry ithuthukiswa kakhulu ngemva kokwengezwa kwe-HPMC, futhi ifana ne-HPMC.Okuqukethwe kwe-HPMC kuhlotshaniswa kahle;lapho okuqukethwe kwe-HPMC kungu-0.10%, 0.20%, no-0.30%, ukucindezeleka kwesivuno sokunamathisela inetha kukhuphuka ku-8.6, 23.7, kanye nezikhathi ezingu-31.8 zeqembu elingenalutho, ngokulandelana;i-viscosity yepulasitiki μ nayo iyanda ngokwanda kokuqukethwe kwe-HPMC.Ukuphrinta kwe-3D kudinga ukuthi i-viscosity yepulasitiki yodaka akufanele ibe mncane kakhulu, ngaphandle kwalokho ukuguqulwa ngemva kokukhishwa kuzoba kukhulu;ngesikhathi esifanayo, i-viscosity yepulasitiki efanelekile kufanele igcinwe ukuze kuqinisekiswe ukuhambisana kwe-extrusion yezinto ezibonakalayo.Kafushane, ngokombono we-rheology, I-HPMC's Incorporation inomthelela omuhle ekuthuthukisweni kokusimama kodaka lokunyathelisa lwe-3D.Ngemva kokufaka i-HPMC, ukunamathisela okuhlanzekile kusahambisana nemodeli ye-Bingham rheological, futhi ubuhle be-fit R2 abukho ngaphansi kuka-0.99.
1.3Umthelela we-HPMC kuzakhiwo zemishini ze-3D printing mortar
Amandla acindezelayo angu-28 d namandla aguqukayo we-3D printing mortar.Ngokukhula kokuqukethwe kwe-HPMC, amandla angu-28 d okucindezela nokuguquguquka kwe-3D printing mortar ehla;lapho okuqukethwe kwe-HPMC kufinyelela ku-0.30%, amandla okucindezela angu-28 d kanye namandla okuguquguquka yi-30.3 kanye ne-7.3 MPa, ngokulandelanayo.Ucwaningo luye lwabonisa ukuthi i-HPMC inomphumela othile wokungenisa umoya, futhi uma okuqukethwe kwayo kuphezulu kakhulu, i-porosity yangaphakathi yodaka izokhula kakhulu;Ukumelana nokusabalalisa kuyanda futhi kunzima ukukukhulula konke.Ngakho-ke, ukwanda kwe-porosity kungase kube isizathu sokuncipha kwamandla odaka lokuphrinta lwe-3D olubangelwa i-HPMC.
Inqubo eyingqayizivele yokubumba i-lamination yokunyathelisa kwe-3D iholela ekubeni khona kwezindawo ezibuthakathaka esakhiweni nasezimpahleni zemishini phakathi kwezingqimba eziseduze, futhi amandla okubopha phakathi kwezingqimba anethonya elikhulu emandleni jikelele engxenye ephrintiwe.Ezifanekiso zodaka lokuphrinta lwe-3D ezixutshwe no-0.20% HPMC M-H0.20 zisikiwe, futhi amandla ebhondi ye-interlayer ahlolwe ngendlela yokuhlukanisa i-interlayer.Amandla ebhondi ye-interlayer yezingxenye ezintathu ayengaphezu kuka-1.3 MPa;futhi lapho inani lezendlalelo liphansi, amandla ebhondi ye-interlayer ayengaphezulu kancane.Isizathu singase sibe ukuthi, ngakolunye uhlangothi, amandla adonsela phansi ongqimba olungaphezulu enza izingqimba ezingezansi zihlangane kakhulu;ngakolunye uhlangothi, ubuso bodaka bungase bube nomswakama owengeziwe lapho unyathelisa ungqimba oluphansi, kuyilapho umswakama ongaphezulu wodaka uncishiswa ngenxa yokuhwamuka kanye ne-hydration lapho unyathelisa ungqimba olungaphezulu, ngakho Ukubopha phakathi kwezingqimba ezingezansi kunamandla.
1.4Umthelela we-HPMC ku-Micromorphology ye-3D Printing Mortar
Izithombe ze-SEM zezibonelo ze-M-H0 kanye ne-M-H0.20 ezineminyaka engu-3 d zibonisa ukuthi izimbotshana ezingaphezulu zezibonelo ze-M-H0.20 zikhuphuka kakhulu ngemva kokwengeza u-0.20% we-HPMC, futhi ubukhulu bembobo bukhulu kunalelo iqembu elingenalutho.Lokhu Ngakolunye uhlangothi, kungenxa yokuthi i-HPMC inomphumela wokungenisa umoya, owethula izimbotshana ezifanayo nezincane;ngakolunye uhlangothi, kungase kube ukuthi ukungezwa kwe-HPMC kwandisa i-viscosity ye-slurry, ngaleyo ndlela kwandise ukumelana nokukhishwa komoya ngaphakathi kwe-slurry.Ukwanda kungase kube isizathu esiyinhloko sokuncipha kwezakhiwo zemishini yodaka.Ukufingqa, ukuze kuqinisekiswe amandla odaka lokuphrinta lwe-3D, okuqukethwe kwe-HPMC akumele kube kukhulu kakhulu (≤ 0.20%).
Ekuphetheni
(1) I-Hydroxypropyl methylcellulose HPMC ithuthukisa ukuphrinta kodaka.Ngokukhuphuka kokuqukethwe kwe-HPMC, ukunwetshwa kodaka kuncipha kodwa kusenokwengezwa okuhle, ukusitika kuyathuthukiswa, futhi okuphrintekayo Isikhathi siyandiswa.Kuqinisekiswe ngokuphrinta ukuthi ukuwohloka kongqimba olungezansi lodaka kuncishisiwe ngemva kokwengeza i-HPMC, futhi isilinganiso esiphansi phezulu singu-0.84 lapho okuqukethwe kwe-HPMC kungu-0.20%.
(2) I-HPMC ithuthukisa izakhiwo ze-rheological zodaka lokunyathelisa lwe-3D.Ngokukhuphuka kokuqukethwe kwe-HPMC, i-viscosity ebonakalayo, ukucindezeleka kwesivuno kanye ne-plastiki viscosity yokwanda kwe-slurry;I-thixotropy iqala ukwanda bese iyancipha, futhi ukuphrinta kuyatholakala.Ukuthuthukiswa.Ngokombono we-rheology, ukwengeza i-HPMC nakho kungathuthukisa ukuphrinta kodaka.Ngemva kokwengeza i-HPMC, i-slurry isahambisana nemodeli ye-Bingham rheological, kanye nobuhle be-fit R2≥0.99.
(3) Ngemva kokungeza i-HPMC, i-microstructure kanye nama-pores wezinto ezibonakalayo ziyakhula.Kunconywa ukuthi okuqukethwe kwe-HPMC akufanele kudlule i-0.20%, ngaphandle kwalokho kuzoba nomthelela omkhulu kuzakhiwo zemishini zodaka.Amandla okubopha phakathi kwezingqimba ezihlukene ze-3D printing mortar ahluka kancane, futhi inani lezendlalelo Uma liphansi, amandla esibopho phakathi kwezingqimba zodaka aphakeme.
Isikhathi sokuthumela: Sep-27-2022