Sisebenzisa iikuki ukuphucula amava akho. Ngokuqhubeka ukhangela le sayithi, uyavuma ukuba sisebenzise iikuki. Ulwazi olongezelelweyo.
Ukwenziwa kwezinto ezongeziweyo (i-AM) kubandakanya ukudala izinto ze-3D, umaleko omnye obhityileyo ngexesha, nto leyo eyenza ukuba kubize kakhulu kunokulungiswa kwendabuko. Nangona kunjalo, yinxalenye encinci yomgubo edityaniswe kwinxalenye ngexesha lenkqubo yokuhlanganisa. Ezinye azidibani, ukuze ziphinde zisetyenziswe. Ngokwahlukileyo koko, ukuba into yenziwe ngendlela yakudala, idla ngokufuna ukugaywa kunye nokulungiswa ukuze kususwe izinto.
Iimpawu zomgubo zimisela iiparameter zomatshini kwaye kufuneka ziqwalaselwe kwasekuqaleni. Ixabiso le-AM aliyi kuba lolona liphantsi xa ucinga ukuba umgubo onganyibilikiswanga ungcolisiwe kwaye awunakuphinda usetyenziswe. Ukonakala komgubo kuphumela kwiziganeko ezimbini: ukuguqulwa kweekhemikhali zemveliso kunye notshintsho kwiimpawu zoomatshini ezifana nemo kunye nokusasazwa kobukhulu bamasuntswana.
Kwimeko yokuqala, umsebenzi ophambili kukudala izakhiwo eziqinileyo ezinee-alloys ezicocekileyo, ngoko ke kufuneka siphephe ukungcoliswa komgubo, umzekelo, ngee-oxides okanye ii-nitrides. Kwimeko yokugqibela, ezi parameters zinxulunyaniswa nokugeleza kunye nokusasazeka. Ke ngoko, naluphi na utshintsho kwiipropati zomgubo lunokukhokelela ekusasazweni okungalinganiyo kwemveliso.
Idatha evela kwiimpapasho zakutshanje ibonisa ukuba ii-flowmeters zakudala azinakubonelela ngolwazi olwaneleyo malunga nokusasazwa komgubo kwi-AM ngokusekelwe kwi-powder bed. Ngokuphathelele ukuchazwa kwezinto eziluhlaza (okanye umgubo), kukho iindlela ezahlukeneyo zokulinganisa ezifanelekileyo kwimarike ezinokuhlangabezana nale mfuneko. Imeko yoxinzelelo kunye nentsimi yokuhamba komgubo kufuneka zifane kwiseti yokulinganisa nakwinkqubo. Ubukho bemithwalo yokucinezela abuhambelani nokuhamba komphezulu okhululekileyo osetyenziswa kwizixhobo ze-IM kwi-shear testers kunye ne-classical rheometers.
I-GranuTools iphuhlise indlela yokusebenza yokuchonga i-AM powder. Injongo yethu ephambili kukuxhobisa ijiyometri nganye ngesixhobo sokulinganisa inkqubo esichanekileyo, kwaye le ndlela yokusebenza isetyenziselwa ukuqonda nokulandelela ukuvela komgangatho wepowder kwiinkqubo ezahlukeneyo zokuprinta. Ii-alloys ezininzi ze-aluminium ezisemgangathweni (AlSi10Mg) zikhethwe ixesha elahlukileyo kwimithwalo eyahlukeneyo yobushushu (ukusuka kwi-100 ukuya kwi-200 °C).
Ukonakala kobushushu kunokulawulwa ngokuhlalutya amandla omgubo wokuqokelela itshaja yombane. Iipowders zihlalutywe ukuze kujongwe ukuhamba kwamanzi (isixhobo seGranuDrum), i-packing kinetics (isixhobo seGranuPack) kunye nokuziphatha kwe-electrostatic (isixhobo seGranuCharge). Ukulinganiswa kwe-cohesion kunye ne-packing kinetics kufanelekile ukulandelela umgangatho womgubo.
Iipowder ezilula ukuzisebenzisa ziya kubonisa i-cohesion indices ephantsi, ngelixa iipowders ezine-fast filling dynamics ziya kuvelisa iindawo zoomatshini ezine-porosity ephantsi xa kuthelekiswa neemveliso ezinzima ukuzizalisa.
Emva kweenyanga ezininzi zokugcina kwilebhu yethu, kukhethwe iipowder ezintathu ze-aluminium alloy ezinokwahlulwahlulwa kobukhulu beentwana (AlSi10Mg) kunye nesampuli enye yentsimbi engagqwali ye-316L, ezibizwa ngokuba ziisampuli A, B kunye no-C. Iipropati zeesampuli zinokwahluka kwezinye abavelisi. Ukwahlulwahlulwa kobukhulu beentwana zesampuli kulinganiswe ngohlalutyo lwe-laser diffraction/ISO 13320.
Ngenxa yokuba zilawula iiparameter zomatshini, iimpawu zomgubo kufuneka ziqwalaselwe kuqala, kwaye ukuba iipowders ezinganyibilikiswanga zithathwa njengezingcolisiweyo kwaye aziphinde zisetyenziswe, ke ukwenziwa kwezongezo akubizi kangako njengoko umntu enethemba. Ke ngoko, kuya kuphandwa iiparameters ezintathu: ukuhamba komgubo, amandla okupakisha kunye ne-electrostatics.
Ukusasazeka kunxulumene nokufana kunye "nobuthambileyo" bomaleko wepowder emva kokusebenza kokuphinda ubeke i-coating. Oku kubaluleke kakhulu njengoko iindawo ezigudileyo kulula ukuziprinta kwaye zinokuhlolwa ngesixhobo seGranuDrum esinomlinganiselo we-adhesion index.
Ngenxa yokuba iimbobo zibuthathaka kwizinto, zinokukhokelela kwiintanda. I-Fill dynamics yiparameter yesibini ebalulekileyo njengoko iipowders ezizalisa ngokukhawuleza zibonelela nge-porosity ephantsi. Olu phawu lulinganiswa ngeGranuPack enexabiso le-n1/2.
Ubukho beetshaja zombane kumgubo budala amandla adibeneyo akhokelela ekwakhiweni kwee-agglomerates. I-GranuCharge ilinganisa amandla eempuphu okuvelisa itshaja ye-electrostatic xa idibana nezinto ezikhethiweyo ngexesha lokuhamba kwamanzi.
Ngexesha lokucubungula, iGranuCharge inokuqikelela ukonakala kokuhamba kwamanzi, umzekelo, xa kusenziwa umaleko kwi-AM. Ngoko ke, imilinganiselo efunyenweyo inovelwano kakhulu kwimeko yomphezulu weenkozo (i-oxidation, ungcoliseko kunye noburhabaxa). Ukwaluphala komgubo ofunyenweyo kunokulinganiswa ngokuchanekileyo (± 0.5 nC).
I-GranuDrum yindlela yokulinganisa ukuhamba komgubo ecwangcisiweyo esekwe kumgaqo wedrama ejikelezayo. Isiqingatha sesampulu yomgubo sikwisilinda ethe tye eneendonga ezisecaleni ezicacileyo. Idrama ijikeleza i-axis yayo ngesantya se-angular se-2 ukuya kwi-60 rpm, kwaye ikhamera ye-CCD ithatha imifanekiso (ukusuka kwimifanekiso engama-30 ukuya kwi-100 ngesithuba sesekhondi eli-1). Ujongano lomoya/lomgubo luchongwa kumfanekiso ngamnye kusetyenziswa i-algorithm yokubona umphetho.
Bala indawo ephakathi yojongano kunye nokujikeleza okujikeleze le ndawo iphakathi. Kwisantya ngasinye sokujikeleza, i-engile yokuhamba (okanye "i-engile eguquguqukayo yokuphumla") i-αf ibalwa ukusuka kwindawo ephakathi yojongano, kwaye i-dynamic cohesion factor σf enxulumene nokubopha kwe-intergrain ihlalutywa ukusuka ekuguqukeni kojongano.
I-engile yokuhamba ichaphazeleka ziiparameter ezininzi: ukungqubana, imo kunye nokuhlangana phakathi kwamasuntswana (i-van der Waals, amandla e-electrostatic kunye ne-capillary). Iipowder ezidibeneyo zibangela ukuhamba okungapheliyo, ngelixa iipowder ezingezizo ezixineneyo zibangela ukuhamba okuqhelekileyo. Amaxabiso aphantsi e-engile yokuhamba αf ahambelana nokuhamba kakuhle. Isalathisi sokunamathela esiguqukayo esikufutshane no-zero sihambelana nomgubo ongadibaniyo, ngoko ke njengoko ukunamathela komgubo kusanda, isalathisi sokunamathela siyanda ngokufanelekileyo.
I-GranuDrum ikuvumela ukuba ulinganise i-engile yokuqala ye-avalanche kunye nomoya womgubo ngexesha lokuhamba, kunye nokulinganisa i-adhesion index σf kunye ne-flow angle αf kuxhomekeke kwisantya sokujikeleza.
Ubungakanani bomthamo weGranuPack, ubuninzi bomthamo we-tapping kunye nomlinganiselo we-Hausner (okwaziwa ngokuba “ziimvavanyo zokuthepha”) zilungele ukuchazwa komgubo ngenxa yokuba lula kwawo kunye nesantya sokulinganisa. Ubuninzi bomgubo kunye nokukwazi ukwandisa ubuninzi bawo ziiparameter ezibalulekileyo ngexesha lokugcina, ukuthuthwa, ukuhlanganiswa, njl. Iinkqubo ezicetyiswayo zichazwe kwi-Pharmacopoeia.
Olu vavanyo lulula luneengxaki ezintathu ezinkulu. Ukulinganisa kuxhomekeke kumqhubi, kwaye indlela yokuzalisa ichaphazela umthamo wokuqala womgubo. Ukulinganisa umthamo uwonke kunokukhokelela kwiimpazamo ezinkulu kwiziphumo. Ngenxa yobulula bovavanyo, asizange siqwalasele amandla okuxinana phakathi kokulinganisa kokuqala nokugqibela.
Indlela esebenza ngayo ipowder efakwa kwi-outlet eqhubekayo ihlalutywe kusetyenziswa izixhobo ezizenzekelayo. Linganisa ngokuchanekileyo i-Hausner coefficient Hr, i-initial density ρ(0) kunye ne-final density ρ(n) emva kokucofa kuka-n.
Inani leetephu lidla ngokumiselwa kwi-n=500. I-GranuPack yindlela yokulinganisa uxinano lokuthepha oluzenzekelayo noluphambili olusekelwe kuphando lwamva nje olutshintshatshintshayo.
Ezinye ii-indexes zingasetyenziswa, kodwa azibonelelwanga apha. Umgubo ufakwa kwityhubhu yesinyithi ngenkqubo yokuqalisa ezenzekelayo engqongqo. Ulwandiso lweparameter eguquguqukayo n1/2 kunye noxinano oluphezulu ρ(∞) lususiwe kwi-compaction curve.
Isilinda esikhaphukhaphu esingenanto sihlala phezu kwebhedi yepowder ukugcina umgangatho womphezulu wepowder/umoya ngexesha lokuxinana. Ityhubhu equlethe isampuli yepowder inyuka iye kubude obumiselweyo ΔZ kwaye iwele ngokukhululekileyo kubude obuhlala buqiniswe kwi-ΔZ = 1 mm okanye ΔZ = 3 mm, obulinganiswa ngokuzenzekelayo emva kokuchukumisa ngakunye. Bala ivolumu V yenqwaba ukusuka kubude.
Uxinano lumlinganiselo wobunzima m ukuya kumthamo womaleko womgubo V. Ubunzima bomgubo m buyaziwa, uxinano ρ lusetyenziswa emva kwempembelelo nganye.
I-Hausner coefficient Hr inxulumene ne-compaction factor kwaye ihlalutywa nge-equation Hr = ρ(500) / ρ(0), apho i-ρ(0) iluxinano lokuqala lwe-bulk kwaye i-ρ(500) yindlela ebaliweyo yokuhamba emva kwemijikelo engama-500. I-Density tap. Xa usebenzisa indlela yeGranuPack, iziphumo ziyaphindaphindeka kusetyenziswa inani elincinci le-powder (ngesiqhelo i-35 ml).
Iimpawu zomgubo kunye neempawu zezinto ezenziwe ngazo isixhobo ziiparameter ezibalulekileyo. Ngexesha lokuhamba, iitshaja ze-electrostatic ziveliswa ngaphakathi komgubo ngenxa yesiphumo se-triboelectric, esikukutshintshana kweetshaja xa izinto ezimbini eziqinileyo zidibana.
Xa umgubo ungena ngaphakathi kwisixhobo, kwenzeka isiphumo se-triboelectric xa kudityaniswe amasuntswana kunye nalapho kudityaniswe amasuntswana nesixhobo.
Xa idibene nezinto ezikhethiweyo, iGranuCharge ilinganisa ngokuzenzekelayo ubungakanani betshaja ye-electrostatic eyenziwe ngaphakathi komgubo ngexesha lokuhamba. Isampulu yomgubo igeleza ngaphakathi kwityhubhu ye-V engcangcazelayo ize iwele kwikomityi yeFaraday eqhagamshelwe kwi-electrometer elinganisa itshaja efunyenweyo njengoko umgubo uhamba ngaphakathi kwityhubhu ye-V. Ukuze ufumane iziphumo eziphindaphindwayo, sebenzisa isixhobo esijikelezayo okanye esingcangcazelayo ukondla iityhubhu ze-V rhoqo.
Isiphumo se-triboelectric sibangela ukuba into ethile ifumane ii-electron kumphezulu wayo ize ngaloo ndlela ibe ne-negative charge, ngelixa enye into ilahlekelwa zii-electron ize ngaloo ndlela ibe ne-positive charge. Ezinye izinto zifumana ii-electron ngokulula kunezinye, kwaye ngokufanayo, ezinye izinto zilahlekelwa zii-electron lula.
Ukuba zeziphi izinto eziba negative kwaye zeziphi eziba negative kuxhomekeke ekubeni izinto ezibandakanyekayo zifuna okanye zilahleke na ii-electron. Ukumela ezi ndlela, uthotho lwe-triboelectric oluboniswe kwiTheyibhile 1 luphuhlisiwe. Izinto ezine-charge trend entle kunye nezinye ezine-charge trend embi zidwelisiwe, kwaye iindlela zezinto ezingabonisi naluphi na uhlobo lwe-charge zidweliswe embindini wetheyibhile.
Kwelinye icala, itheyibhile inika ulwazi kuphela malunga neendlela zokutshaja kwezinto, ngoko ke iGranuCharge yenzelwe ukubonelela ngamanani achanekileyo endlela yokutshaja iipowders.
Kwenziwe iimvavanyo ezininzi ukuze kuhlalutywe ukubola kobushushu. Iisampulu zibekwe kwi-200°C kangangeyure enye ukuya kwezimbini. Emva koko umgubo uhlalutywa ngoko nangoko ngeGranuDrum (igama elishushu). Emva koko umgubo ubekwe kwisikhongozeli ude ufikelele kubushushu obuqhelekileyo uze uhlalutywe kusetyenziswa iGranuDrum, iGranuPack kunye neGranuCharge (oko kukuthi “kubanda”).
Iisampulu ezingavuthwanga zihlalutywe kusetyenziswa iGranuPack, iGranuDrum kunye neGranuCharge kubushushu/ubushushu begumbi elifanayo (umz. 35.0 ± 1.5% RH kunye nobushushu obuyi-21.0 ± 1.0 °C).
Isalathisi sokubumbana sibala ukuhamba kakuhle kweempuphu kwaye sihambelana notshintsho kwindawo yojongano (umgubo/umoya), oluyimikhosi emithathu yoqhagamshelwano kuphela (i-van der Waals, amandla e-capillary kunye ne-electrostatic). Ngaphambi kovavanyo, ukufuma komoya ohambelanayo (RH, %) kunye nobushushu (°C) kwarekhodwa. Emva koko umgubo wagalelwa kwidrama, kwaye uvavanyo lwaqala.
Sigqibe kwelokuba ezi mveliso azichaphazeleki kukudibana xa sicinga ngeeparameter zethixotropic. Okubangel’ umdla kukuba, uxinzelelo lobushushu lutshintshe indlela yokuziphatha kwe-rheological yeepowders zeesampuli u-A no-B ukusuka ekuqineni kwe-shear ukuya ekuncipheni kwe-shear. Kwelinye icala, iiSamples C kunye ne-SS 316L azichaphazelekanga bubushushu kwaye zibonise kuphela ukutyeba kwe-shear. Ipowder nganye yayinokusasazeka ngcono (oko kukuthi i-lower cohesion index) emva kokufudumeza nokuphola.
Isiphumo sobushushu sixhomekeke nakwindawo ethile yee-particles. Okukhona ubushushu buphezulu, kokukhona isiphumo siphezulu kubushushu (oko kukuthi ???225°?=250?.?-1.?-1) kunye ???316?. 225°?=19?.?-1.?-1) Okukhona i-particle incinci, kokukhona isiphumo sobushushu siphezulu. Ii-aluminium alloy powders zilungile kakhulu kwizicelo zobushushu obuphezulu ngenxa yokwanda kokusasazeka kwazo, kwaye neesampuli ezipholileyo zifumana ukuhambahamba okungcono kunee-powders zokuqala.
Kwisilingo ngasinye seGranuPack, ubunzima bomgubo baburekhodwa ngaphambi kovavanyo ngalunye, kwaye isampuli yabethwa amaxesha angama-500 nge-impact frequency ye-1 Hz kunye ne-free fall ye-1 mm kwiseli yokulinganisa (amandla empembelelo ∝). Isampuli isasazwa kwiseli yokulinganisa ngokwemiyalelo yesoftware ezimeleyo yomsebenzisi. Emva koko imilinganiselo iphindwe kabini ukuvavanya ukuphindaphinda kwaye kuphandwe i-mean kunye ne-standard deviation.
Emva kokuba uhlalutyo lweGranuPack lugqityiwe, uxinano lokuqala lwe-bulk (ρ(0)), uxinano lokugqibela lwe-bulk (kwii-multiple taps, n = 500, oko kukuthi ρ(500)), i-Hausner ratio/Carr index (Hr/Cr) kunye neeparamitha ezimbini zokubhalisa (n1/2 kunye ne-τ) ezinxulumene ne-compaction kinetics. Uxinano olufanelekileyo lwe-ρ(∞) nalo luyaboniswa (jonga iSihlomelo 1). Itheyibhile engezantsi ihlengahlengisa idatha yovavanyo.
Imifanekiso 6 kunye no-7 ibonisa i-collection curve iyonke (ubuninzi be-bulk xa kuthelekiswa nenani leempembelelo) kunye nomlinganiselo weparameter ye-n1/2/Hausner. Iibha zempazamo ezibalwe kusetyenziswa i-mean ziboniswe kwi-curve nganye, kwaye ukuphambuka okuqhelekileyo kubalwe ngovavanyo lokuphindaphinda.
Imveliso yentsimbi engagqwaliyo ye-316L yayiyeyona mveliso inzima kakhulu (ρ(0) = 4.554 g/mL). Ngokuphathelele uxinano lwe-tapping, i-SS 316L ihlala ingumgubo onzima kakhulu (ρ(n) = 5.044 g/mL), ilandelwa yiSample A (ρ(n) = 1.668 g/mL), ilandelwe yiSample B (ρ(n) = 1.668 g/ml). /ml) (n) = 1.645 g/ml). ISample C yayiyeyona iphantsi kakhulu (ρ(n) = 1.581 g/mL). Ngokwe-bulk density ye-first powder, sibona ukuba i-sample A yeyona ilula kakhulu, kwaye xa sijonga iimpazamo (1.380 g / ml), iisample B kunye ne-C zilingana nexabiso elifanayo.
Njengoko umgubo ufudunyezwa, umlinganiselo wawo weHausner uyancipha, kwaye oku kwenzeka kuphela ngeesampuli B, C, kunye ne-SS 316L. Kwisampuli A, bekungenakwenzeka ukusebenza ngenxa yobukhulu beebha zempazamo. Kwi-n1/2, umkhwa we-parametric ogxininisayo unzima ngakumbi. Kwisampuli A kunye ne-SS 316L, ixabiso le-n1/2 lehle emva kweeyure ezi-2 kwi-200°C, ngelixa kwiipowder B kunye ne-C lenyuka emva kokulayisha ubushushu.
Kusetyenziswe isixhobo sokutya esingcangcazelayo kuvavanyo ngalunye lweGranuCharge (jonga uMfanekiso 8). Sebenzisa ityhubhu yentsimbi engagqwaliyo engama-316L. Ukulinganisa kuphindwe kathathu ukuvavanya ukuphinda kusetyenziswe. Ubunzima bemveliso esetyenzisiweyo kumlinganiselo ngamnye babumalunga nama-40 ml kwaye akukho mgubo ufunyenweyo emva kokulinganisa.
Ngaphambi kovavanyo, ubunzima bomgubo (mp, g), ukufuma komoya (RH, %), kunye nobushushu (°C) barekhodwa. Ekuqaleni kovavanyo, uxinano lwetshaja yomgubo oyintloko (q0 kwi µC/kg) lwalinganiswa ngokubeka umgubo kwikomityi yeFaraday. Ekugqibeleni, ubunzima bomgubo balungiswa kwaye uxinano lwetshaja yokugqibela (qf, µC/kg) kunye ne-Δq (Δq = qf – q0) ekupheleni kovavanyo zabalwa.
Idatha yeGranuCharge eluhlaza iboniswe kwiTheyibhile 2 kunye noMfanekiso 9 (σ kukuphambuka okuqhelekileyo okubalwe kwiziphumo zovavanyo lokuphinda kuvele), kwaye iziphumo ziboniswe njenge-histogram (kuphela i-q0 kunye ne-Δq eziboniswayo). I-SS 316L inexabiso eliphantsi lokuqala; oku kusenokubangelwa kukuba le mveliso ine-PSD ephezulu. Xa kufikwa ekulayishweni kokuqala komgubo we-aluminium alloy oyintloko, akukho zigqibo zinokuthathwa ngenxa yobukhulu beempazamo.
Emva kokudibana nombhobho wentsimbi engagqwaliyo ye-316L, isampuli A ifumene itshaja encinci, ngelixa iipowders B kunye ne-C zibonise umkhwa ofanayo, ukuba umgubo we-SS 316L ukhuhlwe kwi-SS 316L, kufunyenwe uxinano lwetshaja olusondele kwi-0 (jonga uthotho lwe-triboelectric). Imveliso B isatshaja ngaphezulu kune-A. Kwisampuli C, umkhwa uyaqhubeka (itshaja yokuqala elungileyo kunye netshaja yokugqibela emva kokuvuza), kodwa inani leetshaja liyanda emva kokuwohloka kobushushu.
Emva kweeyure ezi-2 zoxinzelelo lobushushu kwi-200 °C, ukuziphatha komgubo kuba nomdla kakhulu. Kwiisampulu u-A no-B, itshaja yokuqala yehla kwaye itshaja yokugqibela yatshintsha ukusuka kwi-negative ukuya kwi-positive. I-SS 316L powder yayinetshaja yokuqala ephezulu kwaye utshintsho lwayo loxinano lwetshaja lwaba yi-positive kodwa yahlala iphantsi (oko kukuthi, i-0.033 nC/g).
Siphande ngempembelelo yokuwohloka kobushushu kwindlela esebenza ngayo i-aluminium alloy (AlSi10Mg) kunye ne-316L stainless steel powders, ngelixa i-powders yokuqala yahlalutywa emva kweeyure ezi-2 kwi-200°C emoyeni.
Ukusetyenziswa kweempuphu kumaqondo obushushu aphezulu kunokuphucula ukuhambahamba kwemveliso, isiphumo esibonakala sibaluleke ngakumbi kwiimpuphu ezinendawo ethile ephezulu kunye nezixhobo ezinomoya ophezulu wokushisa. I-GranuDrum yasetyenziselwa ukuvavanya ukuhambahamba, i-GranuPack yasetyenziselwa uhlalutyo lokupakisha olunamandla, kwaye i-GranuCharge yasetyenziselwa ukuhlaziya umbane we-triboelectricity wempuphu edibene nombhobho wentsimbi engagqwaliyo ye-316L.
Ezi ziphumo zichongiwe kusetyenziswa iGranuPack, ebonise ukuphucuka kwi-Hausner coefficient kwipowder nganye (ngaphandle kwesampulu A, ngenxa yobukhulu beempazamo) emva kwenkqubo yoxinzelelo lobushushu. Akukho mkhuba ucacileyo ofunyenweyo kwiparameter yokupakisha (n1/2) njengoko ezinye iimveliso zibonise ukonyuka kwesantya sokupakisha ngelixa ezinye zinefuthe elahlukileyo (umz. Iisampuli B kunye no-C).