NGHIEN CUU-TRAODOI >1PHAN TiCH DONG HOC DONG LlTU CHAT TREN DAU OUN ^ MAY TAO MAU NHANH FDM DYNAMIC FLOW ANALYSIS ON EXTRUDE HEAD OF FDM MACHINE Trinh Van Thai, PGS,TS Thai Thi I h u Ha Phdng Thi nghiem Trpng diem Quoc gia Dieu khiln sd va Ky thuat He thdng, Trfldng Dai hpc Bach Khoa, Dai hpc Quoc gia TP Hd Chi Mmh TOM TAT Qud trinh dun tren mdy tao mdu nhanh FDM (Fused deposition modeling) dp lUc dim dUdc tao bdng chuyen ddng di xudng cua sdi vat lieu day phdn vat lieu da dUdc hod long ong hod long qua ddu phun Qud trinh chuyen pha tii vat lieu d trang thdi ran sang trang thdi long phu thuoc vdo tinh chdt vat lieu, nhiet do, kich thUdc hinh hoc cua ong hod long Sdi vat lieu ran chiu mot dp lUc trUc tiep tii ddu phun vd theo [2] khoang 85% ton that dp lUc la tai mieng ddu phun Theo thdng sd D, L, a nhU hinh la cdc thdng sd dnh hUdng Idn den phdn lUc tdc dung lin sdi vdt lieu Khi phdn lUc Idn hdn gidi han ben, sdi vdt lieu se bi be cong ben tren ong hod long (hinh 3) Nghiin ciiu md phong qud trinh ndng chay cua dong vdt Ueu dng hod long, xdc dinh mien be cong sdi vat lieu qud trinh dun tren mdy FDM, dUa van tdc diin hdp ly; Xdc dinh dnh hUdng sU thay ddi cua dUdng kinh mieng ddu phun len qud trinh dim Tfl khoa: Cdng nghe diin lang dong vdt lieu; Cdng nghe tao mdu nhanh During extrusion process by Fused deposition modeling machine, the pressure caused by downwards movement of filament is extruded through the nozzle Phase change of filament from solidification into a liquid state depends on material properties, temperature and geometry of liquefier Filament was pushed directly pressure from the nozzle, and according to [2] about 85% of the pressure loss in the nozzle head Parameters D, L, a as shown in Figure is the major parameters affecting the reaction pressure on the filament When that pressure larger ultimate strength of filament, it was buckled at above of the liquefier Study this process that is useful to present suitable supplying velocity, to finite optimum extrusion velocity; Determining the affect ofnozzel diametter changing on FDM process Keywords: Fused deposition modeling; Rapiad prototyping technology TAP CHi CO KHI V I £ T NAM, Sd 12 nam 2013 ^ NGHIEN CUfU-TRAODdi GlCtt THIEU CHUNG 'i •': Cdng nghe tao mdu nhanh Id cdng nghe tao mau theo tflng ldp, sfl dung vdt Ueu nhfla nhiet deo 6\i0c gia nhiet den trang thai ndng chay va dun qua dau phun Nhiet dp gia nhiet vdo khoan (180- 230)''C vdi dfldng kinh mieng dau phun tfl (0,3 - 0,5)mm Ddng vat lieu dau dun dflpc md hinh hod nhfl sd dd nguyen ly d hinh [1] Theo dd ddng vdt lieu dflpc cap qua he thdng cap Ueu dflpc dieu khiln rieng biet tfl hop cap lieu den dau dun Hinh Soi vdt lieu bi be cong Gia tri tdi han cua dp ben spi vat Ueu dfldc xac dinh theo cdng thflc Euler nhfl sau [2]: Trong dd o Id gidi han be cong, E dp ben nen cua vat lieu Ty sd L/R la ti sd khoang cdch tfl tam lan den b l mat ong hod Idng va ban kinh cua dng hod Idng cho nhfl hinh Khi dieu kien cho viec be cong vlit lieu dfldc xac dinh nhfl sau: AP > cr (2) f^ ^ Hinh 1: Nguyen ly hinh thdnh dong chdy [1] f Hinh 4: Ddu dim tren mdy FDM Hinh 2: Thong sd cua ddu phun XAY D I J N G M O H l N H Khi phan lUc 16n hon dp ben cua sol vat lieu se xay hien W