{"id":4893,"date":"2026-03-13T00:00:11","date_gmt":"2026-03-12T16:00:11","guid":{"rendered":"https:\/\/www.oc-epc.com\/?p=4893"},"modified":"2026-03-13T11:11:17","modified_gmt":"2026-03-13T03:11:17","slug":"vuot-qua-nhung-thach-thuc-trong-meo-duc-bot-bi-mat-va-thuc-tien-tot-nhat","status":"publish","type":"post","link":"https:\/\/www.oc-epc.com\/vi\/news-blog\/industry-news\/overcoming-challenges-in-lost-foam-casting-tips-and-best-practices\/","title":{"rendered":"V\u01b0\u1ee3t qua nh\u1eefng th\u00e1ch th\u1ee9c trong \u0111\u00fac b\u1ecdt b\u1ecb m\u1ea5t: M\u1eb9o v\u00e0 th\u1ef1c ti\u1ec5n t\u1ed1t nh\u1ea5t"},"content":{"rendered":"

M\u1ea5t b\u1ecdt \u0111\u00fac<\/strong><\/a>, c\u00f2n \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u0111\u00fac m\u1eabu bay h\u01a1i (EPC), cung c\u1ea5p m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3 \u0111\u1ec3 l\u00e0m c\u00e1c b\u1ed9 ph\u1eadn kim lo\u1ea1i ph\u1ee9c t\u1ea1p. Nh\u1eefng ph\u1ea7n n\u00e0y g\u1ea7n v\u1edbi h\u00ecnh d\u1ea1ng cu\u1ed1i c\u00f9ng. Ch\u00fang cho th\u1ea5y \u0111\u1ed9 ch\u00ednh x\u00e1c tuy\u1ec7t v\u1eddi v\u1ec1 k\u00edch th\u01b0\u1edbc v\u00e0 b\u1ec1 m\u1eb7t m\u1ecbn. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y s\u1eed d\u1ee5ng m\u00f4 h\u00ecnh b\u1ecdt polystyrene m\u1edf r\u1ed9ng (EPS). M\u00f4 h\u00ecnh n\u00e0y bi\u1ebfn m\u1ea5t khi kim lo\u1ea1i n\u00f3ng ch\u1ea1m v\u00e0o n\u00f3. K\u1ebft qu\u1ea3 l\u00e0, n\u00f3 lo\u1ea1i b\u1ecf s\u1ef1 c\u1ea7n thi\u1ebft cho l\u00f5i th\u00f4ng th\u01b0\u1eddng, \u0111\u01b0\u1eddng chia v\u00e0 nhi\u1ec1u gia c\u00f4ng sau khi \u0111\u00fac. Nhi\u1ec1u ng\u00e0nh c\u00f4ng nghi\u1ec7p s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p n\u00e0y. V\u00ed d\u1ee5 bao g\u1ed3m \u00f4 t\u00f4, m\u00e1y m\u00f3c n\u00f4ng nghi\u1ec7p, thi\u1ebft b\u1ecb n\u0103ng l\u01b0\u1ee3ng v\u00e0 thi\u1ebft b\u1ecb gia d\u1ee5ng. N\u00f3 cho ph\u00e9p t\u1ea1o ra c\u00e1c m\u1eb7t h\u00e0ng chi ti\u1ebft nh\u01b0 kh\u1ed1i \u0111\u1ed9ng c\u01a1, v\u1ecf truy\u1ec1n t\u1ea3i, th\u00e0nh ph\u1ea7n m\u00e1y k\u00e9o v\u00e0 b\u1ebfp \u0111\u1ed1t kh\u00ed.<\/p>\n

\u0110\u00fac b\u1ecdt b\u1ecb m\u1ea5t mang l\u1ea1i l\u1ee3i th\u1ebf r\u00f5 r\u00e0ng. N\u00f3 c\u1eaft gi\u1ea3m ch\u1ea5t th\u1ea3i v\u1eadt li\u1ec7u. T\u1ef1 do h\u01a1n trong thi\u1ebft k\u1ebf. N\u00f3 l\u00e0m gi\u1ea3m chi ph\u00ed c\u00f4ng c\u1ee5 cho c\u00e1c h\u00ecnh d\u1ea1ng kh\u00f3 kh\u0103n. N\u00f3 c\u0169ng gi\u00fap m\u00f4i tr\u01b0\u1eddng v\u00ec c\u00e1t kh\u00f4ng li\u00ean k\u1ebft c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u00e1i s\u1eed d\u1ee5ng. Tuy nhi\u00ean, qu\u00e1 tr\u00ecnh n\u00e0y ph\u1ea3i \u0111\u1ed1i m\u1eb7t v\u1edbi m\u1ed9t s\u1ed1 v\u1ea5n \u0111\u1ec1 k\u1ef9 thu\u1eadt. C\u00e1c v\u1ea5n \u0111\u1ec1 ph\u1ed5 bi\u1ebfn bao g\u1ed3m \u0111\u1ed9 x\u1ed1p, bao g\u1ed3m, n\u1ebfp nh\u0103n b\u1ec1 m\u1eb7t ho\u1eb7c n\u1ebfp g\u1ea5p, c\u00e1t ch\u00e1y, khoang co l\u1ea1i v\u00e0 l\u1ea5p \u0111\u1ea7y kh\u00f4ng ho\u00e0n ch\u1ec9nh. Nh\u1eefng v\u1ea5n \u0111\u1ec1 n\u00e0y c\u00f3 th\u1ec3 l\u00e0m t\u0103ng t\u1ef7 l\u1ec7 ph\u1ebf li\u1ec7u v\u00e0 t\u0103ng chi ph\u00ed n\u1ebfu kh\u00f4ng \u0111\u01b0\u1ee3c x\u1eed l\u00fd t\u1ed1t.<\/p>\n

C\u00e1c nh\u00e0 s\u1ea3n xu\u1ea5t c\u00f3 k\u1ebft qu\u1ea3 \u1ed5n \u0111\u1ecbnh, ch\u1ea5t l\u01b0\u1ee3ng cao. H\u1ecd l\u00e0m \u0111i\u1ec1u n\u00e0y b\u1eb1ng c\u00e1ch \u0111i\u1ec1u ch\u1ec9nh tinh t\u1ebf c\u00e1c y\u1ebfu t\u1ed1 quy tr\u00ecnh ch\u00ednh, l\u1ef1a ch\u1ecdn v\u1eadt li\u1ec7u ph\u00f9 h\u1ee3p, s\u1eed d\u1ee5ng ph\u1ea7n m\u1ec1m m\u00f4 ph\u1ecfng hi\u1ec7n \u0111\u1ea1i v\u00e0 d\u1ef1a v\u00e0o thi\u1ebft b\u1ecb \u0111\u00e1ng tin c\u1eady. C\u00e1c ph\u1ea7n d\u01b0\u1edbi \u0111\u00e2y m\u00f4 t\u1ea3 nh\u1eefng th\u00e1ch th\u1ee9c th\u01b0\u1eddng xuy\u00ean. H\u1ecd c\u0169ng cung c\u1ea5p c\u00e1c l\u1eddi khuy\u00ean \u0111\u00e3 \u0111\u01b0\u1ee3c ch\u1ee9ng minh v\u00e0 th\u1ef1c ti\u1ec5n t\u1ed1t nh\u1ea5t \u0111\u1ec3 gi\u1ea3i quy\u1ebft ch\u00fang.<\/p>\n

Thi\u1ebft k\u1ebf m\u1eabu b\u1ecdt v\u00e0 l\u1ef1a ch\u1ecdn v\u1eadt li\u1ec7u<\/strong><\/h2>\n

 <\/p>\n

\"M\u00e1y<\/div>\n

Thi\u1ebft k\u1ebf m\u1eabu b\u1ecdt t\u1ea1o th\u00e0nh c\u01a1 s\u1edf ch\u00ednh cho \u0111\u00fac kh\u00f4ng c\u00f3 khuy\u1ebft t\u1eadt. C\u00e1c m\u1eabu c\u1ea7n x\u1eed l\u00fd chuy\u1ec3n \u0111\u1ed9ng, l\u1edbp ph\u1ee7 v\u00e0 \u00e9p c\u00e1t. H\u1ecd ph\u1ea3i gi\u1eef v\u1eefng ch\u1eafc m\u00e0 kh\u00f4ng u\u1ed1n cong. \u0110\u1ed3ng th\u1eddi, ch\u00fang n\u00ean ph\u00e1 v\u1ee1 s\u1ea1ch s\u1ebd trong khi \u0111\u1ed5. Thi\u1ebft k\u1ebf k\u00e9m th\u01b0\u1eddng g\u00e2y ra s\u1ef1 s\u1ee5p \u0111\u1ed5 m\u00f4 h\u00ecnh, l\u1ed7i k\u00edch th\u01b0\u1edbc ho\u1eb7c c\u00e1c v\u1ea5n \u0111\u1ec1 nh\u01b0 g\u1ea5p v\u00e0 n\u1ebfp nh\u0103n.<\/p>\n

Th\u1ef1c ti\u1ec5n t\u1ed1t \u0111\u1ec1 ngh\u1ecb ch\u1ecdn m\u1eadt \u0111\u1ed9 b\u1ecdt EPS th\u01b0\u1eddng l\u00e0 t\u1eeb 20-30 kg \/ m\u00b3 cho c\u00e1c h\u00ecnh d\u1ea1ng ph\u1ee9c t\u1ea1p. L\u1ef1a ch\u1ecdn n\u00e0y gi\u1eef cho m\u00f4 h\u00ecnh m\u1ea1nh m\u1ebd trong khi s\u1ea3n xu\u1ea5t \u00edt kh\u00ed khi n\u00f3 b\u1ecb ch\u00e1y. B\u1ecdt c\u00f3 m\u1eadt \u0111\u1ed9 th\u1ea5p h\u01a1n gi\u1ea3m c\u00e1c v\u1ea5n \u0111\u1ec1 n\u1ebfp nh\u0103n. H\u1ecd t\u0103ng t\u1ed1c qu\u00e1 tr\u00ecnh \u0111\u1ed1t ch\u00e1y. Ngay c\u1ea3 \u0111\u1ed9 d\u00e0y t\u01b0\u1eddng v\u00e0 g\u00f3c d\u1ef1 th\u1ea3o b\u1ed5 sung gi\u00fap kim lo\u1ea1i ch\u1ea3y tr\u01a1n tru. C\u00e1c v\u1eadt li\u1ec7u h\u1ea1t m\u1edbi h\u01a1n, ch\u1eb3ng h\u1ea1n nh\u01b0 c\u00e1c \u0111\u1ed3ng polymer EPS-PMMA, l\u00e0m gi\u1ea3m c\u00e1c khi\u1ebfm khuy\u1ebft carbon b\u00f3ng trong \u0111\u00fac s\u1eaft d\u1ec5 ch\u1ecbu. H\u1ecd \u0111\u1ea3m b\u1ea3o m\u1ecdi th\u1ee9 b\u1ed1c h\u01a1i ho\u00e0n to\u00e0n m\u00e0 kh\u00f4ng c\u00f3 v\u1eadt li\u1ec7u c\u00f2n l\u1ea1i. C\u00e1c l\u1edbp ph\u1ee7 tr\u01b0\u1edbc ho\u1eb7c ch\u1ea5t ph\u1ee5 gia tr\u00ean c\u00e1c m\u1eabu c\u0169ng c\u1ea3i thi\u1ec7n ch\u1ea5t l\u01b0\u1ee3ng b\u1ec1 m\u1eb7t. Ch\u00fang l\u00e0m gi\u1ea3m c\u01a1 h\u1ed9i g\u1ea5p.<\/p>\n

X\u1eed l\u00fd, l\u01b0u tr\u1eef v\u00e0 l\u1eafp r\u00e1p m\u00f4 h\u00ecnh<\/strong><\/h2>\n

M\u00f4 h\u00ecnh b\u1ecdt<\/strong><\/a> c\u00f3 th\u1ec3 b\u1ecb thay \u0111\u1ed5i trong m\u00f4i tr\u01b0\u1eddng ho\u1eb7c do \u0111i\u1ec1u tr\u1ecb th\u00f4 l\u1ed7. S\u1ef1 dao \u0111\u1ed9ng \u0111\u1ed9 \u1ea9m c\u00f3 th\u1ec3 g\u00e2y bi\u1ebfn d\u1ea1ng. X\u1eed l\u00fd c\u1ee9ng c\u00f3 th\u1ec3 t\u1ea1o ra c\u00e1c v\u1ebft n\u1ee9t. C\u1ea3 hai \u0111\u1ec1u g\u00e2y h\u1ea1i cho \u0111\u1ed9 ch\u00ednh x\u00e1c \u0111\u00fac cu\u1ed1i c\u00f9ng.<\/p>\n

C\u00e1c m\u1eabu c\u1ea7n l\u01b0u tr\u1eef trong \u0111i\u1ec1u ki\u1ec7n \u1ed5n \u0111\u1ecbnh. Gi\u1eef nhi\u1ec7t \u0111\u1ed9 kho\u1ea3ng 20-25 \u00b0 C v\u00e0 \u0111\u1ed9 \u1ea9m d\u01b0\u1edbi 60%. \u0110i\u1ec1u n\u00e0y ng\u0103n ch\u1eb7n s\u1ef1 thay \u0111\u1ed5i k\u00edch th\u01b0\u1edbc. S\u1eed d\u1ee5ng x\u1eed l\u00fd c\u1ea9n th\u1eadn v\u1edbi c\u00e1c c\u00f4ng c\u1ee5 t\u1ef1 \u0111\u1ed9ng ho\u1eb7c h\u1ed7 tr\u1ee3 b\u1ea3o v\u1ec7. Ki\u1ec3m tra th\u01b0\u1eddng xuy\u00ean v\u1edbi m\u1eaft gi\u00fap duy tr\u00ec ch\u1ea5t l\u01b0\u1ee3ng. Khi k\u1ebft h\u1ee3p m\u1ed9t s\u1ed1 m\u1ea3nh m\u1eabu, \u00e1p d\u1ee5ng ch\u1ea5t k\u1ebft d\u00ednh n\u00f3ng ch\u1ea3y th\u1ea5p. S\u1eed d\u1ee5ng c\u00e1c ph\u01b0\u01a1ng ph\u00e1p fileting c\u0169ng. Ch\u00fang t\u1ea1o ra c\u00e1c k\u1ebft n\u1ed1i v\u1eefng ch\u1eafc m\u00e0 kh\u00f4ng th\u00eam l\u1ed7i.<\/p>\n

\u1ee8ng d\u1ee5ng l\u1edbp ph\u1ee7 v\u1eadt li\u1ec7u ch\u1ecbu l\u1eeda<\/strong><\/h2>\n

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\"M\u00e1y<\/div>\n

L\u1edbp ph\u1ee7 ch\u1ed1ng ch\u00e1y tr\u00ean m\u00f4 h\u00ecnh b\u1ecdt l\u00e0m c\u00e1c c\u00f4ng vi\u1ec7c quan tr\u1ecdng. N\u00f3 gi\u1eef khu\u00f4n c\u00e1t sau khi b\u1ecdt bi\u1ebfn m\u1ea5t. \u0110i\u1ec1u khi\u1ec3n c\u00e1ch kim lo\u1ea1i di chuy\u1ec3n. N\u00f3 cho ph\u00e9p kh\u00ed r\u1eddi \u0111i. N\u00f3 c\u0169ng c\u1ea3i thi\u1ec7n b\u1ec1 m\u1eb7t. \u1ee8ng d\u1ee5ng l\u1edbp ph\u1ee7 x\u1ea5u khi\u1ebfn kim lo\u1ea1i th\u1ea5m v\u00e0o, bao g\u1ed3m c\u00e1t, c\u00e1c khu v\u1ef1c th\u00f4 ho\u1eb7c b\u1ecb ch\u00e1y.<\/p>\n

\u00c1p d\u1ee5ng l\u1edbp ph\u1ee7 v\u1edbi \u0111\u1ed9 d\u00e0y 0,5-2 mm. L\u00e0m cho n\u00f3 th\u1eadm ch\u00ed b\u1eb1ng c\u00e1ch nh\u00fang ho\u1eb7c phun. L\u1edbp ph\u1ee7 c\u00f3 \u0111\u1ed9 th\u1ea5m th\u1ea5m cao v\u00e0 \u0111\u1ed9 d\u00e0y th\u00edch h\u1ee3p tr\u00e1nh l\u1ed7i. H\u1ecd v\u1eabn c\u00f2n \u0111\u1ee7 s\u1ee9c m\u1ea1nh. S\u1ea5y kh\u00f4 ch\u00fang b\u1eb1ng h\u1ec7 th\u1ed1ng b\u01a1m nhi\u1ec7t ti\u1ebft ki\u1ec7m n\u0103ng l\u01b0\u1ee3ng \u0111\u1ec3 ng\u0103n ch\u1eb7n c\u00e1c v\u1ebft n\u1ee9t. Nh\u1eefng c\u1ea3i ti\u1ebfn m\u1edbi nh\u00ecn v\u00e0o thi\u1ebft k\u1ebf l\u01b0\u1ee1i, t\u1ed1c \u0111\u1ed9 tr\u1ed9n v\u00e0 nhi\u1ec7t s\u1ea5y. Ch\u00fang gi\u00fap \u0111\u1ea1t \u0111\u01b0\u1ee3c \u0111\u1ed9 d\u00e0y v\u00e0 l\u01b0\u1ee3ng l\u1edbp ph\u1ee7 ph\u00f9 h\u1ee3p. B\u1eb1ng c\u00e1ch n\u00e0y, c\u00e1c v\u1ea5n \u0111\u1ec1 b\u1ec1 m\u1eb7t gi\u1ea3m.<\/p>\n

Thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng Gating, Riser v\u00e0 Filling<\/strong><\/h2>\n

D\u00f2ng ch\u1ea3y kim lo\u1ea1i nhanh ch\u00f3ng, kh\u00f4ng \u0111\u1ed3ng \u0111\u1ec1u d\u1eabn \u0111\u1ebfn bao g\u1ed3m, l\u1ed7 th\u1ed5i, oxyt, \u0111\u00f3ng l\u1ea1nh v\u00e0 thi\u1ec7t h\u1ea1i cho khu\u00f4n. Trong \u0111\u00fac b\u1ecdt b\u1ecb m\u1ea5t, \u00e1p l\u1ef1c t\u1eeb s\u1ef1 ph\u00e1 v\u1ee1 b\u1ecdt l\u00e0m cho c\u00e1c v\u1ea5n \u0111\u1ec1 n\u00e0y t\u1ed3i t\u1ec7 h\u01a1n.<\/p>\n

Thi\u1ebft k\u1ebf t\u1ed1t h\u01a1n s\u1eed d\u1ee5ng c\u00e1c m\u00e1y ch\u1ea1y c\u00f4n v\u00e0 c\u1eeda d\u01b0\u1edbi. t\u1ed1c \u0111\u1ed9 th\u1ea5p h\u01a1n. \u0110\u1eb7t risers c\u1ea9n th\u1eadn \u0111\u1ec3 cho \u0103n c\u00e1c khu v\u1ef1c co l\u1ea1i. C\u00e1c m\u00f4 ph\u1ecfng cho th\u1ea5y \u0111\u01b0\u1eddng d\u00f2ng ch\u1ea3y, khu v\u1ef1c n\u00f3ng v\u00e0 c\u00e1c \u0111i\u1ec3m khuy\u1ebft t\u1eadt. \u0110i\u1ec1u n\u00e0y cho ph\u00e9p thay \u0111\u1ed5i \u0111\u1ec3 l\u1ea5p \u0111\u1ea7y b\u00ecnh t\u0129nh. H\u1ec7 th\u1ed1ng v\u1edbi ch\u00e2n kh\u00f4ng gi\u00fap khu\u00f4n th\u1ea5m. lo\u1ea1i b\u1ecf kh\u00ed t\u1ed1t h\u01a1n. \u0110i\u1ec1u n\u00e0y ho\u1ea1t \u0111\u1ed9ng \u0111\u1eb7c bi\u1ec7t t\u1ed1t cho c\u00e1c b\u1ed9 ph\u1eadn nh\u00f4m m\u1ecfng ho\u1eb7c ph\u1ee9c t\u1ea1p.<\/p>\n

\u0110\u1ed5 nhi\u1ec7t \u0111\u1ed9, t\u1ed1c \u0111\u1ed9 v\u00e0 \u0111i\u1ec1u khi\u1ec3n l\u00e0m m\u00e1t<\/strong><\/h2>\n

C\u00e0i \u0111\u1eb7t \u0111\u1ed5 \u1ea3nh h\u01b0\u1edfng tr\u1ef1c ti\u1ebfp \u0111\u1ebfn l\u1ed7i. Qu\u00e1 nhi\u1ec1u bi\u1ebfn \u0111\u1ed9ng ho\u1eb7c l\u00e0m m\u00e1t nhanh t\u1ea1o ra c\u0103ng th\u1eb3ng nhi\u1ec7t, v\u1ebft n\u1ee9t, \u0111\u1ed9 x\u1ed1p co l\u1ea1i ho\u1eb7c l\u00e0m \u0111\u1ea7y k\u00e9m.<\/p>\n

S\u1eed d\u1ee5ng nhi\u1ec7t \u0111\u1ed9 \u0111\u1ed5 t\u1ed1t nh\u1ea5t (v\u00ed d\u1ee5: 700 \u00b0 C cho h\u1ee3p kim nh\u00f4m A356) v\u00e0 t\u1ed1c \u0111\u1ed9 \u1ed5n \u0111\u1ecbnh. Ch\u00fang cung c\u1ea5p l\u1ea5p \u0111\u1ea7y m\u01b0\u1ee3t m\u00e0 kh\u00f4ng m\u1ea5t qu\u00e1 nhi\u1ec1u nhi\u1ec7t. Ch\u1eadm, th\u1eadm ch\u00ed l\u00e0m m\u00e1t gi\u00fap. N\u00f3 d\u1ef1a v\u00e0o \u0111\u1ed9 d\u1eabn nhi\u1ec7t c\u00e1t ph\u00f9 h\u1ee3p (kho\u1ea3ng 0,5 W \/ m \u00b7 K) v\u00e0 truy\u1ec1n nhi\u1ec7t t\u1ea1i giao di\u1ec7n. \u0110i\u1ec1u n\u00e0y l\u00e0m gi\u1ea3m c\u0103ng th\u1eb3ng. Theo d\u00f5i tr\u1ef1c ti\u1ebfp v\u00e0 h\u1ed7 tr\u1ee3 ch\u00e2n kh\u00f4ng l\u00e0m cho k\u1ebft qu\u1ea3 th\u1ed1ng nh\u1ea5t h\u01a1n.<\/p>\n

Khu\u00f4n n\u00e9n, th\u00f4ng gi\u00f3 v\u00e0 ch\u1ea5t l\u01b0\u1ee3ng c\u00e1t<\/strong><\/h2>\n

Khu\u00f4n c\u00e1t kh\u00f4 kh\u00f4ng li\u00ean k\u1ebft ph\u1ea3i gi\u1eef h\u00ecnh d\u1ea1ng t\u1ed1t. H\u1ecd c\u0169ng c\u1ea7n \u0111\u1ec3 c\u00e1c kh\u00ed t\u1eeb s\u1ef1 ph\u00e1 v\u1ee1 b\u1ecdt tho\u00e1t d\u1ec5 d\u00e0ng. \u0110\u00f3ng n\u00e9n y\u1ebfu ho\u1eb7c th\u00f4ng gi\u00f3 k\u00e9m b\u1eaby kh\u00ed. \u0110i\u1ec1u n\u00e0y g\u00e2y ra l\u1ed7 h\u1ed5ng ho\u1eb7c khu\u00f4n th\u1ea5t b\u1ea1i.<\/p>\n

S\u1eed d\u1ee5ng c\u00e1t kh\u00f4 t\u1ed1t v\u1edbi k\u00edch th\u01b0\u1edbc h\u1ea1t \u1ed5n \u0111\u1ecbnh. Compact n\u00f3 b\u1eb1ng rung ho\u1eb7c ch\u00e2n kh\u00f4ng. \u0110i\u1ec1u n\u00e0y gi\u1eef cho khu\u00f4n v\u1eefng ch\u1eafc. Th\u00eam \u0111\u01b0\u1eddng th\u00f4ng gi\u00f3 v\u00e0 \u0111\u1ed9 th\u1ea5m t\u1ed1t h\u01a1n \u0111\u1ec3 tr\u00e1nh t\u00edch t\u1ee5 \u00e1p l\u1ef1c. Gi\u1eef t\u1ea5t c\u1ea3 \u0111\u1ed9 \u1ea9m xa. \u0110i\u1ec1u n\u00e0y lo\u1ea1i b\u1ecf c\u00e1c khuy\u1ebft t\u1eadt li\u00ean quan \u0111\u1ebfn kh\u00ed.<\/p>\n

C\u00e1c bi\u1ec7n ph\u00e1p kh\u1eafc ph\u1ee5c c\u1ee5 th\u1ec3 l\u1ed7i v\u00e0 t\u1ed1i \u01b0u h\u00f3a quy tr\u00ecnh<\/strong><\/h2>\n

L\u1ed7i ph\u1ed5 bi\u1ebfn v\u00e0 s\u1eeda ch\u1eefa c\u1ee5 th\u1ec3 bao g\u1ed3m:<\/p>\n