Chisel work
Chisel hom thiab hniav txoj hauj lwm
Yog tsis ua hauj lwm nrog ib tug chisel, mastering nyob rau hauv tsev tsis tuaj yeem ua tiav tag nrho. Kev sib koom ua ke ntawm cov rooj tog zaum siv cov qhov thiab cov ntsaws ruaj ruaj, txhim kho cov xauv, kho qhov rooj hinges tsis tuaj yeem ua yam tsis siv lub chisel.
Rau kev ua haujlwm nruab nrab ntawm ntau hom chisels yuav tsum muaj li ntawm peb lossis plaub. Chisels nrog ntau cov ntaub ntawv nyuaj (slanted, ib nrab lub hli zoo li, thiab lwm yam) yog siv los ntawm sculptors thiab cov kws ntoo los ua cov rooj tog stylish.
Cov hniav ntawm lub chisel yog ua los ntawm cov hlau, thiab tus kov thiab rauj siv los ntaus nws yog ua los ntawm ntoo. Qhov tseem ceeb tshaj plaws ntawm cov chisel yog cov hniav, uas feem ntau yog lub kaum sab xis ntawm 25° (daim duab 1, ntu 1).
Cov chisels siv tshaj plaws yog:
- tiaj tus chisel nrog cov duab plaub;
- tiaj tus chisel nrog beveled npoo;
- hollowed carpentry chisel;
- ntev chisel rau qhib.
Lub tes tuav ntawm lub chisel yuav tsum tau nruab rau saum lub nplhaib hlau uas npog lub qhov nqaim me ntsis ntawm tus kov kom tus kov tsis tawg thaum ntaus nrog rauj ntoo.
Cov hniav ntawm lub chisel yog ncaj (tsuas yog nyob rau hauv lub hollow chisel nws yog bulged) thiab yuav tsum tau tuav nyob rau hauv lub txiav dav hlau. Lub beveled ib feem ntawm lub chisel yuav tsum fim ib feem ntawm cov ntoo uas raug txiav, pov tseg (daim duab. 1, ib feem 2–5).
- Daim duab1- Txoj hauj lwm ntawm cov hniav thiab qhov sib lawv liag ntawm kev ua haujlwm nrog chisel.*
Ua qhov thiab tuav lub chisel
Thaum ua hauj lwm nrog ib tug chisel, xyuam xim rau cov kev taw qhia ntawm lub grain ntawm cov ntoo, vim hais tias nrog ib tug muaj zog tshuab, ntoo yuav tawg nyob rau hauv cov kev taw qhia ntawm lub grain. (fig.1, ib feem6,7).
Thaum peb xav txiav ib qho chaw so rau lub ntsaws nrog lub chisel, peb yuav tsum xub txiav qhov uas ib txwm ua rau cov kev taw qhia ntawm cov fiber ntau thiab tsuas yog tom qab ntawd qhov seem uas yog sib npaug rau cov fiber ntau (fig.1, ib feem2,2/a, 3,3/a). Peb yuav tsum xub muab cov khoom tso rau ntawm qhov chaw ruaj khov kom tsis txhob muaj kev vibration thaum ua haujlwm, clamp nws kom ze li sai tau rau qhov yuav tsum tau txiav, txawm tias peb yuav tsum txav cov khoom thaum ua haujlwm. Thaum ua haujlwm, lub chisel yuav tsum tuav kom ruaj khov, tsis yog los ntawm cov hlau, tab sis los ntawm tus kov nrog koj cov ntiv tes nyob ib ncig ntawm nws.
Ib qhov ntev, nqaim chisel tuaj yeem siv los txiav square qhov tob rau lub ntsaws. Yog hais tias lub ntsaws yuav tsum dhau los ntawm cov khoom siv ces nws yog qhov zoo dua los laum lub qhov los ntawm ob sab ua ke. Tom qab ntawd qhov txiav qhov tob yuav me dua ntawm ob sab.
Ib tug semicircular chisel yog siv los txiav cov voj voog qhib thiab tshem tawm cov npoo ntse ntawm cov ntoo.
Ib feem ntawm lub chisel rov qab cov hniav yog taw tes thiab square-puab, thiab yog siv rau “implantation” nyob rau hauv tus kov. Qhov chaw tshaj plaws uas cov chisels tawg yog qhov tapered nyob rau hauv tus kov. Thaum lub chisel tawg ntawm qhov ntawd, nws yuav siv tsis tau rau kev ua haujlwm ntxiv. Yog tias lub chisel kov tsis ua haujlwm, nws tuaj yeem hloov tau yooj yim. Yog tias muaj kev puas tsuaj rau cov hniav, nws tuaj yeem rov ua dua los ntawm kev sib tsoo.
Tus kov tau hloov kho raws li qhov ua ntej lub chisel yog nias rau hauv tus kov nrog qhov kawg taw tes, tom qab ntawd nws tuav tus kov thiab tuav nws saum huab cua, ntaus rau ntawm tus kov nrog rauj ob peb zaug.
Drilling
Drilling cuab tam thiab npaj
Koj yuav tsum paub xyaum xyaum! Nyob rau saum npoo, drilling zoo li qhov yooj yim tshaj plaws hauv kev ua haujlwm ntoo, tab sis hauv kev xyaum nws tsuas yog tias koj muaj cov cuab yeej zoo. Cov cuab yeej tseem ceeb tshaj plaws rau qhov drilling qhov rau cov ntsia hlau thiab cov ntsia hlau yog rab koob xyaum. Drilling qhov loj dua kuj yuav tsum tau xyaum, raws li kev ua haujlwm nrog rab koob loj dua lossis kev sib tw twist yuav tsum muaj qee qhov kev xyaum (daim duab 2).
Duab 2 — Tes xyaum thiab hom ntoo laum khoom.
Vim tias peb tsis tuaj yeem muaj tag nrho cov cuab yeej hauv peb lub rooj cob qhia me me, nws yog qhov zoo tshaj yog tias peb muab ib qho kev xyaum tes hu ua “American”. Qhov kev xyaum no tuaj yeem ua haujlwm nrog ob qho tib si twist thiab me me twist xyaum. Nws tsis tas yuav tsum tau siv zog ntau los ua haujlwm ntawm tus kov vim yog lub gearing, yog li txawm tias cov neeg tsis paub yuav ua haujlwm tau. Cia peb muab lub hauv paus phaj rau hauv cov khoom uas peb tab tom drilling, txawm hais tias qhov drilling yog ua los ntawm tes los yog lwm yam laum (xav tias lub laum yuav dhau los ntawm cov khoom) thiab tuav txhua yam ua ke kom ruaj khov kom lub laum tsis ntes cov khoom thiab pib tig nws.
Rau cov ntoo drilling, koj yuav tsum xaiv tus lej qis dua. Yog hais tias peb ua hauj lwm nrog ib tug hluav taws xob laum thiab nyob rau hauv lub qis tshaj ntawm revolutions, drilling yuav tsum tau cuam tshuam txhua txhua 15-20 vib nas this. Thaum drilling ceev, ntoo tuaj yeem kub heev uas nws hloov xim thiab txawm tias hluav taws kub. Lub suab nrov, haus luam yeeb nyob rau hauv daim ntawv ntawm ib tug nplua zoo band los yog tsis hnov tsw ntawm ib tug hlawv hav zoov ceeb toom ntawm nws. Tshem tawm ntawm cov khoom siv qee zaus thaum drilling tsis tsuas yog txias me ntsis tab sis pab tau cov chips tawm ntawm lub qhov. Ib nti daig rau hauv lub qhov zoo heev txo qhov drilling efficiency.
Ua ntej pib drilling, qhov chaw yuav tsum tau drilled yuav tsum tau me ntsis indented nrog ib tug ntsia thawv los yog lub qhov punch. Qhov no yog tshwj xeeb tshaj yog tsim nyog rau beginners. Qhov kev taw qhia thawj zaug - hauv cov lus tshaj lij, “kirner” - pab tshem tawm qhov xyaum thaum nws thawj qhov kev hloov pauv. Cia peb them sai sai rau qhov tseeb tias lub hau ntawm lub laum me ntsis tsis beveled ntawm ib sab, vim hais tias nyob rau hauv cov ntaub ntawv no lub qhov yuav loj tshaj qhov xav tau tom qab drilling.
Txiav cov pobzeb loj dua los ntawm cov khoom siv thinner kuj hu ua drilling, txawm tias nws yog hom kev ua haujlwm sib txawv kiag li. Ib rab riam adjustable qhov yog ib qho cuab yeej. Txhawm rau “xov” nrog cov cuab yeej no, nws yog qhov yuav tsum tau ua ntej tho ib lub qhov me me nyob rau hauv nruab nrab ntawm qhov txiav tawm thiab tso lub hau ntawm rab riam rau ntawd. Peb teem lub riam mus rau qhov yuav tsum tau nyob deb raws li txoj kab uas hla ntawm lub qhov peb xav xyaum. Tam sim no peb tig cov hniav ob peb zaug thiab nws pib txav zoo li rab koob ntawm cov ntaub ntawv gramophone, tab sis ib txwm nyob ntawm qhov deb ntawm qhov chaw txiav cov ntaub ntawv (daim duab 3).
Drilling loj thiab qhov muag tsis pom qhov
Duab 3 - Txiav ib lub voj voog nrog rab riam kho tau.
Yog tias cov ntoo yuav tsum tau nkag mus thaum lub sijhawm drilling, qhov drilling yuav tsum pib los ntawm lub ntsej muag ntawm cov khoom. Lub qhov ntawm sab ntawd tseem zoo, txawm tias muaj cov npoo ntse thaum nyob rau sab nraud lub laum me ntsis rips cov khoom thaum nws xyaum. Yog tias peb tab tom drilling lub qhov ntsia hlau nrog lub taub hau los yog lub taub hau countersunk, ces peb yuav tsum siv lub tshuab tho qhov taub kom hollow tawm sab sauv ntawm lub qhov rau lub taub hau ntsia hlau. Yog hais tias peb tsis muaj ib tug tshwj xeeb laum me ntsis rau qhov ntawd, ib tug thicker laum ntsis uas lub ntsis peb yav tas los av rau ib tug loj lub kaum sab xis yuav ua. Kev ua haujlwm drilling yuav tsum tau ua tib zoo kom tsis txhob nkag mus tob rau hauv cov khoom.
Yog tias lub qhov tsis dhau los ntawm cov khoom, ces peb yuav tsum xub kos lub laum me ntsis, nyob rau hauv qhov chaw uas peb xav kom nws nkag mus rau hauv cov khoom (xws li nrog xim mem hluav, ntsia thawv polish, thiab lwm yam). Ua li ntawd peb yuav tsis tas yuav nqa tawm lub laum thiab ntsuas qhov tob ntawm lub qhov (daim duab 4).
Duab 4 - Kos lub laum los tswj qhov tob tob.
Planing
Xaiv thiab sharpening ntawm lub planer
Txhawm rau kom tsis txhob npaj, tib txoj kev xaiv yog yuav cov khoom uas twb tau npaj lawm. Txij li cov khoom zoo li no yeej tsis tuaj yeem tau txais, thiab peb feem ntau yuav tsum tau ua cov npoo, nws yog qhov zoo tshaj plaws kom muaj ib lub tswv yim hauv tsev rhiav. Peb xav tau peb lub planers: ib qho rau roughing (loj planer), ib tug zoo npaj thiab ib tug planer rau grooves. Ntawm peb qhov no, peb tuaj yeem tawm ntawm cov grater loj, vim tias peb yuav tsis tshua muaj qhov xwm txheej los ua cov txheej txheem loj, ntxhib. Thiab thaum peb yuav tsum ua nws, peb tuaj yeem siv lub grater rau kev ua haujlwm zoo. Tau kawg, txoj haujlwm yuav siv sijhawm ntev dua.
Lub plawv ntawm lub planer yog ib tug zoo-sharpened riam (daim duab. 5) nrog ib tug ncaj hniav. Lub kaum sab xis yog 25°. Thaum ua haujlwm, rab riam yuav tsum tau tiv thaiv los ntawm kev ntaus ib yam khoom hlau, xws li. tus ntsia thawv tsis nco qab los yog nws lub shank tuaj yeem ua rau cov hniav puas thiab ua rau nws siv tsis tau. (Yog tias peb tso siab rau txoj kev npaj rau tus kws tsim khoom thiab yog tias vim peb tsis saib xyuas qee tus ntsia thawv zais lossis ib feem ntawm cov khoom siv tseem nyob hauv cov khoom, tus nqi ntawm cov saw lossis rab riam yuav tsum tau them rau txhua daim).
Duab 5 - Qhov tshwm sim ntawm lub phiaj xwm thiab txoj haujlwm ntawm nws qhov chaw.
Cov hniav ntawm lub planer yuav tsum tau sharpened rau ntawm loj sib tsoo pob zeb li sai tau kom cov hniav tsis dented, piv txwv li kom pom tsis tau lub roundness ntawm lub whetstone. Thaum sharpening, peb tuaj yeem siv cov cuab yeej pabcuam, ua los ntawm lub rooj tsavxwm ntawm lub kaum sab xis ntawm 25°, uas peb tuaj yeem tuav rab riam thaum lub sijhawm ua kom zoo, vim tias nws nyuaj rau tus kws tshaj lij los txiav txim lub kaum sab xis ntawm 25°.
Tom qab xuas riam rau ntawm lub pob zeb puag ncig, peb yuav tsum du cov npoo ntawm cov hniav ntawm lub tiaj tus whetstone. Nws yuav tsum tsis txhob hnov qab tias lub luag hauj lwm ntawm lub planer yog flatten lub saum npoo ntawm lub rooj tsavxwm kom zoo nkauj li sai tau, thiab qhov no tsuas yog ua tau nyob rau hauv cov kev tshwm sim hais tias cov hniav yog zoo tagnrho. Lub pob zeb tiaj tiaj tuaj yeem tau txais los ntawm cov khw muag khoom kho vajtse. Ntxig ib rab riam rau ntawm lub pob zeb ntub dej yuav tsum tau ua los ntawm kev rub cov hniav (raws li nrog rab riam niaj hnub) hla lub pob zeb hauv kev ncig. Cov npoo ntse ntawm cov hniav yuav tsum tau muab tshem tawm los ntawm kev xuab zeb kom lawv tsis txhob tawm cov cim ntse hauv cov khoom thaum npaj. Ib tug pib yuav tsum tsis txhob txaj muag rau “nyem” qhov kev paub no los ntawm tus tswv.
Kho rab riam
Cov hniav ntawm lub planer yog tsau nrog ib tug ntoo wedge nyob rau hauv lub qhib ntawm lub planer. Thaum kho, tuav rab riam thiab txiab nrog tus ntiv tes xoo ntawm koj sab laug tes. Nrog rau lub tshuab me me ntawm rauj, uas peb tuav ntawm peb sab tes xis, peb kho cov riam. Qhov no yuav tsum tau ua deftly tuav lub grater nyob rau hauv cov huab cua nrog xibtes thiab lwm yam ntiv tes ntawm sab laug tes.
Cov riam yuav tsum protrude me ntsis ntawm hauv qab ntawm lub planer, thiab cov hniav yuav tsum tau yaug nrog rau hauv qab ntawm lub planer. Nws yog qhov zoo tshaj plaws uas cov riam tsis protrude los ntawm qhov qis ntawm lub planer txhua lub sijhawm thaum ntxig nws, tab sis hais tias rab riam raug kho nrog rauj me me tshuab tom qab ntoo wedge tau kho. Yog hais tias riam sticks tawm ntau dhau, nws tsis ua haujlwm kom nrawm vim nws yooj yim heev txiav rau hauv cov khoom sib sib zog nqus heev. Nws yooj yim dua rau swb rab riam kom koom nrog ntau dua li rub nws rov qab. Nws yog ib qho tseem ceeb uas tapping rab riam ntawm ib sab ntawm cov hniav siv txoj haujlwm kom raug. Qhov kev ua haujlwm no tau ua dua nyob rau hauv “cua” thaum tuav lub grater ntawm sab laug tes (daim duab 6).
- Daim duab 6 — Kho qhov chaw ntawm rab riam.*
Thaum peb xav tshem riam, nws yog ib qho tsim nyog yuav tsum tau ntaus lub nraub qaum ntawm lub cev grater ob peb zaug nrog rauj, tau kawg thaum nws tsa.
Ib qho tseem ceeb ntawm cov grater yog qhov ntxig (cov xeb tawg), uas txuas nrog rab riam nrog lub hau. Lub luag haujlwm ntawm qhov ntxig yog txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau hauv rab riam, nws raug nquahu kom tshem tawm cov khib nyiab pov tseg.
Kev taw qhia thiab txheej txheem
Kev npaj ua haujlwm ua haujlwm raws li hauv qab no: nrog sab tes xis, peb puag sab nraub qaum ntawm lub planer kom tus ntiv tes xoo nyob ntawm sab laug, thiab lwm tus ntiv tes ua ke ntawm sab xis ntawm lub npoo; nrog sab laug tes, tuav lub grater los ntawm lub ntsis - lub hauv ntej kawg ntawm tus kov, thiab tswj lub grater. Sab tes xis muab siab txaus ua hauj lwm. Scrape tus sib npaug los ntawm kev txav lub grater rov qab mus rau hauv cov hlab ntsha loj, tsis txhob tso siab rau lub grater. Thaum rub rov qab, peb khoov lub grater me ntsis ntawm ntug, yog li txuag lub riam.
Koj yuav tsum tau npaj raws li cov qoob loo ntawm cov ntoo, vim tias txawm tias qhov zoo tshaj plaws ntxig tsis tuaj yeem txuag lub rooj tsavxwm lossis lath los ntawm kev sib cais yog tias kev npaj ua tiav nyob rau hauv qhov sib txawv. Kev siv zog ua kom lub rooj tsavxwm teeb tsa kom zoo tsis yog yuav tsum tau khuv xim. Yog hais tias cov kev taw qhia ntawm cov fibers hloov, peb yuav tsum muab lub planer ib txwm nyob rau hauv cov kev taw qhia ntawm lub fiber, yog li ntawd peb yuav npaj tej zaum nyob rau hauv ib qho kev taw qhia thiab nyob rau hauv lwm txoj kev, ib txwm cia lub fibers (daim duab 7).
Qhov nyuaj tshaj plaws yog kev npaj ntawm qhov chaw hla ntu, vim tias rab riam yuav tsum hlais cov fibers thiab yog li ntawd tawg thiab tawg. Qhov no yog qhov kawg ntawm cov laug cam. Hauv cov xwm txheej zoo li no, koj yuav tsum npaj los ntawm cov npoo sab nraud mus rau nruab nrab. Qhov no tsis yog ib txoj hauj lwm yooj yim tshwj xeeb vim tias cov grater rub tes (duab 7, nruab nrab).
Image 7 — Npaj kev taw qhia thiab kev txhawb nqa ntawm lub workpiece.
A tu grater yog siv rau leveling planed nto. Nws yog ib daim duab plaub steel nrog ib tug ntse ntug, uas, tuav nrog ob txhais tes, yog dragged hla lub planed nto thiab yog li ntxuav qhov seem unevenness.
Planing xav kom lub workpiece yuav tsum tau machined clamped ruaj thiab khiav ruaj khov nyob rau hauv cov kev taw qhia ntawm kev npaj, raws li muaj zog jerking tshwm sim thaum machining. Yog li, cia peb muab cov khoom tso rau ntawm lub rooj zaum ua haujlwm, yog tias peb tsis muaj tus kws ntoo lub rooj zaum, thiab khi nws rau ntawm lub hau nrog lub tes tuav. Peb yuav tsum tsis txhob siv lub rooj polished nrog nyias ob txhais ceg ua lub rooj, tab sis peb yuav tsum xaiv lub rooj ua noj hnyav dua. Peb lean lub rooj tiv thaiv phab ntsa los yog, txawm zoo dua, ib sab ntawm lub rooj tsavxwm ua tiav. Txawm li cas los xij, nyob rau hauv rooj plaub no muaj qhov txaus ntshai uas tus ntiv tes xoo ntawm peb sab tes laug yuav tau daig ntawm phab ntsa thiab lub ntsis vim yog inertia.
Kev daws teeb meem: cia peb tso ib lub rooj ntev zaum npog nrog cov ntaub tuab ntawm lub rooj ua haujlwm thiab phab ntsa kom cov npoo ntawm lub rooj thiab lub rooj zaum tsis sib tsoo thiab qhov cuam tshuam ntawm phab ntsa yog maj mam. Tam sim no peb kho lub workpiece nrog clamps rau lub rooj npog nrog ib daim pam. Peb tseem tuaj yeem tso ib daim nyias nyias ntawm cov npoo ntawm lub qhov (socket) thiab phab ntsa (daim duab 7, hauv qab).
Yog tias peb dav hlau hla ntu ntawm cov fibers, peb clamp lub workpiece nyob rau hauv ib lub vise kom cov fibers khiav vertically. Yuav tsum tsis txhob muaj ib yam khoom nyob ze ntawm tes uas tuaj yeem ua mob rau tes.
Rasps thiab ntaub ntawv rau woodworking
Nrog cov ntaub ntawv thiab cov khoom siv, cov ntoo tuaj yeem ua tiav yam tsis muaj kev paub tshwj xeeb. Cov khoom siv no suav nrog cov ntaub qhwv thiab cov ntaub ntawv ntoo. Qhov yuav tsum tau ua tiav yuav tsum tau kho ntawm qhov siab ntawm lub luj tshib (daim duab 8). Peb tuav cov ntaub ntawv los ntawm lub taub hau nrog peb sab laug tes, thiab los ntawm kev tuav nrog peb sab tes xis, thiab nias nws tawm tsam cov khoom npaj, peb rub nws rov qab thiab tawm kom tag nrho qhov ntev ntawm cov ntaub ntawv hla mus rau saum npoo kom tiav. Thaum leveling qhov chaw ntawm qhov chaw, luv luv strokes nrog cov ntaub ntawv ua rau lub hom phiaj. Ib cov ntaub ntawv feem ntau yog siv los ua kom tiav cov npoo, laum qhov, sib dhos, ua tiav thiab ua tiav cov ntu ntawm cov fibers. Ntawm no, ib yam nkaus, muaj peev xwm tawg tawm ntawm ib qho me me lossis loj dua. Yog tias cov khoom siv tau raug ntes ntawm ob daim ntoo zoo sib xws, qhov ua tau ntawm ntug kev tawg yog txo.
Duab 8 - Txoj hauj lwm ntawm lub workpiece thaum npaj thiab ua ntaub ntawv.
Cov resin los ntawm cov ntoo thiab cov shavings me me nrawm nrawm rau cov hniav ntawm cov ntaub ntawv, uas nyuaj rau kev ntxuav. Ib txoj hauv kev los ntxuav cov ntaub ntawv yog siv cov txhuam hlau. Txawm li cas los xij, cov hlau txhuam hniav puas tsuaj rau cov hniav ntawm cov ntaub ntawv, thiab kev ntxuav tseem tsis yog 100%. Ib txoj kev tu kom zoo dua yog muab cov ntaub ntawv tso rau hauv dej kub thiab tom qab ntawd ntxuav nws nrog txhuam tsis tu ncua. Ua li no, cov resin thiab shavings ntawm cov ntaub ntawv yas raug tshem tawm. Tom qab xws li ntxuav, cov ntaub ntawv yuav tsum tau muab so thiab qhuav, txwv tsis pub nws yuav xeb. Yog tias cov ntaub ntawv yuav tsis siv sij hawm ntev, peb tuaj yeem npog nws nrog ib txheej nyias ntawm cov roj, uas peb yuav tshem tawm ua ntej siv dua los ntawm kev xa cov khoom seem.