CLU <Jom' o .
- B9 nQi suy. cap cae l¢nh chuyen dQng may giiJa cac diem diJ Ji¢u de cho chuyen djch dl,lng CI,J.
- Phan cUng cua vong phan hoi ca dieu khien vi tri eho tat d cac ITI,JC chuyen dQng, (; da m6i trI,Jc ca mQt vang liip dieu khien ricng bi¢t.
- Cae vong l~p dieu khitn toc dQ, 6 do yeu du dieu khien toc dQ tic·n.
- Cic m~ch giam gia t6c va khiI ra.
- Dieu khien ChlIc nang h6 trq nhu dang/ngat, lam mat, thay d6i ehuyen dQng banh rang. dieu khien dong/ngat tn,lc ehrnh.
Du!u khicn may cong CI,1 NC 111I!e hi~n dugc bang cach bien dich rna NC
thanh cae I~nh may. Ck rna NC c6 th~ ehia ra thanh 2 nh6m 1611 nhu lhe hi~n trong hinh 3.28.
I. cae lenh dicu khi~n eae thanh phan
may dC1J1 !lhu dieu khitin
d(>ng ca. eh()n t6c d¢
tf'l:lC ehrnh. thay dao,
di~u khitn d6ng/ngal
lucri mal (nhiing nhi~m
vl,1 nay duqe Ih!!e hi~n
bang gui xung di~n toi
h~ thong role hO~le m~ng
dicu khien logie).
2. cae I~nh dicu
Cae kiell !hUi1c
~ 2 Chu~n d6ng th~ng Chuang Innh NC I .j, H! lh6ng !hue hien I I
lIinh 3.28. Philll/oaJ lellll
Cae I!nh
Il<) dieh
SOlcnoil
khicn chuyen vi tUO'ng (Iiiu khii'n cl/II)'eil d¢ng'NC
d6i cua dl,mg el,1 doi voi chi liet. NhU'ng I~nh nay bao gom cae thOng lin nhu V!
trf tfl,1C va khming each phai dich ehuy6n 11;li mQt dan vi Ihai gian Cl,l Ih~. 01l1ng duqc bi~n dich lhanh eac I~nh may dieu khien ehuytn dQng. may eo Ih~ th!!c hi~n duge. Ck I~nh nay duge Ih,!e hi¢n IXri h~ thong dieu khicn cO di~n IU.
M<')I minh hO<;l dUQ'c pMn Ilch qua h~ thong dicu khien 56 eua may phay
CNC. hinh 3.29.
1. CNC
2. XlI II cOng ngh!
3. Xu Ii hinh h9C
4. 9i~u ehlnh dieh eIllnh
5. 9,~u kh'~n lrue
6. G,a 111 hiM !hOi (ho, hoan) Nhap dii lI!u Xli II dii lI!u Xuat dO lil!u
Cac dii li~u rna may cong cl.] dn M ho~t d¢ng va gia cong chi tiet dugc viet thanh chUo'ng tdnh NC nhtjp til bim phim (hlnh 3.29). Ok cac dll' li~u nay duqc
Xl( Ii boi bi) di6u khi~n CNC. Oic dii h¢u cong ngh¢ nhu chQn dao, huang quay
tfl.]C ho~c b~t/tat chat lam mat v ... v. dtIqc CNC xii If theo xfch ho 2- 4 tm. thanh ph{in tuo'ng tIng ciia may cong cl,l CNC. Cac thong tin hinh hQc cua ehuo'ng tr'inh NC dtIqc truyen tir b¢ dieu khi~n CNC vao cac gia th thiet l~p cho cac bQ truy6n dQng dQc trl,lc khac nhau co sl.! can nhac den toc dQ tien dao. Cac chuy~n dich dtra ra cae gia tri vj tri hi¢n thai, lu6n dUQ'c ki~m tra lien tl,lC boi vang kiem v~
tri cua trl.]c an dao va dUQ'c phan h6i theo xfch kin 3~5; trl,lc dl,lng Cl.] 6 -3, bQ vi xu If so sanh vj tr( hi~n thai va gia tri dich. TfI,lc chi dugc dung l<;ti khi vj tri clla trl.]c d~t dtrqc vj to dii l~p trinh.
3.4.2. Cae phuang thire dieu khi~n so (NC)
Cac h~ thong di6u khi~o CNC dUQ'c chia vao 3 lo~i CC1 biin, khac nhau a
cach thl.!c hi¢n ciia chung nhtr sau:
1. Dieu khie'n die'm la di6u khien
ch~y nhanh den m¢t di~m dii ll).p trinh.
Phl,l thuQc vao ki~u b¢ dieu khiefi, cac truycn dQng trJ.]c duqc khCri d¢ng d6ng thCri. ho~c tuan tl.! cho den khi vi trf di~m
dUQ'c thiet l~p (kh6ng co quan h¢ ham). Dieu khi~n diem thuemg hay duqc Slr dl,lng de d~nh v~ nhanh d1,lng cl.] (tuc di
chuyen khong an dao voi toc d¢ cao, (hinh 3.30a) ho~c Slr dl,lng trong may khoan ho~c may him diem.
2. Diiu khlin dl(ang thdng cho phep
dl,lng C1,J. d~ch chuyen song song theo cae
trl,lc may (X, y, Z) voi cae toc dQ gia cong djnh tmac (hloh 3.30b). Tuy nhien, t~i mQt thai gian thi chi m6i mQt truyen dQng tfl,lc dugc dua vao hO<;lt dQng. Di6u khien duemg thing dtrQ'c sir dl.]ng de gia cong cac dU"emg th~ng va cae ranh song
b) £lieu khien dvong
c) £lieu khien bien dang
Hinh 3.30: Car plllMng t/u"tc diell khiin
d~ng trang cae may phay va may ti¢n do'n gian.Cac be) di~u khien duang luon c6 khi nang di~u khi~n diem.
3. IJilu khiln bien d(lf/g (contur) cho phep:
- Dinh vi, khi di chuycn nhanh khong an dao. - An dao thea chi~u trl,!c song song.
- Di chuyen an dao tai bat Cll diem nao trcn chi tiet, nhu thea quy d<,lo th5ng
ho~c tron (hlnh 3.30c).
Dieu khiCn contur co cac muc dieu khien phI,! thuQc truac het la d.c kich thuoc trong khong gian, quan M ham giii'a cac trl,!c M t<:to nen quy d<,lo dl,!ng Cl,!. D6 1a di~u khien contur 2D, 21/2D va 3D, tiep thea 1a sO' trl,!c co kha nang d6ng thai di~u khien, ttl do CNC c6 the 1a b¢ di~u khitn 4 tr~c hoij.c 5 trl,!c. Ok he) dieu khien si'r dl,!ng cho cac may phay CNC ngay nay 1a cae be) 3D.
z
.... "---1"
a)
Hinh 3.31: B¢ Il¢i SIIY
a) nQi suy dIJcmg Ih~ng b) nOi suy cung tron
B(J n(Ji suy
,
•
b)
De thl!C hi~n djch chuyen dong thai cac trl,!c may, cac gia tri trung gian tren dU6ng baa giua diem dau va diem diem cuoi phai duqc be) dieu khien ne)i suy.
BQ m)i suy co cau truc clla mot may tfnh do'n chue nang, duqe Jap tTong CLU, tfnh tmin thea ehl1o'ng trinh duqc clii d~t san tren cC1 sa clla gia tr! to~ dQ
diem dau (dc djnh boi dong I¢nh tren)va to1,\ d¢ gia tri diem dich (de dinh hoi dong I~nh hi¢n th6i) de n¢i suy cae gia tTi trung gian Ung vai quy d~o djeh ehuyen boi dl,!ng Cl,1. Quy d<,lo gia cong thl!e iuon dUQ'e CNC so sanh vm guy d<,lo chuin va dUQ'e hi¢u ehlnh tue thai trong qua trlnh gia cong. BQ ne)i suy thl,l'c hi~n 2 ph6p nQi suy co ban sau:
+ Nqi suy da/mg thdng ( tuyln tinll)
B9 dieu khi~n CNC sc tfnh toan chUDi cac diem thea dUCmg thimg n6i v~ tri
bilt dfiu va V! trf cuoi cua dl;lng CI,I . Ok diem trung gian se duqc tfnh thea:
y==Xt+b. Trong khi dl,lng CI,I chuy~n d¢ng tu diem nay t6i diem khac lhi cac chuyen d¢ng chicu tn:lc luon dugc dieu chinh sao cho d~ng cy. kh6ng di I¢ch so v6i diem do nhicu hC1Il dung sai cho phep (hlnh 3.31 a). cac diem trung gian sc dUQ"c tfnh b:lng cach c¢ng lien tl.]C d.c do<).n th~ng tang them hang nhau vao gia tri to<:1 d¢ ella di6m dau tien.
+ NQi sily duang trim (phi tuye'n)
H¢ thong CNC tfnh toan ehuDi cae di~m theo quy d<;lo duang tron yeu du
'.
vai phep n¢i suy tfeh phan: y == IX(t)dt tIen cd sa to<:1 d¢ diem dfiu tien d1l xae
d!nh. Cac diem nay duqc su dl,lng de sua cae ehuyen d¢ng huang trl,lc sao eho ehuyen d¢ng tron k.h6ng di J¢eh so vai quy d~o duem.g tron chfnh xac va khong VUql qua dung sai cho truae (hlnh 3.31 b).
3.4.3. L~p trlnh NC
ChUC1Ilg trinh NC la m¢t vari ban (text) co cau t<;LO hai cac Cilu chuO'I1g trlnh (I¢nh, tu, dja chi, gia tri) theo m¢t d<;lng thuc (format) xae djnh, chi th~ may cong Cl.] NC thl.Je hi¢n cac nguyen cong el.] the de gia cong m(H chi tiet.
3.4.3.1. Cae phuang phap lap trinh NC
.:. L~p trlnh thll cong
- Thl.Jc hi¢n t<;Ii b;;m giily. vai cong Cl.l t6i thi~u (giay, hULl.
- Chi I~p tdnh duqe cho may eong Cl.] NC el,l the (bo dieu khien Cl.] the). - Su dl,lng s6 tay ebng ngh¢. s6 tay toan hQe va kinh nghiÂm bim than . ã :. L~p trlnh cong xui1ng (ban thll eong)
-L~p tdnh vai sl.J hD trg ella bang may (control panel) bO dieu khien Cl.] the. - SU dl.]ng b¢ so~n thao ehuC1Ilg tdnh "Programeditar".
- Sir dl;lng trg giup ella ky thu~t dO ho?, cae menu, h9i tho?! va kha nang rna ph6ng ella bO dieu khien .
- H¢ th6ng dtI<;1c Sll dl}ng d~ l~p trlnh lil h¢ th6ng CADINC (tuc ph<in rn~rn CAD/CAM), garn cac tlch hqp giao di¢n CAD va b¢ ti~n xii li (preprozessor), b¢ vi Xlc l( (processor), bQ h~u XlI H (postprocessor).
- XU<1t phat ttr CAD-3D, preprozessor chUiln bi thong tin hlnh hQc duai d,.mg cac t~p CAD (CAD- file) cho prozessor.
- Prozessor bien dich diI li¢u hinh hQC va cong ngh¢ thanh t¢p chuC1I1g tdnh NC ngu6n (NC source program).
- Postprozessor sinh chuang trlnh NC v6i ngon ngiI lUang thlch bQ dicu
khi~n cl! th€ thea postprozessor duqc chQn Iva.
3.4.3.2. M. G
Ma G \a cac chuc nang chuan bi, duqc gan bC1i chu G va 2 kf t\! s6. Day W. rna quan tf(;mg nhat trong l~p tdnh NC VI h¢ thong CNC co th~ xlI Ii tn!c tie'p du li¢u to~ dQ thea rna G. M(lt s6, vi dl,l nhu dinh vi nhanh, nQi suy chuy~n d¢ng
th~ng/tron, gia congkhoan da: duqc rna hoa cong nghi¢p (ISO 6983). Cac rna G
daqc phan thanh lo~i nhu sau: