1

CHNG 1: LCH S RA I & PHT TRIN CA MY CNG C CNC

1: S ra i & pht trin ca my cng c CNC

1. Cc giai on pht trin t my cng c thng n h thng CIM

Cc ngn ng

NC: Numerical Control

DNC: Direct Numerical Control

CNC: Computered Numerical Control

CME: Center Machine Engineering

FMS: Flexible Machine System (+ Robotics)

CIM: Computer Intergrated Manufacturing (robotics)

Mechanic + Electronic + Infomatic + Control

CAD: Computer aided Design

CAM: Computer aided Manufacturing

Nm 1949 Vin cng ngh Masachusetts ra i tng iu khin s NC cho my cng

c trn c s:

Ch to nhng chi tit c kch thc ln, bin dng phc tp (VD: khng lc ca Hoa

K)

K thut thng thng i hi nhiu thi gian v tin ca

Bin dng ca chi tit c th c thay th bng cc hm chc nng ton hc

Cn phi ch to b iu khin my phay

o C nhim v bin dch i lng u vo c m t di dng s:

+ Hnh trnh chuyn ng

+ Chc nng vn hnh

o Hiu v x l cc i lng u vo

o Pht lnh iu khin cc c cu chp hnh thc hin gia cng

Nm 1950 ra i my phay ng iu khin s u tin trn th gii (Milling machine)

trn c s s pht trin ca ngnh x l tn hiu in t, iu khin v cp

Cc trc dch chuyn bn my x, y, z c truyn ng bi cc ng c c lp

Thng tin v hnh trnh v cc chc nng my cn thit c ghi trn bng c l vi

dng m ha 0,1 n chng trnh NC

c im c bn ca cc th h my NC u tin:

o Chng trnh gia cng c ghi trn bng giy c l vi m ha chng trnh l cc

ch s ch ci v cc k t c bit

o K hiu s:

+ : du hiu chuyn cng

- : du hiu chuyn tr

NUL: khong trng

0: s 0

1: s 1

2

2:

.

.

.

9: s 9

o My tnh trung tm (iu khin) x l cc thng tin v hnh trnh & chc nng my

o Cc trc chuyn ng chy dao x, y, z (my phay) & x, z (my tin) cng vi trc

chnh c dn ng bi cc ng c ring bit

o H thng o & kim tra lun phn hi v tr ca dng c v trng thi lm vic ca

my v b iu khin

u nm 1970 ra i my CNC: do s ra i, pht trin ca b vi x l & my tnh (PC),

mi my CNC c b vi x l c lp nn c nhiu chc nng mi:

C kh nng lp trnh ti ch cc chi tit c bin dng phc tp

C kh nng m phng ha qu trnh gia cng ngay trn my

Khng cn s h tr ca cc cng c ton hc bn ngoi

Chng trnh gia cng c m ha v ghi di dng cc file d liu

Hin nay vi s pht trin ca ngnh sn xut linh kin vi in t, iu khin s, my cng

c, dng c ct v.v ch to cc trung tm gia cng (CME), h thng sn xut linh hot

(FMS), h thng sn xut vi s tch hp ca my tnh (CIM)

2. Phng hng pht trin ca my CNC

Nghin cu ch to cc trung tm gia cng ng b vi chnh xc cao nht

Gia cng vi tc ct gt cao, khoan vi chnh xc cao nht

Cng giao tip, ngun tin vi cng sut ln, tc cao

Gim khi lng lp trnh cho tng nhim v gia cng

H thng lp trnh n gin, d thao tc, giao din ha, hiu qu cao, m phng ng

tng thch vi cc qu trnh gia cng

Phn tch vi s tr gip ca ha trn cc my CNC v h thng sn xut ni chung

2: Nhim v iu khin my cng c theo chng trnh

1. Nhim v iu khin t ng my cng c

Khi ng, dn dt v kt thc chnh xc cc chuyn ng ca my, chuyn ng trc

chnh, cc chuyn ng chy dao.

Bin i tc , lc, momen hay cng sut trong cc xch ng theo yu cu iu khin

n v chnh xc ca cc i tng chuyn ng (m bo chnh xc chnh xc tng

quan gia dao & phoi)

Trong my iu khin s dng ng c Servo v n nh c s vng quay khi khng

ti cng nh tng ti

3

Ch : gia i lng u vo & i lng u ra ca qu trnh iu khin c xut hin

s tr thi gian

Cc tr lc qun tnh (c tnh hai mt)

Ngn cn lm chm qu trnh bin i tc theo yu cu

Lm tin cc ng cong ni suy

Hnh 1

Cc tr khng ma st, in t v.v, do thng s dng ma st trt trong ma st ln

S nguyn tc mch iu khin n v

Hnh 2

Bn my 3 c ng c v trc vt me y ti mt v tr xc nh

V tr xc nh bi b SS hot ng nguyn tc

Qu trnh y bn my 3 kt thc gi tr x (i lng dch chnh) bng gi tr cn w (i

lng dn), sai lch iu chnh Sw = w x = 0 ng c dng li

2. Cc nguyn l iu khin theo chng trnh

Din bin ca chng trnh c iu khin c th c lp trnh theo mi quan h ph

thuc thi gian v khng gian vo cc i lng vt l thay i: lc, nhit , p sut,

cng sng hay theo thng tin v ta c a ra lin tc t b iu khin s.

iu khin theo chng trnh thi gian

Chng trnh iu khin c lp theo k hoch thi gian xc nh

Cc chuyn ng k tip c iu khin bt chp cht lng ca cc chuyn ng

trc n

Cc chng trnh ny cng v kh thay i

p dng trong cc h c kh c iu khin bng cam

Hnh 3

iu khin theo chng trnh qu o

Chuyn ng k tip s c iu khin ch khi chuyn ng trc n hon thnh trit

Cc chng trnh c tnh cng tuy nhin vn c th thay i trong mt phm vi nht

nh

Khng iu khin phi tuyn

p dng trong my cng c c h thng thy lc & kh nn

Hnh 4

S dng trong h thng thay dao

iu khin theo i lng dn: c tnh lin tc

Ta thay i lin tc ca bin dng trong di chp hnh u d hay cam

p sut, lut, cng sng.

Lp trnh tn km: th, to cam, b tr ng c. i hi cng sut cao => chng

trnh cng kh thay i.

Ta c a ra lin tc bi b iu khin s NC.

4

3. Cc c trng c bn ca my CNC:

Tnh kinh t cao:

Tc gia cng cao, tng ng vi lp cv, cha nhiu dao, t chc sn xut tt

nn thi gian cng tc, thi gian ph gim, do thi gian chu k gia cng nh.

My CNC ph hp vi dng sn xut va, nh k c sn xut n chic.

Hnh 5

chnh xc gia cng cao, cht lng n nh

Ti u ch ct gt, iu kin gia cng tt nn n nh cht lng ca sn phm.

iu khin NC l nguyn tc cao nht cho vic m bo cht lng n nh.

Cp cng sut ca my cao.( 0,001 hoc 0,0005 mm)

Thi gian vn hnh my cao:

Tp trung nguyn cng cao: thc hin nhiu nguyn cng m khng cn thay i v

tr g t.

Cc vn hnh ca my c thc hin hon ton t ng vi tc cao.

Thay dao hon ton t ng, thi gian ngn 3/14s

Tnh linh hot trong sn xut cao:

Thi gian chun b v kt thc sn xut ngn: c lp v khng gian v thi gian hoc

lp trnh trc tip trn my.

Lu tr cc chng trnh gia cng ,cc chng trnh con, chng trnh macro.

C kh nng chun b phi v dng c ct c lp, g lp nhanh.

Tnh nng t ng ha cao:

Cc hot ng ca my hon ton t ng mc cao c iu khin bi my

tnh vi phn mm tch hp.

CHNG 2: CU TRC MY CNG C CNC

3: S iu khin v c im cu trc my CNC

1. S nguyn tc iu khin my CNC

S nguyn tc iu khin:

S (hnh 6)

iu khin theo chng trnh s l phng php t ng iu hnh cc my mc, trong

hnh ng iu khin c tin hnh trn c s cung cp d liu dng m ha bao gm

cc ch ci, ch s, k t c trng hp thnh chng trnh NC.

iu khin NC l phng php t ng ha cc chc nng ca my vi tnh linh hot cao.

Theo thi gian, th h cc thit b thay i, ct b rng buc to hnh qua cc c cu m

tin n m vng m xung lm cn c cho my hot ng.

5

Tnh nng k thut ca my hon ton m rng v cp tc , thu thp v x l hin trng

ca cc c cu chp hnh ( tc trc chnh, tc chy dao, dung dch trn ngui, hot

ng lm mt my v bi trn.

2. c im cu trc CNC

2.1. Phn truyn ng

2.1.1. iu khin chy dao v iu khin quay trc

Cc trc chy dao dn ng bi cc ng c servo c lp c iu khin v iu chnh.

Cc chuyn ng quay tay nh my cng c thng s khng cn.

My tin CNC: C t nht 2 chuyn ng chy dao c iu khin v iu chnh: X & Z

My phay CNC c t nht 3 chuyn ng chy dao c iu khin v iu chnh: X, Y, Z.

Ngoi ra cn c cc chuyn ng quay A,B,C xung quanh cc trc x, y, z.

Cn 5 trc quay v 9 trc thng m t tt c cc chuyn ng: U,V,W ; P,Q,R

Hnh 7: H trc ta

2.1.2. Truyn ng chnh

Cc c cu truyn ng hin i bao gm:

ng c, ly hp c kh chng qu ti, hp tc , phanh kh nn, phanh in t c

iu khin t ng bng in t.

H thng vt me ai c v ng dn hng ma st ln bi lm cho qu trnh lc v

chuyn ng khng c khe h.

Mi trc chuyn ng c cm bin o.

Khuch i cng sut vi thit b gin tip bng s o hoc tng t iu khin

CNC.

Truyn ng chnh:

6

m bo cng sut ct gia cng cc chi tit.

Thng tn tht ms trong cc c cu c kh.

C n nh cao mi chuyn ng ct

ng lc p ng thay i nhanh ca tc ct, khng b rung (3 giy)

S dng ng c in 1 chiu c kh nng iu chnh v cp ( nhng b mn chi than),

ng c in xoay chiu ( bin tn), ng c thy lc .

Tc quay trc chnh: 12.000 20.000 v/ph (my phay) ; 6.000 v/ph (my tin)

2.2. Phn kp cht

2.2.1. C cu kp cht chi tit

Nhim v, chc nng:

nh v chnh xc v tr ca chi tit gia cng.

Kp cht chi tit gia cng, c kh nng chng li c lc ct.

Thay i chi tit nhanh, thao tc n gin.

D dng tip cn v c kh nng lp li vi tc chnh xc cao.

V tr: lp trn trc chnh i vi my tin v trn bn my i vi my phay.

My CNC.

Mi tm kp hp mm tc, tc mt u, mi tm xoay iu chnh c.

ng kp (sanga) khi gia cng cc chi tit nh.

Mm cp thy lc t nh tm, c kh nng hiu chnh li tm khi c s vng quay cao.

Dng phng php i trng mm cp dng thanh chm v dng c cu n by.

Hnh 8

Trc g, bng kp chi tit c l.

Khi g kp chi tit khng i xng vi trc quay cn phi c mm quay c i tng

cn bng.

=> My phay CNC.

o Thit b kp c kh: n kp, gi , bu long kp u ch T.

Hnh 9

o t kp a nng lc kp bng tay.

o t kp kh nn (lc kp khng ln) thy lc c lc kp ln iu chnh c ( t

nh tm hoc khng).

o Kp bng bn t tnh.

o Dng h thng gi modun ( xoay ng h) khng cn thay i g.

o H thng g kp vt bn quay c 2 v tr: g ngoi,

7

Hin i: kt hp robot v mm cp, c cu kp iu khin t ng ng m ( thy

lc hay kh nn) lc kp ph thuc vo trng lng, vt liu, chiu di, ng knh,

chiu su ct

2.2.2. Thit b thay dao trn my CNC

My cng c CNC c h thng thay dao hot ng hon ton t ng, thi gian thay dao

tnh bng giy.

Ph thuc vo dng gia cng v vng chuyn tc th cc thit b thay dao c kh nng ng

thi m nhim 3 nhim v:

Cha, lu gi dng c.

Thay dng c ang c s dng.

Ci t dng c mi c gi bi chng trnh NC vo v tr lm vic.

Thit b thay dao trn my CNC c cc dng chung l: u dng c revonve (my tin) v

cp dao (trn my phay).

a) u revonve

Khi chng trnh NC gi mt dng c mi th u revonve s quay ti v tr g dng

c vi t = 0,2 7s

Ph thuc hnh dng, kch c my, u revonve c th cha 8 16 dng c.

Cc trung tm gia cng tin phong c ln c th c 3 u revonve c s dng

ng thi.

b) cp dao

cp dao vng, xch cp dao.

Dng khi ln hn 48 dao.

Mun thay dao phi s dng c cu thay dao t ng l tang my thay dao t cha

dao vo trc chnh hoc s dng cha dao t hnh.

Hnh 10

S dng tay my thay dao:

Chuyn ng dng c c gi bi chng trnh NC v trc chnh vo v tr thay dao

tc l vo mt phng thay dao.

Tay my tnh tin vo v tr thay dao ri quay 900 kp ng thi dng c trn cha

dao v trn trc chnh.

Phi hp vi trc chnh y dng c ra khi trc chnh v cha dao.

Tay my quay 1800 i ch dng c.

y dng c vo cha dao v vo trc chnh, h thng kp cht trc chnh s kp cht

dng c.

Tay my quay ngc chiu 900 sau li v v tr ban u.

Hnh 11

S dng cp dao t hnh:

8

a trc chnh vo v tr thay dao (mt phng thay dao)

cha dao tin vo kp dng c trn trc chnh.

Trc chnh i ln tho dao.

cha dao quay ti v tr dao mi c gi bi chng trnh NC.

Trc chnh i xung kp cht dao.

cha dao li v v tr ban u

Hnh 12

2.3. Trc chnh & dn hng

2.3.1. Trc chnh

a) My tin CNC

Trc chnh thng c tch hp vi h thng mm cp & kh nn.

Trong mt s trng hp nht nh th trc chnh ca my CNC c th tch hp h thng

ng c in.

m bo kh nng ng hc th c phanh kh nn, phanh in t

Do trc chnh lm vic vi tc cao nn i vi h thng tch hp ng c th phi c

lm mt bng du.

b) My phay CNC

Trc chnh c tc quay rt cao, c th t n 1200020000 (v/ph), nn c h thng bi

trn c bit l khng tun hon nh trn my cng c thng

Trc chnh tch hp vi c cu kp hot ng bng kh nn hay ng c in servo

S nguyn l thay dao t ng

Hnh 13

Tho dng c: kh nn vo xy lanh y piston i xung, nn trc kp p vo l xo, nh

m kp ng thi kh nn vo tm trc y dng c ra khi trc chnh

Kp dng c: a dao vo trc chnh, kh nn vo bung di piston, y piston ln, l

xo a y trc kp ln, m kp i ln kp cht ui dng c.

2.3.2. Dn hng

Ma st trt bi trn t

H s ma st nh, tn hao thp, n nh cao

cng vng cao, gim dao ng v tng tui th

p ng c yu cu gia tc ca chuyn ng chy dao

m bo dch chuyn nh c 1/1000 mm

Hnh 14

Ma st ln

9

Tn hao ma st nh, nhy cao, c th iu chnh khng khe h

c tiu chun ha v m un ha nng cao cht lng & chnh xc thng qua

cc bin php cng ngh & vt liu

Bi trn: Phun sng hay nh git trc tip theo thi gian iu khin

p ng c yu cu gia tc ln, dch chuyn nh, gin on, trnh c ma st trt

kiu bc nhy khi ma st gii hn.

Hnh 15

2.3.3. Trc vt me ai c bi

Chuyn ng chy dao tnh tin thng c dn ng bi cc ng c servo quay do

cn c mt c cu bin chuyn ng quay thnh chuyn ng tnh tin trong my cng

c CNC s dng trc vt me ai c bi

Trc vt me ai c bi bo m truyn lc v chuyn ng khng c khe h, nhy cao

Mi trc vt me c h

thng o, khi o gin tip,

u o lp ngay trn trc

vt me

ai c bi trn my CNC

thng c lp ghp t

hai phn c lp vi nhau, nhm to ra cc kt cu kh khe h & to di ban u

Ghp theo phng dc trc dng trong cc c cu i hi truyn ng chnh xc

Nguyn tc kh khe h

o Gi 2 phn ai c khng c chuyn ng quay nhng to ra dch chuyn tnh tin

o Gi 2 phn ai c khng c dch chuyn tnh tin nhng to ra chuyn ng quay

Hnh 17: Kt cu chnh khe h ai c bi

Ghp theo phng hng knh dng trong cc c cu ch i hi kh khe h & truyn

ng m, nh

10

Nguyn tc

o Sai s v bc ca ai c, trc vt c th c t cn i iu chnh trong qu trnh

vn hnh my, nh b iu khin CNC lu tr cc gi tr o kim tra ca trc vt

& ai c khi ci t my ban u

2.4. H thng o

Vai tr: Tp hp tt c cc trng thi hot ng v cht lng trong trng thi ca c

cu chp hnh

Ngun truyn ng o gm:

H thng o kiu tnh tin

H thng o kiu quay

a) o trc tip (o tnh tin)

Thc o c gn trc tip ln bn dao hay bn my chnh xc truyn ng ca

trc vt me ai c bi, khp ni, b truyn ng dy ai rng s khng nh hng n gi

tr o.

Cc gi tr o c nhn bit trc tip bi cc cm bin quang hc trn vch chia thang

o, bin thnh tn hiu in truyn cho b iu khin

Hnh 18

Nhc im: chu nh hng ca mi trng lm vic

b) o gin tip

Chuyn ng o c thc hin trn trc vt me bi quay

a o c gn trc tip u trc vt me l a pht xung

Cc xung o c cm nhn bi u o, bin thnh tn hiu in chuyn cho b iu

khin

B iu khin tnh chnh xc v tr bn my, bn dao trn xung quay

Hnh 19

Nhc im: chu nh hng ca sai s truyn ng t trc vt me n bn my

4: H ta , nguyn tc iu khin my cng c CNC

1. H ta trn my CNC

Gm 2 h ta : - H ta cc

- H ta cc

1.1. H ta cc

11

Cn c gi l h ta vung gc c dng m t chnh xc tt c cc im ca b

mt chi tit trong khng gian lm vic ca my ng thi cn phc v cho vic lp trnh

NC

H ta 2 trc h ta phng: iu khin 2D

H ta 3 trc h ta khng gian: iu khin 3D

Hnh 20: Cc h ta trn my

H ta khng gian c xc nh theo nguyn tc bn tay phi

Trong iu khin NC th mi im trong khng gian u c xc nh chnh xc theo cc

ta xyz ngay c khi gc ta c tnh tin n v tr

khc nhng phi tun th nguyn tc: Gc ta ca chi

tit gia cng do ngi s dng nh ngha lun phi trng

vi gc ta ca chng trnh NC

Chuyn ng quay xung quanh cc trc x, y, z k hiu :A,

B, C c chiu (+) theo ci vn nt chai

1.2. H ta cc

Thng p dng lp trnh NC cho cc chi tit c bin

dng trn xoay i xng

Bn knh r: khong cch t im xt ti gc ta

Gc : gc gia tia ni im xt & gc ta vi 1 trc

Trong xOy gc l hp vi trc X

Gi tr trong mt phng xOy th chiu (+) l chiu ngc

chiu kim ng h

Quay quanh 0z (chuyn ng trn mt phng xOy) chuyn ng A

Quay quanh 0x (chuyn ng trn mt phng yOz) chuyn ng B

Quay quanh 0y (chuyn ng trn mt phng xOz) chuyn ng C

1.3. H ta my v chi tit

H ta my

H ta my CNC do nh sn xut qui nh & khng th thay i trong qu trnh vn

hnh.

Z

Y

X

O O

Y

X

X Y

Z

X

Y

12

im gc ca h ta my c gi l im 0 ca my (M)

H ta chi tit

H ta chi tit gia cng c xc nh bi ngi lp trnh v c th thay i trong

qu trnh gia cng

im gc ca h ta chi tit l im 0 ca chi tit v c th dch chuyn trong qu

trnh gia cng

lp trnh NC cn phi gi nh

Trn my CNC khi gia cng chi tit ch c dng c chuyn ng cn chi tit lun ng

im

H ta s dng khi lp trnh NC lun da vo h ta ca chi tit gia cng

1.4. Ghi kch thc theo nguyn tc NC

Ghi kch thc tuyt i: mi kch thc lun lin quan n im 0 ca chi tit (chun

thng nht) (hnh a)

Ghi kch thc tng i: lun s dng chui kch thc ni tip (hnh b)

Hnh 21: Cch ghi kch thc trn my CNC

u im ca ghi kch thc tuyt i so vi tng i

Dung sai kich thc khng b tch ly

Thay i ca tng kch thc khng lm nh hng kch thc khc

Mt kich thc sai khng dn ti li cc kch thc khc

Cc ta tuyt i (G90) ch ra khong hnh trnh dch chuyn ca dng c ct do

d dng xc nh c cc bc lp trnh ring l cn cc kch thc tng i chnh l

hnh trnh chy dao ca cc bc gia cng. Do d dng xc nh c cc bc lp

trnh ring l gia bn v gia cng v chng trnh NC

Trng hp cn phi ghi kch thc tng i (G91) l gia cng cc chi tit c bin

dng lp i lp li, VD: khi tin rnh cnh nhau ca chi tit van thy lc

a)

b)

13

2. Cc im tham chiu trn my CNC

2.1. K hiu cc im tham chiu

im khng ca my: M (Machine zero point)

im khng ca chi tit: W (Work part zero point)

im hiu chnh dng c: B (Tool setup point)

im tham chiu ca my: R (Reference point)

im chun ca dng c: E (Tool reference point)

im g dng c: A (Tool shank point)

im thay dng c: N (Tool change point)

2.2. im khng ca my M

Mi my cng c CNC lm vic trong h ta nht nh v gi h ta l h ta

my

im gc ca h ta my c gi l im khng ca my, k hiu l M im M l

do nh sn xut quy nh nn khng thay i trong qu trnh gia cng

2.3. im tham chiu R

H thng o ng dch chuyn kiu tng i cn c mt im vt l hiu chnh phc

v cho qu trnh iu khin dng c v dch chuyn chi tit

im hiu chnh h thng o l R

R c xc nh mt cch chnh xc bi gii hn chuyn dch ca mi trc vt me

Ta ca im R so vi M l lun khng thay i v c nh sn xut ci t trong b

nh ca my

Sau khi khi ng my phi c s tip cn R t mi trc chuyn ng h thng iu

khin dch chuyn chun li h thng o

2.4. Khng gian lm vic ca my

L vng khng gian m dng c c th tip cn i tng gia cng, thng thng n s l

1 hnh hp ch nht c 2 nh i din l im M & im c ta xmax, ymax, zmax

Ph thuc vo kch thc ca my v chiu di cng tc trc vt me

Trn mt my c th c nhiu im chun R

Cc v tr khc nhau ca im tham chiu trong khng gian lm vic ca my.

14

Hnh 22: Khng gian lm vic ca my

2.5. im 0 ca chi tit: W

2.6. im chun ca dng c ct E

L mt im c nh trn u dao Revonve (tin 0), trn u trc chnh (phay)

iu khin CNC phi to ra lin kt gia im chun ca dng c ct vi tt c cc im

ch gm:

Mi dao tin

Tm mt u dao phay

Cn phi xc nh chnh xc cc kch thc hiu chnh dng c ct ca dao tin & dao

phay

o dng c cng vi cc g dao bn ngoi bng thit b o hiu chnh dng c hoc o

trc tip trn my CNC nh cc dng c o quang hc

Thit b o quang hc c g lp ti mt im c nh trn my CNC, ta c lu tr

trong b iu khin

Dng c g lp trn u dng c hay trc chnh, di chuyn ti im chun ca thit b

o bng tay quay in t

H iu khin tnh ton gi tr hiu chnh v nhp trc tip vo b nh hiu chnh dng

c

Thit b o hiu chnh dng c bn ngoi my CNC

Dng c g lp trn u dng c ca thit b o, di chuyn ti im chun ca thit b

o

Gi tr hiu chnh c c trn mn hnh ca thit b hiu chnh v nhp bng tay vo

b nh ca h iu khin

2.7. im hiu chnh dng c ct B

Phc v vic chun b dao bn ngoi my CNC

B: im hiu chnh dng c ct

L: khong cch t im hiu chnh n mi ct theo z

Q: khong cch hiu chnh theo phng X

R: khong cch mi dao (tin), khong cch dao phay (phay)

15

2.8. im g dao A

L im chun xc nh v tr g dao, n nm trn u revonve ca my tin hay trn

u trc chnh ca my phay

Nu h thng dng c ct (gm cn g dao & dao) c g t vo c cu mang dao th

im hiu chnh dng c ct B & im g dao A trng nhau to ra im chun dng c ct

E

2.9. im thay dao A

L im thuc khng gian lm vic ca my cng c CNC

Ti im ny c cu thay dao s thc hin chuyn ng thay dao m khng xy ra va chm

vi cc b phn khc ca my cng c CNC

2.10. o & hiu chnh dng c trc tip trn my

o dng c trc tip trn my CNC

Chi tit (phi) v dng c c g trn my

R chm dng c vo cc im c trng ca bin dng chi tit nhm xc nh mi

tng quan vi im 0 ca my, gi tr o c ghi vo b nh hiu chnh dng c

Lm tng t vi cc dao khc, ti v tr thc mi ca cc dao, b iu khin s tnh

ton gi tr hiu chnh cho cc dao & dng c tip theo

o song song dng c vi dng c tiu chun trn my phay CNC

Vi dng c chun (dng c s 0), gi tr z o c khi r vo b mt chi tit g trn

my c ci t bng 0

Dao tip theo c lp v r vo chi tit, gi tr tc thi ca z s c nhp vo b hiu

chnh dng c tng ng vi tng con dao.

Sai lch chiu di ca cc dng c vi chiu di dao tiu chun chnh l gi tr hiu

chnh chiu di dng c

2.11. H ta chi tit gia cng trong h ta my

H ta chi tit gia cng trong h ta my

H iu khin s nhn bit v hin th nhng ch tng ng ln mn hnh

C 2 h ta m h iu khin CNC tip nhn

Gin tip: S dng cc lnh di chuyn gc ta G54 G59 km theo l cc ta X,

Y, Z l khong dch chuyn gc ta t gc ta my n gc ta chi tit

16

Hnh 23: H ta gin tip trong h iu khin CNC

Trc tip: Ci t trc tip gc ta chi tit gia cng W. V tr ca im W so vi gc

M v cc gi tr 0 hin th trn mn hnh.

3. iu khin CNC & iu khin DNC

3.1. Mch iu khin kn, mch iu khin h

Mch iu khin h

H iu khin a ra cc gi tr cn vo my cng c v khng trc tip iu chnh gi

tr ny.

Mch iu khin s dng trn my CNC c ngun ng lc l ng c bc, khng c

h thng o

Hnh 24: Mch iu khin h

Mch iu khin kn c phn hi

Do qu trnh iu khin b nhiu ngu nhin nn c th cho tn hiu u ra khng chnh

xc

Tn hiu u ra lin tc c phn hi v h iu khin

H iu khin lin tc tnh ton & iu chnh li cc gi tr thc theo yu cu iu

khin ch cc trc ca my CNC

Hnh 25: Mch iu khin kn

3.2. iu khin CNC

X

Y

W1

W2

W3

41 2

3

41 2

3

5

1 Tn hiu vo 2 Tn hiu ra 3 Tn hiu nhiu 4 Qu trnh bin i

1 Tn hiu vo 2 Tn hiu ra 3 Tn hiu nhiu 4 Qu trnh bin i 5 Thit b o

17

Nhim v iu khin CNC

Gii m chng trnh NC

X l cc thng tin c lin quan:

+ Thng tin v cng ngh

+ Thng tin v hnh dng hnh hc

+ iu khin & iu chnh cc c cu chp hnh nhm hnh thnh chi tit gia cng

m bo cht lng

Hnh 26: Trnh t iu khin CNC

Chc nng ca h iu khin CNC

Nhp d liu

+ Trn bng iu khin (bn phm, mn hnh): lp chng trnh, qun l d liu, m

phng qu trnh

+ Chng trnh NC nm trong file d liu c th lu trn b nh ngoi: bng t, a

mm, USB, CD

+ Lin kt vi bn ngoi thng qua cng giao tip, mng n my ch

X l d liu: Ly thng tin t chng trnh NC iu khin, iu chnh vn hnh c

cu thc hin vic gia cng chi tit

+ D liu cng ngh: Chn dao, vng quay trc chnh, chiu quay cc lng chy dao,

chiu su ct, dung dch trn ngui (h lnh ng ngt, tng ng qua b iu khin

thch nghi)

+ D liu hnh dng hnh hc: Chng trnh NC c h CNC bin dch, tnh ton cho

tng bc tng trc chuyn ng ng thi hnh trnh chuyn ng ca dng c ct

cng lin tc c iu chnh bi h iu khin kn c phn hi nhm to ra bin dng

ca chi tit gia cng

Xut d liu: lu, in, truyn d liu, iu khin cc c cu chp hnh

S cu trc tng qut CNC hin i

1

2

3 5

4

6

CNC

X

YZ

1 iu khin CNC 2 X l cng ngh 3 X l hnh hc 4 iu khin thch nghi 5 iu khin v tr cc trc 6 Gi tr thc ca v tr

18

Hnh 27

3.3. iu khin DNC

L bin dng iu khin trong c nhiu thit b nh my NC, CNC, thit b o c ni

mng vi nhau cho php loi b vt mang tin, cc thit b c ghi:

Thit b o, hiu chnh & chun b dng c ct

Cc vt tr lp trnh

H thng qun l dng c, vt liu

c im

My tnh ch thng qua thit b giao tip qun l v sp xp thng tin ng lc & chnh

xc

Xc nh thng s ca my & d liu gia cng cng vi d liu lu tr

iu khin t xa

Chc nng c bn ca iu khin DNC

Lu tr & qun l chng trnh NC, h thng

Phn phi chng trnh NC n my gia cng

Tip nhn cc chng trnh NC sa v ti u ha cc my cng c

Chc nng m rng

Qun l cc thng tin v dng c v hiu chnh dng c

iu hnh chi tit gia cng & cc tm g

Phn chia thi gian cc bc gia cng

iu hnh dng vt liu (kho lu tr vt liu)

An ton d liu

M phng

Kim tra d liu ca my v ton x nghip

Lu tr chng trnh NC vi bin dch Post processor

u im ca h thng DNC so vi CNC

T chc sn xut tt hn

Truy nhp nhanh chng trnh v cc thng tin h tr

Gim thi gian chun b kt thc

Gim li nhp d liu

Qun l tt lu tr sn xut (Tcng tc, Tphc v, Tdng my)

bo tr h thng & bo li

5: Cc chuyn ng ni suy, cc dng iu khin qu o trn my CNC &

Cc ngun lc my cng c CNC

19

1. Cc chuyn ng ni suy, cc dng iu khin qu o trn my CNC

1.1. Cc dng ni suy

Dng ni suy chuyn ng thng

L dng c chuyn ng theo ng thng t im xut pht n im ch m khng

song song vi bt k trc chuyn ng chy dao no.

t c qu o thng ca dng c, chuyn ng ca cc trc chy dao phi c

xc nh tun t theo 1 t l nht nh (X, Y, Z)

Dng ni suy chuyn ng cung trn

Dng c di chuyn t im xut pht ti im ch theo qu o cung trn.

+ Thun chiu kim ng h

+ Ngc chiu kim ng h

m bo qu o la cung trn th cc dch chuyn ca trc chy dao phi c xc

nh lun lun trong tng quan qung ng dch chuyn

Mi trc chuyn ng chy dao li chuyn ng theo dng sin hay cos kt hp thnh

cung trn

S ni suy dng cung trn

Hnh 28

1.2. Cc dng iu khin qu o CNC

H iu khin CNC nhn thng tin t chng trnh NC, x l v xut tn hiu iu khin

cc ng c truyn ng truyn ng phi hp to thnh hnh trnh dch chuyn ca dng

c chnh xc

Cn c vo dng hnh trnh dch chuyn ca dng c ct ca chi tit s phn bit dng iu

khin qu o:

iu khin im

iu khin on

iu khin ng: + iu khin 2D

+ iu khin 2D

+ iu khin 3D

1.2.1. iu khin im

Dng iu khin n gin nht

Dch chuyn iu khin vi tc nhanh (G00) ch yu thc hin qu trnh nh v, khng

tham gia cng ngh

Dch chuyn ca cc trc c thc hin c lp

Dch chuyn ca trc Z (chuyn ng n dao) c iu khin ring

Khoan, khot, doa, taro, hn im, dt dp

Hnh 29

1.2.2. iu khin on

Dch chuyn ca dng c vi lng chy dao xc nh lun song song vi cc trc

Bin dng chi tit ch c th l cc ng song song hoc vung gc

20

Ch yu gia cng cc b mt song song vi bng my

Tin tr, tin mt u, phay mt phng song song, phay rnh.

Hnh 30

1.2.3. iu khin ng

Dch chuyn ca dng c vi lng chy dao S xc nh theo ng thng hay ng cong

trong mt phng hay trong khng gian (khng song song vi bt k chuyn ng chy dao

no)

Bin dng chi tit c thc hin bi vic iu khin ng thi 2 hay nhiu ng c chy

dao ng thi

Cc im trung gian gia im xut pht v im ch c tnh ton bi b iu khin

trn c s cc ng cong ton hc

Hnh 31

a) iu khin 2D

L 2 trc chy dao iu khin ng thi

Dch chuyn ca dng c trn mt phng, qu o l ng thng, cung trn

My phay CNC ni suy 2 trc cn trc th 3 l tin dao vi my tin CNC ni suy trn

trc X, Z

b) iu khin 2D

Dch chuyn dng c trong mt phng, ni suy c tin hnh mt trong ba mt phng

chnh ti tng thi im

Hnh 32

Ty thuc vo mt phng gia cng (mt phng ni suy) cc trc chy dao s c iu

khin tng ng

Ti mt thi im trn mt phng ni suy ch c 2 trc c iu khin ng thi cn trc

th 3 coi l trc tin dao

c) iu khin 3D

3 trc chy dao c ni suy ng thi

Dng c chuyn ng trong khng gian 3D

Gia cng cc b mt c bin dng phc tp

Phn ln my CNC l 3D

Ch to khun mu, ch to dao v cc b mt phc tp

2. Cc ngun ng lc c bn ca my cng c CNC

2.1. ng c thy lc

S dng ch yu trong giai on pht trin ban u ca my NC

iu khin v cp cc c cu chp hnh: trong my NC iu khin bng cc loi van servo

Cng sut ng c c th t ti 100kw

Hn ch do h thng thy lc cng knh, kh iu khin, t tin

2.2. ng c 1 chiu

21

iu khin v cp cc c cu chp hnh

n = f (Ukch t , Iphn ng)

Cng sut ng c thng s dng t 0,36kw

ng c in 1 chiu servo (DC servo motor) c chi than, nn c hin tng mn chi

than

ng c in 1 chiu servo khng c chi than, c tch hp h thng phn hi tc

2.3. ng c bc

iu khin v cp: iu khin bng cc xung in, bc gc cho mi xung iu khin nh

Hn ch v cng sut: 0,22kw

2.4. H thng ng c bc thy lc

ng c bc ng vai tr b iu khin, ng c thy lc ng vai tr b khuch i

(servo)

Hn ch: kt cu phc tp, cng knh, iu khin kh

2.5. ng c in xoay chiu 3 pha (AC servo) n = 120v/ph

iu khin ng c v cp da trn c s bin i tn s

Dng kh ph bin trong chuyn ng chy dao ca my cng c CNC

n = 120f / P vi f tn s ; P s i cc

Cng sut c th t hng trm Kw

Hn ch: b iu khin ng c phc tp v t tin

3. Nguyn l cu to chung ca ng c bc

3.1. Khi nim ng c bc

ng c bc l mt h thng ng c bc in ng vai tr b bin i s tng t

u vo l s lng xung v tn s xung, u ra l gc quay v tc gc

Cu truc gn, h thng iu khin khng cn h thng o

Bc gc t 0,750 - 1,80 - 7,50 - 150 - 300 - 900

Cc loi ng c bc s dng trong my CNC

ng c bc PM (Permanent Magnet stepper motor) roto l nam chm vnh cu

ng c bc VR (Variable Reluctance stepper motor) roto c cu to t st non c

kh nng dn t cao

ng c bc kiu hn hp (hibride stepper motor) kt cu c 2 thnh phn c bn

ca c 2 loi trn

3.2. Nguyn l cu to

R to:

Vt liu t, c s rng cc Zr

R to gm nhiu h thng ghp ng trc pha

Stato:

C s rng cc stato Sz: gc chia rng l z

Trn cc rng cc c cc cun dy t ha

Stato gm nhiu h thng ghp ng trc, lnh pha v

22

Hnh 33

Nguyn l hot ng ca ng c bc

Mi xung in s lm r to quay 1 bc gc tng ng

Cc rng cc i din vi t trng chu tc ng ca M quay ty thuc vo v tr ca

n vi t trng (rng cc ca Stato)

Rng cc r to s c v tr n nh khi n nm i din vi rng cc stato c kch t

4. Cc ng c bc in

4.1. ng c bc PM (r ro bng nam chm vnh cu)

Trn stato c cc cp cun dy pha lp i xng, hnh thnh cc cp cc t tng ng

Trn r to l nam chm vnh cu c 1 cp cc t

Cp in U vo tng cp cun dy s lm r to quay theo tng ng

Bc gc v = 3600 / zs vi zs s rng stato

Hnh 34

4.2. ng c bc VR (r to c nhiu rng cc)

Trn mi stato c cc cp cun dy pha lp khng i xng, hnh thnh cc cp cc t

tng ng (khng i xng) ng thi cc stato b tr lnh pha nhau

R to l thp non hay vt liu dn t cao c s rng Zr

Cp xung in U vo tng h thng stato, t trng trong cc cp cun dy tng ng s

lm r to quay theo chiu ngc li

v = 3600/Zr . S hay zr /S = v

Hnh 35

4.3. ng c bc kiu hn hp

Trn cc stato c cc cp cun dy pha lp khng i xng, ng thi lin kt gia cc

stato vi nhau hnh thnh cc cp cc t tng ng zs

Trn r to (thng l 2RT) l thp non hay vt liu c kh nng dn t cao c b tr 2

u ca trc nam chm (RT c t ha) c cc rng cc i nhau zr > zs

Cp in U vo tng pha ca cc stato, t trng trong cc cp cun dy s lm r to quay

theo tng ng theo chiu ngc li

Hnh 36

5. Nguyn l h thng ng c bc thy lc

5.1. ng c bc thy lc

ng c bc truyn chuyn ng quay cho c cu iu phi servo thy lc, iu khin

ng c thy lc chuyn ng quay tng ng vi ng c bc

ng c thy lc c th thc hin chuyn ng quay hay chuyn ng tnh tin vi c cu

o phn hi

Hnh 37

5.2. ng c bc thng

Khai trin rng cc stato v r to trn mt phng stato l thn my, r to l bn my

23

Cp cc xung in U vo cc cun dy ca thn my

Bn my dch chuyn tng bc tnh tin ph thuc vo chu k pht xung

Hnh 38

CHNG 3: KHI QUT LP TRNH NC

6: Cu trc lp trnh trn my CNC

1. Lp trnh th cng v lp trnh my

Lp trnh th cng

Chng trnh NC c vit trc tip theo h iu khin CNC c th

Thi gian lp trnh ty thuc vo phc tp hnh hc ca chi tit v kh nng ca h

iu khin

Kh nng mc li rt d xy ra v kh nhn bit, hin nay kim tra ngi ta thng

s dng cc phn mm m phng kim tra chng trnh

Lp trnh bng my (my tnh v phn mm chuyn dng)

S dng h thng phn mm ng b t thit k n to lp chng trnh NC cng

vi phn mm m phng qu trnh gia cng

H tr vic tnh ton ta v tnh ton cc thng s cng ngh

C th vin v cc thng s ca dng c ct, thit b g kp,

C h tr ti u ha qu trnh gia cng

C th vin v cc loi my cng c CNC, cng cc h iu khin tng thch

Cc bc lp trnh my

Thit lp hnh dng hnh hc ca chi tit v phi (CAD)

Xc nh cc bc gia cng, phn mm h tr la chn dng c & cc thng s cng

ngh tng ng vi vt liu c la chn lm phi ca chi tit gia cng

M phng qu trnh gia cng, la chn my cng c CNC, la chn h iu khin sau

xut ra file NC v a ra my CNC gia cng

2. Nguyn tc cu trc lp trnh trn my CNC

2.1. Tiu chun ha lp trnh NC

Chng trnh NC cha cc thng tin v h lnh ng i v h lnh ng ngt

Chng trnh NC hnh thnh t mt chui cc cu lnh, n c dng iu khin my

cng c CNC

Cc lnh m ha di dng ch s, ch ci v cc k t c trng

Tiu chun ISO-6983 qui nh gii hn chung ca cc lnh cng nh cu trc c bn

ca chng trnh NC

Cc nh sn xut h iu khin m rng phm vi m ha ca cc lnh NC c th cho

ring h iu khin ca mnh trn c s qui nh chung ca ISO-6983

2.2. Cu trc c bn chng trnh NC

24

Bt u chng trnh (VD: % Phay 018): Mc ch d dng qun l, lu tr v truy

nhp khi cn thit

N c bt u bng k t c trng do nh sn xut h iu khin qui nh (%)

Tip theo l tn ca chng trnh do ngi s dng t gm 6 k t bao gm cc ch

ci v ch s

Thn chng trnh

Bao gm cc cu lnh c sp t theo trnh t nht nh gia cng chi tit ti u

nht

Cc cu lnh cha cc thng tin v hnh hc, cng ngh v k thut ca chng trnh v

ca my

Thng thng mt cu lnh phi cung cp y thng tin cho mt bc gia cng

Kt thc chng trnh

Chng trnh c kt thc bi lnh M30 & M02

Cn lu rng cc ch thch v din gii t trong ngoc n s c h iu khin b

qua khi thc hin chng trnh

2.3. Cu trc cu lnh, t lnh

Cu trc cu lnh

VD: N0035 G01 X10.01 F100 S2000 M08 LF

u tin l s th t ca cu lnh N0035, ch c cp 1 ln trong 1 cu lnh. N khng

lm nh hng n tc ng ca tng cu lnh

iu khin hnh trnh dch chuyn ca dng c ct G01 cng vi 2 ch s qui nh qu

o chuyn ng ca dng c ct

Ta im ch X10.01, Y, Z cng vi cc con s l ta ca im ch m dng c di

chuyn n.

Cc thng s ni suy: I, J, K cng vi cc con s l ta ca tm cung trn theo gi tr

tng i vi im xut pht

Lng chy dao F100 cng vi cc con s n dng iu khin tc dch chuyn ca

dng c ct, mc nh l mm/ph hoc mm/vng

Tc quay ca trc chnh S2000 c s dng iu khin s vng quay ca trc chnh

theo v/ph

Chc nng ph tr M08 l chc nng ca my dng iu khin cc thng s cng ngh,

c nhp vo sau cc t lnh F, S, T trong 1 dng lnh c khng qu 3 chc nng my

Chc nng dng c ct T06 dng ch nh dng c ct c s dng, ngha ca a

ch ny khng ging nhau trong cc h iu khin v thng c 2 nhim v c bn:

Gi dng c c ch nh trong cha dao

Truy cp kch thc hiu chnh dng c ct trong b nh my

Cn lu cc con s ty thuc vo cc ch ci iu chnh s c ngha l mt m lnh

hay la mt ga tr khi n c th c gi tr m, dng ca con s ty thuc vo quy nh

ca tng h iu khin khc nhau

25

Thng thng c 3 nhm t lnh trong 1 cu lnh: iu khin hnh trnh, cc ta ch,

cc chc nng cng ngh v ph tr

Cu trc t lnh

T lnh c hnh thnh t mt ch ci v cc con s

ngha v trnh t ca cc t lnh c qui nh trong tng h iu khin (do nh sn xut

qui nh)

7: M lnh c bn khi lp trnh

1. c im

Tiu chun quc t ISO 6983 quy nh mt b m (ISO code) cho cc my NC, CNC

iu khin qu trnh gia cng c kh

Chng trnh NC lp theo ISO l mt tp k t c c php ring

c lu gi trn a mm hay a cng

c lp bng tay vi s h tr ca mt h son tho vn bn no

hoc lp t ng (bng phn mm lp trnh t ng trn my tnh ni vi h iu khin

ca my CNC)

2. Cc chc nng iu khin v k t m ha

26

27

3. Cc lnh dch chuyn v chu trnh

M Chc nng M Chc nng

G00 Chuyn ng chy dao nhanh G75 Chy n n im mc ca trc th 3 v th 4

G01 Dch chuyn ct thng (chuyn ng ni suy ng thng vi lng chy dao xc nh)

G79 Chu trnh tin rnh

G02 Chuyn ng ni suy cung trn cng chiu kim ng h G80 Hy b chu trnh chn

G03 Chuyn ng ni suy cung trn ngc chiu kim ng h G81 Chu trnh khoan l thng

G04 Thi gian gia cng G83 Chu trnh khoan l su

G14 Cu lnh nhy v lp li G84 Chu trnh taro l

G17 Gia cng theo mt phng XY G85 Chu trinh doa l

G18 Gia cng theo mt phng XZ G86 Chu trnh khot l

G20 i n v o ra mm G87 Chu trnh phay l vung

G21 i n v o ra inch G88 Chu trnh phay rnh then

G22 Gi chng trnh con G89 Chu trnh phay l trn

G23 Lp li on chng trnh G90 Kch thc tuyt i

G26 n dao 100% G91 Kch thc tng i

G27 Chuyn ng chy dao qu m G92 t b nh

G28 Chuyn ng chy dao dng chnh xc G94 Lng chy dao mm/pht

G29 Cu lnh nhy c iu kin G95 Lng chy dao mm/vng

G40 B ch hiu chnh dao G96 Tc ct theo m/pht

G41 Hiu chnh dao theo bn knh bn tri ng bin dng G99 Bin dng chi tit gia cng

G42 Hiu chnh dao theo bn knh bn phi ng bin dng X_, Y_, Z_ Ta theo trc X, Y, Z

28

G43 B dao m theo qu o ct I_, J_, K_ Ta tm cung trn theo ta tng i X, Y, Z

G44 B dao dng theo qu o ct S_ S vng quay ca trc chnh (v/ph)

G45 Vo v ra dng c song song vi bin dng F_ Lng chy dao

G46 Vo v ra dng c theo cung trn T_ Ch nh dng c

G47 Vo v ra dng c theo cung trn M06 Thay dng c

G53 Hy b lnh x dch im chun (im 0) chn M03 M trc chnh quay phi

G54,G59 Dch chuyn im chun (im 0) M04 M trc chnh quay tri

G62 nh v v tr nhanh M07, M08 M dung dch trn ngui

G63 S dng 100% lng chy dao M09 Tt dung dch trn ngui

G64 Thay i s vng quay M30 Kt thc chng trnh

G70 Chy dng c n v tr ra theo trc Z

G73 Chay dao theo lp trnh

G74 Chy n n im mc ca trc th 1 v th 2

29

CHNG 4: MY PHAY IU KHIN THEO CHNG TRNH S

8: c im cu trc & H ta cho my phay CNC

1. c im cu trc

1.1. Cc c im kt cu phn bit cc my cng c iu khin CNC vi cc my cng c

thng

Hnh 39 : My phay thng thng

Hnh 40: My phay CNC

1.2. c im ca cc ng c truyn dn

Truyn ng chnh: ng c dng mt chiu hoc dng xoay chiu

ng c dng mt chiu: iu chnh v cp bng dng kch t

ng c dng xoay chiu:

iu chnh v cp tc bng b bin i tn s

Thay i s vng quay n gin, momen truyn ti cao

Khi thay i lc tc dng, s vng quay vn gi khng i

30

Truyn ng chy dao: ng c dng mt chiu v dng xoay chiu vi b vitme ai c bi

cho tng trc chy dao c lp X, Y, Z

ng c dng 1 chiu c c tnh ng hc tt cho cc qu trnh gia tc v qu trnh

phanh hm, moomen qun tnh nh, chnh xc iu chnh cao cho nhng on ng

dch chuyn chnh xc

B vt me/ ai c/ bi c kh nng bin i truyn dn d dng, t ma st v khng c

khe h khi truyn dn vi tc cao

1.3. Gii thiu bng iu khin ca my phay CNC

Hnh 41 : Tng th bng iu khin

Hnh 42: H thng cc nt iu khin

a) Cng dng ca cc nt iu khin

1-Cng tc la chn ang vn hnh ; 2-Chc nng ng ngt; 3-Ngt in t iu khin; 4-

ng in t iu khin; 5-Phm ngt mch in khn cp; 6-Cc chuyn ng chy dao

(ct phoi); 7-Chuyn ng trn cc trc X, Y, Z theo chiu + v - dng tt c cc trc; 8-

Trc chy dao nhanh n v tr nh v; 9-Tc chy dao; 10-Cc chc nng ha trc

iu khin C; 11-Cc chc nng ha v hm trc iu khin C

Truyn ng chnh: 12-S vng quay trc chnh; 13-Trc chnh quay (tri v phi); 14-

Dng quay trc chnh; 15-Kp dao v tho kp dao; 16-Cng tc cha kha ct gi

chng trnh; 17-Bi trn bng tay; 18-ng v ngt mch bm dung dch trn ngui; 19-

31

Dng chu k hoc dng chng trnh; 20-Khi ng chu k hoc khi ng chng trnh;

21-Ch th i dao; 22-i mch cho c cu kp dao (ng vi trc phay nm ngang/thng

ng)

Bng nt bm (t nt 7 n 18) trng thi vn hnh Graphic u lm vic vi 2 chc

nng

b) Cng tc la chn dng vn hnh

2-t b im gi tr thc ; 3-i ti

im chun; 4-Vn hnh phng chng

(bc nhch 0,01mm); 5-Chy dao

theo dng vn hnh phng chn; 6-

Chy dao theo dng vn hnh n nh;

7-Cp lnh bng tay trong tng cu

lnh; 8-Chy chng trnh theo tng

cu lnh ring l; 9-Chy chng

trnh theo cu lnh k tip; 10-Hiu

chnh thng s cho dao; 11-Np

chng trnh thng qua cc phm bm; 12-Danh mc thng s (la chn); 13-Qun l

chng trnh; 14-Vo-ra chng trnh; 15-Vn hnh DNC (la chn); 16- ha v cc d

liu v my

c) Bn phm

Hnh 44: Bn phm

2. H ta my phay CNC

2.1. H ta chi tit i vi my phay CNC

Trc Z ca h ta nh hng theo trc chnh ca my, hng t chi tit ln dng c

Trc X song song mt phng kp, hng theo tay phi khi ng trc my

32

Trc Y l trc cn li ca h ta phi

im 0 ca chi tit do ngi lp trnh xc nh nhng u tin 2 trng hp sau:

Trng hp 1: nm mt trc, pha trn, bn tri

Trng hp 2: nm mt trc, pha di, bn tri

Xc nh nhanh chiu trc ta : dng lut bn tay

phi: ta t ngn gia ca bn tay phi theo chiu ca

trc Z th ngn tay ci s tr theo chiu trc X v ngn

tay tr s ch theo chiu trc Y

2.2. Nhng im quan trng trong mt h ta

im chun: l im gc 0 ca h ta my

im 0 chi tit: l im gc 0 ca h ta chi tit, n c gi c nh cho mt chi tit

im 0 lp trnh: l im gc 0, t xc nh cc d liu cp nht trong mt chng

trnh. im ny c th thay i thng qua lnh dch chuyn im 0

2.3. Chun ha li cc bn v

Trn mt bn v, thng cc s o kch thc khng c a vo trc tip, chng phi

c tnh li tm ra cc thng tin v ng dch chuyn dng cho lp trnh. B iu

khin cng thun tin th d liu np vo cng n gin. Nh s dng cc h thng lp

trnh thch

hp,

thng cc

vn t

ra c

gii quyt

mt cch

n gin.

Trong

trng hp

ch c mt

h thng

lp trnh

cha mc thun tin cn thit, ta phi tin

hnh theo cc bc sau y:

Chuyn cc kch thc o theo chui thnh cc

kch thc o tuyt i (hnh 47)

Tnh ton thm cc ta cha r

33

9: Lp trnh cho my phay CNC

1. Lp trnh theo kch thc tuyt i, tng i

1.1 Lp trnh theo kch thc tuyt i

Lp trnh theo v tr im ch

Lnh dch chuyn: G90

im ch c cc gi tr ta lun c gn vi im 0 ca chi tit (W) l gc kch

thc xc nh v tr ca cc im ch

V d:

Lp trnh tuyt i ch D

Lp gi tr im ch

P X Y

P0 P1 10 10

P1 P2 10 70

P2 P3 20 70

P3 P4 20 10

P4 P1 10 10

P1 P0 0 0

Vit thnh cu lnh

G00 X10 . Y10 . ;

G01 Y70 . F80 ;

X20 .

G02 Y10 . R30 . F50 ;

G01 X10 . F80 ;

G00 X0 . Y0 ;

Ch :

Sau tr s ca ta th phi vit du chm (.) my hiu n v l mm, kt thc

cu lnh th phi vit du chm phy (;)

Khi ct gt theo cung trn th ngoi ta im ch phi vit gi tr ca bn knh

cung hoc thng s ni suy I, J, K

Cu lnh G01 xut hin 1 ln v c duy tr cho n khi c mt cu lnh ch bin

dng G02, G03 hay G00 ph nh n

Cc ta X hoc Y im ch trng vi ta X hoc Y im u th khng cn

nhc li

Lp trnh ch J

34

Lp gi tr ta im ch

P X Y

P0 P1 10 70

P1 P3 50 70

P3 P2 40 70

P2 P3 40 25

P3 P4 10 20

P4 P0 0 0

Vit thnh cu lnh

G00 X10 . Y70 . ;

G01 X50 . F80 ;

X20 . F120 ;

X40 . Y25. F80 ;

G03 X10 . Y20 . R15 . F50 ;

G00 X0 . Y0 ;

Lp trnh ch C

Lp gi tr ta im ch

P X Y

P0 P1 50 50

P1 P2 10 50

P2 P3 10 30

P3 P4 50 30

P4 P5 0 0

Vit thnh cu lnh

G00 X50 . Y50 . ;

G03 X10 . I20. J0. F50; ;

G01 Y30 . F80 ;

G03 X50 . I20 . J0 . F50 ;

G00 X0 . Y0 ;

1.2. Lp trnh theo kch thc tng i

Lp trnh theo gia s

Lnh dch chuyn: G91

im ch c cc gi tr ta lun c gn vi dng c ct n trc

Ch :

+ Khi lp trnh chi tit tin th phi thay i a ch: X chuyn thnh U, Y chuyn thnh W

+ Khi lp trnh phay vn gia nguyn

V d:

Lp trnh ch D

35

Lp gi tr im ch

P X Y

P0 P1 10 10

P1 P2 10 60

P2 P3 10 0

P3 P4 0 -60

P4 P1 -10 0

P1 P0 -10 -10

Vit thnh cu lnh

G00 X10 . Y10 . ;

G01 Y60 . F80 ;

Y0 .

G02 X0. Y-60 . R30. (J-30.I0). F50 ;

G01 X-10. Y0. F80 ;

G00 X-10. Y-10 ;

2. Tc chy dao F

Nh b cng tc hiu chnh lng chy dao (override-contactor) m nhng lng chy dao

lp trnh c th chn li c m khng cn thot ra khi chng trnh ang chy (hiu

chnh gim ti O% hoc tng ti 25%

3. S vng quay trc chnh S (vng/pht)

Trn my phay FP2-NC c cc cp vng quay sau y lp trnh: 0- 31.5 40 50

63 80 100 125 160 200 250 315 400 500 630 - 800 1000 1250

1600 2000 2500 3150

Nu gi tr d liu np vo khong gia hai cp th b iu khin s ng mch t ng

cho s vng quay thp hn k bn

S+0: dng khi khng ng mch quay trc chnh trong vn hnh iu khin (t vo ch

chy khng)

Chn chiu quay trc chnh

Trn my FP2-NC, trc chnh quay phi S+, quay tri S-

Trn cc may c th dng lnh M03 cho trc chnh quay phi, M04 trc chnh quay tri

Lnh dng trc chnh S0 khng c du pha trc

4. Chng trnh gia cng

Trn my FP2-NC chng trnh bt u vi k t % v mt s hiu chng trnh

4.1. Cu lnh

Cc cu lnh c s l k tip nhau (VD: s vng quay trc chnh hay ng bin dng

dch chuyn)

Mt cu lnh thng c bt u bng ch ci N v s th t cu lnh (c th la chn t

N0 N9999)

36

S cu lnh khng nh hng n th t x l cc cu lnh trong mt qu trnh gia cng.

Trnh t gia cng do c xc nh bi trnh t cc cu lnh

Mi cu lnh c dng 1 ln trong chng trnh, nu khng ch s dn n nhiu lon

qu trnh tm cu lnh hoc qu trnh nhy tr li chng trnh sau mt gin on

Hnh 48: V d v cu lnh

4.2. T lnh

Mi lnh ring l lm vic cho my c gi l t lnh

Mi t lnh = mt a ch + mt con s.

Con s ny c ngha nh 1 m s . VD: G00 chy nhanh

Nh 1 gi tr . VD: X100 im ch trn trc X; F200 tc chy dao 200mm/ph

Trong mt s b iu khin, khi lp trnh, nhng t lnh c cc s 0 ng trc con s

c ngha c th b bt

VD: N0001 = N1; G00 = G0

Chng hn

Ngoi cc ch ci biu th a ch cn c cc k t c bit cng c in ra hay cc k t

khng c in ra m ch phc v cho b nh d liu

K t c bit c th cng c in ra Cc k t khng in ra

K t ngha K t ngha

% Bt u 1 chng trinh LF Ht cu

( Bt u mt ch DELL Xa

) Kt thuc mt ch NUL Du cch

+ Cng

- Tr

. Chm thp phn

T lnh ca mt cu lnh c xp vo cu lnh theo mt trnh t xc nh gi l c php

37

VD: N01 G00 X15 Z2 S+1000 M08

Mi t ca cu lnh l mt lnh iu khin my

Lnh c hiu lc tc dng ko di cho n khi n b xa hoc b thay th bi mt lnh

c cng ch ci v cng a ch gi l phng thc tc dng MODAL

Lnh ch c tc dng trong bn thn cu lnh cha phng thc tc dng Theo cu lnh

5. Cu trc mt chng trnh

thit lp mt chng trnh cn c cc bc:

1. Chia bin dng thnh cc yu t bin dng hnh hc n gin

2. Chia qu trnh gia cng thnh cc bc gia cng (theo d liu cng ngh)

3. To lp chng trnh

4. Np trnh vo b iu khin

5. Chy th chng trnh (simulation)

6. Khi ng chng trnh

7. B iu khin thc hin gia cng chi tit

10: Cch vn hnh, Hiu chnh i vi my phay CNC

1. Vn hnh theo h DNC

Trong nguyn tc vn hnh DNC, cc my CNC c mt thit b in ton trung tm

cung cp trc tip cc chng trnh gia cng

Cc chng trnh gia cng c ghi nh trn cc a t v c np vo my in ton

trung tm, t n c th c truyn i thng qua cc ng dy chuyn ti d liu n

cc b nh ni ti ca h CNC (hnh 54). Ta gi l dng vn hnh DNC (Direct

Numerical Control)

38

Hnh 51: My CNC trong ch vn hnh DNC

2. Cc chc nng hiu chnh

2.1. Hiu chnh chiu di dao

Hiu chnh chiu di dao c ci t khi trong chng trnh c nhiu dao c chiu di

khc nhau (Hnh 52). Chiu di thc ca dao s c so vi dao chun v c ci t vo

trong b nh v s c b trong qu trnh gia cng cu lnh.

Hnh 52: Hiu chnh chiu di dao

M lnh hiu chnh chiu di dao l:

G43: Hiu chnh theo chiu dng

G44: Hiu chnh theo chiu m

Trnh t hiu chnh:

Chn dao chun (Standard tool) c b nh hiu chnh bng 0

So chiu di cc dao vi dao chun

a vo b nh s liu hiu chnh c ch n du

Cu lnh:

G43 Z. H

39

Khi hiu chnh chiu di dao, gi tr hiu chnh c ghi vo b nh v s c thm vo

gi tr Z c lp trnh c ch n du

VD: H2: C gi tr hiu chnh 10.0

H3: C gi tr hiu chnh 20.0

G90 G43 Z100. H1; Z s t ng chuyn ti gi tr Z110

G90 G43 Z100. H2; Z s t ng chuyn ti gi tr Z120

2.2. Hiu chnh bn knh dao

Khi lp trnh gia cng theo bin dng

chi tit th phi tnh ton sao cho

ng i ca dao ch c tip cn

ng bin dng gia cng (Hnh 53)

V vy lp trnh n gin v

chng trnh gia cng khng b l

thuc vo mt bn knh dao phay,

trong my NC dng lnh hiu chnh.

Vi lnh ny, h thng iu khin

bin dng NC s t tnh ton bin dng dao phay (khong cch tng ng) vi vic hiu

chnh bn knh dao phay cho php lp trnh ng bin dng gia cng khng ph thuc

vo bn knh dao phay.

Khi bt u vo gia cng chi tit nu ta

nhp cc kch thc bn knh dao khc

nhau vo h iu khin, th trc khi bt

u gia cng, h iu khin s t tnh

ton ng tm dao phay hiu chnh

dao tin ti tip cn bin dng ct

chnh xc v h iu khin cn c

thng bo l dao bn phi hay bn tri

ng bin dng gia cng thng qua

chgn trnh gia cng vi iu kin dch

chuyn

2.3. Hiu chnh bin dng Lnh G41/G42

G41: Gi hiu chnh bin dng, dao

lm vic pha tri bin dng theo hng

ct phay

G42: Gi hiu chnh bin dng, dao

lm vic bn phi bin dng theo

hng ct phay (hnh 55)

Lnh tin ti tip cn (hnh 56)

G45 Tin ti tip cn theo ng song song

G46 Tin ti tip cn theo na cung trn (ng knh ca cung trn ti thiu l 0.02mm)

40

G47 Tin ti tip cn theo mt phn t cung trn (bn knh ca cung trn ti thiu l

0.02mm

Hnh 56 Cc cch tip cn bin dng

2.4. c tnh chy trn bin dng G60 / G61 / G64 (Hnh 57)

G60 dng khi gia cng tinh cc gc bn trong theo kch thc (dao chy theo bin dng

vng gc trong chy thng vo gc dng mt lc, chy tip)

G61 dng lp trnh khi gia cng th cc gc bn trong (dao chy ti vng gc trong

theo mt cung chuyn tip bn knh cung chuyn tip khong 0,4mm khi Rdao < 4mm,

Rdao>4mm th Rcung chuyn tip > 10%Rdao)

G64 Dao ct chy trn bin dng qu ph thuc vo tc ct. Cc bn my theo trc

iu khin khng b dng gia tng cu lnh ring bit

Hnh 57 c tnh chy trn bin dng

2.5. Ti u ha chy dao M60 / M61 / M62 (Hnh 58)

M60 chy dao khng i trn ton bin dng (lng chy dao s c hn ch khi phay

cc gc bn trong v s tng ln khi phay cc gc bn ngoi gia cng tinh )

M61 lng chy dao khng i trn bin dng, t ng gim bt khi ct ra gc ngoi

M62 chy dao khng i trn trc dao

41

Hnh 58 Ti u ha chy dao

2.6. Xa lnh hiu chnh bin dng

G40 xa lnh hiu chnh bin dng

H iu khin cn i hi cc lnh:

G45 chy thot khi bin dng theo ng song song

G46 chy thot khi bin dng theo na vng cung trn (ng knh ca cung chy thot

dao ti thiu l 0.02mm)

G47 chy thot khi bin dng theo mt phn t cung trn (bn knh ca cung chy thot

dao ti thiu l 0.02mm)

Hnh 59 Cch thot ra khi bin dng ct: a) thot theo ng song song b) thot theo

ng cung trn c) thot theo ng cung trn

VD: Dao phay tr mt u 40

Hnh 60 Chi tit gia cng vi kch thc o tuyt i

42

%1 S hiu chng trnh

N1 G17 T1; i dao, gi cc gi tr hiu chnh dao,

hiu chnh chiu di theo trc Z

N2 G00 X5. Y-22. Z2 Chy nhanh vo v tr xut pht

F500 S+1600;

N3 G00 Z-7; Chy nhanh iu chnh n Z-7

N4 G41 G45 X16. Y16. Gi hiu chnh bin dng, dao ct bn tri bin dng theo hng

G01 G60 M62; ct phay

N5 G01 Y35. ;

N6 G01 X53. Y65 ;

N7 G01 X90. Y35. ;

N8 G01 Y16. ;

N9 G01 X16. ;

N10 G40 G45 Xa lnh hiu chnh bin dng

N11 G00 Z2. ; Dao chy nhanh thot khi chi tit

N12 G00 Y120. Z120. S0 Dao chy nhanh t do v trc chnh dng

N13 M30 Kt thc chng trnh

11: Ni suy vng v ngha ca vic s dng my CNC i vi cc x

nghip cng nghip

1. Ni suy vng G02 / G03 trong h ta cc

Bin dng gia cng phi nm trong mt mt phng chnh (Hnh 61 & 62)

Hnh 61: Cc mt phng chnh Hnh 62: Cc hng quan st

1.1. Lnh G02 theo chiu kim ng h

43

Lnh G03 ngc

chiu kim ng h

my FP2-NC,

dch ng cung

trn nh nht l

0.02mm v ln

nht l 16000mm

1.2. Khi gia cng trn

mt XY th ta

im kt thc trn

trc X v Y (o

tuyt i) cn

c a ra (hnh

63)

- Nu kch thc trn bn v cha ph hp th phi tnh ton li cc ta . Nu tnh sai v

khi lp trnh t im ch lch ra ngoi cung trn th trn mn hnh s bo li s 95

- Sai lch cho php ti a: 0.06mm

- Nu cung trn tnh ton khng ng khng c gia cng chi tit khng b hng

- Nu cung ni suy l ton vng

trn th im kt thc ni suy

khng cn lp trnh

1.3. Cc thng s ni suy I, J, K

(hnh 64)

- L ta ca tm cung trn k t

im bt u bin dng cung trn

- D liu o lun lun t im bt

u cung trn n tm cung trn

- Lun l ng vung gc, khng

bao gi l ng cho.

- Khng l thuc cc gi tr ta ca im kt thc cung trn

- Cc thng s ni suy xc nh v tr ca tm vng trn theo tng trc ring le

I ta tm o theo trc X

J - ta tm o theo trc Y

K - ta tm o theo trc Z

Ch : Trong phn chng trnh, trc khi ni suy vng ta phi lp trnh y :

+ S vng quay trc chnh (trong h ta cc)

+ S vng quay trc chnh v lng chy dao (trong h ta cc)

44

Nu khng c tc ng ca s vng quay trc chnh v lng chy dao th h iu khin

khng thc hin cc lnh G02 / G03

V d:

- Hnh 65

G17 T1;

G00 X10. Y25. Z2. S+3150;

G01 Z-5. F120;

G02 F250 I20. J0.;

G00 Z2.;

G00 Y100. Z100.;

M30;

- Hnh 66

G17 T1;

G00 X40. Y60. Z2. S+3150;

G01 Z-10. F120;

G02 F250 X15. Y35. I0. J0.;

G00 Z2.;

G00 Y100. Z100.;

M30;

2. Cc yu t chuyn tip G7/ G8

Khi s dng cc yu t

chuyn tip phi ch

(Hnh 67)

- Ch lp trnh c trong

phm vi mt lnh hiu

chnh bin dng

- Hai b mt c mt im

ct chung

- Cc b mt phi ln hn bn thn yu t chuyn tip

- Cung chuyn G7 c t tip tuyn (khng gy khc, khng nhn thy b cnh)

- Mun lp trnh cho mt yu t chuyn tip, buc phi tn ti mt trong s chuyn ng

G01/G02 hoc G03 sau khi gi v trc khi xa lnh hiu chnh bin dng

Mt bin dng c th c gc ln ti im giao nhau gia:

45

- Hai ng thng

- Mt ng thng

v mt cung trn

- Hai cung trn

(Hnh 68)

V d: Dao phay

16 mm (Hnh 69)

N01 G17 T1;

N02 G00 X-40. Y-50.

Z2. S+2000 M08;

N03 G00 Z-10. F200;

N04 G42 G45 A2 X-40.

Y-37. G01 G60

M62;

N05 G01 X40. ;

N06 G08 R10. ;

N07 G01 Y31. ;

N08 G07 R7.5. ;

N09 G01 X-4. Y37.;

N10 G01 X-30. ;

N11 G01 Y12.5. ;

N12 G07 R5;

N13 G01 X15. ;

N14 G02 X15. Y-12.5. I0. J-12.5. ;

N15 G01 X-40. ;

N16 G07 R5. ;

N17 G01 Y-37. ;

N18 G40 G45 A2;

N19 G00 Z2. M09;

N20 G00 Y100. Z100. ;

N21 M30;

2. ngha ca vic s dng my CNC i vi cc x nghip cng nghip

46

Nh ng dng ca k thut vi in t, phng php cng ngh ny c nhng u, nhc

im ng ch :

1. u im c bn

chnh xc lm vic cao

Thng cc my CNC c chnh xc my l 0,001 mm, do c th t c chnh

xc gia cng cao hn

Cht lng gia cng n nh, chnh xc lp li cao

Tc ct cao

Nh cu trc c kh bn chc ca my, nhng vt liu ct hin i nh kim loi cng hay

gm oxit c th s dng tt hn

2. Thi gian gia cng ngn hn Cc u im khc

Tnh kinh t cao ngay c vi chi tit gia cng lot nh

t phi dng my v k thut, tiu ph khi phi dng

my nh

Tiu hao kim tra t, gi thnh o kim gim

Thi gian hiu chnh my nh

Khng cn dng cc g v dng (v d g khoan)

C th gia cng hng lot

3. Nhc im

Gi thnh ch to my cao hn

Gi mua my t hn

Gi thnh bo dng, sa cha my cng cao hn

Vn hnh my phc tp hn

Thay i ngi ng my kh khn hn

4. Cc yu cu t ra

Cn c s phi hp cht ch gia cc khu thit k,

chun b sn xut v thc hin gia cng ch to

Cn o to nng cao cho th chuyn mn. Mt kha

o to v k thut CNC l phi c, v my mc ch

hot ng tt nu ngi s dng c kin thc thun thc