Lap Trinh Tien Cnc

TRNG I HC CNG NGHIP TP.HCM KHOA CNG NGH C KH B MN CAD/CAM-CNC

TP.HCM 07-2013

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CHNG 1 C S LP TRNH NC

1.1. Chng trnh NC Bao gm chui ch th di chuyn dao, ch th ng ngt v ph tr cn thit iu khin my t ng thc hin cng vic gia cng. C nhiu nh dng ca mt chng trnh NC, ph bin nht l nh dng a ch lnh (word address format). nh dng bao gm cc m lnh (commands) c truyn n h thng servo, rle, cng tc thc hin cc tc v gia cng. Cc m lnh lin kt nhau to thnh khi lnh (Block). B iu khin my s thc hin cc thao tc iu khin theo tng khi lnh mt. Kt thc mt khi lnh s c du kt thc khi (EOB). Cu trc ca mt chng trnh CNC c minh ha nh sau: a) a ch lnh (Address): L ch ci alphabet u lnh, ch th v tr lu tr d liu s theo sau. Bng 1. Cc a ch lnh:

Nhm lnh a ch ngha

S hiu chng trnh O S hiu chng trnh

S th t khi lnh N S th t khi lnh

Lnh G G Phng thc ni suy chuyn ng

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Kch thc X,Y,Z Trc chuyn ng tnh tin theo ta tuyt i

U,V,W Trc chuyn ng tnh tin tin theo ta tng i

I,J,K Ta tm cung trn

R Bn knh cung trn

Tc chy dao F Tc chy dao

Tc trc chnh S Tc quay trc chnh

Chn dao T S hiu dao

Lnh ph M Lnh ng/ ngt (ON/OFF)

b) T Lnh (Word): L chui k t, s, ch th mt i lng iu khin nht nh. V d:

N10 : s th t khi lnh G01 : ni suy ng thng X2.0: ta phng X F300: tc chy dao T0100 : s hiu dao M09 : ngt bm dung dch trn ngui,

c) Khi lnh (Block): L chui cc lnh y thc hin mt th tc di chuyn hoc mt tc v hot ng ca my. Khi lnh c coi l n v c bn ca chng trnh NC. Cu trc in hnh ca khi lnh nh sau: N__ G__ X__ Z__ M__ S__ T__ EOB(;) V d: N05 G21; : h mt N10 G00 X0 Z0; : ta tuyt i, chy dao nhanh n (0,0) N15 G00 U30. W20.; : ta tng i, chy dao nhanh n (30,20) N20 G01 X20. Y40. F120.;: ta tuyt i ni suy ng thng n ta

(20,40), tc chy dao 120 mmpm

S th t khi lnh

Lnh G Lnh kch thc Lnh ph Lnh tc trc chnh

Lnh chn dng c ct

K t kt thc khi lnh

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N30 U-30. W-10.; : ta tng i, ni suy ng thng n ta (-30,10)

N40 G00 X0 Y0; : ta tuyt i, chy dao nhanh v (0,0) d) Cu trc chng trnh NC: C 2 lai chng trnh:

- Chng trnh chnh (main program) - Chng trnh con (subprogram): L chng trnh ph c gi t

chng trnh chnh, thng dng khi trong chng trnh chnh c nhiu on lp li.

Cu trc tng qut ca chng trnh NC bao gm: - u tp tin (Tape start): k t (%) khai bo bt u tp tin

chng trnh. - Nhn tp tin (Leader section): tiu tp tin chng trnh. - u chng trnh (Program start) : k t khai bo bt u chng

trnh. - Thn chng trnh (Program section): cc lnh gia cng. - Ch thch (Command section): ch dn hoc ch thch cho ngi

vn hnh. - Cui tp tin (Tape end): k t khai bo kt thc tp tin chng

trnh.

1.2. Cc phng thc lp trnh NC

Theo s tr gip ca my tnh i vi lp trnh, c th phn bit 2 phng thc lp trnh NC: Lp trnh trc tip (khng c tr gip ca my tnh) v lp trnh t ng (c tr gip ca my tnh). a) Lp trnh trc tip:

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Ngi lp trnh c th t bin son chng trnh NC trn c s nhn dng hon ton chnh xc ta chy dao. Thng s dng cho cc trng hp gia cng n gin. Vic truyn chng trnh NC vo b nh ca h iu khin my bng 2 phng php:

- Nhp t cc thit b ngoi: a mm, bng t, cng giao tip (hnh a)

- Nhp t Panel iu khin theo ch MDI (Manual Data Input) (hnh b)

b) Lp trnh t ng: Ngi lp trnh s dng ngn ng h tr lp trnh hoc phn mm CAD/CAM nh cng c tr gip chuyn i t ng d liu hnh hc v d liu cng ngh thnh chng trnh NC. C 3 phng php:

- Lp trnh bng phn mm NC (hnh a) - Lp trnh bng ngn ng x l hnh hc: APT (hnh b) - Lp trnh bng phn mm CAD/CAM

1.3. Lp trnh theo cng ngh CAD/CAM L phng php lp trnh t ng ph bin nht hin nay. Phng php lp trnh ny cho php ta to nn c cc chng trnh gia cng nhng chi tit

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rt phc tp mt cch d dng, chnh xc. V c bn, CAD/CAM bao gm 2 thnh phn.

- CAD : xc lp hnh hc chi tit gia cng, to nn m hnh vt th cn gia cng bao gm: cc im, ng, b mt, khi.

- CAM : s dng d liu hnh hc sn phm to ng chy dao v thc hin chc nng qun l v iu khin sn xut nh lp trnh ch to, lp k hoch sn xut, qun l cht lng, hoch nh ngun lc sn xut,

Quy trnh lp trnh NC theo cng ngh CAD/CAM gm cc bc c bn sau:

a) Thit k mu gia cng trn phn mm CAD b) Xc lp tin trnh gia cng c) La chn cng ngh gia cng NC (phng thc chy dao) cho tng

bc gia cng d) Xc lp thng s NC cho chc nng gia cng NC tng ng e) Thc thi trnh x l i vi chc nng gia cng NC to ng chy

dao (toolpath generation) f) Thc thi trnh hu x l (post processing) bin dch d liu chy dao

thnh chng trnh NC (M G, M).

1.4. Nhp/xut chng trnh NC Phng php nhp/xut chng trnh NC ph bin hin nay l dng ng truyn trc tip RS-232-C nhp/xut d liu t my tnh sang my CNC v ngc li.

Nhp/xut d liu qua RS-232-C

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CHNG 2: LP TRNH TIN CNC

2.1. Cc im chun trong my tin CNC

Ngi vn hnh my tin CNC cn quan tm n 3 im chun chnh: im khng ca my (Machine zero - M) do nh sn xut quy nh, im khng ca chi tit hay phi (Workpiece zero - W) do ngi lp trnh xc nh, v im thay dao (Tool change point).

2.2. H to trong my tin CNC

Tt c cc my tin CNC s dng h thng to hai chiu bao gm hai trc:

Trc c bn trc nm ngang k hiu l Z.

Trc th hai trc vung gc k hiu l trc X.

Qui c cch xc nh chiu trong my tin CNC hai trc.

My tin CNC 10T l loi my thuc h thng ta tay tri.

Hng nhn

Hng nhn

a) H thng ta tay phi b) H thng ta tay tri

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2.3. Lp trnh theo ng knh v bn knh

Trong tin CNC, cc bn v chi tit thng cho kch thc ng knh hn l bn knh. thun tin trong vic lp trnh h iu khin CNC cung cp cho chng ta c hai phng php lp trnh kch thc theo phng X: lp trnh theo ng knh v bn knh. Nh vy gi s phi c ng knh 100mm, dch chuyn dao ct ra khi phi nu s dng to tuyt i phi ghi l X100. Vi phng php lp trnh theo bn knh ta ghi l X50. Thng xc nh phng php lp trnh theo ng knh hay bn knh cn chnh cc thng s trong h iu khin my. ch mc nh ca my l lp trnh theo ng knh.

2.4. H to tuyt i v tng i trong tin CNC

Tng t nh phay CNC, c hai cch xc nh to trong qu trnh di chuyn dao: to tuyt i v tng i. Mt s h iu khin s dng lnh G90 v G91 khai bo, mt s khc nh h iu khin FANUC s dng t kho a ch X, Z trong lp trnh tuyt i v U, W trong lp trnh tng i.

Ta im xc nh theo phng php tuyt i nh hnh v di y nh sau:

A (X4,Z2) theo bn knh hay theo ng knh l A (X8,Z2)

B (X3,Z-7) theo bn knh hay theo ng knh l B (X6,Z-7)

C (X2,Z-9) theo bn knh hay theo ng knh l C (X4,Z-9)

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Ta im xc nh theo phng php tng i nh hnh v trn nh sau:

A (U4,W2) theo bn knh hay theo ng knh l A (U8,W2)

B (U-1,W-9) theo bn knh hay theo ng knh l B (U-2,W-9)

C (U-1,W-2) theo bn knh hay theo ng knh l C (U-2,W-2)

2.5. Cc b phn c bn ca my tin CNC

H thng dng c tin CNC ni chung bao gm thnh phn sau:

u g dao

Mt s kiu dao tin CNC

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2.6. Cc quy trnh tin CNC

Bao gm cc quy trnh c bn sau:

Facing (Kha mt) Turning (Tin thng)

Profiling (Gia cng mt nh hnh) Grooving (Tin rnh)

Drilling (Khoan)

Threading (Gia cng ren)

Cutting off (Ct t)

2.7. Cc lnh tin NC c bn

Lnh G:

Lnh G s dng trong cng ngh tin v c bn c chia thnh 2 nhm. Nhm A c s dng vi h iu khin Nht, nhm B s dng vi h iu khin M. y, chng ta ch tm hiu v h iu khin FANUC ca Nht.

Lnh G Chc nng

G00 nh v nhanh khng ct gt

G01 Ni suy ng thng vi tc F

G02 Ni suy ng trn theo chiu kim ng h (CW)

G03 Ni suy ng trn ngc chiu kim ng h (CCW)

G20 H n v Inch

G21 H n v Mt

G28 T ng tr v im chun my - M

G30 Tr v im chun th 2,3,4

G32 Lnh tin ren

G34 Lnh tin ren vi bc tin ren thay i

G40 Hy b b tr bn knh mi dao

G41 B tr bn knh mi dao v bn tri

G42 B tr bn knh mi dao v bn phi

G50 Ci t gc ta hoc ci t tc ct ln nht

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G70 Chu trnh tin tinh (chu trnh hn hp)

G71 Chu trnh tin tr th (chu trnh hn hp)

G72 Chu trnh tin mt th (chu trnh hn hp)

G73 Chu trnh tin chp hnh (chu trnh hn hp)

G76 Chu trnh tin ren hn hp

G90 Chu trnh tin trc n

G92 Chu trnh tin ren n

G94 Chu trnh tin mt n

G96 Ci t ch tc mt khng i

G97 Hy b ch tc mt khng i

G98 Tc ct tnh theo n v/pht

G99 Tc ct tnh theo n v/vng

Lnh M:

Di y l danh sch cc ln M c s dng ph bin cho my tin CNC:

M00 Dng chng trnh

M01 Dng chng trnh khng iu kin

M02 Kt thc chng trnh

M03 Quay trc chnh theo chiu kim ng h (CW)

M04 Quay trc chnh ngc chiu kim ng h (CCW)

M05 Dng trc chnh

M08 M dung dch trn ngui

M09 Tt dung dch trn ngui

M23 Rt dao nghing 45 khi ct ren

M24 Hy ln M23

M30 Kt thc chng trnh, t ng tr v u chng trnh

M98 Gi chng trnh con

M99 kt thc chng trnh con, tr v chng trnh chnh

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2.8. Chn, thay dao trong tin CNC

Lnh chn dao bt u bng t kha T v bn ch s i km, T ----, trong :

Hai ch s u: s th t dao trn dao

Hai ch s sau: xc nh thng s hiu chnh dao thng qua s th t hiu chnh dao.

Ch : Nu s th t hiu chnh dao l 00 c ngha l hy b chc nng hiu chnh dao, thng s dng trc khi gi lnh thay dao hoc khng xt n b tr dao.

V d: T0101 chn dao s 1 v s th t hiu chnh dao l 1.

2.9. Lnh v ch ct

a) Lng tin dao

Tng t khi phay, lng tin dao c xc nh bi t lnh F. L lnh hnh thc, c tc dng trong nhng cu lnh gia cng (G01,G02, G03).

Trong cng ngh tin, lng tin dao c th xc nh theo 2 h n v sau:

H mt: G21

o Theo n v mm/pht khi s dng vi G98

o Theo n v mm/ vng khi s dng vi G99

H inch: G20

o Theo n v inch/ pht khi s dng vi G98

o Theo n v inch/vng khi s dng vi G99

V d:

G21 G98 F10.0; tc ct 10mm/pht

G21 G99 F0.05; tc ct 0.05mm/vng

b) Tc trc chnh

Tng t khi phay, tc trc chnh khi tin c xc nh bi t lnh S. L lnh hnh thc. Quan h gia tc quay trc chnh v tc mt khi

tin theo cng thc sau: Dv

npi

1000=

, trong :

- D: ng knh ct (mm)

- v: tc mt (m/pht hoc feet/pht)

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- n (vng/pht)

Do vy, nu tc trc chnh khng i khi ng knh ct ln th tc vng trc chnh nh, v ngc li khi ng knh ct nh th tc vng trc chnh ln. vn tc mt l khng i khi ng knh ct thay i nhm m bo cc yu cu k thut, nng xut gia cng s vng quay trc chnh phi c th thay i v cp theo ng knh ct. Trong cng ngh tin CNC tc trc chnh c th ci t theo 2 ch sau.

- Ci t ch tc mt khng i - G96

Tc mt: l tc tng i gia mi dao ct so vi b mt phi ti im tip xc. Lnh G96 s gi tc ct lun n nh theo gi tr khai bo trong cu lnh ti cc v tr khc nhau trn b mt chi tit. Thng s S phi lun i km trong cu lnh.

V d: G21 G96 S100; tc mt 100 MPM;

G20 G96 S200 ; tc mt 200 FPM

- Ci t tc vng ln nht G50

Khi s dng G96, tc mt khng thay i ti cc v tr bn knh khc nhau. m bo c iu ny, tc vng ca trc chnh phi thay i mt cch v cp. Khi bn knh tin dn n 0, tc vng s tin n v cng. gii hn tc vng ti mt gi tr cho php ln nht nhm m bo an ton v ty theo kh nng ca my, ta s dng lnh G50.

o nh dng: G50 Ss; Vi s: gi tr tc vng ln nht cho php

Th d: G50 S3500 ; - tc vng khng vt qu 3500 vng/pht

- Ci t tc vng c nh - G97

Lnh G97 dng ci t tc vng trc chnh c nh theo n v vng/pht. Do tc vng khng i nn tc mt s thay i ty theo ng knh chi tit. Lnh G97 cn s dng hy lnh G96 (ch tc mt c nh).

o nh dng: G97 Ss ; vi s: gi tr tc trc chnh theo n v vng/pht

V d: S dng mi khoan T01 v dao tin l T03 gia cng bin dng trong nh hnh v sau:

- Tc khoan 700RPM

- Tc mt khng i 500 FPM

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- Tc ln nht trc chnh 3500RPM

on chng trnh sau m t vic chn dao v ci t tc trc chnh:

T0101; Thay dao T01, s th t b tr dao l 01

G20 G97 S700; Ci t tc vng trc chnh l 700 RPM

M03; Trc chnh quay theo chiu kim ng h

---------- Chu trnh khoan vi tc vng 700 RPM

T0100; Hy b b tr dao

T0303; Thay dao T03, b tr dao s 03

G50 S3500; Ci t tc trc chnh ln nht l 3500 RPM

G96 S200; Ci t tc mt khng i l 500 FPM

M03 Trc chnh quay theo chiu kim ng h

---------- Thc hin lnh tin l trong

M05; Dng trc chnh

2.10. Lnh v im chun my tin

- im chun my

i vi cc my tin NC/CNC , im chun my thng l im nm gc xa nht tnh t v tr mm cp.

- Tr v im chun my

Vn hnh trc tip:

Nhn nt chc nng tr v im chun my

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2.11. Lnh h trc ta

Tng t nh phay CNC, trong cng ngh tin CNC ta cng c th dng 3 loi h ta sau:

- H ta my (Machine coordinate system)

- H ta gia cng (Workpiece coordinate system) G54 G59

- H ta cc b ( Local coordinate system)

a. H ta my (Machine coordinate system)

Mi my c mt im xc nh l im khng (zero point), thng n l im tham chiu th nht. Ci t im khng ca my c thc hin bi nh sn xut. H ta ly im khng lm gc c gi l h ta my. Trn my tin CNC, thng h ta my l im xa nht so vi mm cp.

H ta my c thit lp khi tr v im tham chiu v c gi cho n khi tt my. Khi lp trnh mun s dng h ta my ta dng lnh G53.

G53 l lnh tc ng mt ln (one shot): ch c tc dng trn cu lnh m n tham gia. Lnh G53 khng nh hng h to gia cng c thit lp.

- nh dng: G53 Xx Zz; vi: x, z gi tr ta tuyt i.

H ta my

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- Trc khi s dng G53, mi lnh b tr dao phi c hy b.

- G53 ch s dng vi ta tuyt i.

b. H ta gia cng (workpiece coordinate system)

L h ta gn lin vi chi tit gia cng. H ta ny thng c s dng khi lp trnh gia cng nn gi l h ta gia cng. xc nh h ta gia cng trn my tin c 2 cch sau:

Dng lnh G50

- L Lnh hnh thc (modal)

- Mc ch:

o ci t h ta gia cng.

o B tr s khc bit gia h ta lp trnh v h ta gia cng

- nh dng: G50 Xx Zz;

Trong x,z l ta ca dao v tr hin ti so vi gc ta mi.

Khi c nhiu dao c s dng trong cng mt chng trnh, cn nh ngha li gc ta cho mi dao ty theo thng s v kch thc dao. Lc ny ta s dng G50 vi gi tr ta tng i:G50 Uu Ww;

trong u,w l khong cch tng i gia mi dao chun v mi dao ang xt theo phng X v Z.

V d:

Dao T01 c mi dao cch tm chi tit X20.3, Z25.5

Dao T02 c mi dao cch mi dao T01 U0.4, W0.35

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on chng trnh sau nh ngha h ta chi tit trong mi trng hp, lnh G50 c s dng nh sau:

T0101; chn dao T1

G50 X20.3 Z25.5; nh ngha gc ta chi tit theo dao T1

--------

T0202; thay dao T2

G50 U0.4 W0.35; b tr dao T2 so vi T1

--------

Lu : C th dng G50 ci t ta gia cng ch MDI hoc trong chng trnh gia cng.

Dng lnh G54-G59

Khi chng trnh yu cu s dng nhiu h ta , vic thay i gi tr ta tr nn phc tp. Phn ln cc h iu khin CNC u c kh nng xc lp cng mt lc nhiu h ta lm vic. Lc ny ta s dng G54-G59. Ngoi ra dng G54-G59 c rt nhiu u im so vi G50, do vy khi lp trnh gia cng a s ta s dng G54 G59 thay cho G50.

- Ci t G54 G59

Nu trong chng trnh s dng G54 G59, trc khi thc thi chng trnh ta phi ci t v tr ca G54 -> G59 vo b nh my. Trnh t cc bc ci t G54 nh hnh sau:

Phng php ci t ta G54 G59 trn my tin CNC

100

X:-220 Z: -100

G54 G56 X: -320 X:0.0 Z: -100 Z:0.0

G55 G57 X:0.0 X:0.0 Z:0.0 Z:0.0

To im hin ti. WORK OFFSET SCREEN

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- G t chi tit gia cng ln mm cp.

- Xc nh to x ca h ta cn ci t so vi im khng ca h ta my. Khi khng cn chnh xc ta c th di chuyn dao n v tr mong mun bng ch Jog Feed hoc Manual Handle Feed ri quan st bng mt. Khi cn chnh xc ta phi dng phng php ct th v dng thc o xc nh v tr ta cn ci t.

- a gi tr ny vo b nh h iu khin (mn hnh work offset). vo mn hnh ny thng thng ta chn Offset > WORK > G54 - G59.

- nh tm chun (Z) ca chi tit so vi im khng ca h ta my: di chuyn dao n v tr mong mun theo phng Z. m bo chnh xc ta khng cho dao tip xc trc tip vi phi m dng c o (Block gauge). To Z a vo mn hnh offset s l ta hin ti tr i kch thc ca c o.

- a gi tr Z ny vo b nh h iu khin (mn hnh work offset). Khi G54 c ch nh, chng trnh s s dng tm ca workpiece lm im chun gia cng.

V d:

O0001; G90 G54 G00 X0Y0; .. M30;

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Ch : Khi lp trnh, phi nh xc nh la chn G54-G59. Mt s h iu khin mc nh G54.

Dng ta my kt hp vi b tr hnh hc xc nh ta gia cng:

Vi my tin, trong mt s trng hp n gin v nhanh chng ta dng lng b tr hnh hc theo cc phng tng ng xc nh ta gia cng. Cch ci t lng b tr cng tng t nh ci t ta G54.

Khi lp trnh ta dng cu lnh T0101, lng b tr x,z tng ng s c cng thm vo to trong chng trnh.

2.12. Lnh ta v n v

a) Ta :

Tng t nh phn phay, c hai cch xc nh ta trong qu trnh di chuyn dao: ta tng i v ta tuyt i. Mt s h iu khin US s dng 2 lnh G90 v G91. H iu khin FANUC da vo t kha ca a ch phn bit ta tng i hay tuyt i.

- X Z : h ta tuyt i

- U W: h ta tng i

b) n v:

- G20 : h inch

- G21 : h mt

2.13. Cc lnh di chuyn dao

a) Chy dao nhanh - G00/G0

- Ta tuyt i: G00 Xx Zz;

- Ta tng i: G00 Uu Ww;

ng dng: nh v dao nhanh gia cc vng gia cng.

b) Chy dao ni suy ng thng vi tc F - G01

- nh dng: G01 Xx Zz Ff; theo ta tuyt i

G01 Uu Ww Ff; theo ta tng i

- ng dng: C th s dng G01 tin mt u, tin tr thng, tr cn, tin rnh, khoan v doa l.

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c) Chy dao ni suy cung trn

- nh dng:

Theo ta tuyt i:

G02/G03 Xx Zz Rr Ff; tnh theo bn knh

G02/G03 Xx Zz Ii Kk Ff; tnh theo ta tm cung trn

Theo ta tng i:

G02/G03 Uu Ww Rr Ff; tnh theo bn knh

G02/G03 Uu Ww Ii Kk Ff; tnh theo ta tm cung trn

- Chiu : chiu ca ni suy cung trn trn my tin CNC nh sau:

G02: CW, hng t trc X n trc Z

G03: CCW, hng t trc Z sang trc X.

Trn cc my tin, chy dao ni suy cung trn s dng to nn cc khi tr li hoc lm hay cc gc ln, mp vt trn xoay. Ni suy cung trn ch thc hin trn mt phng ZX, tr mt s my nhiu hn 2 trc.

Ch :

- Dng R ch p dng cho nhng cung nh hn 1800. Cung ln hn 1800 th phi chia cung ra thnh nhng cung nh.

- Lp trnh theo tm(I,K) c th s dng cho nhng cung c ln bt k.

- Cch n gin trnh lm ln gia G02, G03 l: d my tay phi hay tay tri, i t ngoi vo trong (Z-) cung li l G03, lm l G02 v ngc li.

V du: Vit chng trnh gia cng chi tit sau:

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B MN CAD/CAM-CNC

Gc ta ca chi tit c xc nh ngay ti tm mt u ca mm cp. Lp trnh theo ng. Dao s di chuyn nhanh n v tr trc im A khong 0.3 inch theo phng Z, sau di chuyn dc theo bin dng A-B-C-D-E-F-G-H v tr v im gc.

--- theo ta tng i -----

N5 G50 X12.5 Y20.0; ci t gc ta chi tit

N10 T0101; thay dao T1 v b tr

N15 G50 S2000; ci t tc trc chnh ln nht 2000RPM

N20 G96 S500 M03; ci t tc mt khng i 500 FPM

N25 G0 X0 Z10.3; di chuyn nhanh n (0, 10.3)

N30 G1 W-0.3 F0.003; di chuyn ti A(0,10) vi tc 0.003IPM

N35 U1.5; tin thng n B(1.5,10);

N40 G3 U1.5 W-0.75 R0.75; tin cung trn BC

N45 G1 W-2.25 ; tin thng n D(3,7)

N50 G2 W-3.0R4.0; tin cung trn lm DE

N55 G1 W-1.5; tin thng n F(3,2.5)

N60 G2 U1.0W-0.5 R0.5; tin cung trn FG

N65 G1 U0.5; tin thng n H(4.5,2)

N70 G0 U8.0W18.0; di chuyn dao nhanh n im ban u

Lp trnh Tin CNC 22

B MN CAD/CAM-CNC

---- theo ta tuyt i ------ N5 G50 X12.5 Y20.0; N10 T0101; N15 G50 S2000; N20 G96 S500 M03; N25 G0 X0 Z10.3; N30 G1 Z10.0 F0.003; N35 X1.5; N40 G3 X3.0 Z9.25 R0.75; N45 G1 Z7.0 ; N50 G2 Z4.0R4.0; N55 G1 Z2.5; N60 G2 X4.0Z2.0 R0.5; N65 G1 X4.5; N70 G0 X12.5 Z20.0; N75 T0100; N80 M30;

2.14. Lnh ct ren - G32

Lnh G32 s dng ct ren thng, ren cn, ren xon vi bc tin ren khng i. y l lnh ct ren n, thng c s dng vi lnh G00 hon thnh chu trnh ct ren.

Cu trc lnh: G32 Xx Zz Ff; ta tuyt i

G32 Uu Ww Ff; ta tng i

Trong x,z l ta tuyt i ca im kt thc ren, u,w l khong cch tng i gia im cui ren so vi im bt u theo hai phng X,Z. F l tc ct.

V d ct ren thng ngoi:

Lp chng trnh ct ren 3/4 - 10 UNC nh trn hnh v.

Lp trnh Tin CNC 23

B MN CAD/CAM-CNC

Cc thng s cn thit:

- Bc ren = bc tin ren = 1/10= 0.1 inch.

- Chiu cao ren H = 0.6403 P = 0.064 inch.

- Ta lp bng s bc cn thit tin ht chiu cao ren v chiu su cho mi bc ct nh sau:

Bc 1: 0.0394 Bc 2: 0.0276 Bc 3: 0.0236

Bc 4: 0.0157 Bc 5: 0.0157 Bc 6: 0.0060

Khong cch vo ren 0.3 inch

Khong cch thot ren 0.15 inch

To X (chiu su ct) cho mi bc c cho trong bng sau:

Th t Ta X

Bc 1 0.7106 (=0.75-0.0394)

Bc 2 0.683 (=0.7106-0.0276)

Bc 3 0.6594 (=0.683-0.0236)

Bc 4 0.6437 (=0.6594-0.0236)

Bc 5 0.628 (=0.6437-0.0157)

Bc 6 0.622 (=0.628-0.0060)

Chng trnh:

N5 G20 G50 X4.5 Z5.3; Ci t gc ta chi tit

N10 T0101; Chn dao T01 v b tr

N15 G97 S200 M3; Quay trc chnh 200 RPM;

N20 G00 X0.95; Di chuyn nhanh ti (0.95, 3.05)

Z3.05; ---

N25 X0.7106; Di chuyn nhanh ti chiu su ct ca bc u tin

N30 G32 Z0.6 F0.1; Tin bc th nht, chiu su ct 0.0394

N35 G0 X0.95; Di chuyn nhanh theo chiu x+ n v tr X0.95

N40 Z3.05; Di chuyn nhanh theo chiu z+ n v tr Z3.05

N45 X0.683; ---

Lp trnh Tin CNC 24

B MN CAD/CAM-CNC

N50 G32 Z0.6 F0.1; Tin bc 2

N55 G00 X0.95; ---

N60 Z3.05; ---

N65 X0.6594; ---

N70 G32 Z0.6 F0.1; Tin bc 3

N75 G00 X0.95; --

N80 Z3.05; --

N85 X0.6437; --

G90 G32 Z0.6 F0.1; Tin bc 4

N95 G00 X0.95; --

N100 Z3.05; --

N105 X0.628; --

N110 G32 Z0.6 F0.1; Tin bc 5

N115 G00 X0.95; --

N120 Z3.05; --

N125 X0.622; --

N130 G32 Z0.6 F0.1; Tin bc cui

N135 G00 X0.95; --

N140 X4.5 Z5.3; --

N145 M30; --

Lp trnh Tin CNC 25

B MN CAD/CAM-CNC

C

A

B

D R

C

CChhuu trnh ntrnh n

CHNG 3: CC CHU TRNH TIN

3.1. Cc chu trnh tin trn my CNC

a) Chu trnh n:

- Chu trnh tin trc thng (G90)

- Chu trnh tin mt u (G94)

- Chu trnh tin ren (G92)

b) Chu trnh hn hp

- Chu trnh tin tinh (G70)

- Chu trnh tin th hng trc (G71)

- Chu trnh tin th hng knh (G72)

- Chu trnh tin chp hnh (G73)

- Chu trnh tin rnh mt u (G74)

- Chu trnh tin rnh tr (G75)

- Chu trnh tin ren hn hp (G76)

c) Chu trnh gia cng l

3.2. Chu trnh n

thun li v n gin cho vic lp trnh trn my tin CNC, cc b iu khin u h tr cc lnh chu trnh n nh sau.

F

Lp trnh Tin CNC 26

B MN CAD/CAM-CNC

Gm 4 chuyn ng c bn sau:Gm 4 chuyn ng c bn sau:

11)) A: im bt u chu trnhA: im bt u chu trnh

22)) B: im bt u gia cngB: im bt u gia cng

33)) C: im kt thc gia cngC: im kt thc gia cng

44)) D: im li dao trung gianD: im li dao trung gian

55)) R: di chuyn nhanhR: di chuyn nhanh

6) F: di chuyn vi tc ct FF: di chuyn vi tc ct F

a) Chu trnh tin trc thng - G90

Mc ch: G90 c s dng gia cng cc bin dng trn xoay thng.

Th d: tin trc thng, trc cn

Tin trc thng nh dng lnh:

G90 Xx Zz Ff; ta tuyt i.

G90 Uu Ww Ff; ta tng i.

x,z ta im kt thc gia cng.

u,w khong cch tng i ca im kt thc gia cng so vi im u.

Dao phi c di chuyn n im bt u chu trnh trc khi G90 c gi

Chu trnh tin tr thngChu trnh tin tr thng

A

C B

D R

F

Lp trnh Tin CNC 27

B MN CAD/CAM-CNC

V d: V d: Tin chi tit hnh sau.Tin chi tit hnh sau.

LnLng d gia cng 2 mm. S g d gia cng 2 mm. S ddng G90 gia cng bin dng trn ng G90 gia cng bin dng trn theo ba bc: hai bc gia cng th v mt bc gia cng tinh.theo ba bc: hai bc gia cng th v mt bc gia cng tinh.

Gia cng th: Chiu su ct 0.9mm, F150mm/phGia cng th: Chiu su ct 0.9mm, F150mm/ph

Gia cng tinh: Chiu su ct 0,2mm, F100mm/ph; im bt u chu Gia cng tinh: Chiu su ct 0,2mm, F100mm/ph; im bt u chu trnh A(trnh A( 8855,,22))

onon chng trnh gia cng nh sau:chng trnh gia cng nh sau:

G00 X85. Z2.;

G90 X78.2 Z-30. F150.;

X76.4;

X76.0 F100;

..

Tin trc cn: Cu trc lnh: G90 Xx Zz IiCu trc lnh: G90 Xx Zz Ii Ff; to tuyt iFf; to tuyt i GG9900 UUuu WWww Ii Ff; ta tng iIi Ff; ta tng i ii: sai lch b: sai lch bn knh ti v tr mt ctn knh ti v tr mt ct bt u so vi mt cbt u so vi mt ct kt thc .t kt thc . ii == ((DDii DDee)) //22

Di: ng knh mt uDi: ng knh mt u

De: ng knh mt kt thDe: ng knh mt kt thcc

Lu : V ta phi c khong vo dao nn khi xc nh cn ta cLu : V ta phi c khong vo dao nn khi xc nh cn ta cn tnh n tnh ngng knh Di nh sau:knh Di nh sau:

DDii == DDss ((ee//LL))..((DDee--DDss))

80 76

A

B

D R

C

De C

Di

L C

e

Ds C

Chu trnh tin cn dng G90Chu trnh tin cn dng G90

Lp trnh Tin CNC 28

B MN CAD/CAM-CNC

Chu trnh tin mt u - G94

Mc ch:Mc ch:

Dng tin mt u thng v tin mt u cn.Dng tin mt u thng v tin mt u cn. Tng t G90, Tng t G90, G94 gm hai ng chy dao nhanh v hai ng chy dao vi G94 gm hai ng chy dao nhanh v hai ng chy dao vi tc F, nhng trong trtc F, nhng trong trng hp ny dao tin theo phng hng ng hp ny dao tin theo phng hng knh. G94 thng dng kho mt hoc tin cc b mt c knh. G94 thng dng kho mt hoc tin cc b mt c ng knh ln nhng chiu di ngn.ng knh ln nhng chiu di ngn.

Tin mt u thngTin mt u thng

Cu trc lnh:Cu trc lnh:

GG9944 XXxx ZZzz FFff;;

GG9944 UUuu WWww FFff;;

x,z ta tuyt i dix,z ta tuyt i dim kt thc gia cngm kt thc gia cng

u,w khong cch tng i ca im cuiu,w khong cch tng i ca im cui so vi im u theo hai phng X,Zso vi im u theo hai phng X,Z

Tin mt u cnTin mt u cn


GG9944 XXxx ZZzz KKkk FFff;;

GG9944 UUuu WWwwKKkk FFff;;

x,z ta tuyt i dim kt thc gia cngx,z ta tuyt i dim kt thc gia cng

u,w khong cch tngu,w khong cch tng i ca im cuii ca im cui so vi im u theo hai so vi im u theo hai pphhnngg XX,,ZZ

K: chnh lch to z gia im u v cui.

A

B

D R

A B

D

R

Chu trnh G94

Lp trnh Tin CNC 29

B MN CAD/CAM-CNC

Lu : V ta phi c khong vo dao nn khi xc nh cn ta cn tnh n trng hp ny nu yu cu chnh xc cao.

bb)) Chu trnh tin Ren (G92) Mc ch:Mc ch: G92 c s dng gia cng Ren tr, Ren cn thay cho vic G92 c s dng gia cng Ren tr, Ren cn thay cho vic dng lnh tin ren G32 v lnh di chuyn G00, G01. Chu trnh dng lnh tin ren G32 v lnh di chuyn G00, G01. Chu trnh tin Ren G92 c minh ha nh tin Ren G92 c minh ha nh hhnnhh 1199..

Tin ren tr thngTin ren tr thng

C phC php lnh: p lnh:

G92 Xx Zz Ff; ta tuyt iG92 Xx Zz Ff; ta tuyt i

G92 Uu Ww Ff; ta tng iG92 Uu Ww Ff; ta tng i

x,z ta im kt thc gia cngx,z ta im kt thc gia cng

u,w khong cch tng i ca im kt thc gia cng so vi im u,w khong cch tng i ca im kt thc gia cng so vi im u u

LLu :u : Dao phi c di chuyn n im bt Dao phi c di chuyn n im bt u chu trnh trc khi u chu trnh trc khi G92 c giG92 c gi

M23 dng kt hp vi G92 khi ta mun rt dao t t theo mt gc no , thng l 45 . Ta c th thay i gi tr gc ny trc tip trn my.

Tin Ren tr cn:Tin Ren tr cn:


Lp trnh Tin CNC 30

B MN CAD/CAM-CNC

GG9922 XXxx ZZzz IIii FFff;; to tuyt i to tuyt i

GG9922 UUuu WWww IIii FFff;; ta tng ita tng i

ii: sai lch bn knh ti v tr mt ct bt u so vi mt ct kt thc: sai lch bn knh ti v tr mt ct bt u so vi mt ct kt thc::

ii == ((DDii DDee)) //22

Di: ng knh mt uDi: ng knh mt u

De: ng knh mt kt thcDe: ng knh mt kt thc

V d v tiV d v tin ren dng G92. Ren h inch 1.0n ren dng G92. Ren h inch 1.0--1122UUNN

Lp trnh Tin CNC 31

B MN CAD/CAM-CNC

c) Chu Trnh Tin Hn hp (Multiple Repetitive Cycle)

Chu trnh tin th dc trc G71(Rough Turning Cycle)

Cng dng: Dng ht b vt liu (stock removal) trn cc trc nhm t c kch thc gn ging vi chi tit gia cng chun b cho chu trnh gia cng tinh tip theo. Khi dng G71, dao ct s thc hin cc ng chy dao lin tip nhau theo phng dc trc cho n khi t c kch thc mong mun.

Ty theo h iu khin m G71 c c php khc nhau.

Vi h iu khin Fanuc: 10T/11T/15T

Cu lnh: G71 Pp Qq Uu Ww Dd Ff Ss;

Vi h iu khin OT/16T/17T/18T/20T/21T

G71 Ud Rr;

G71 Pp Qq Uu Ww Ff Ss;

Ff lng chy dao th (Roughing feedrate)

Ww - lng d gia cng tinh theo phng z (Z-axis finish stock)

Uu - lng d gia cng tinh theo phng x, tnh theo ng knh (X-axis finish stock)

Chu trnh tin th G71

Lp trnh Tin CNC 32

B MN CAD/CAM-CNC

Ud - chiu su mi bc ct th (Depth of cut)

D: chiu su mi bc ct th (depth of cut, khng dng du thp phn)

Qq S th t cu lnh kt thc (Sequence number of cycle ending block)

Pp - S th t cu lnh bt u (Sequence number of cycle starting block)

Rr -Retraction amount (lng rt dao)

Ui -Distance of retraction in the X direction (khong rt dao theo x)

Wk -Distance of retraction in the Z direction (khong rt dao theo z)

Lu :Ty thuc vo im u chu trnh v im P m ta c th tin c tr ngoi hoc trong.

Chu trnh gia cng tinh G70 (Finish Cycle G70)

c dng kt hp vi cc chu trnh gia cng th nhm gia cng tinh t c hnh dng chi tit gia cng v cc yu cu k thut.

Cu lnh: G70 Pp Qq F_ S_;

V d v dng G70 v G71.

Gia cng chi tit sau

Chiu su ct 4mm, rt dao 2mm, v tr bt u chu trnh x74, z5.

Chng trnh nh sau:

%

O0000

G21 G28 U0 Z0

T0101

G50 S3600

G96 S150. M03

G00 X74. Z5.

G71 U4. R2.

G71P100Q102U.4W.2F.2

N100 G0 X20. S200.

G1 Z-20. F3.

G54

Lp trnh Tin CNC 33

B MN CAD/CAM-CNC

G3 X40. Z-30. R10.

G1 Z-35.

G2 X50. Z-40. R5.

G1X60.

N102G40X70.Z-80.

G0Z2.

G28U0.W0.M05

T0100

M01

T0202

G50S3600

G96S200M03

G70P100Q102

G28U0.W0.M05

T0200

M30

%

Chu trnh tin th tin dao hng knhG72 (Rough Facing Cycle)

Dng ht b vt liu trn cc trc nhm t c kch thc gn ging vi chi tit gia cng chun b cho chu trnh gia cng tinh tip theo. Khi dng G72, dao ct s thc hin cc ng chy dao lin tip nhau theo phng vung gc vi trc.


- Vi h iu khin 10T/11T/15T

G72 Pp Qq Dd Uu Ww Ff Ss;

- Vi h iu khin OT/16T/17T/18T/20T/21T

G72 Wd Rr;

G72 Pp Qq Uu Ww Ff Ss;

Ww: Depth of cut

Cc thng s cn li tng t nh G71.

Chu trnh tin th G72

d) Chu trnh gia cng th chp hnh-G73 (Contour Repeating Cycle)

Dng ht b vt liu (stock removal) trn cc trc nhm t c kch thc gn ging vi chi tit gia cng chun b cho chu trnh gia cng tinh tip theo. Khi dng G73, dao ct s thc hin cc ng chy dao lin tip nhau theo phng dc theo bin dng ca chi tit cn gia cng.

Chu trnh tin th chp hnh G73



G73 Pp Qq I.. K..Dd Uu Ww Ff Ss;


G73 Ui Wk Rr;

G73Pp Qq Uu Ww Ff Ss;

D, R: s ln ct th.

I,K: Tng chiu su ct theo phng x,z (c du).

e) Chu trnh tin Ren hn hp - G76

Cng dng:

- Dng thc hin nhiu ln chy dao lin tip nhau tin ren.

Lp trnh Tin CNC 35

B MN CAD/CAM-CNC

Chu trnh tin ren tng hp G76


G76 X. (U) Z..(W) I .. K.. D ..F.. A..P..;

I: cn (tnh theo bn knh).

K: chiu su ren (tnh theo bn knh)

D: chiu su bc ct u tin

A: gc ren (ren h Mt A60)

P: Cch n dao (mc nh P1): c gi tr nh sau:

1: tin dao nghing din tch ct cc ln bng nhau (one edge cutting equal amount).

3: tin dao nghing chiu su ct cc ln bng nhau (one edge cutting equal depth).

2: tin dao 2 phng din tch ct cc ln bng nhau (two edge cutting equal amount).

4: tin dao 2 phng chiu su ct cc ln bng nhau (two edge cutting equal amount)

Tin dao 1 pha v tin dao 2 pha

Lp trnh Tin CNC 36

B MN CAD/CAM-CNC

Mt s h iu hnh khng dng t lnh P xc nh cch tin dao m ci t trc tip cho b iu khin my. Thng thng ta dng phng php tin dao nghing v chiu su bc ct u tin c tnh nh sau.

NKD = (N: s ln ct, K: chiu cao ren)


G76 PxxxxxxQqRr;

G76 X..(U) Z..(W) P..Q.. R.. F..;

P: xxxxxx Gm 6 ch s

- 2 s u l s ln gia cng tinh

- 2 s tip l s Ren rt dao t t cui ng ren

- 2 s cui l gc ren

Qq: chiu su ct nh nht (ko c du thp phn)

Rr: lung d gia cng tinh.

R: chnh lch bn knh (dng khi tin Ren cn).

P : Chiu cao ren.

Q: chiu su bc ct du tin.

Lu :

Tng t G92, ta c th dng M23 khi ng ch rt dao t t, hu b M23 bng M24.

3.3. B dao khi tin

a. B tr hnh hc (Geometry Offset):

Cc thng s b tr dao: B tr dao trong cng ngh tin gm cc thng s sau. Cc thng s ny c a vo mn hnh TOOL OFFSET trc khi chng trnh gia cng c thc thi.

- X offset: B tr theo phng x

- Z offset: B tr theo phng z

OFFSET No X Z R Tip 01 . . . . 02 . . . 03 . . .

Lp trnh Tin CNC 37

B MN CAD/CAM-CNC

Cc thng s b tr X, Z dng b tr s khc bit v kch thc hnh hc gia cc dao. Thng s ny tng t nh b tr chiu di trong cng ngh phay. Khi dao v lng b dao c ch nh lng b tr s c t ng tnh n m khng cn lnh khi ng b tr.

V d: T0102: lng b tr trong Offset 02 s c cng thm vo cho dao s 1.

- R: Bn knh mi dao.

Do mi dao tin thng c bn knh r nn khi ct cc bin dng cung trn hoc tin cc mt cn, im ct thc t v im canh chnh dao khng trng nhau. Dn n sai s gia bin dng ct thc t v bin dng mong mun.

Do vy, m bo chnh xc yu cu, trong cng ngh tin CNC, hu ht cc h iu hnh u h tr chc nng b tr bn knh mi dao. Tng t phay, b tr bn knh mi dao c khi ng bi lnh b tr G41, G42 v hu b tr bi lnh G40. Bn knh mi dao c a vo OFFSET ca my trc khi chng trnh c thc thi.

Mi dao l thuyt

Bin dng mong mun

Bin dng thc

Lp trnh Tin CNC 38

B MN CAD/CAM-CNC

Lnh b tr bn knh G41, G42, G40

- T(tip): Hng mi dao.

Khi b tr bn knh, cn phi ch r hng mi dao, hng mi dao s quyt nh n lng b tr. Hng mi dao c ch nh bi cc s nguyn t 1-> 9 nh bng sau.

Bng 1: hng mi dao

Lp trnh Tin CNC 39

B MN CAD/CAM-CNC

Lp trnh Tin CNC 40

B MN CAD/CAM-CNC

b. B tr mn dao (Wear Offset)

B tr mn dao l chc nng dng b tr do trong qa trnh s dng dao b mn nh hng n chnh xc gia cng. Cc thng s trong b tr mn dao cng tng t nh b tr hnh hc nhng c ci trong mn hnh WEAR OFFSET SCREEN. Thng thng khi khng yu cu chnh xc cao ta khng cn b tr mn dao. B tr Mn dao theo cc phng X, Z thng c s dng hn so vi b tr bn knh mi dao. c bit l khi ct theo cc phng ring r (tin tr, kho mt). B tr bn knh mi dao do mn l do trong qa trnh ct mi dao b mn nn bn knh mi dao cng ngy cng tng ln.

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