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LUN VN TT NGHIP

ti: Tm hiu v cng ngh CNC

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Bo co thc tp GVHD: Duy Ph

SVTH: Lng Pht Ngc Lp: in 1_K1

1

MC LC

LI NI U....1

PHN A : GII THIU CHUNG V SODICK2PHN B : NI DUNG BO CO THC TP

PHN 1: TNG QUAN V CNG NGH EDM........5

1.1.Nguyn l gia cng tia la in ( EDM).5

1.1.1. Gia cng tia la in dng in cc nh hnh 6

1.1.2. Gia cng tia la in bng ct dy... 6

1.2. Bn cht vt l ...7

1.3.Cc thng s cng ngh ca EDM..........9

1.3.1. c tnh v in ca s phng tia la in......9

1.3.2. Cc thng s iu chnh.......9

1.4.Gia cng EDM c th c phn loi nh sau.....12

1.5.Cc trc cn bn ca my EDM....13

PHN 2:TM HIU V MY CT XUNG( DIE SINKING EDM)..14

PHN 3: MY CT DY EDM( WIRE CUT EDM)...21

PHN 4: B IU KHIN CHNH TRONG MY CT EDM34

4.1.H thng servo AC...34

4.2.Mt s h thng mch trong my EDM...39
http://greub-machines.com/pmn-sodick-sink-e.htmlhttp://greub-machines.com/pmn-sodick-sink-e.html

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2

LI NI U

Trong qu trnh hc tp trong cc trng i hc, s kt hp gia lthuyt v thc hnh lun c nh trng v sinh vin t ln hng u. V

vy thc tp tt nghip l mt trong nhng phn rt quan trng gip sinh

vin nm cui hon thin kin thc, l bc chun b tt nht cho sinh vin

trc khi ra trng. Thc tp tt nghip gip cho sinh vin k thut tip cn

c r nht vi thc t sn xut ti cc nh my, x nghip, c tm hiu

v tip xc trc tip vi my mc thit b c hc trn l thuyt. Ngoi

ra trong qu trnh thc tp sinh vin cn c c hi nm bt c cng vic,

phng thc lm vic c nhng chun b tt nht v khng b b ng

trc khi tt nghip ra trng.

Trong qu trnh thc tp ti cng ty VPD Sodick, tuy ch c mt

khong thi gian ngn nhng vi s ch bo tn tnh ca thy gio hng

dn thc tp DUY PH cng cc anh ch em trong cng ty gip em

hiu hn v cng ngh CNC, c bit l cc my ct xung EDM.

Do thi gian thc tp c hn cng vi s hiu bit cn hn ch, bi vit

khng th trnh khi nhng sai st. Knh mong thy c, cng cc bn gip

v ch bo .

Em xin chn thnh cm n!

H Ni, ngy 12 thng 4 nm 2010Sinh vin thc hin

Lng Pht Ngc

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3

PHN A

LI GII THIU

Sodick Co., Ltdl mt tp on sn xut my EDM (my tia la in)hng u Nht Bn chim 49% th phn my EDM ti th trng Nht vi

mng li trn khp th gii t Bc&Nam M, Chu u n chu Thi

Bnh Dng vi 4 nh my sn xut chnh (1 nh my ti Nht Bn (Fukui),

2 nh my ti Trung Quc(Shuzhou v Amoy) v mt nh my ti Bangkok

Thi Lan). Trong Cng ty Sodick(Thailand) Co., Ltd. ti Thi Lan l mt

cng ty trc thuc ph trch kinh doanh, phn phi thit b cho 3 nc Thi

Lan, n , Vit Nam. VPD Sodick (Thailand) Co., Ltd c a ch ti

P503 CT1 To nh Vimeco, Khu th Nam Trung Yn, Qun Cu Giy,

H Ni.

Sn phm chnh ca Sodick l cc my CNC trong lnh vc ch to khun

mu nh: My xung, my ct dy, my khoan l, trung tm gia cng, my

nh bng, my p nha, my Nano. y l nhng dng my cao cp cho

nhng sn phm c bng cao ng thi c chnh xc c m v nm.

Trn th trng Vit Nam c rt nhiu khch hng ln v ang s dng

thit b ca Sodick nh : Canon, Toho, Brother, Vietnam Auto Part, Iritani,

Nissei, Muto Technology, Hokuyo Precision..v..v..v.. v rt nhiu doanh

nghip Vit Nam khc nh Vin Cng Ngh B Quc Phng, Cng ty

HTMP, Cng ty Tn Ha..v..v.v.v.

Nh mt nh tin phong EDM, Sodick lin tc tin hnh nhng nghincu v pht trin v c kt qu trong cc my vi cc tnh nng tinh vi v

c o to nn kt qu chnh xc v hiu sut s dng cao.

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4

Mt s a ch wed ca Sodick:

http://www.sodick.jp

http://www.sodick.org

http://www.sodick.com
http://www.sodick.jp/http://www.sodick.org/http://www.sodick.com/http://www.sodick.com/http://www.sodick.com/http://www.sodick.org/http://www.sodick.org/http://www.sodick.jp/

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5

PHN B: NI DUNG BO CO THC TP

PHN I

TNG QUAN V CNG NGH EDM

Trong na u th k 20, nhu cu v cc vt liu lu mn tng ln khng

ngng cc nc cng nghip pht trin. Nhng vn l gia cng nhng

vt liu bng cng ngh thng thng th rt kh khn, nhiu khi khng

thc hin c. S xut hin ca cc my CNC EDM (Electrical Discharge

Machining) nhanh chng thay i vic sn xut cng nghip. Cc ng

cong c thc hin d dng nh ng thng, cc cu trc phc tp 3 chiu

cng d dng thc hin, v mt lng ln cc thao tc do con ngi thc

hin c gim thiu.

1.1.Nguyn l gia cng tia la in ( EDM)
http://vi.wikipedia.org/w/index.php?title=S%E1%BA%A3n_xu%E1%BA%A5t_c%C3%B4ng_nghi%E1%BB%87p&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=S%E1%BA%A3n_xu%E1%BA%A5t_c%C3%B4ng_nghi%E1%BB%87p&action=edit&redlink=1

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V nguyn l gia cng th y l hiu qu n mn vt liu gy ra bi s

phng in. Khi cc tia la in c phng ra, vt liu trn b mt phi b

ht i bi mt qu trnh in-nhit thng qua s nng chy v bc hi kim

loi - l qu trnh gia cng bng tia la in gi tt l gia cng EDM

(Electrical Discharge Machining).

Cho n nay qu trnh EDM c pht trin kh rng ri cc nc pht

trin. Nhiu gam my hot ng trong lnh vc EDM c sn xut vi

nhiu kiu khc nhau phc v nhng mc ch khc nhau. N a quy v

2 dng sau:

1.1.1.Gia cng tia la in dng in

cc nh hnh

Gi tt l phng phpxung nh hnh.

in cc l mt hnh khng gian bt k, n s

in hnh ca mnh ln phi to ra lng khun thng dng to hnh nhngchi tit c l nhng khng thng.

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1.1.2. Gia cng tia la in bng ct dy

Ct dy tia la in l mt hnh thc c bit ca gia cng tia la in. imkhc nhau c bn gia ct dy tia la in v xung in (gia cng bng in

cc thi) l thay v s dng nhng in cc thi c hnh dng phc tp th

trong WEDM in cc l mt si dy c ng knh t 0,1 0,3mm. Dy

ny c cun lin tc v chy theo mt bin dng cho trc, ct c b

mt 2D v3D phc tp.

Trong qu trnh gia cng, dng c v chi tit l hai in cc, trong dng

c l catt, chi tit l ant ca mt ngun in mt chiu c tn s 50

500kHz, in p 50 300V v cng dng in 0,1 500A. Hai in cc

ny c t trong dung dch cch in c gi l cht in mi.Khi cho hai in cc tin li gn nhau th gia chng c in trng. Khi

in p tng ln th t b mt cc m c cc in t phng ra, tip tc tng

in p th cht in mi gia hai in cc b ion ha lm cho chng tr nn

dn in, lm xut hin tia la in gia hai in cc.

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Nhit vng c tia la in ln rt cao, c th t n 12.0000C, lm

nng chy, t chy phn kim loi trn cc dng. Trong qu trnh phng

in, xut hin s ion ha cc mnh v to nn p lc va p rt ln, y

phoi ra khi vng gia cng.

Ton b qu trnh trn xy ra trong thi gian rt ngn t 10-4 n 10-7s. Sau

mch tr li trng thi ban u v khi in p ca t c nng ln n

mc phng in th qu trnh trn li din ra im c khong cch

gn nht.

Phoi ca qu trnh gia cng l nhng git kim loi b tch khi cc in cc

v ng c li thnh nhng ht nh hnh cu v b y ra khi vng gia

cng bng lung dung mi c p sut cao. Khi cc ht ny b y ra khi

vng gia cng, khe h gia hai in cc ln ra v s phng in khng cn

na. tip tc gia cng cn di chuyn hai in cc li gn nhau v qu

trnh lp li lin tc. Gia cng bng tia la in, EDM (Electrical Discharge

Machining) l mt qu trnh tch kim loi bng mt tia la in trong thi

gian rt ngn vi cng dng in ln gia dng c ct v chi tit.Qutrnh EDM c th so snh vi mt phn thu nh ca mt tia st va vo mt

b mt to nn vng tp trung nhit ln lm nng chy b mt gia cng.

1.2. Bn cht vt l

t mt in p gia in cc v phi.- Khng gian gia in

cc v phi phi c in y bi mt cht in mi.- Cho 2

in cc tin li gn nhau, n mt khong cch ( no thxy ra s phng tia la in, xut hin mt dng in tc thi.

Nu 2 in cc chm nhau th s khng c tia la in m s

sy ra ngn mch c hi cho qu trnh gia cng.- Nu khe h

qu ln th s khng th xy ra s phng tia la in iu

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lm gim nng sut gia cng.- c th lm pht sinh tia la

in, mt iu khng th thiu c l mt thi gian ngn sau

khi c dng in chy qua 2 in cc th phi ngng cung

cp nng lng. n gin ngi ta dng b pht xung RC nh

trn cung cp xung rng ca.

1.3. Cc thng s cng ngh ca EDM.

1.3.1. c tnh v in ca s phng tia la in.

Cc c tnh v in c nhn ra da vo cc c tnh thi gian ca s

phng tia la in. Cc c tnh ny chnh l cc thng s iu chnh quan

trng nht ca qu trnh gia cng.

Mi my pht ca thit b gia cng tia la in u c mt nhim v l cung

cp nng lng lm vic cn thit. My pht xung hin i ca mt thit b

gia cng tia la in l mt my pht xung tnh. y nng lng c iu

khin bng in t nhng khng c yu t b. Nguyn l tc dng ca my

pht xung tnh thc hin trc ht thng qua s pht trin ca Transistormnh v cc sn phm in t hin i. My pht xung tnh c u vit ln

linh hot ca cc thng s iu chnh. Qua mi trng hp gia cng

c th c gii quyt di quan im l in cc t mn nht v cht lng

b mt l ti u. mun vy cc thng s ca qu trnh gia cng phi c

iu chnh cho ph hp.

1.3.2. Cc thng s iu chnh. in p nh la Ui: y l in p cn thit dn ti s

phng tia la in. N cung cp cho in cc v phi khi my

pht c ng in, gy ra s phng tia la in t chy

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vt liu. in p nh la Ui cng ln th phng in cng nhanh

v cho php khe h phng in cng ln.

Thi gian tr nh la td: l thi gian gia lc ng in

my pht v lc xy ra phng tia la in. Khi ng in my

pht lc u cha xy ra iu g. in p duy tr gi tr ca

in p nh la Ui, dng in bng 0. Sau mt thi gian tr td

mi xy ra s phng tia la in. Dng in t 0 vt ln Ie.

in p phng tia la in Ue: khi bt u phng tia la in

th in p tt xung t Ui n Ue. y l in p trung bnh

trong sut thi gian phng tia la in. Ue l mt hng s vt l

ph thuc vo cp vt liu in cc/phi. Ue khng iu chnh

c.

Dng phng tia la in Ie:l gi tr trung bnh ca dng in

t khi bt u phng tia la in n khi ngt in. Khi bt u

phng tia la in dng in tng ln t 0 n gi tr Ie, km

theo s t chy. Ie nh hng ln nht n lng ht vt liu, mn in cc v cht lng b mt gia cng. Nhn chung Ie

cng ln th lng ht vt liu cng ln, nhm b mt cng

ln nhng mn in cc gim.*Dng in v din tch b mt

b n mn: Mt dng in (A/mm2) s sinh ra lng nhit ln

lm qu nhit in cc v gy mn in cc nhanh hn. Do vy

gia cng mt vng nh cn chn dng in nh v ngc li.

Nh vy, khi gia cng ch c mt in cc hay c nhiu in cc

thay th th phi ch la chn dng in cho ph hp sao

cho n cho php t c lng ht vt liu ln nht c th t

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c trong khi vn duy tr nhn bng v mn in cc

trong gii hn yu cu.

ko di xung ti:l khong thi gian gia hai ln ng ngt

ca my pht trong cng mt chu k phng tia la in. N bng

thi gian tr (td) v thi gian phng tia la in ie: ti = td + te.

ko di xung ti nh hng n nhiu yu t quan trng c lin quan trc

tip n cht lng v nng sut gia cng.Cc yu t b nh hng:- ti nh

hng ln n lng ht vt liu: thc nghim cho thy khi gi nguyn

dng in Ie v khong cch xung to, nu tng ti th ban u Vw tng nhng

ch tng n gi tr cc i ti nht nh no sau Vw gim i, nu vn

tip tc tng ti th nng lng phng in khng cn c s dng thm na

ht vt liu phi m n li lm tng nhit ca cc in cc v dung

dch in mi.

Khong cch xung to:l thi gian gia hai ln ngt-ng ca

my pht xung thuc 2 chu k phng in k tip nhau, to cn

c gi l ko di ngh ca xung.Cng vi t l ti/to, to cnh hng rt ln n lng ht vt liu. Khong cch to cng

ln th lng ht vt liu Vw cng nh v ngc li.Phi gi to

nh nh c th c n c th t mt lng ht vt liu ti

a. Nhng khong cch xung to phi ln c thi gian

thi in ho cht in mi trong khe h phng in. Nh s

trnh c li ca qu trnh nh to h quang hoc dng ngn

mch. Cng nh trong thi gian ca khong cch xung dng

chy s y cc vt liu b n mn ra khi khe h phng

in.Do vy, tu thuc vo kiu my v trng hp gia cng c

th m la chn to, ti ph hp thng qua t s ti/to :

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Khi gia cng rt th chn: ti/to > 10

Khi gia cng th chn: ti/to = 10

Khi gia cng tinh chn: ti/to = 5

Khi gia cng rt tinh chn: ti/to < 5 (thng chn = 0,4).

Khe h phng in: cho ti y, ta c rt nhiu cc thng s iu chnh

nh: I, ti, to, U.... m chng ch tc ng ln s phng ta la in. d

kin c lng ht vt liu t u n cui sau mt s ln phng tia la

in th vn l phi duy tr khe h v mt chiu rng ti u. Qu trnh

gi l s iu chnh khe h phngin. l cch m bo chc chn

rng ic cc tip tc n xung thm nhp vo phi.Trn my xung, vic

o khe h ( c thc nghim gin tip thng qua vic o Ue. Ue l mt i

lng in chnh xc khi in cc tin gn n phi, Ue tng th khe

h cng tng. duy tr mt chiu rng khe h phng in l hng s th

tng ng vi n l mt gi tr danh ngha ca Ue. Trong qu trnh gia cng,

do in cc v phi b n mn lm cho ( ln ln, iu chnh th Ue c

o lin tc v c so snh vi gi tr danh ngha. Thng thng trong giacng, ngi vn hnh my chn I, ti, to, Ui ph hp vi yu cu nng sut

v cht lng b mt, lc h iu khin s t ng iu chnh ( cho ph

hp vi I v Ui).

1.4. Gia cng EDM c th c phn loi nh sau:

Gia cng xung nh hnh EDM (Die Sinking EDM hay Ram-

EDM) Gia cng EDM bng dy ct (Wire-cut EDM hoc Wire EDM)

Gia cng vi EDM (Micro EDM)

Khoan EDM (EDM drilling)

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1.5. Cc trc cn bn ca my EDM

My ct EDM c tng cng 05 trc c iu khin h trc ta my da

trn 2 tiu ch l trc chnh ca my v bn my.

Trc X : chuyn ng (+) theo chiu tay tri

sng tay phi

Trc Y : chuyn ng (+) xa ngi thao tc

Trc Z: thng ng, chiu (+)l hng ln

trn

Trc U : trc // vi trc X( l trc bn my)

chiu (+)t tri sang phi

Trc V: trc // vi trc Y( l trc bn my) chiu (+) xa ngi thao tc.

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PHN 2:

TM HIU V MY CT XUNG ( DIE SINKING EDM)
http://greub-machines.com/pmn-sodick-sink-e.htmlhttp://greub-machines.com/pmn-sodick-sink-e.html

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NGUYN L GIA CNG MY CT XUNG EDM

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H thng gia cng tia la in (Electrical Discharge Machining -EDM) bao

gm c hai b phn ch yu: my cng c v ngun cung cp in. My

cng c gn in cc nh hnh (ng vai tr l dao) v in cc tin ti b

mt chi tit gia cng sinh ra mt l chp hnh hnh dng ca dng c.Chi tit

gia cng lp trn bn my cng c, cn in cc th gn vi u my. Mt

ng c servo AC hoc xylanh thy lc iu khin in cc theo phng

thng ng v duy tr mt v tr thch hp ca in cc so vi chi tit giacng.

Ngun nng lng cung cp sn sinh ra mt tn s cao, to ra mt lot tia

la in gia in cc v b mt chi tit v bc i mt lp kim loi bi s n

mn ca nhit v s ha hi.V tr ny c iu chnh mt cch t ng

vi s chnh xc cc k nh h thng servo v ngun cung cp. Trong qu

trnh vn hnh my thng thng in cc khng bao gi chm b mt chi

tit, gia chng c mt khe h phng in nh.C chi tit v in cc u

ngm chm trong dung dch in mi. Dung dch ny ng vai tr nh cht

cch in iu khin s phng tia la in. Trong gia cng EDM cht

in mi cng thc hin chc nng ca mi trng lm ngui v lm gim

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nhit cc k cao trong khe h phng

in. Quan trng hn, dung dch in

mi c bm vo theo khe h hnh

cung y i nhng ht b xi mn

gia chi tit v in cc.

Mt s hnh nh v u cc:

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Mt s dng my ct xung EDM ca SODICK nh C32, AP1L, AD3L,

AG75L...

Mt s thng s v my C32

Hnh trnh dch chuyn cc trc

X/Y/Z

300x250x150 mm

Hnh trnh dch chuyn cc trc

U/V

35x45mm.

Khoang lm vic ca my 450x300 mm

Khi lng vt gia cng ti a 50kg

Trng lng in cc ti a 20kg.

Kch thc bn 600 x 400mm

Kch thc thng cha du 925 x 555 x 300

H iu khin LMX32 hot ng trn nn

Window XP

Mn hin th cm ng TFT 15"

Phn mm h tr gia cng LN Assit

Khi lng my 2500kg

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C32 dng my ct xung EDM

mi nht ca Sodick vi

truyn ng ng c tuyn

tnh th h th 5 c thit k

nh gn, C32 s dng h iu

khin LMX32 hot ng trn

nn Window XP vi mn hin

th cm ng TFT 15". Phn

mm h tr gia cng LN Assit

gip ngi vn hnh d dang

to cc chng trnh NC (vi

cc iu kin gia cng v ch

b ti u) t mi bi ton

sn phm.

C32 l my EDM u tin ng dng cng ngh truyn tn hiu serial siu tc1Gbit/giy cho h thng iu khin. H thng truyn tn hiu tc cao ny

gip nng cao hiu sut truyn ng, phn hi iu khin servo cng nh

tin cy ca my trong qu trnh gia cng.

H iu khin LMX32 vi h mch "zero wear" gip gim hao mn in

cc graphite di 0.06% trong khi tng tc gia cng ti 20%. Vi tnh

nng ny, C32 gip gim s lng in cc khi gia cng cc l hc. Trong

khi, mt my EDM thng thng i hi t 2-3 in cc cho gia cng th,

gia cng bn tinh v gia cng tinh, C32 c th ch cn n 1 in cc duy

nht. iu ny khng ch gip tit kim thi gian v chi ph sn xut m cn

gim thiu cc sai s gia cng.

MY C32

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C32 cng c trang b cng ngh truyn ng ng c tuyn tnh tin tin

ca Sodick, gip trc Z c th t tc dch chuyn cao ti 1.400"/pht v

gia tc trng trng ti 1.2G. Vi tc dch chuyn trc Z cao gip t ro

ra hiu ng bm y phoi ra khi cc hc gia cng; nh ngi s dng

khng cn s dng vi xi m vn m bo c cht lng gia cng n

nh nht.

Sodick l nh sn xut hng u trong lnh vc my gia cng tia la in vi

s lng hn 50.000 my bn ra trn ton th gii. Model C32 c tin

tng s l sn phm t ph trong chin lc "ton cu ha my EDM" ca

Sodick .

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PHN 3

MY CT DY EDM( WIRE CUT EDM)

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Cc nguyn tc c bn ca phng

php ct dy EDM cng ging nh gia

cng xung nh hnh EDM c m t

trn. im khc bit c bn l thay v

s dng nhng in cc c hnh dng

phc tp, trong ct dy EDM in cc

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l nhng si dy c hnh dng n gin, ng knh t 0.006-0.012. Dy

thng s dng l dy ng.Thay v s dng cht in mi nh trong gia

cng xung nh hnh EDM th trong ct dy EDM li dng nc ion ha.

Nc y c tc dng lm mt v loi b cc ht xi mn cng nhanh cng

tt.Trong qu trnh ct nc c nh nhng chy qua khng lm chch

hng cc dy.

EDM wirecut machine

Diefluid Centre (ct p thu lc)pressure: 6bar

Controller

DiefluidCentre

Table

WireCenter

Sng phu

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Wire Center (qun dy) c ng knh: 0.2mm

Machining Center (max. table size: x-300mm y-300mm z-200mm)

Controller system

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DATA ANALYSIS

NC code programming: y l 1 on chng trnh vit gia cng

chi tit.

L 0303;

H1=0.131;

E3501 F19.2 M20 H1 0.131;

M80;

M82;M84;

G90;

G40;

G00 X0 Y0;

G02 X10 Y0;

G01 X10 Y5;G01 X20 Y5;

G01 X20 Y10;

G01 X10 Y10;

G01 X10 Y15;

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G02 X0 Y 15;

G01 X0 Y0;

M00

M02

Mt s dng my ct dy EDM ca SODICK: AD325L,AP200L, AP450L,

EXC100L, AQ237L, TW423, TW533.

Gii thiu v my ct dy EDM TW

Model: TW-423, TW-533

Tng quan

Kiu lm vic bn chm (submersible worktable)

Thn my t gang hp kim MEEHAMITE, kh ng sut d, m bo

thn my cng vng v chnh xc cao

S dng ngun cp AC c tr khng thp, m bo gia cng nhanh v

chnh xc

Mn hnh th hin hnh nh lp th trong qu trnh gia cng

Kh nng ct dc nghing ti a 15o
http://www.dbm.com.vn/products/images/Maycongcu/maycnc/xungdien/catdayEDMTW2.jpg

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H thng dn ng vi ng c servo, bng my tuyn tnh v trc

vt me

My trc khi xut xng c kim tra chnh xc bng cc thit

b laser

Thng s k thut

Thng s k thut TW-423 TW-533

Phng php gia cng Loi bn chm Loi bn ch

Kch thc thng lm vic 850x660x430

mm

950x760x49

mm

Kch thc phi ti a 640x490x300

mm

740x590 mm

Trng lng phi ti a 650 kg 750 kg

Hnh trnh trcXxY 420x270 mm 520x370 mm

Hnh trnh trcZ 300 mm 300 mm

Hnh trnh trcU, V 50 mm 50 mm

Motor dn ng cc trcXYZUV ng c AC

Servo

ng c A

Servo

Tc di chuyn ca bn lm vic 4000 mm/pht 4000 mm/ph

ng knh dy ct 0.1-0.3

mm

0.1-0.3

mm

cng dy ct 200-2400 gf 200-2400 gf

Tc ct cc i (dy ng 0.3 mm,

ct AC)

255 mm/pht 255 mm/ph

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Tc di chuyn dy 0-15 m/pht 0-15 m/ph

nhm b mt tt nht Ra 0.28m Ra 0.28m

Gc cn ti a 15o (tychn 22.5o)

15o (tchn 22.5o

Trng lng ti a ca cun dy 6 kg 6 kg

Trng lng my 2650 kg 3000 kg

H thng lc

Phng php lc: lc giy

Th tch thng nc: 650 lt

B lc x l nha trao i ion: 15 lt

Kim sot dn in: t ng

iu khin nhit nc: ty chn

Ngun cp

Loi mch: cng sut Transitor MOS

On time: 10 bc

Off time: 20 bc

Cng sut: ct AC

Mt vi thng s ca my AD325L:

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Mt s sn phm sau khi ct bng my EDM:

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SO SNH GIA CNG XUNG NH HNH V CT DY

Gia cng bng in cc thi ngi ta s dng du lm cht in

mi th trong WEDM li dng nc kh khong.

Khi gia cng bng in cc thi, s phng in xy ra gia mt

u in cc vi chi tit gia cng cn khi gia cng bng dy ct

th s phng in xy ra gia mt bn dy ct vi chi tit gia

cng .

Vng phng in khi gia cng bng in cc thi bao gm mt

u v gc ca in cc. Cn vng phng in khi gia cng bng

dy ct ch bao gm mt 180o ca dy cc khi n tin n ct chi

tit gia cng.

U IM

Bi v EDM n mn kim loi bng vic phng tia la in thay cho cc dng

c ct gt to phoi nn cng vt liu khng tr thnh nhn t quyt nh

xem vt liu c th gia cng bng EDM hay khng. Cc in cc kim

loi hoc than ch mm c th gia cng cc loi thp dng c ti hoctungsten carbide (cacbt vonfram). y l mt trong nhng li ch hp dn

ca vic s dng phng php EDM. C th nhit luyn chi tit trc ri

sau c th gia cng bng EDM. iu ny loi b ri ro ca nhng h hi

v bin dng c th bin nhng chi tit t tin thnh ph liu trong khi x

l nhit.

NHC IM

Phi v dng c (in cc) u phi dn in

V tc ct gt thp nn phi trc gia cng EDM thng phi

gia cng th trc. Do vng nhit ti vng lm vic cao nn

gy bin dng nhit.

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PHM VI NG DNG

Gia cng cc l c ng knh nh 0,15mm ca cc vi phun

cao p c nng sut cao (t 15 n 30s/chic), gia cng l su t

60mm cho sai s 5m. Cc l 0,05mm 1mm vi chiu su

ln nh cc l lm mt trong cnh tuabin lm bng hp kim siu

cng, cc l su vi t s chiu di trn ng knh ln n 67.

Ly cc dng c b gy v kp trong chi tit (bulng, tar)

Gia cng khun mu v cc chi tit cn chnh xc cao bng

vt liu hp kim cng.

CHNH XC GIA CNG

chnh xc ph thuc vo nhng yu t sau :

chnh xc ca my.

Dng c.

Khe h phng in.

nhm b mt ph thuc vo nng lng mt ln phng

in.Gia cng kim loi c cng khng gii hn (v da vo

tnh cht vt l).

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PHN 4:

B IU KHIN CHNH TRONG MY CT EDM

4.1.H thng servo AC

H thng Servo AC l mt h

thng iu khin vng kn

c gn thm encoder ly

tn hiu hi tip nh tc , v

tr. Dng iu khin o

lng c kh, p ng rt chnh

xc cc yu cu v v tr v tc

c lp trnh trc. . Nuc bt k l do no ngn cn

chuyn ng quay ca ng c, c cu hi tip s nhn thy tn hiu ra cha

t c v tr mong mun. Mch iu khin tip tc chnh sai lch cho ng

c t c im chnh xc.

My EDM s nhn ch th nh v( Drive motor servo AC signal) t chng

trnh NC. ng c ch ng (

Drive motor) chy s vng

tng ng quay trc dch

chuyn. Khi v tr cn thit

ti thit b phn hi(feedback

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device) gi tn hiu ti b iu khin kt thc lnh.

Mt lnhNCthc hin bn trong b iu khin s bo cho m t ch ng

quay ng s vng cn thit ko theo trc vitme bi quay s vng tng ng.Ti lt mnh vitme bi ko theo chuyn ng thng ca bn my hoc tay

gn in cc. Thit b phn hi u kia ca vitme bi cho php kim sot

kt thc lnh ng khi s vng quay cn thit c thc hin.

Servopact(b driver servo): b ny c chc nng iu khin ng c servo.

Mt s hnh nh v b Servopact:
http://ltk52-humg.com/blog/?tag=cnchttp://ltk52-humg.com/blog/?tag=cnc

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Cc my CNC EDM hin ti u s dng AC servo dn ng cc trc,

cc i c hn th xi DC servo.Ngi ta s dng ng c ac servo v

momen n nh trong di tc rng, tc cao, t n, ko yu cu bo tr ,

c th ch to cng sut ln.

Thng thng cc my ct EDM u c t 45 trc ( X/Y/Z/U/V ) tng

ng l s ng c servo v drive. M drive s iu khin s di chuyn ca

mt trc.

AC servo motor dc iu khin thng qua driver. Driver thng c 2 cch

iu khin:

Dng tn hiu analog, p cp vo thng l -10V +10V

Dng tn hiu xung.

to xung, c th s dng IC 555

S chn:

Chn 1: ni xung t ly dng cung cp cho IC.
http://tudiencongnghe.com/Special:Search/DChttp://tudiencongnghe.com/Special:Search/DC

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Chn 2: ng vo ca 1 tn s so p, mch so p dng cc n bn dn

thun (mc p chun l 2*Vcc/3).

Chn 3: Ng ra.

Chn 4: dng lp nh mc trng thi ra. Khi chn 4 ni mass th ng

ra mc thp, cn khi chn 4 ni ln mc p cao th trng thi ng ra

tu theo mc p chn 2 v 6.

Chn 5: dng lm thay i mc p chun trong IC theo VR hay R

ngoi cho ni mass. Tuy nhin trong cc mch ng dng thng chn

s 5 ni mass qua 1 con t t 10nF -100nF tc dng lc b nhiu cho

mc p chun n nh.

Chn 6: ng vo ca 1 tn so p khc, mch so snh dng cc

Transistor ngc Vcc/3.

Chn 7: c th xem nh 1 kho in.

Chn 8: Cp ngun nui cho IC. Ngun nui cp cho IC khong t

+5V n +15V , ti a l =18V.

Mch iu khin ng c servo i hi mt mch in t chnh xc quay

trc ra ca n.Mt IC 555 c th cung cp cc xung cn thit cho servo.

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Khi hot ng, IC 555 sinh ra mt tn hiu xung c chu k nhim v khc

nhau iu khin hot ng ca servo. Chnh Vnk nh v servo. VIC555 c th d dng to xung rt di v rt ngn nn servo c th hot ng

ngoi v tr bin thng thng.

Khi servo gp vt cn v ku lch cch ta phi ngt ngun ngay, nu khng

cc bnh rng bn trong s b trn.

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4.2.Mt s h thng mch trong my EDM

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KT QU THU C SAU THC TP

Sau khi kt thc thc tp, hc tp v nghin cu h thng my ct EDM

cng cc anh, cc ch trong cng ty.Nh s gip ch bo tn tnh ca ban

lnh o v cc ch,cc anh trong cng ty em tip thu hc hi,rt ra nhiu

bi hc qu bu:

Bit c qu trnh hot ng ca, nguyn l hot ng v ng dng ca cc

my ct EDM nh my ct xung EDM, my ct dy EDM.

Tip cn thc t c vi cng ngh CNC ,mt cng ngh hin i m em

ch c dp c trn sch v, thu thp nhiu ci mi,cng c li c nhng

g hc.

Hc hi c tc phong cng nghip kinh nghim thc t,ni quy,o c

ngh nghip v c bit l tnh cn thn trong ngnh in.

Tinh thn cu tin,tnh cch trung thc,cn c,t m v trch nhim trong

cng vic.Tt c nhng iu gp phn hon thin bn thn em c th tr thnh

ngi k s tt.

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LI CM N

Trong qu trnh thc tp ti Cng ty VPD Sodick em may mn c c

hi c i kh nhiu khu cng nghip nh Bc Thng Long, Quang Minh ,

Phc in v c vo cc xng sn xut ca cc cng ty ln nh

Canon, Toho, Brother,Vin Cng Ngh B Quc Phng. Qua gip em

hiu bit thm v lnh vc in c ng dng trong i sng, c va

chm v lm vic trong mi trng thc t, c nhiu ci b ng, nhng qua

em hc hi c nhiu kinh nghim cho bn thn. Nhng kinh nghim

hc hi c vi nhng kin thc trn gh nh trng s gip ch rt nhiu

cho em sau khi tt nghip.

c c kt qu , em xin trn thnh cm n ban lnh o, cn b,

cc anh ch lm vic ti Cng ty VPD Sodick to iu kin v gip

em hon thnh tt t thc tp ca mnh.

Em xin trn thnh cm n thy gio DUY PH, ging vin Trng

i Hc Cng Nghip H Ni, l gio vin hng dn em trong qu trnh i

thc tp v vit bo co thc tp.

Xin trn trng cm n!

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NHN XT CA GIO VIN HNG DN THC TP

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