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Analele Universit ii Constantin Brncui din Trgu Jiu, Seria Inginerie, Nr. 2/2010

Annals of the Constantin Brncui University of Trgu Jiu, Engineering Series, Issue 2/2010

45

STUDII PRIVIND

POSIBILITILE DE UTILIZARE

ALE PRELUCRRIIDIMENSIONALE PRIN

EROZIUNE CU ULTRASUNETE

Prof. univ. dr. Dan DOBROTUniversitatea Constantin Brncui

din Trgu-Jiu

Rezumat: Lucrarea prezinto serie de studiipr ivind posibili t ile de utilizare ale prelucrriidimensionale prin eroziune cu ultrasunete.Studiu efectuat se refer n mod deosebit la

posibi li t ile folosirii ultrasunetelor laintensificarea procedeelor de prelucrare prinachiere de tipul strunjirii i rectificrii. Aceststudiu prezentat n lucrare se impunea deoarece

prelucrarea dimensional cu ultrasunete igsete n tehnica modern un cmp deaplicabilitate din ce n ce mai larg, remarcndu-

se n mod deosebit n prelucrarea materialelordure i fragile neelectroconductoare, acolo undealte procedee de prelucrare nu dau rezultatesatisfctoare sau sunt imposibil de aplicat.

Cuvinte cheie: ultrasunete, prelucrare prineroziune, burghiere, rectificare

1. Introducere

Prelucrarea prin aeroziune cuultrasunete poat folosi sisteme

ultraacustice ce utilizeaz: vibraiilongitudinale, vibraii transversale,vibraii de torsiune.

Construcia simpl i robust esteavantajul pe care l prezint sistemeleultraacustice care utilizeaz vibraiilongitudinale, lanul ultraacustic fiindformat din transductor, concentrator iscul. Sistemele ultraacustice careutlizeazvibraii longitudinale prezintio serie de dezavantaje, cum ar fi:

STUDY ON POSSIBILITIES OF USE

OF PROCESSING DIMENSIONAL

ULTRASONIC EROSION

Prof. PhD Dan DOBROTConstantin Brancusi University of

Trgu Jiu

Abstract: This paper presents a series ofusability studies of erosion dimensionalultrasound processing. Study refers specificallyto the possibility of using ultrasound to further

processing procedures such turning, dr il ing andgrinding. The study presented in paper

processing as required dimensional ul trasoundfinds in a field of application modern technologyincreasingly wider remarked is especially hardmaterials processing and fragileneelectroconductoare there which do not give

other working satisfactory or unenforceable.

Key words: ultrasonic erosion, temperature,Conduction Transfer Function

1.

Introduction

The processing by ultrasounderosion can use ultrasonic systemsapplying: longitudinal vibration,transversal vibrations, torsion vibrations.

The simple and massiveconstruction is the advantage thatultrasonic systems, using longitudinalvibrations present, the ultrasonic chain

being formed from transducer,concentrator and tool. The ultrasonicsystems using longitudinal vibrationsalso present a series of disadvantages,like: the impossibility of applying them

to a series of processing (internal turning


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imposibilitatea aplicrii acestora la oserie de prelucrri (strunjirea interioarcu vibraii tangeniale, burghierea ialezarea cu vibraii torsionale etc.) i

limitri impuse de construcia acestora launele prelucrri (de exemplu la strunjireacilindric exterioar exist un diametrumaxim al piesei ce poate fi prelucrat io distan minim ntre cuit idispozitivul universal de prindere a

piesei) [1].Sistemele ultraacustice cu vibraii

transversale ofer urmtoarele avantaje[1]: eliminarea limitrilor de micarelongitudinal i n ceea ce privete

diametrul maxim al piesei de prelucrat iposibilitatea prelucrrii cu mai multecuite n cazul strunjirii cilindriceexterioare i posibilitatea utilizriiacestora la strunjirea cilindricinterioar. Sistemele ultraacustice cuvibraii transversale prezintdezavantajul unei construcii complicaten care acordarea pe frecvena derezonan a lanului ultraacustic serealizeazrelativ greu datoritpierderilor

energetice n planele nodale n care sefixeaz cuitul. n cazul acestor sisteme,concentratorul longitudinal i cuitul se

proiecteaz conform literaturii despecialitate [2].

Sistemele ultraacustice cu vibraiitorsionale pot fi utilizate la diferite

prelucrri n vederea orientriioscilaiilor dup direcia forei Fc (nacest caz micarea vrfului cuitului dupun arc de cerc cu lungimea de 10 20

m este aproximat cu o micarerectilinie pe direcia forei Fc). Acestea

pot fi acionate de transductoaretorsionale [1], [3] de lanuri acusticelongitudinale ce acioneaz excentric n

punctele ventrale ale unui concentratortorsional [3] sau de lanuri acusticetorsionale ce acioneaz n punctelenodale ale unui cuit cruia i se imprimastfel vibraii transversale n planul XOY

[2]. Sistemele ultraacustice care

with tangential vibrations, drilling andboring with torsional vibrations) andlimitations imposed by their constructionin some processing (for example at

external cylindrical turning there is amaximum diameter of the piece that canbe processed also at a minimal distancebetween the knife and the universaldevice of catching the piece) [1].

The ultrasonic systems withtransversal vibrations offer the followingadvantages [1]: elimination of thelongitudinal movements limitation andregarding the maximal diameter of the

piece to be proccesed also the possibility

of processing with more knives in case ofexternal cylindrical turning and the

possibility to use them at internalcilyndrical turning. The ultrasonicsystems with transversal vibrations havethe advantage of a complicatedconstruction in which granting onresonance frequency of the ultrasonicchain is realised quite difficult, due toenergetic losses in nodal plans, where theknife is fixed. Regarding those systems,

the longitudinal concentrator and theknife are designed according to thespecialty literature [2].

The ultrasonic systems withtorsional vibrations can be used atdifferent processing to target oscillationsaccording to the direction of force Fc (inthis case the movement of the edge of theknife, after a circle with the length of 10 20 m is approximated with a

rectilinear movement on the direction ofthe force Fc). These can be driven bytorsional transducers [1], [3] bylongitudinal acoustic chains acting in aneccentric manner in ventral points of atorsional concentrator [3] or by torsionalacoustic chains acting in nodal points ofa knife to which are impressed thetransversal vibrations in plan XOY [2].The ultrasonic systems usign torsionalvibrations offer the advantage of

introducing ultrasonic vibrations on the


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utilizeaz vibraii torsionale oferavantajul introducerii vibraiilorultrasonore dup direcia forei Fc, launele prelucrri unde acestea nu se pot

realiza prin alte construcii [4]: alezare,burghierea materialelor dure, frezare etc.,precum i avantajul realizrii construciein plan orizontal n cazul strunjiriicilindrice exterioare. Ca principaledezavantaje se pot menionacomplexitatea construciei acestorsisteme i dificult ile ntmpinate laacordarea lor pe frecvena de rezonan .

2.

Prelucrri dimensionale prineroziune cu ultrasunete

Prin procedeul de prelucraredimensional cu ultrasunete este posibilrealizarea unei game foarte variate deconfiguraii a orificiilor sau cavit ilor

prelucrate n cele mai diverse materiale.Cele mai des folosite operaii de

prelucrare dimensional cu ultrasunete seprezintn figura 1,deosebindu-se:

-gurirea ptruns sau neptrunsa unor materiale dure i extradureneelectroconductoare sauelectroconductoare (fig. 1,a);

-debitarea la dimensiune (fig. 1,b);-execuia orificiilor i cavit ilor

complexe (fig. 1,c);-perforarea simultana mai multor

orificii sau debitarea simultan a maimultor piese din industria electronic,cum ar fi plcuele semiconductoare,lentilele etc.(fig.1,d);

-prelucrarea matrielor pentruextrudare i tragere sau a filierelor

pentru trefilare (fig. 1,e);-execuia orificiilor curbe ptrunse

sau neptrunse (fig. 1,f);-finisarea prin rectificare

ultrasonic a suprafeelor plane sauprofilate (f ig. 1, g);

-filetarea interioar sau exterioar

a unor materiale dure i extradure

direction of force Fc, at some processingwhere these cannot be realised by otherconstructions [4]: boring, drilling harshmaterials, cutting, etc, as well as the

advantage of realising the construction inhorizontal plan in case of externalcylindrical turning. As maindisadvantages can be mentioned thecomplexity of the construction of thosesystems and the difficulties encounteredat granting them on resonance frequency.

2. Dimensional processing by

ultrasonic erosion

By the procedure of ultrasounddimensional orcessing it is possible therealization of a varied scale ofconfigurations of the holes or cavities

processed in different material. The mostoften used processing operation ofultrasound dimensional processing is

presented in figure 1, beingdifferentiated:

-the penetrated or unpenetrated

perforation of some rigid or extra-rigidmaterials that are not eletro-conducer orwhich are electro-conducer (fig. 1,a);

-cutting off at dimension (fig.1,b);

-execution of the complex holesand cavities (fig. 1,c);

-simultaneous perforation ofseveral holes or simultaneous cutting offof several parts from electronic industry,like semi-conducer plates, lenses, etc(fig.1,d);

-processing matrixes for extrusionand drawing cutters for slitting (fig.1,e);

-execution of the holes forpenetrated or unpenetrated curves (f ig.1,f);

-finishing by ultrasonicrectification of plan or profiled surfaces(fig. 1, g);

-internal or external threading of


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neelectroconductoare cu scul profilat(fig. 1,h);

-canelarea dupo curbplan(fig.1,i);

-finisarea prin honuire ultrasonica suprafeelor interioare cu sculeprofilate corespunztor (fig. 1,j);

-durificarea stratului superficial ncmp ultrasonor (fig. 1,k).

Cele mai spectaculoase realizrisunt n prelucrarea sticlei optice,

prelucrarea i fasonarea lentilelor iprismelor. Precizia de prelucrare este de

0,025 mm, iar dimensiunea minim aorificiului de prelucrare este de 0,5 mm.

Un beneficiar de seam alrezultatelor prelucrrii cu ultrasunete amaterialelor dure i fragile este industriaelectrotehnic, unde se pune n moddeosebit problema prelucrrii i debitriimaterialelor semiconductoare, aceramicilor izolatoare, a feritelorutilizate n radiotehnic i tehnica decalcul, a elementelor de memorie i aaltor materiale fragile. Cu rezultatedeosebite se aplic prelucrareadimensional cu ultrasunete naeronautic, n ceasornicrie i elementede mecanic fin n industria aparatelormedicale i de cercetare, unde se pune i

problema prelucrrii unor materiale castelitul, cuarul, mica, rubinul, safirul ialte pietre preioase i semipreioaseutilizate la confecionarea lagrelor demare precizie i finee.

some rigid material and non-electroconducer extrusion with a sectional tool(fig. 1,h);

-grooving according to a plan

curve (fig. 1,i);-finishing by ultrasonic honing ofthe internal surfaces withcorrespondently sectional tools (fig. 1,j);

-hardening the superficial layer onultrasonic field (fig. 1,k).

The most spectacular realizationsare in processing optical glass,

processing and moulding lenses andprisms. The processing exactness is of0,025 mm, and the minimal dimension of

the processing hole is of 0,5 mm.As main beneficiary of the results forultrasound processing of rigid anddelicate materials is the electro technicalindustry, where is underlined the problemof processing and cutting-off semi-conducer materials, of insulatingceramic, of ferrite used in radio-techniques and calculus technique, of thememory elements and other fragilematerials. With special results it isapplied the ultrasound dimensional

processing in aeronautics, in watchmakerindustry and elements of fine mechanicsin the industry of medical and researchdevices, where is discussed the problemof processing materials like satellite,quartz, mica, ruby, sapphire and other

precious and semi-precious stones usedfor realising high precision and delicacy

bushing.


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PP

P

P

gfed

P P P P

a

P PP

bc

PP

i

P

jh

P

k

A

A

A

A A A A

AA ns

A

A

nsA

fe

np

np

AA

Fig. 1. Tipuri de operaii de prelucrare dimensionalcu ultrasunete:a- gurirea; b- debitarea; c- execuia orificiilor i cavitilor complexe; d- perforarea simultan; e-

prelucrarea filierelor;f- execuia orificiilor curbe;g- rectificarea ultrasonic; h- filetarea; i-canelarea dupo curbplan;j- honuirea ultrasonic; k- durificarea stratului superficial;A

amplitudinea oscilaiilor ultrasonore;P fora staticde apsare; ns, np turaia sculei i respectiv apiesei.

Fig. 1. Types of ultrasound dimensional processing operations:a- perforation; b cutting-off; c execution of complex holes and cavities; d simultaneous

perforation; e processing cutters;f processing of curve holes;g ultrasound rectification; h-


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threading; i grooving after a plan curve;j ultrasound honing ; k hardening of the superficiallayer;A amplitude of ultrasound oscillations;P pressing static force; ns, np speed of the tool and

of the piece

n industria constructoare de mainiprelucrarea dimensional cu ultrasunete i-agsit o arie larg de aplicare n prelucrareacomplex i de mare finee a carburilor dewolfram i a unor aliaje dure i fragileutilizate la construcia sculelor imatrielor.Dezvoltri recente au pus nevideni utilizarea cu succes a prelucrriicu ultrasunete la materialele sinterizate i la

prelucrarea bioxidului de uraniu utilizat n

centralele atomo-electrice.Creterea eficienei procedeelorclasice de prelucrare prin achiere se poateface prin introducerea n sistemul tehnologica vibraiilor ultrasonore. Astfel, s-au fcutnumeroase cercetri pentru a stabili influenaultrasunetelor asupra unor procedee clasicecum ar fi: strunjirea, frezarea, gurirea,lrgirea, alezarea, filetarea, broarea,rectificarea, polizarea, lefuirea, honuirea,lepuirea, ascuirea sculelor achietoare,

danturarea etc.Cercetrile experimentale ntrepinse

au scos n eviden o serie de avantaje alesuprapunerii oscilaiilor ultrasonore pesteforele din sistemul clasic de achiere, dintrecare:

-permite prelucrarea economic aunor materiale dure i extradure i greu

prelucrabile prin procedeele clasice;- mrete considerabil durabilitatea

sculelor achietoare(uneori cu peste

400600 0/0);- permite obinerea unei caliti

foarte bune a suprafeei, prin anihilareavibraiilor proprii ale sistemului tehnologic;

- conduce la reducerea cmpuluitermic i a tensiunilor remanente;

- creazposibilitatea creterii vitezeide achiere i a unor productiviti multsporite;

- conduce la micorarea substaniala momentelor i forelor de achiere;

In machines constructing industry,ultrasound dimensional processing found alarge application area in complex anddelicate processing of the wolfram carbideand of some tough and fragile alloys used atthe construction of tools and matrix. Recentdevelopment underlined the successful useof ultrasound processing of sinteredmaterials and processing uranium dioxidethat is used in atom-electrical stations.

Increasing the efficiency of classicalsplintering processing procedures can berealised by introducing in the technologicalsystem of ultrasonic vibrations. So, have

been realised numerous researches toestablish the ultrasound influence on someclassical procedures like: turning, trimming,

perforation, boring, threading, binding,correction, shaping, polishing, honing,lapping, shaping blade tools, toothing, etc.

Experimental researches that have

been realised underlined a series ofadvantages of over posing the ultrasonicoscillation over the forces from the classicalchipping system, from which:

-allows economic processing of somerigid and extra-rigid materials and hardly

processing ones by classical procedures;- increases in a considerable manner

the durability of the splintering tools(sometimes with over 400600 0/0);

- allows the procurement of some

very good qualities of the surface, byannihilation of own vibrations of thetechnological system;

- leads to the reduction of the thermalfield and or the remnant tensions;

- creates the possibility of increasingthe splintering speed and of some increased

productivities;-leads to the substantial attenuation

of the splintering moments and forces;- allows the alienation of burnings


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- permite nlturarea arsurilor imicrofisurilor la operaiile de finisare;

- permite binerea unor proprietifizico-mecanice net superioare ale suprafeei

prelucrate etc.

2.1. Burghierea n cmp ultrasonor

Execuia unor guri cu diametre marisau mici i pe lungime mare, n materialegreu prelucrabile, constituie o problemdificil, mai ales cnd se cere i o calitate

bun a suprafeelor prelucrate i o preciziemare la poziionare n raport cu alte

suprafee. Cercetrile ntreprinse au vizatintroducerea energiei ultrasonore fie n sculade achiere, fie n piesa de prelucrat sau nambele (fig. 2) n funcie de configuraia

piesei i a sculei introducndu-se oscilaiilongitudinale, torsionale saucomplexe.Experimentrile efectuate peoeluri carbon obinuite, pe oeluri aliateinoxidabile, oeluri refractare i rezistente lacoroziune, alam, bronzuri, i duraluminiu,folosindu-se scule din Rp3, n condiii

diferite de achiere au demonstrat o reducerecu 5990 0/0 a efortului axial i amomentului de torsiune odat cu cretereavitezei de achiere.

Eficiena sporit n cazul acestorprocedee se obine prin introducerea energieiultrasonore prin scul, dimensionareaacesteia fcndu -se n aa fel nct n ea sse excite unde longitudinale- torsionale. La

procesul de achiere o importan deosebito au oscilaiile longitudinale, care permit

ptrunderea uoar a lichidului de rcire nzona de desprindere a achiilor, iaroscilaiile torsionale permit reducereasubstanial a presiunilor specifice n zonade contact n momentul desprinderii sculeide pies i accelerarea procesului dedeformare plastic, urmat de fisurarea idesprinderea materialului n momentulcontactului scul- material.

and micro-fissures from the finishingoperations;

- allows the procurement of somephysical mechanical properties that are

superior to the processed surface etc.

2.1. Drilling in ultrasound field

The execution of some holes withgreat diameters and on great lengths, inhardly processing materials, is a difficult

problem, especially when is required a goodquality of the processed surfaces and a great

precision at positioning in rapport with other

surfaces. The researches that have beendeveloped, aimed the introduction ofultrasound energy either in the splinteringtool, or in the processing tool or in both (fig.2), depending on the configuration of the

piece or of the tool, introducing longitudinal,torsional or complex oscillations. Theexperiments that have been realised oncommon carbon steel, brass, bronze andduraluminium, using tools from Rp3, indiverse splinterign conditions showed a

reduction with 5990 0/0of the axial effortand of the torsion moment, once with theincrease of the splintering speed.

The increased efficiency as part ofthese procedures is obtained by introducingthe ultrasonic energy through the tool, itsdimensioning beign realised so that to berealised torsional longitudinal waves. At thesplintering process, a special importance is ofthe longitudinal oscillation, allowing a easy

penetration of the coolant in the area ofseparation of the chips, and the torsionaloscillations allow the substantial reduction ofthe specific pressures in the contact area, inthe moment of separating the tool from the

piece and the acceleration of the plasticallydeformation process, followed by thecracking and detachment of the material inthe moment of tool-material contact.


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P

fv

ns aL

a r

a 'Ln

Fig. 2 Introducerea undelor ultrasonore prin sculi prin piesla gurirea n cmp ultrasonor:aL, aL- amplitudinea de vibraie longitudinala sculei i respectiv a piesei; ar- amplitudinea

vibraiilor radiale;sv- avansul; ns, np- rotaia sculei, respectiv a piesei;P fora staticde apsare.Fig. 2 The introduction of the ultrasound waves through the tool and throug the piece at perforating in

ultrasound field:aL, aL the amplitude of longitudinal vibration of the tool and of the piece; ar- the amplitude ofradial vibrations;sv- advance; ns, np rotation of the tool, namely of the piece;P static pressure

force.

Suprapunerea oscilaiilor ultrasonoreconduce la o reducere a momentului detorsiune de 3,55 ori i a forei axiale cu30..60 0/0 fa de procedeul clasic,durabilitatea sculelor crete de 2,56 ori ntimp ce rugozitatea suprafeelor prelucrate sembuntete substanial.

2.2. Rectificarea n cmp ultrasonor

n cazul utilizrii energiei ultrasonoren procesul de rectificare, o deosebitimportan o prezint direcia i tipuloscilaiilor ultrasonore introduse deoareceacestea conduc direct la modificarea curseisi a vitezei granulei de abraziv. Rezultate

bune au fost obinute introducnd energiaultrasonor n piatra de rectificat (fig. 3,a)sau n piesa de prelucrat (fig.3.b).

Over posing the ultrasound oscillationsleads to a reduction of the torsion moment3,55 times and of the axial force with 30..600/0 regarding the classical procedure, thedurability of the tool increases 2,56 timesmeanwhile the asperity of the processedsurfaces improves in a substantial manner.

2.2. Rectification in ultrasound field

In case of using ultrasound energy inthe rectification process, a special importanceis presented by the direction and the types ofoscillations that are introduced, as these leaddirectly to the modification of the stroke andof the speed of the abrasive granule. Goodresults have been obtained by introducing theultrasound energy in the rectification stone(fig. 3,a) or in the piece to be processed(fig.3.b).


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a

Piatrde

f

sConcentrator de

energie ultrasonic

rectificat

Piesa-semifabricat

b

Concentrator de energieultrasonic

Piatrde

aLar

n (v )s

n

Piesa-semifabricat

p

rectificat

c

l

L

cn (v )

a

(vfc)

Fig. 3. Introducerea energiei ultrasonore n procesul de rectificare:

a- n piatra abraziv; b- n piesa semifabricat; ns(vc)- turaia pietrei abrazive (viteza micriiprincipale de achiere); np(vfc) turaia piesei(viteza de avans circular); aL; ar amplitudinea

oscilaiilor longitudinale i respectiv radiale;fl avansul longitudinal.Fig. 3. The introduction of the ultrasound energy in the rectification process:

a in the grinding stone; b in the semi-produced piece; ns(vc) the revolution of the grinding stone(the speed of the main splintering movement); np(vfc) revolution of the piece (speed of circular

advance); aL; ar the amplitude of the longitudinal and radial oscillations;fllongitudinal advance

S-a constatat c sub aciuneavibraiilor ultrasonore se obine oachiere mai rapid, calitatea suprafeeise mbuntete mai ales la rectificrileinterioare adnci, pericolul arderii seelimin i se mrete foarte multdurabilitatea sculei datorit intensificriiaciunii de autocur ire a pietrei.

Rezultate asemntoare au fostobinute i la alte prelucrri din domeniulfinisrii suprafeelor, cum ar fi ascuireasculelor, honuirea i lepuirea suprafeelori altele, problemele importante derezolvat fiind legate de modul deintroducere a energiei ultrasonore nfocarul de prelucrare.

It was observed that under theaction of ultrasound vibrations, it can beobtained a faster splintering, the qualityof the surface improves especially at thedeep internal rectifications, the burningdanger eliminates and increases much thedurability of the tools due to theintensification of the self-cleaning action

of the stone.Similar results have been obtainedalso at other processing from surfacesfinishing field, like shaping tools, honingand lapping surfaces as well as others, theimportant problems to be solved beingconnected to the modality of introducingan ultrasonic energy in the processingfocal point.


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3.

Concluzii

- introducerea n sistemul tehnologic avibraiilor ultrasonore duce la creterea

eficienei proceselor clasice de prelucrareprin achiere.- n cadrul cercetrilor realizate privindaplicarea vibraiilor ultrasonore ladiferite procedee de prelucrare prinachiere n literatura de specialitate aufost studiate trei direcii posibile deorientare a vibraiilor corespunztoarecelor trei componente ale forei deachiere. Problema stabilirii direcieioptime de aplicare a vibraiilor n

vederea obinerii unor anumiteperformane este abordat de un numrfoarte restrns de lucrri n care se aratc, exceptnd cteva cazuri particulare,numai aplicarea vibraiilor dup direciacomponentei principale a forei deachiere este practic i cu avantajevizibile.- la prelucrarea prin burghiere n cmpultrasonor cele mai multe cercetriexperimentale au fost efectuate pe oeluri

carbon obinuite, pe oeluri inoxidabile,oeluri refractare i rezistente lacoroziune, alam, bronzuri iduraluminiu, folosindu-se scule din Rp3,n condiii diferite de achiere. n toatecazurile s-a constatat o reducereimportant a efortului axial i amomentului de torsiune odat cucreterea vitezei de achiere. Cretereaamplitudinii oscilaiilor ultrasonoreconduce la reducerea efortului axial i amomentului de torsiune n condiiile

pstrrii unei viteze de achiereconstante. Mrimea amplitudinii areinfluene deosebite asupra eforturilor deachiere, acestea crescnd aproape

proporional cu amplitudinea pn la oanumit valoare funcie de naturamaterialului de prelucrat, dup careefectul rmne practic constant orict arcrete amplitudinea, lucru explicabil

deoarece odat cu creterea amplitudinii

3.

Conclusions

- introducing in the technologicalsystem of the ultrasonic vibrations lead to

the increase of efficiency of the classicalproducts of processing by splintering.- as part of realised researches

regarding the application of ultrasonicvibrations at different splintering

processing procedures in the specialtyliterature, have been studied three

possible directions of orientation of thevibration corresponding to the threecomponents of the splintering force. The

problem of establishing the optimal

direction for the application of vibrations,in order to obtain certain performances isapproached by a restricted number ofworks in which it is shown that, exceptingsome particular cases, only the applicationof vibrations, on the direction of the maincomponent of the splintering force is

practical and with visible advantages.- at processing by drilling in

ultrasonic field, most experimentalresearches have been realised on common

carbon steel, on stainless steels, refractorysteels, that are corrosion resistant, brass,

bronze and duraluminium, using toolsfrom Rp3, in different splinteringconditions. In all cases it was observed animportant reduction of the axial effort andof the torsion moment once with thesplintering speed. The increase of theamplitude of ultrasound oscillations leadsto the reduction of the axial effort and ofthe torsion moment in conditions ofmaintaining a constant splintering speed.The increase of the amplitude has specialinfluences on splintering efforts, theseincreasing almost proportionally withamplitude up to a certain value, dependingon the nature of the processed material,after that the effect remains constant notmatter the increase of the amplitude, thingthat can be explained as once with theincrease of the amplitude over a certain

critical value that is specific, would be


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peste o anumit valoare critic specificncepe s se desprind particule dematerial din tiul sculei.-toate cercetrrile, indiferent de metoda

de introducere a vibraiilor ultrasonore laprocedeele de rectificare, au demonstratefectele pozitive ale acestora asuprarezultatelor prelucrrilor i anume:scderi ale valorii forelor de achiere ia rugozit ii; o mrire a adncimii urmeilsate de granula abrazivi o diminuareaproape totala rsfrngerilor laterale dematerial pe marginile urmei lsate degranula abraziv; o reducere afenomenului de mbcsire a corpului

abraziv i autoascuirea acestuia pentruanumite valori ale amplitudinii vibraiilorultrasonice

separated material particles from thecutting edge of the tool.

-all researches, no matter themethod of introducing ultrasonic

vibrations to rectification procedures,showed their positive effects on theresults of processing, namely: decrease ofthe value of splintering speed and ofasperity; an increase of the depth left bythe abrasive granule and an almost totaldiminution of lateral reflection of materialon edges of the trace from the abrasivegranule; a reduction of the cogging

phenomenon of the abrasive body and itsauto-shaping for certain values of the

amplitude of ultrasonic vibrations.


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Bibliografie

1.Amza, Gh., DobrotD., Ultrasunetele Aplicaii active - Ediie revizuit

Editura Agir, Bucureti, 2007;2.Dobrot Dan, Amza Gheorghe, Bazeleproiectrii proceselor de prelucrare prin

achiere, Editura Sitech, Craiova, ISBN973-746-442-7, ISBN 978-973-746-442-7, , 20073. Shimizu, M., Jindai, A., Cutting devicefor an ultrasonic vibration system, UnitedStates Patent no. 3859 876/1975;4. Chirculescu G., DobrotD., Ultrasonicfield turning, Analele Universit ii

Constantin Brncui, Trgu-Jiu, SeriaInginerie, nr. 1/ 2006, pag. 43-46, ISSN1842-4856.

Bibliography

1.Amza, Gh., Dobrot D.,Ultrasounds Active applications

Reviewed edition Agir PublishingHouse, Bucharest, 2007;2.Dobrot Dan, Amza Gheorghe,

Basis of designing the splintering

processing, Sitech Publishing House,Craiova, ISBN 973-746-442-7, ISBN 978-973-746-442-7, , 2007

3. Shimizu, M., Jindai, A., Cuttingdevice for an ultrasonic vibration system,United States Patent no. 3859 876/1975;

4. Chirculescu G., Dobrot D.,

Ultrasonic field turning, Annals of theUniversity Constantin Brncui, Trgu-Jiu, Engineering Section, no. 1/ 2006,

pag. 43-46, ISSN 1842-4856.

5 dan dobrota

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