Acest capitol a rezumat câteva aspecte importante din literatură privind procesele de prelucrare hibridă pentru a înțelege mecanismele proceselor hibride existente și capacitățile acestora. Procesele de prelucrare în general sunt clasificate în procese mecanice, termice, chimice și electrochimice pe baza mecanismului lor dominant de îndepărtare a materialului. În consecință, prelucrarea are loc atunci când energia furnizată este suficientă pentru a provoca deformare plastică, schimbare de fază sau dizolvare. Când există posibilitatea ca mecanismul dominant să obțină asistență copleșitoare sau chiar redusă de la unul sau mai multe dintre celelalte mecanisme, este posibil să se dezvolte un sistem hibrid. Acest lucru este evidențiat în următoarele exemple (Kozak și Rajurkar 2000):
This chapter has summarized some important aspects of the literature on hybrid machining processes to understand the mechanisms of existing hybrid processes and their capabilities. Machining processes in general are categorized into mechanical, thermal, chemical, and electrochemical processes based on their dominant material removal mechanism. Accordingly machining occurs when the energy supplied is sufficient to cause plastic deformation, phase change, or dissolution. When there is scope for the dominant mechanism to get overwhelming or even subdued assistance from one or more of the other mechanisms, it is possible to develop hybrid system. This is highlighted in the following examples (Kozak and Rajurkar 2000):

1. Asistență termică: Creșterea temperaturii ajută la accelerarea defecțiunii prin forfecare în tăierea mecanică și reacții cinetice în interacțiuni chimice/electrochimice.
2. Asistență mecanică: Îndepărtarea mecanică a straturilor subțiri de oxizi și alți compuși intensifică dizolvarea anodică. Cavitația și agitația generate de vibrațiile ultrasonice îmbunătățesc performanța proceselor EDM, ECM și LBM.
3. Asistență chimică/electrochimică: Schimbarea densității de dislocare și creșterea vitezei de dislocare datorită reducerii potențialului de suprafață cauzată de reacțiile chimice facilitează deformarea plastică. Generarea de bule de gaz în reacția electrochimică facilitează descărcările electrice. Oxidarea crește absorbția de radiație a metalelor și scade pragurile de densitate de radiație pentru topire și vaporizare în timpul prelucrării cu laser.
1. Thermal assistance: The temperature rise helps to accelerate the shear failure in mechanical cutting and kinetic reactions in chemical/electrochemical interactions.
2. Mechanical assistance: The mechanical removal of thin layers of oxides and other compounds intensifies the anodic dissolution. Cavitation and agitation generated by ultrasonic vibrations enhance the performance of EDM, ECM, and LBM processes.
3. Chemical/electrochemical assistance: Change of dislocation density and increase of dislocation velocity due to surface potential reduction caused by chemical reactions facilitate plastic deformation. Generation of gas bubbles in electrochemical reaction facilitates electrical discharges. Oxidation increases the radiation absorptivity of metals and decreases the radiation density thresholds for melting and vaporization during laser machining.

Rata de îndepărtare a materialului (MRR) într-un proces hibrid H format din combinația a două procese constitutive A și B poate fi exprimată prin QH= QA+QB+QAB unde QA este MRR datorat lui A, QB este MRR datorat lui B și QAB este efectul lor sinergetic care poate fi determinat din rezultatele experimentale. Semnificația lui QAB va ajuta la identificarea procesului de prelucrare hibrid viabil din punct de vedere economic. Modelele teoretice și ecuațiile de energie sunt disponibile în literatură pentru majoritatea proceselor. Cunoașterea semnificației lui QAB va fi utilă în dezvoltarea unui model global pentru procesul hibrid. Este obișnuit să existe doi sau trei constituenți, așa cum se arată în Tabelul 1. A fost dezvoltat și un proces hibrid cu până la patru constituenți, cum ar fi prelucrarea electrochimică asistată de abraziv magnetic. Cu toate acestea, complexul fizico-chimic, electric, termic, și interacțiunile mecanice asociate proceselor de prelucrare hibridă nu sunt încă pe deplin înțelese. Fezabilitatea proceselor marcate cu „?” în Tabelul 1 și motivele incompatibilității/absenței nu sunt clare. Mai multe probleme enumerate mai jos rămân nerezolvate.
Material removal rate (MRR) in a hybrid process H formed by the combination of two constituent processes A and B can be expressed by QH¼ QA+QB+QAB where QA is the MRR due to A, QB is MRR due to B, and QAB is their synergetic effect which can be determined from the experimental results. The significance of QAB will help to identify economically viable hybrid machining process. Theoretical models and energy equations are available in literature for most of the processes. Knowing the significance of QAB will be useful in the development of global model for the hybrid process. It is common to have two or three constituents as shown in Table 1. Hybrid process with as many as four constituents such as magnetic abrasive-assisted electrochemical machining has also been developed. However, the complex physicochemical, electrical, thermal, and mechanical interactions associated with hybrid machining processes are yet to be fully understood. The feasibility of processes marked “?” in Table 1 and the reasons for the incompatibility/absence are not clear. Several issues as listed below remain unresolved.

De exemplu:

1. Există vreo limită tehnică sau economică a numărului de componente în procesul de prelucrare hibridă?
2. Numărul de constituenți modifică mecanismul de interacțiune/eficiența constituenților individuali? Dacă da, atunci de ce? Cum?
3. Cum se identifică compatibilitatea (sau incompatibilitatea) proceselor constitutive pentru a obține efectele lor sinergice?

Potențialul de investigare constă în continuare în modelarea matematică a diferitelor procese hibride pentru evaluarea efectelor diferiților parametri de intrare asupra calității prelucrării. Acest lucru va îmbunătăți și mai mult aplicațiile industriale ale tehnologiilor hibride.

For example:
1. Is there any technical or economic limit on number of constituents in hybrid machining process?
2. Does the number of constituents change the interacting mechanism/efficiency of individual constituents? If yes, then why? How?
3. How to identify the compatibility (or incompatibility) of constituent processes to reap their synergetic effects?

Potential for investigation lies further in mathematical modeling of different hybrid processes for evaluating effects of various input parameters on machining quality. This will further enhance industrial applications of hybrid technologies.

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