Contouring accuracy of a machine tool: design of a performance test and optimization of the Jerk

• Autorzy: Pittala G. M. , Monno M.
• Języki publikacji: EN

Abstrakty

EN

With increasing demand of high feed rates the dynamical characterization of a milling center is becoming a strategic aspect. The contouring accuracy at high feed rates and high acceleration is vital in order to preserve the tolerance integrity of parts produced with high speed machining. The dynamic accuracy is influenced by the velocity, acceleration and Jerk. While the cutting speed depends from technological considerations and the maximum velocity and the acceleration depends from the mechanical structure, what value assign to the Jerk is not well defined. The Jerk has an important impact on the execution time of a tool path in a mould/die production, where there are frequent accelerations and decelerations, and a high jerk leads to a deteriorated surface accuracy and an unsmooth machining process. In this paper, experimental test were conducted on various milling centers in order to define the Jerk value. Firstly, some tool path features are introduced in order to consider the effect of the trajectory. Then a tool path, called STAR, is designed and it has been tested by changing the Jerk. A mathematical model able to estimate the execution time it was prepared. A performance test is designed in order to estimate the contouring accuracy in relation with Jerk for all tool paths. The best value of Jerk is the compromise between high accuracy and high productivity. Then an objective function is introduced in order to optimize the Jerk.

Słowa kluczowe

EN

contouring accuracy; jerk; productivity; milling center

• Wydawca: Wydawnictwo Wrocławskiej Rady FSNT NOT
• Czasopismo: Journal of Machine Engineering
• Rocznik: 2009
• Tom: Vol. 9, No. 3
• Strony: 29--41
• Opis fizyczny: Bibliogr. 14 poz., tab., rys.

Twórcy

autor

Pittala G. M.

• Department of Mechanical Engineering, Politecnico di Milano, Via La Masa 1, 20156, Milan, Italy

autor

Monno M.

• Department of Mechanical Engineering, Politecnico di Milano, Via La Masa 1, 20156, Milan, Italy

Bibliografia

• 1. ALTINTAS Y., ERKORKMAZ K., 2003, Feedrate optimization for spline interpolation in high speed machine tools, Annals of CIRP, 52/297–302.
• 2. DEMAUREX M. O., 1979, Approche Theorique de la conception de la structure mecanique d’un robot industrie, Ph.D. Dissertation, EPFL, Lausanne, Switzerland.
• 3. DONG J., FERREIRA P.M., STORI J.A., 2007, Feed-rate optimization with jerk constraints for generating minimum trajectories, 47/1941-1955.
• 4. DONMEZ M.A., 1985, A general methodology for machine tool accuracy enhancement: Theory application, and implementation, Ph.D. Dissertation, Purdue University, West Lafayette, IN.
• 5. ERKORKMAZ K., ALTINTAS Y., 2001, High speed CNC system design. Part I: jerk limited trajectory generation and quintic spline interpolation, International Journal of Machine Tools and Manufacturing, 41/1323-1345.
• 6. FLORES V., ORTEGA C., ALBERTI M., RODRIGUEZ C.A., DE CIURAMA J., ELIAS A., 2007, Evaluation and modeling of productivity and dynamic capability in high-speed machining center, Int. J. Adv. Manuf. Technol., 33/403-411.
• 7. JYWE W., 2003, The Devolopment and Application of a Planar Encoder Measuring System for Performance Tests of CNC Machine Tools, Int. J. Adv. Manuf. Techn, 21/20-28.
• 8. MANN B. P., EDES B. T., EASLEY S. J., YOUNG K.A., MA K., 2008, Chatter vibration and surface location error prediction for helical end mills, Int. J. of Mach. Tools & Manuf., 48/350-361.
• 9. SCHIMITZ T. L., ZIEGERT J., 2000, Dynamic evaluation of spatial CNC contouring accuracy, Precision Engineering, 24/99-118.
• 10. SCHMITZ T., MANN B. P., 2006, Closed-form solutions for surface location error in milling, Int. J. of Mach. Tools& Manuf., 46/1369-1377.
• 11. SCHMITZ T. L., COUEY J., MARSH E., MAUNTLER N., HUGHES D. 2007, Runout effects in milling: Surface finish, surface location error, and stability, Int. J. of Mach. Tools & Manuf., 47/841-851.
• 12. SCHMITZ T. L., ZIEGERT J. C., CANNING J. S., ZAPATA R., 2008, Case study: A comparison of error sources in high speed-milling, Precision Engineering, 32/126-133.
• 13. SHLESINGER G., 1932, Inspection Test on Machine Tool, Machinery Publishing Co. Ltd London.
• 14. SRINIVASA N., ZIEGERT J. C., MIEZE C. D., 1996, Spindle thermal drift measurement using the laser ball bar, Precision Engineering, 18/118-128.