Papers by Keyword: Force Modeling

Abstract: Boring operations of deep holes with a slender boring bar are often hindered by the precision because of their low static stiffness and high deformations. Because of that, it is not possible to remove much larger depths of cuts than the nose radius of the tool, unlike the case of turning and face milling operations, and consequently, the relationship between the cutting force distribution, tool geometry, feed rate and depth of cut becomes non-linear and complex. This problem gets worse when working with a rotating boring head where apart from the cutting forces and the variation of the inclination angle because of shape boring, the bar and head are affected by de centrifugal forces. The centrifugal forces, and therefore the centrifugal deflection, will vary as a function of the rotating speed, boring bar mass distribution and variable radial position of the bar in shape boring. Taking in to account all this effects, a load and deformation model was created. This model has been experimentally validated to use as a corrector factor of the radial position of the U axis in the boring head.

Abstract: Rough end mill tools with serrated cutting edges profile are extensively used for removing a bulk of material and suppressing the chatter vibrations during milling operations. The serrated profile of cutting edge has phase shift from one flute to the next and interfere with the regeneration of waviness of the cut surface. In this research, serrated cutting edges are analytically defined and geometrically modeled as a NURBS curve. In addition; the chip load on the serrated cutting edges is calculated by a newly proposed algorithm. The validity of the algorithm is investigated by applying solid modeling techniques using ACIS 3D solid Modeler. In order to validate the results, several experiments were performed by utilizing serrated end mill. Verification of simulated and experimental results shows that the developed algorithm can be effectively implemented to simulate the cutting force for any geometry of milling tools as well as serrated end mills.

Abstract: Due to influence of size effect, the force properties in nanoscale are greatly different from those in macroscale and the traditional models of operation are becoming difficult to meet the development of nanoscale manipulation. To provide guiding theory for practical nano-manipulation, the nanoscale forces of contact and non-contact operation of nanowires are analyzed for nano-manipulation in SEM. The Vander Waals models among the probe, nanowire and substrate are modeled according to the force properties in nanoscale, and then the simplified models are simulated with MATLAB. The influence degree of various factors and the relationship of them during the operation are obtained. At last, experimental system is established to verify the correctness of the proposed models.

Abstract: With the development of aerospace, biomedical and chemical industries, titanium alloy Ti-5Al-5Mo-5V-1Cr-1Fe (TC18) is becoming widespread used. TC18 has even better mechanical property than Ti-6Al-4V (TC4). For better cutting TC18, simulation model was set up. PVD and CVD coated carbide inserts were used to machine titanium alloy TC18. The cutting forces were measured. Milling model was set up for the extraction of the cutting force coefficients and chip flow angle. Results were compared. All the coefficients of CVD coated carbide insert were found to be larger than those of PVD coated carbide insert. The model was proved to be reasonable after validation.