This research presents the theoretical model, simulation and experimental verification of the maximum stepover estimation for different cases on the machine surface profile using the end-filleted ...cutter in multi-axis machining. Where in this research, the equations that detect the maximum stepover at allowable scallop height value have been taking into consideration and derived to predict the tool path generation for different inclination angles of tool axis. A set of inclination angles of cutter tool axis that can machine the workpiece have been taken into consideration depending on the shape of the workpiece. The inclination angle of the tool axis, effective cutter radius, and the geometrical shape of the workpiece have been studied and experimentally verified for milling operation. The results show that the proposed model for estimating stepover at constant scallop height can predict the tool path generation for machining sculpture surfaces using CNC multi-axis machine.
At many building sites there isn't sufficient space to manoeuvre the dumper in various directions to discharge the material to the front and side ways. In such situations, there is a growing demand ...of multi-axis articulated dumpers. This work deals with the fabrication of scale down prototype of three way dropping dumper wherein the dumper is operated using pneumatic tilting mechanism. There are three hydraulic cylinders which are operated by motor and gearbox to tilt the dumper body in all three directions. To maintain optimum efficiency of pneumatic system, the pressure drop between generation and consumption of compressed air is kept very low. Based on the initial prototype and tilting trials, it is demonstrated that this multi-axis system can be fully implemented in large scale. Further, the proposed pneumatic system can be automated with additional control system replacing the socket-pin arrangement to change the tilt directions with minimum human intervention.
A laboratory study was conducted to investigate the effects of lateral and horizontal vibration on the difference threshold of vertical vibration. Twelve male subjects sat on a rigid seat and were ...exposed to four different vibration conditions (pure vertical vibration; combination of horizontal and vertical vibration; combination of lateral and vertical vibration; combination of horizontal, lateral and vertical vibration). Vertical vibration for four conditions was 5 Hz sinusoidal with a magnitude of 1 ms-2 r.m.s. Horizontal and lateral vibration for the last three conditions were sinusoidal with magnitude 0.5 ms-2 r.m.s. and contained ten frequencies (1 to 8 Hz in third-octave band step). The frequency-weighted acceleration of the ten frequencies was equal. Results showed that horizontal and lateral vibrations have different effects on the difference threshold of vertical vibration. The combination of vertical and horizontal vibration gave a significantly lower difference threshold of vertical vibration than the combination of vertical and lateral vibration.
The paper presents a survey of five-axis computer numerical controlled (CNC) machining optimization methods employing adaptable geometric patterns. First, the survey introduces evolution of CNC ...interpolators from the simplest Taylor series-based routines to sophisticated procedures based on constraint minimization from dynamic systems control theory. Furthermore, a variety of methods based on spline interpolation, NURBS interpolation and Farouki’s Pythagorean–hodograph curves is presented and analyzed. Next, the survey deals with techniques to optimize the positions and orientations of the tool in a particular neighborhood of the part surface. The most important application of these techniques is cutting by a flat-end or a fillet mill while avoiding local overcuts or undercuts due to the curvature interference and rear gouging. This section is supplemented by detection of global interference using visibility cone schemes and their recent modifications and improvements. Solutions offered by solid modeling are presented as well. Finally, adaptable geometric patterns employed for tool path generation are considered and analyzed. The adaptation is performed using certain criteria of the tool path quality, such as kinematics error, scallops, possible undercuts or overcuts, and the continuity of the path. Also covered are complex pocket milling employing geometric patterns capable of following the boundary, such as the offset methods, regional milling, the potential path methods, and clustering. The chapter also presents tool path optimization based on the adaptable curvilinear grids connecting the cutter location points. Finally, navigation approaches and the shortest-path schemes are considered, along with the adaptive space-filling curve algorithms and their combinations with grid generation.
The determination of the local field direction enables, for instance, migratory birds to find their annual routes from one continent to another, or magnetotactic bacteria to move towards soil rich in ...nutrients. In analogy, for microelectromechanical systems (MEMS), the ability of detecting the local direction of a magnetic field as a 2D or 3D vector can allow, in principle, a reliable autonomous navigation through environments with a complex or unknown topology. These applications demand, however, a very low power consumption, miniaturizability and fast response times in the milliseconds range. In the following, we present novel 2D sensors based on exchange-biased IrMn / CoFe / Cu / CoFe – NiFe spin valves fulfilling all these requirements. In addition, we test different sensor arrangements. The spatial sensitivity of the constituent single GMR meanders is defined by means of microscopic laser heating and subsequent in-field cooling. By this, a relative pairwise geometric alignment of 90° or 180°, respectively, is achieved for the individual antiferromagnetic pinning layers, providing a maximum signal response for each sensor layout. On the basis of fabricated prototypes with a size of < 0.5 mm2, we demonstrate that these sensors can readily be employed to detect small magnetic fields as a 2D vector with a high temporal resolution of 100μs.
This study aims to establish a practical method for simulating the spindle coupled multi-axial loading fatigue test of a rear axle. A dynamic finite element model of the minivan rear axle was ...constructed and validated using a static calibration test. Based on the theory and methodology of the Schenck ITFC system, a simulation process was devised which includes system identification, calculation of the input loading signals for the finite element model, calculation of the response stress signals based on this model, calculation of the response strain signals from the corresponding stress signals, and finally, a comparison of the desired and achieved signals. The corresponding data processing programs were made using MATLAB, ensuring their easy reproducibility. The desired signals were measured on the Hainan proving ground for a duration of 2441.216 s, using strain gauges and rosettes placed in important stress-prone locations of the rear axle. The results indicate that the desired signals can be reproduced quite accurately, ensuring that the strain distribution of the rear axle in the field can be reasonably predicted.
With the evolution of machine tools and the emergence of new cutting tools such as cermet, CBN; and in framework of the production of parts with complex geometry, the manufacturers were able to ...realize more and more parts of complex shape. The multi-axis machining is the main technique for achieving the free form; in fact the multi-axis milling with ball end tools attracts the interest of the aerospace industry and the mussel industry which continues to seek ways to improve the surface quality of finished parts. The titanium alloy is widely used in aerospace industry is the subject of this study in fact, the integrity of the surfaces of parts produced by multi-axis milling is an issue more relevant than ever for the aerospace industry. This paper aims to study the influence of the tool position and the parameters cutting precisely the speed feed Vf, the engagement of the tool on the roughness 3 D, micro-hardness and microstructure alteration created in sub-surface during the milling of concave surface of titanium alloy type Ti-6Al-4V.
This paper proposes a methodology for enabling a 3 axes Mill CNC machine to work in a synchronized operation with 5 axes. Different alternatives for communicating the fifth axis were analyzed, as ...using a TRT-160 with a microcontroller and an analog multiplexer. Another option could be done by using a CNC via serial bus and a Microcontroller digital I/O ports, passing the code through a converter code, replacing some command lines and directing the additional axis instructions to the servomotors via RS-232 serial bus to generate displacement on the servomotors that emulates the fourth and fifth axis. It could achieve synchronization of two conventional servomotors with a HAAS VF-2 Mill Machine that opens the possibility for evaluating six o more axes movement related to a complex machining process, as well as connecting a robotic arm or a conveyor belt in a manufacturing cell.
Three-axis processing of laser inner engraving machine control system can carry on multi-axis linkage control. Furthermore, it ensures multi-axis of high feeding speed and trajectory control of high ...precision. This article introduces the design of laser inner engraving machine movement control system. The core is a digital integrator of linear interpolation algorithm to generate the desired trajectory and control XYZ axis linkage. Wide speed range of servo motor and position detector resolution is adequate to constitute a half-closed loop drive. With integral separation algorithm being introduced in the controller, the speed of numerical control system, track speed and positioning accuracy are guaranteed in order to achieve optimal specification for dynamic and static characteristics of the whole system.
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