Plane Machining by Inner-Jet Electrochemical Milling of TiB2/7050 Aluminum Matrix Composite

Electrochemical milling (ECM) is an ideal technique for machining thin-walled structural parts of aluminum matrix composites. Adopting a reasonable tool cathode structure, feed rate, and processing method can improve the machining efficiency. In this study, a tool cathode with a reasonable structure was selected through flow field simulation. Then, the material removal rate (MRR) and surface roughness were studied using various ECM parameters. Finally, the transverse movement and processing method in which the starting position was rotated 90° were studied, and a plane of 59 × 59 mm was machined. The experimental results show that using an appropriate tool cathode can create a more uniform flow field. The MRR was 168.6 mm3/min and the surface roughness (Ra) was 3.329 µm at a feed rate of 30 mm/min. For machining larger plane structures, a transverse movement of 7 mm is verified to be the most suitable because of the best smoothness in the middle of the two processes. By using the same machining method and rotating the starting position 90°, the flatness of the processing plane decreased from 0.296 mm to 0.251 mm, a reduction of 15.2% compared to that obtained in the first processing.

Exploiting limitations of fused deposition modeling to enhance mixing in 3D printed microfluidic devices

Purpose The purpose of this study is to introduce an alternative construction for microfluidic micromixers, where the effect of the extruded filaments in the fused deposition modeling (FDM) technique is used to enhance mixing performance identified as a challenge in microfluidic micromixers. Design/methodology/approach A simple Y-shaped micromixer was designed and printed using FDM technique. Experimental and numerical studies were conducted to investigate the effect of the extruded filaments on the flow behavior. The effects of the extruded width (LW), distance between adjacent filaments (b) and filament height (h1) are investigated on the mixing performance and enhancing mixing in the fabricated devices. The performance of fabricated devices in mixing two solutions was tested at flow rates of 5, 10, 20, 40, 80 and 150 µL/min. Findings The experimental results showed that the presence of geometrical features on microchannels, because of the nature of the FDM process, can act as ridges and generate a lateral transform through the transverse movement of fluids along the groove. The results showed the effect of increasing ridge height on the transverse movement of the fluids and, therefore, chaotic mixing over the ridges. In contrast, in the shallow ridge, diffusion is the only mechanism for mixing, which confirms the numerical results. Originality/value The study presents an exciting aspect of FDM for fabrication of micromixers and enhance mixing process. In comparison to other methods, no complexity was added in fabrication process and the ridges are an inherent property of the FDM process.

Research Motor Capabilities of the Executive Authority (MP) PKM When Making Cross Motion Angle

For the manufacture of parts of complex shapes, it becomes necessary to move the cutting tool along the line at a certain angle. For this, machines equipped with mechanisms of parallel structure are used. Only a study of the movable capabilities of these mechanisms makes it possible to introduce them into production. The studies focus on the transverse movement of the center of the moving platform of the parallel structure mechanism for a hexapod machine, as a material point moving along a line depending on the angle of contact of the tool and the perpendicular to the plane of the work surface (axis of symmetry of the mechanism). To determine the possible positions of the center of the moving platform, we consider a generalized scheme of the parallel structure mechanism. Given the restrictions on movement, the area of possible positions is divided into zones: Zrp - without a cutting tool; Zri - the zone of positions of the top of the instrument. The part that is being processed is installed on the technological device, which is placed on the basis of a parallel structure mechanism. Parameters of a machine with a parallel structure mechanism: a, b - distance between the supports of the stationary carrier system and the executive body, respectively; Lmax is the maximum length of the kinematic links; lmin is the minimum length of the kinematic links; li is the current length of the kinematic links; l is the magnitude of the transverse movement; φ is the angle of inclination of the executive body; hi is the current position of the executive body of the mechanism of the parallel structure in height. The assessment of motor capabilities is determined by the displacement index, which is the ratio of the actual displacement value l to the theoretically possible one (taken equal to the maximum rod length Lmax). From the above dependencies it is seen that the influence of the motor capabilities of the rods on the relative displacement provides an increase in the displacement index in the indicator section from 0.45 to 0.65, then the section that is affected by the slope of the displacement line, with a decrease in which the displacement in the area of0.8 up to 1 movement decreases again, this is due to the complex geometry of the service area ofthe working space of the machine with a parallel structure mechanism. On the effect of the ratio of the sizes of the movable to the fixed platform on the relative displacement, we have that with an increase in the indicator, the initial indicator of the relative displacement also increases, with a value of the exponent n starting from 0.6 its value decreases in all cases. The influence of the ratio of the maximum displacement of the rods to the size of the fixed platform, on the relative displacement has the opposite of the previous character. With an increase in the indicator m, the relative displacement indicator increases, with a further increase in the indicator m, it can be seen that significantly decreases the displacement indicator and with a value less than 0.6.

Targeting the user experience in the development of mobile machinery using real-time multibody simulation

Applying a semi-recursive multibody approach enables the solution of the equations of motion of a complex system in real time. This makes it possible to conduct human-in-loop simulations and analyse the user experience. The idea of recognizing the user experience to produce more efficient, competitive, and user-friendly products has been limited thus far to the field of information technology and the development of light physical products. This study introduces a simulation modelling procedure for a complex forklift mast system that can be used to help analyse the user experience. A multibody forklift model is introduced that includes the electric motors, a pump, a freelift, a mainlift and tilt cylinders, actuators, pulley and chain mechanisms, contacts, and tyres. The viscoelastic behaviour of the chain during longitudinal and transverse movement is simulated using a discrete model approach. Triplex mast speeds and hydraulic system efficiencies across working cycles are used to verify the performance of the introduced real-time simulation model against measurements taken from an equivalent reference forklift. To better evaluate the developed model, experienced and inexperienced forklift drivers were asked to drive an updated simulator and provide feedback. User experience inputs that can be made available early on in development using this new modelling approach will permit experts to evaluate and design more efficient complex mechanical systems.

Influence of the solenoid magnetic field on the self-modulation mechanism

For the guarantee of the long-distance transport of the bunches of China Initiative Accelerator Driven System (CIADS), a new scheme is proposed that extra magnetic field is used in the accelerator-target coupling section before the windowless target to minimize the self-modulation (SM) mechanism. Particle-in-cell simulations are carried out to study the influence of the solenoidal magnetic field on the self-modulation mechanism when long proton bunches move in the background plasmas. The long proton bunches used in the simulations are similar to these in the linear accelerator of CIADS. It is found that the presence of the solenoidal magnetic field will significantly inhibit the self-modulation process. For the strong magnetic field, the longitudinal separation and transverse focusing of the long bunches disappear. We attribute these phenomena to the reason that the strong solenoidal magnetic field restricts the transverse movement of plasma electrons. Thus, there are not enough electrons around the bunch to compensate the space charge effect. Moreover, without transverse current, the longitudinal pinched effect disappears, and the long bunch can not be separated into small pulses anymore.

Object Model of Technical Solutions for Designing a Locomotive Train

The task of creating a method for constructing components and parts of a locomotive drive, allowing not only to simulate the physical properties of the latter but also to form and automate the recognition of technical solutions, is considered. A model of a traction drive, which is a system of sets of descriptions of real objects of the set which makes it possible to create mathematical models of the structure in the form of a set of related elements included in the libraries of well-known solutions, is proposed. In contrast to previously known methods based on the procedure of creating new solutions under which a prototype of the structure is made and then improved on the basis of an empirical analysis of its development (while the design task is to create new structures). In the proposed method the basis for the construction of the technical system objective model is the classification of technical systems. Solutions to eleminate jamming of the sleeves of the axes with the transverse movement of the engine are proposed. A patent for the invention and two patents for the utility models are obtained.