Vibratory Feeder Research Articles

Piezoelectric Driving of Vibration Conveyors: An Experimental Assessment

Vibratory feeders or vibratory conveyors have been widely used for the transport and orientation of individual parts and bulk materials in many branches of industrial activity. From the designer's standpoint, the current endeavor is to conceive efficient vibratory feeders, satisfying constraints of power consumption, vibration transmission and noise emission. Moreover, the interest in the reduction of maintenance cost is always present. In this context, this paper investigates experimentally the concept of vibratory conveying based on the use of piezoelectric materials for motion generation. A small-size prototype of a linear conveyor, in which lead-zirconate-titanate (PZT) patches are bonded to the resilient elements, is described. One of the main design goals is that the prototype is intended to be fed directly from the electric network, aiming at avoiding the use of electronic equipment for driving. To comply with this feature and, at the same time, enable to adjust the transport velocity, a mechanical device has been conceived in such a way that the first natural frequency of the conveyor can be changed. It is shown that the transport velocity is determined by the proximity between the excitation frequency and the first natural frequency of the conveyor. The experimental tests performed to characterize the dynamic behavior of the prototype are described and the range of transport velocities is determined.

Validation of dynamic modelling of an industrial vibratory bowl feeder

This paper presents a simple approach to model an industrial vibratory bowl feeder. The vibratory feeder is a device used to separate, feed and locate automatically a variety of parts in order to speed up the process of manufacture and assemble in industry. The analytical model obtained is validated through an experimental setup, assembled in laboratory, composed by a capacitive MEMS accelerometer and a data acquisition board all integrated in a LabVIEW application. The accelerometer is composed by an integrated circuit with a capacitive cell and gives an electric signal proportional to the acceleration. This digital signal is integrated twice in order to obtain the level of displacement inside the feeder. Preliminary results show that a good agreement between the experimental and analytical models was achieved. Key words: Vibratory bowl feeder, vibration, modeling.

Influence of Material Moisture on the Tribocharging Process of Plastic Granules

The control of the triboelectrification factors is the key for a successful application of electrostatic separation to the recycling of mixed plastics waste. This article focuses on the influence of material moisture on the tribocharging process of three granular materials: polyamide (PA), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). Different values of moisture content were obtained by immersing the material in water or drying it in a laboratory oven. Afterward, the granular material was tribocharged on the tray of a vibratory feeder and the accumulated charge was measured by an electrometer. The maximum charge/mass ratio was obtained for the three plastic materials at different values of moisture content: 0.27% for PA, 0.12% for PET 0.1% for PVC. Series of 5 consecutive tribocharging experiments performed on the same sample, show that the first contributes with the greater amount of granules charge while the other four only slightly increment this value. The graphical representation of the evolution of the charge/mass ratio versus number of tribocharging experiment conducts to the conclusion that: i) the charge of the granules tends to saturate; ii) it is useless to excessively increase the duration of the tribocharging process.

A numerical 2D simulation of part motion in vibratory bowl feeders by discrete element method

Vibratory bowl feeder is known as one of the major machines in automatic assembly. The feeding parts in a vibratory bowl feeder are experiencing repeated impacts with friction that can be considered as a typical non-linear dynamic problem. In this paper, a 2D numerical model based on discrete element method has been developed to perform a more accurate investigation on the dynamic behavior of a feeding part. In contrast to previous researches, it was assumed that the feeding part was not a point mass, instead, a rectangular shape that can rotate and have three degrees of freedom. By performing the simulation for various vibration amplitudes, a good degree of agreement was observed between calculated data and the experimental data reported in the literature. It was shown that, depending on the vibration amplitude, the graph of mean conveying velocity versus amplitude was composed of three distinct regions. It was found that while the coefficient of friction mostly affects the conveying velocity in sliding regime, it did not have a significant effect on the conveying velocity after a critical point in hopping regime. The mean conveying velocity was dependent on the part shape and vibration angle. The proposed model is capable of demonstrating both the periodic and chaotic behavior of the feeding part.

Practical Comparison of Commercial Starter Diets for Feed Training Largemouth Bass Fingerlings

We compared performance (growth, survival, and condition) of northern largemouth bass Micropterus salmoides salmoides fingerlings fed one of three commercial starter feeds: Otohime Marine Weaning (OMW; Marubeni Nisshin Feed), Bio-Oregon BiVita Fry (BVF; Bio-Oregon), and Purina Aquamax Starter (PAS; PMI Nutrition International LLC). Nine 833-L circular tanks, connected in parallel to a recirculation system, were stocked with 465 fish (1.4 kg), each to provide a rearing density of 1.1 fish/L. Water temperature was maintained at 27°C, and photoperiod was 15:9 h light:dark. Feed sizes (1.5–1.6 mm) were comparable and had similar protein composition (48%–50%). Feed was dispensed by vibratory feeders at a rate of 5% BWPD from 0730 h to 2130 h every 0.5 h for a total of 29 feedings per day (trial duration = 22 days). Overall performance was best for fish fed OMW, followed by BVF, then PAS. The PAS feed resulted in significantly lower growth, survival, and condition factor (P ≤ 0.05). Though not statistically significant, the BVF feed resulted in lower growth, condition factor, and survival than OMW (P > 0.05). Performance measures were positively correlated with crude fat and negatively correlated with protein to energy ratio of feeds. The OMW or BVF diets may be more appropriate for intensive culture when the artificial feed is the sole food supply, while the PAS diet may be more suitable for extensive culture as a supplemental food source.

Set point identification of a tribocharging process for mixed granular solids

Identification of the optimal operating conditions is a critical issue for the industrial application of tribocharging techniques. The aim of this paper is to formulate a set of recommendations regarding the choice of tray length, vibration amplitude and material feed-rate values for a vibratory-type tribocharger. The study was carried out on a laboratory vibratory feeder with granular plastics originating from waste electrical and electronic equipment. Several one-factor-at-a-time experiments followed by a composite factorial experiment were performed based on a two-step strategy: 1) identifying the domain of variation of the controlled variables; 2) finding the best choice of the set point.

Research on the Mechanism of Multi-Source Piezoelectric Vibratory Feeder

Vibration feeder is the device of subsequent orientation feeding using vibration for the granular or power materials. This device could be used in food, medicine, chemistry and so on. We announce the phenomenon of materials handling based on testing and analyzing the granular materials in the multi-source piezoelectric vibratory feeder. The results show that the vibratory spreads is the traveling wave in this device, when the device is operated. The elastic particle is the elliptic movement at the end of the stuff box. The dynamic of material movement mainly come from the traveling wave caused by particle elliptical movement, the destruction to the grain’s natural balance status caused by the vibration and the geometric position-limit guiding structure of the device and so on.

A Study on the Machine Vision Assisted Vibratory Feeding System

Vibratory feeding is the most significant approach for parts orientation and feeding in production; the process of production automation has been seriously hindered due to the problems with low feeding efficiency, high jamming rate. This project combines machine vision and vibratory feeding technology in substitute for the currently used mechanical orientation mechanism, in order to automatically recognize work pieces of different size, shape and color. The special vibratory feeder and frame are designed. According to the system work requirement, in the thesis, the adjustable light source and illumination system are designed, and the CCD camera and optical lens are chosen. The pneumatic actuator is also designed with the microcomputer as the controller. The area, perimeter, dispersion and invariant moment parameters are used in parts type identification. The image centroid is used to confirm parts position. By using the Hough transform, the image edge can be extracted to get the deflection angle. By using Matlab, the image can be captured, processed, analyzed and judged, meanwhile, communicate with actuator and control it.

Elastodynamic analysis of vibratory bowl feeders: Modeling and experimental validation

This work addresses the elastodynamic modeling of vibratory bowl feeders and its experimental verification. The bowl feeder mainly consists of a bowl connected to a base by three or four inclined leaf springs. The springs constrain the bowl so that its vertical displacement causes a coupled rotation around its vertical symmetry axis. The feeder is actuated by electromagnets, while rubber mounts are positioned under the base for reducing the vibration transmission to the floor. The developed model is a linear lumped-parameter model for the prediction of the dynamic behavior of bowl feeders. The model has been experimentally verified by means of modal analyses and operational accelerations. Model parameters, such as the stiffness and damping of rubber mounts, leaf spring stiffness and time-varying excitation, have been experimentally estimated. The proposed model can be used for the analysis of feeder dynamics and for evaluating the effects of changes in design and operational parameters in terms of bowl and base vibration and dynamic forces transmitted to the floor.

Design and Study on the Automatic Extrusion Device for Curved Chassis of Vibratory Feeder

Vibratory feeder is a device which is used to arrange small workpieces in neat rows and convey them from one place to another by vibratory feeding. It has been playing a key role in automation production. According to manufacturing equipments for the chassis of vibratory bowl feeder, this paper makes studies mainly in the followings: (1) introduces the principle of the vibratory feeder briefly, (2) the mechanical structure of the automatic extrusion device for curved chassis of vibratory feeder is designed, including frame, moulds and guiding mechanism, (3) static analysis, mould stress analysis are done by using the finite software ANSYS, (4) based on the electro-hydraulic proportional control technology, a hydraulic system is designed, (5) a control system based on STC89C52RC MCU(Micro Control Unit) is given. The problems of automatic extrusion for the curved chassis of vibratory feeder are successfully solved through the theoretical and experimental studies, which achieves the expected design goals and fills in a gap in this field in China, which brings great economic and social potential benefits and has wide application prospect.

A Study on the Teaching Platform of Linear Vibratory Feeder

It is known that vibratory feeders are the most versatile of all hopper feeding devices for small engineering parts and play a key role in assembly automation. However, there are still no reliable and effective professional teaching platforms for researching or demonstrating the principle of the parts conveying. The aim of this paper is to develop an optimal teaching platform based on the analysis of the working principle that the feeder follows. The structural design, elastic system and control system are studied in this paper. The vibration principle is verified by the teaching platform through the experiment and the results are promising.

A Study on the Integrated Modeling of Decoupled Vibratory Feeder

Vibratory feeders play an important role in automated systems and the decoupled vibratory feeder is a novel design which is excited in two different directions. The research on decoupled vibratory feeder concentrates on the modeling, the control system and structural optimization. The aim of this work is to focus on the integrated modeling of the decoupled vibratory feeder. The integrated modeling consists of the mechanic modeling, the electrical modeling and the control strategy. The modeling of all modules including the PID control, the power amplifier, the electromagnet, the feeder, the part motion and the feedback are discussed to reveal the relation between the input signal and the part motion. The block diagram of the integrated modeling of the whole system programmed with MATLAB is given in this paper. A deeper understanding of the decoupled vibratory feeder can be obtained by the integrated modeling to optimize the structural design and improve the conveying efficiency.

A Study on the Motion of Micro-Parts on a Saw-Tooth Surface by the PTV Method

This study investigates the motion of micro-parts of different sizes on a symmetrically vibratory feeder system that consists of a saw-tooth surface made of carbide, brass, and zirconia. The velocity and position of micro-parts are time-dependently measured by the particle tracking velocimetry method. We investigate the micro-parts motion for a range of frequencies applied to the surface. The obtained results show that unidirectional motion can be attained by the present feeder system regardless of the surface material and the micro-part size. The motion behavior of micro-parts varies for different experiments and surfaces in spite of the same driving voltage and frequency. This implies that the motion of micro-parts is affected by uncertainties in the system. The micro-part motion consists of numerous frequencies, and the first frequency coincided with the exciting frequency. The results also show that the carbide saw-tooth surface produces the largest micro-part velocity among the three surface materials. Comparing relationship between feeding velocity and velocity spectrum clarifies that the micro-part moves faster when spectrum was clear. The experiments on the carbide surface indicate that the micro-part moves smoothly and a large velocity is observed within 50-70 Hz of driven frequency.

A Study on the Vision-Based Flexible Vibratory Feeding System

This paper describes a vision-based flexible vibratory feeding system (VBFVFS) for agile manufacturing, which mainly consists of a decupled vibratory feeder, a machine vision system, displacement sensors, power amplifiers and a computer system. Its major feeding parameters such as the vibration angle, frequency, acceleration amplitude, and phase difference all can be easily adjusted online by software means. Consequently, the system not only can feed a wide range of parts without any retooling of the feeder, but also can feed various parts made of different material in a way close to the optimal state. The VBFVFS also has intelligence. It can find out the natural frequencies of the decoupled vibratory feeder by means of automatic frequency response analysis and hence determine the best frequency for the driving signals. It can also find out any parts jamming and eliminate it by making the parts move in reverse directions. Prototypes of the decoupled vibratory feeder have been successfully developed. Experimental investigation is carried out based on the prototypes and the results agree well with the simulation results. Moreover low-cost vision technique is also discussed for the commercialization of the vision-based flexible vibratory feeding system.

A Constrained Convex Approach to Modal Design Optimization of Vibrating Systems

Abstract This paper introduces a general and flexible design method for the inverse modal optimization of undamped vibrating systems, i.e., for the computation of mass and stiffness linear modifications ensuring the desired system eigenstructure. The technique is suitable for the design of new systems or the optimization of the existing ones and can handle several design requirements and constraints. Paramount strengths of the method are its capability to modify an arbitrary number of parameters and assigned vibration modes, as well as the possibility of dealing with mass and stiffness matrices with arbitrary topologies. To this purpose, the modification problem is formulated as a constrained inverse eigenvalue problem and then solved within the frame of convex optimization. The effectiveness of the method is assessed by applying it to two different test cases. In particular, the second investigation deals with a meaningful mechanical design application: the optimization of a system recalling an industrial vibratory feeder. The results highlight the generality of the method and its capability to ensure the achievement of the prescribed eigenstructure.

The way to choose resonance vibratory feeder parameters to form the structure of a unit surface

It is revealed how granulated solids influence the effect (revealed earlier for the point mass) of hard excitation of forced vibrations under planar transportation. The vibratory feeder with electro-dynamic microexciter has been analyzed in the first approximation by the averaging method. For the granulated solids, the effect is connected with the system structure variation (equation of motion), but, in addition to the number of degrees of freedom variation, other parameters and mode conditions can be varied. The relationships between machine parameters and the cross section of the flow and material consumption put on to the unit surface are obtained. Comparison with experimental data shows that the results correlate well qualitatively and numerically. The estimation of maximal possible error of the first approximation obtained according to the small parameter value is close to maximal disagreement between the experiment and the theory.

Research and Analysis on the Multi-Point Piezoelectric Vibratory Feeder of Driving Mode

The effect on the feeding rate and feeding stability of the multi-point piezoelectric vibratory feeder, of various factors such as driving mode, operating frequency and input signal phase difference is analyzed in detail through many experimental researches by means of the multi-point piezoelectric vibratory feeder developed by ourselves. It is found that the driving mode has critical influence on the conveying performance of the multi-point piezoelectric vibratory feeder. Symmetrical two-point, front single-point and rear single-point vibration sources, these three driving modes have their conveying performance relatively stable. However, three-point, asymmetrical two-point and bottom single-point vibration sources, these three driving modes have their feeding rate somewhat lower than that of the former three modes in the same conditions and their conveying performance is extremely unstable. In particular for the driving mode of single-point vibration source with the bottom close to the rear, conveyance of materials is almost impossible. The effect of phase difference is represented in the driving mode of multi-point vibration sources.

306 衝突系に生じる自励振動の解析

There are some mechanical systems that involve impacts, e.g. vibratory feeders, impact dampers, vibrating screens and so on. Sometimes unwanted low frequency vibration occurs in such vibroimpact systems. This paper regards such vibration as self-excited vibration generated in vibro-impact systems. Experimental and calculated results show that the self-excited vibration occurs in the parameter range where unstable periodic solutions exist. Further numerical simulations demonstrate that distance between a bouncing mass and a main system has an exciting or damping effect on the center of gravity of the system.

Self-Excited Vibration Generated in a Vibroimpact System

There are some mechanical systems that involve impacts, e.g. vibratory feeders, impact dampers, vibrating screens and so on. Sometimes unwanted low frequency vibration occurs in such vibroimpact systems. This paper regards such vibration as self-excited vibration generated in vibroimpact systems. Experimental and calculated results show that the self-excited vibration occurs in the parameter range where unstable periodic solutions exist. Further numerical simulations demonstrate that distance between a bouncing mass and a main system has an exciting or damping effect on the center of gravity of the system.

Performance Analysis of Large Radial Equal-Thickness Vibratory Feeder

The radial equal-thickness feeder in the paper is designed for the rotary hearth furnace and achieves radial equal-thickness distributing for material. Vibratory feeder is a complex elastomer. Dynamic analysis is an important part for the large radial equal-thickness vibratory feeder. In order to attain the vibration characteristics of the basis and the screen body, such as amplitude, frequency, vibration locus, vibrating direction angle, and improve design quality, so the vibration feeder is tested and analyzed. Dynamic response parameters of large radial equal-thickness vibratory feeder are tested in field and the data in different time are collected by software DH5920. Material transportation speed and throughput are derived. The real average velocity is νmmax=0.054m/s, the real throughput is Q=3600hBνγ=25.19t/h. The results showed that the feeder can meet the production process requirements.