Vibratory Feeder Research Articles

In-line particle size measurement based on image analysis in a fully continuous granule manufacturing line for rapid process understanding and development

The present paper serves as a demonstration how an in-line PAT tool can be used for rapid and efficient process development in a fully continuous powder to granule line consisting of an interconnected twin-screw wet granulator, vibrational fluid bed dryer, and a regranulating mill. A new method was investigated for the periodic in-line particle size measurement of high mass flow materials to obtain real-time particle size data of the regranulated product. The system utilises a vibratory feeder with periodically altered feeding intensity in order to temporarily reduce the mass flow of the material passing in front of the camera. This results in the drastic reduction of particle overlapping in the images, making image analysis a viable tool for the in-line particle size measurement of high mass-flow materials. To evaluate the performance of the imaging system, the effect of several milling settings and the liquid-to-solid ratio was investigated on the product’s particle size in the span of a few hours. The particle sizes measured with the in-line system were in accordance with the expected trends as well as with the results of the off-line reference particle size measurements. Based on the results, the in-line imaging system can serve as a PAT tool to obtain valuable real-time information for rapid process development or quality assurance.

Continuous downstream processing of milled electrospun fibers to tablets monitored by near-infrared and Raman spectroscopy

Electrospinning is a technology for manufacture of nano- and micro-sized fibers, which can enhance the dissolution properties of poorly water-soluble drugs. Tableting of electrospun fibers have been demonstrated in several studies, however, continuous manufacturing of tablets have not been realized yet. This research presents the first integrated continuous processing of milled drug-loaded electrospun materials to tablet form supplemented by process analytical tools for monitoring the active pharmaceutical ingredient (API) content. Electrospun fibers of an amorphous solid dispersion (ASD) of itraconazole and poly(vinylpyrrolidone-co-vinyl acetate) were produced using high speed electrospinning and afterwards milled. The milled fibers with an average fiber diameter of 1.6 ± 0.9 µm were continuously fed with a vibratory feeder into a twin-screw blender, which was integrated with a tableting machine to prepare tablets with ~ 10 kN compression force. The blend of fibers and excipients leaving the continuous blender was characterized with a bulk density of 0.43 g/cm3 and proved to be suitable for direct tablet compression. The ASD content, and thus the API content was determined in-line before tableting and at-line after tableting using near-infrared and Raman spectroscopy. The prepared tablets fulfilled the USP <905> content uniformity requirement based on the API content of ten randomly selected tablets. This work highlights that combining the advantages of electrospinning (e.g. less solvent, fast and gentle drying, low energy consumption, and amorphous products with high specific surface area) and the continuous technologies opens a new and effective way in the field of manufacturing of the poorly water-soluble APIs.

Dynamics of part motion on a linear vibratory feeder

The motion of a part on a curved surface mounted upon a linear vibratory feeder is of great importance in mass production. In this article, the conveying surface or track is modelled by a bilinear surface inclined to all axes with the curvature varying throughout the surface. An experimental test rig is fabricated to study the part motion on the feeder surface. Dynamics of the part on the surface is derived and the path traced by the part is obtained numerically. The numeric model closely correlates with experimental results. Based on the control parameters two distinct regimes—slide and hop—are presented, highlighting their relation to frequency and amplitude of vibration of the feeder.

Modeling and analysis of vibratory feeder system based on robust stick–slip motion

This study presents model and analysis of a robust one-dimensional stick–slip transportation of an object, on dry contact with an oscillating platform suspended by nonlinear leaf spring. The oscillating platform is designed and modeled such that the elastic spring constant is direction dependent. A recursive analytical solution algorithm is proposed to solve nonlinear system dynamics. The system and the input force parameters are both investigated with goal to optimize the average velocity of the object. Both experimental and analytical results showed that the stick–slip motion is highly nonlinear and sensitive to the system and input force parameters. Moreover, the simulations showed that it is feasible to design a platform with robust sets of parameters (natural frequencies) and further use the input force parameters (amplitude and driving frequency) to tune for desired average velocity, under given dry friction conditions.

Theoretical Analysis and Optimization of Process Parameters for Part Motion Time in Vibratory Part Feeders for Mass Production Assembly Lines

Low cost automation techniques play a significant role in reducing the lead time andproduction cost. Automation technique is implemented by developing a part feeding system. Itseffectiveness is verified both experimentally and theoretically. Drop test is used to find the natural restingorientation. Real time experiments are conducted using designed trap to determine the part motion time.The Input parameters considered for the research are trap angle and frequency of vibration and they arevaried while conducting the experiments. An ANOVA model is developed to verify its accuracy. Thedeveloped model shows that the value of R-sq is 90.32 % and it reveals that forecasted values seem verynearer to the real response values. Regression equation is evolved to forecast the optimum values of trapangle and frequency and the same is solved using LINGO software. It was found both experimentallyand theoretically that greater values of both the input parameters resulted in least part motion time.

A two-way linear piezoelectric vibratory conveyor actuated by a composite sinusoidal voltage input

Piezoelectric vibratory conveyors are widely used in many industrial fields such as factory automation. However, there is still a limitation for most cases that the vibratory conveyor can only feed in the designed direction. In today's multitasking intelligent machinery, how to sort different parts from the same feed source and convey them efficiently in different directions remains a challenge to be overcome. This study proposes an innovative design that uses a composite sinusoidal control signal to drive a linear two-stage piezoelectric vibratory feeder. By simply tuning the amplitude and phase of the input composite signal, the conveying velocity and direction can be altered easily. The dynamic characteristics of this feeder were both investigated by theoretical formulation and experimental measurement. It is found that the conveying performance of this feeder is better suited for using the composite signal with two sinusoidal components of double frequency. With the composite control signal synthesized by two sinusoidal components of 237.5 Hz and 475.0 Hz, which were close to the feeder’s first two resonance frequencies to increase the response gain of the structure, and the input voltage of 60 V, which corresponded to the trough’s displacement amplitude of 54.5 m, the measured conveying speeds were +30.8 mm/s and –33.3 mm/s for setting the phase angles 180° and 0°, respectively. The result demonstrates the feasibility of the proposed two-way vibratory feeder design.

Vibratory Feeding Performance Improvement Through Discrete Element Analysis for High-Speed Optical Detection of LED Chips

A high-speed vibratory bowl feeder is a key equipment of the optical detection of light emitting diode (LED) chips. Addressing the stationarity-losing problem induced by transporting small-size and light-weight LED chips, this study designs a vibratory bowl feeder for the high-speed detection of small LED chips based on theoretical and numerical analyses. To understand the influence of the structural parameters of the feeder on its performance, we create a mathematical model of the part's behavior base on the Hertz-Mindlin contact theory. The numerical model indicates that the property of the part, the track angle and the friction coefficient of the track are the main factors that affect the behavior of the part in the feeding process. Through the discrete element method (DEM) simulation, we observe the part behavior under different track angles and friction coefficients of the feeder. The motion stationary of the LED chip is evaluated by its standard deviation (STD) of velocity and hopping height. Thus, we can appropriately determine these parameters of the vibratory feeder in order to get the optimal feeding performance. Finally, an experimental platform of the LED chip detection device is built to verify the performance of the vibratory bowl feeder. The experimental results show that the performance of the feeder was in good agreement with the simulation results. With the theoretical analysis and experimental verification, the vibratory bowl feeder was successfully implemented for LED transportation and reached a high feeding velocity of 1516.5 pieces/min at the working frequency of 223 Hz.

DYNAMICS OF HEAVY VIBRATING MACHINES TAKING INTO ACCOUNT INSTABILITY IN TIME OF THEIR PARAMETERS

Underground mining of uranium ores consists of several technological processes, one of the most important of which is the release of broken rock from the working excavation zone and loading it into transportation vehicles. The issue of increasing the intensity of production requires a simultaneous increase in the productivity of all production processes, including the production of mineral raw materials. At the same time, it is necessary to create both a high-performance and a safe process. This problem is successfully solved by the use of vibration machines with elastic links made of elastomeric materials, which, along with an increase in productivity, can reduce energy consumption and the number of freezes. An integrated approach was used, which includes analytical studies and results of industrial tests of vibratory feeders for underground mining and delivery of uranium ores and building materials. On the basis of the developed algorithm and synergistic model of fatigue microfracture of rubber links in vibratory feeder, mathematical equations were obtained, which made it possible to describe dynamics of feeders with time-depending parameters; when solving the integro-differential equation of the oscillatory system, the dependence of the amplitude characteristics of the feeder on the time of its operation is obtained. An original algorithm and synergistic model were developed, and on their basis, a mathematical apparatus was created, which allowed determining change of amplitude of vibratory feeder oscillations during its operation. On the basis of analytical calculations, a method was developed and introduced for predicting changes of parameters change of oscillation amplitudes of vibratory feeder used for underground mining and feeding of uranium ores.

Analysis of Excitation Force and its Application in Vibratory Bowl Feeders

Analysis of Excitation Force and its Application in Vibratory Bowl Feeders

Response optimization of underactuated vibration generators through dynamic structural modification and shaping of the excitation forces

Resonant vibration generators, such as vibratory feeders or ultrasonic sonotrodes, are often employed in manufacturing to generate harmonic vibrations with suitable amplitude, spatial shape, and frequency, in order to meet the process requirements. These underactuated systems are usually excited in open loop by few actuators, and therefore, it is not ensured that the desired response is correctly achieved, since the feasible motions should belong to the subset of the allowable motions. To achieve the closest approximation of the desired vibrations, some new solutions are here proposed. The first strategy is the optimal shaping of the harmonic forces exerted by the actuators, by solving an inverse dynamic problem through a coordinate transformation and the projection of the desired response onto the subspace of the allowable motion. By exploiting the formulation of such a subspace, a second approach that involves concurrently both the force shaping and the modification of the inertial and elastic system parameters is proposed. The idea of this approach is to exploit the modification of the elastic and inertial parameters to properly shape the allowable subspace in such a way that it spans the desired response. A solution method is developed, and analytical sensitivity analysis is proposed to choose the design variables. Validation is proposed through a linear vibratory feeder with a long flexible tray, taken from the literature. The results show the effectiveness of the proposed strategies that lead to a very precise approximation of the desired response.

Vibratory feeders with elongated conveying surface in rehandling of mined rock in open pit mines

Deep-level mining in open pits involves increased volumes of overburden. It is difficult to operate heavy-duty dump trucks at bottom levels of deep open pit mines due to limited size of working areas and high angles of roads. In this case, it is expedient to use more maneuverable crawler dumps or articulated dump trucks of comparatively low capacity and to rehandle mined rocks to larger capacity dump truck at bin trestles with forced discharge constructed on accumulation horizons. This article discusses mined rock discharge from an accumulating bin of the rehandling point by a set of vibratory feeders representing the bottom of the bin. These vibratory feeders are to provide reliable operation under high static and dynamic loads.

Ensuring self-synchronization of unbalanced vibration exciters for transveyers of overburden spreaders

Deep-level mining in open pits involves increased volumes of overburden. It is difficult to operate heavy-duty dump trucks at bottom levels of deep open pit mines due to limited size of working areas and high angles of roads. In this case, it is expedient to use more maneuverable crawler dumps or articulated dump trucks of comparatively low capacity and to rehandle mined rocks to larger capacity dump truck at bin trestles with forced discharge constructed on accumulation horizons. This article discusses mined rock discharge from an accumulating bin of the rehandling point by a set of vibratory feeders representing the bottom of the bin. These vibratory feeders are to provide reliable operation under high static and dynamic loads.

Improving the performance of vibration feeders with an electromagnetic vibration drive and a combined vibration system

Vibration loading devices are widely used in various branches of mechanical engineering to load piece blanks of automatic machines and automatic lines as well as robotic systems, automated systems and flexible automated production. Vibration devices for transportation and loading of miniature, small and medium-sized products are the most widely used. Modern designs of vibratory feeders, made according to the classical dynamic scheme and having a two-mass oscillating system, do not fully use the energy of the vibratory exciter to perform useful work. In addition, due to the presence of a heavy reactive mass, they have a fairly large weight. When the vibrating feeder is operating, the energy of the vibration exciter is spent on pumping both the hopper, which performs useful work, and the reactive plate, which performs idle vibrations. Thus, part of the energy of the vibration exciter is not used for performing useful work, but is spent idly. To increase the efficiency of the device, increase its performance and reduce its weight and metal consumption, it is necessary to change the design of the vibratory feeder and some of its elements, which affect the redistribution of the oscillation amplitudes of the working (hopper) and reactive mass of the vibratory feeder. Modern production involves the creation of new models of machines with high technical and economic indicators, therefore, improving the efficiency of existing equipment and the development of new schemes of machines is an important task for designers and manufacturers of technological equipment, as the minimum improvement of its technological and operational performance can lead to a tangible economic effect. To solve this problem we developed a new design vibrating hopper feeder, in which the increase of the horizontal component of the oscillation amplitude of the working element (hopper) is not at the expense of increased power of the vibratory exciter, but due to internal redistribution of energy between the elements of the oscillating system that makes better use of the energy of the vibratory exciter to perform useful work, i.e. to increase the coefficient of useful action. In addition, the weight and metal content of the vibrating feeder structure are simultaneously reduced.

Performance and noise analysis of vibratory feeder using dynamic rubber spring model

In vibratory feeder, material feeding occurs due to the vibration of a trough mounted on helical springs. High vibration amplitude of trough causes the springs to jump and usually results in higher noise level generation and increase in force transmissibility in the support structure of the feeder. Reducing this noise without having significant changes in the dynamics of the feeder unit is a major challenge in the present industries. This paper presents a dynamic rubber spring model for vibratory feeders to reduce the noise level and the force transferred to the support structure of the feeder. Measurement of dynamic parameters such as vibration amplitude and magnitude of force transmitted to support structure, noise level, and conveying speed of particle analyses have been conducted experimentally on vibratory feeder with and without rubber gasket installed at spring support structure. The use of rubber gaskets at spring supports and their implication on force transmissibility and noise level of feeder is established experimentally. The performance analysis of feeder was also conducted using particle conveying speed on trough for different setups of feeder unit. It was found that the introduction of rubber gaskets at spring supports of the feeder increases the system damping, which helps in noise reduction as well as reduced amplitude of vibration and higher acceleration of trough. The increased acceleration leads to higher particle conveying velocity on the feeder trough.

A new three-dimensional dynamic model and experimental validation for motion of a part in a vibratory bowl feeder

In this research, dynamics of a part in a vibratory bowl feeder is studied. So far, studies have been done in two dimensions which is an inaccurate approximation to the 3D part motion. Hence, a new dynamic model is introduced for motion of the part under the effect of base excitation which is moving on or separating from a 3D spiral track. Different scenarios which may occur due to the interaction of the part and the track such as sliding and hopping are predicted. The equations of motion of the part are derived for each scenario and a solution algorithm is presented. The system of equations is solved numerically to obtain the position of the part as a function of time. To validate the proposed dynamic model and the numerical solution, experimental tests are carried out. Good agreement between the results of these methods demonstrates the accuracy of this model. It is observed that the excitation frequency would greatly affect the motion of the part. For low excitation frequencies, the only mechanism involved in the motion of the part is the sliding one. By increasing the excitation frequency, the major driving mechanism changes to hopping.

Reinforcement learning–based design of orienting devices for vibratory bowl feeders

The sorting of small parts is one of the common tasks in the field of industrial manufacturing. Vibratory bowl feeders (VBF) are commonly used to accomplish this task. Nowadays, the design process of the VBF is based on a manual and expensive trial-and-error approach, in which different traps are arranged and tuned. This paper outlines a method which modifies this conventional process using Reinforcement Learning to automate the VBF design. To enable this, a software agent is used to model the placement of traps on multiple positions and measure the subsequent configuration efficiency. A physics simulation provides the characteristics of the individual traps. During the training, Q-learning is applied to determine the environmental indicators under which a certain trap should be replaced. A 3D matrix is used to store information in a problem-related representation. Due to the trial-and-error principle of Reinforcement Learning, this training is comparable with the traditional proceedings. In addition, valuable action paths are stored in a memory and the agent frequently is trained on these paths in order to remember good solutions. Additionally, a knowledge base is used to exclude inefficient sets of traps. The rules for the knowledge base are built upon knowledge from the conventional design process. In first test cases, the trained agent is able to assemble traps achieving promising configurations. The results of the agent will be validated in the next step using physics simulation.

Optimization of the structure of the vibratory feeders with electromagnetic vibrating drive and a combined oscillating system

Vibration loading devices are widely used in various branches of mechanical engineering to load piece blanks of automatic machines and automatic lines as well as robotic systems, automated systems and flexible automated production. Vibration devices for transportation and loading of miniature, small and medium-sized products are the most widely used. In the study of vibration transport, one of the most important issues is the study of the dependence of the average transport speed on the parameters of the oscillation of the carrier tray. It is most convenient to conduct a study in dimensionless quantities when expressing the speed of transportation through the speed coefficient, which shows how much the real speed of the part is close to the maximum speed of the transporting surface. For vibration conveyors and vibratory feeders with non-separable transportation parts using modes that are implemented mainly elliptical or asymmetric longitudinal vibrations of the bearing plane. Asymmetric laws of motion of vibration conveyors provide the highest performance in a non-invasive mode of movement of billets, but such conveyors have found a very limited distribution due to the complexity of the implementation of asymmetric vibrations by simple means. To implement the asymmetric laws of oscillation of the working body and thereby increase the speed coefficient used as power sources generators asymmetric types of oscillations, which have a very high cost. Modern production involves the creation of new models of machines with high technical and economic indicators, therefore, improving the efficiency of existing equipment and the development of new schemes of machines is an important task for designers and manufacturers of technological equipment, as the minimum improvement of its technological and operational performance can lead to a tangible economic effect. To solve this problem, the authors developed a new design of vibration hopper feeder, which carries out the transportation of products in the mode without throwing with an asymmetric law of oscillation of the carrier tray when connected directly to the AC network without using an asymmetric pulse generator and conducted an experimental study of its design to determine the speed coefficient during vibration transportation.

A METHOD TO DESIGN VIBRATORY BOWL FEEDER BY USING FEM MODAL ANALYSIS

This paper presented a digital simulation study, using the finite element method with modal analysis on the ANSYS Workbench platform, to determine the fundamental frequencies of the mechanical system and to affirm the design and manufacture parameters of the vibratory bowl feeders. Then an experiment was conducted to verify the results. The results suggest that the simulation model can be used to identify parameters of the bowl’s structure before the device is manufactured.

Dynamics of vibratory partitioned feeders for the uranium ore drawing and feeding

In this paper, the authors consider dynamics of partitioned vibratory feeders with rubber elastic couplings. Use of vibratory feeders (including partitioned ones) and schemes for the ore vibrating drawing, feeding and loading in underground conditions allowed to mechanize one of the most time-consuming and dangerous processes of uranium ore mining and to solve the following problems: to improve effectiveness of the lumpy rock mass drawing and loading by 2.5-3 times; to increase intensity of mining operations and reduce life of the excavation blocks and horizons; to reduce labor intensity and cut cost of the process of ore drawing and loading; to improve uniformity of the rock-mass outflowing from the discharge opening and to reduce by 3-5 times frequency of the large-lump material freezing (use of partitioned feeders reduces number of freezes by 25-60 times); to increase size of commercial lump panels; practically to exclude traumas during the process of ore drawing and loading (usually, it presents 30-60 % of all traumas caused by the underground operations); to mechanize process of ore drawing and loading, and to create conditions for implementation of low-waste cyclic-and-continuous mining technology.

Advances in machine vision for flexible feeding of assembly parts

Human-robot collaboration can be used to share workload to form semi-automated production systems. Assembly operations are recognized with high potential to increase productivity by using the best skills of humans and robots in a combination. Components and parts to be assembled need to be structured and presented to the robot in a known location and orientation. The process of presenting parts to the robot for assembly tasks is referred to as parts feeding. Feeding system needs to be adaptable to dynamics of parts’ design, shape, location, and orientation to have flexibility in the production. The traditional automation methods for parts feeding are part-specific mechanical devices e.g. vibratory bowl feeders which are inflexible towards part variations. This comes as a hindrance in getting maximum advantage of the flexibility potential of human-robot collaboration in assembly. The recent years have seen advances in machine vision and has potential for feeding applications. This paper explores the developments in machine-vision for flexible feeding systems for human-robot assembly cells. A specification model is presented to develop a vision-guided flexible feeding system. Various vision-based feeding techniques are discussed and validated through an industrial case study. The results helped to compare the efficiency of each feeding technique for industrial application.