Feed Screw Research Articles

Development and parameter optimization of health promising extrudate based on fenugreek oat and pea

Abstract The purpose of this study was to develop health promoting extruded snack products. Extruded snacks were prepared using a blend of oat, green pea and fenugreek seed flour and leaf powder. Effect of feed moisture (12–16% wet basis), barrel temperature (90–110 °C) and screw speed (100–200 rpm) on the product properties like lateral expansion (LE), bulk density (BD), water absorption index (WAI), water solubility index (WSI) and hardness was investigated. The product responses were significantly affected by changes in moisture, temperature and screw speed. The regression models for product responses like LE, BD, and hardness were highly significant (P≤0.0001), whereas WAI and WSI were significant at a (P≤0.001) respectively. Desirable extruded products were obtained at moisture of 12%, 110 °C temperature and 200 rpm screw speed. It was revealed that fenugreek, oat and dried green pea can be used to produce snack products with desirable quality characteristics.

Three-dimensional discrete element method simulation of the effect of bottom structure on solid flow in COREX shaft furnace

COREX is an industrially and commercially proven smelting reduction process. The shaft furnace (SF) for the pre-reduction of iron ore is one of the two major reactors of COREX. As one of the industrial systems using screw feeders, the burden descending behaviour in SF can be directly affected by the bottom structure such as the design of screw and associated charging container. In this work, a three-dimensional actual size model of COREX-3000 SF is established by means of the discrete element method. The effect of bottom structure, for example, the guiding cone and the design of screw, on solid flow is investigated. The results show that burdens are mainly drawn down from the first flight of the screw in the reference case, while the slow-moving particles located above the end of the screw. Placing a guiding cone and reducing the flight diameter of screw have a benefit for restraining the descending velocities in the central area of the SF and help to obtain a uniform flow pattern. An optimised case is also proposed. In the optimised case, a relatively uniform solid flow profile can be obtained and the uniformity of descending velocity along the radius is improved greatly. The findings of this work should be useful for the design, control and optimisation of the SF operation.

Optimization and Prediction of Mechanical and Thermal Properties of Graphene/LLDPE Nanocomposites by Using Artificial Neural Networks

The focus of this work is to develop the knowledge of prediction of the physical and chemical properties of processed linear low density polyethylene (LLDPE)/graphene nanoplatelets composites. Composites made from LLDPE reinforced with 1, 2, 4, 6, 8, and 10 wt% grade C graphene nanoplatelets (C-GNP) were processed in a twin screw extruder with three different screw speeds and feeder speeds (50, 100, and 150 rpm). These applied conditions are used to optimize the following properties: thermal conductivity, crystallization temperature, degradation temperature, and tensile strength while prediction of these properties was done through artificial neural network (ANN). The three first properties increased with increase in both screw speed and C-GNP content. The tensile strength reached a maximum value at 4 wt% C-GNP and a speed of 150 rpm as this represented the optimum condition for the stress transfer through the amorphous chains of the matrix to the C-GNP. ANN can be confidently used as a tool to predict the above material properties before investing in development programs and actual manufacturing, thus significantly saving money, time, and effort.

Effect of Extrusion Variables on the Extrudate Properties of Wheatplantain Noodle

Matured green plantain (Musa paradisiaca) was processed into plantain flour and composted with wheat flour prior to extrusion. In this study, the effect of extrusion cooking variables [Barrel Temperature (BT, Feed Moisture Content (FMC) and Screw Speed (SS)] on the extrudate properties of whate-plantain noodles were investigated, while predictive models were also developed. Results obtained showed that changing the cooking variables significantly (p ≤ 0.05) affected all the extrudate properties studied. An increase in the screw speed (6.3-8.4 m/s) and feed moisture content (40-50%) resulted in a substantial increase in the expansion ratio (48%), residence time (62%) and specific mechanical energy (83.6%) Likewise, an increase in barrel temperature increased the mass flow rate (64.5%) of the extrudates significantly (p ≤ 0.05). Regression analysis also revealed that the screw speed and the feed moisture content were the major extrusion cooking variables, as they showed significant (p ≤ 0.05) linear quadratic and interaction effects on mass flow rate, residence time, specific mechanical energy and expansion ratio. The study showed that optimization of the combined effects of a 50% feed moisture content, 6.3 m/s screw speed of 6.3 m/s and a 100°C barrel temperature gave the optimum processing conditions for expanded wheat-plantain noodles. These variables are important considerations for commercial and mass production of wheat-plantain noodles.

Development of Nutritious Snack from rice industry waste using twin screw extrusion

Deoiled rice bran, a byproduct of rice milling industry was transformed into highly nutritious snack by the application of twin screw extrusion process. Response Surface Methodology (RSM) with four- factor- five level central composite rotatable design (CCRD) was employed to investigate the effects of extrusion conditions including moisture content of different raw flours, feed composition, barrel temperature and screw speed of extruder on properties of extrudates was studied. Second order quadratic regression model fitted adequately in the variation. The significance was established at P ≤ 0.05. The regression models can be used to interpret the effect of feed composition, moisture content, screw speed and barrel temperature on the properties of the final product. It was shown that higher rice bran in feed composition showed in minimum water absorption index and maximum water solubility index. Numerical optimization technique resulted in 123.83°C of barrel temperature, 294.68 rpm of screw speed, 13.94 % of feed moisture and 17.73 % of deoiled rice bran. The responses predicted for these optimum process conditions resulted water absorption index, 5.91468 g/g and water solubility index of 18.5553 % for the development of value added product with health benefits.

Analytical Modeling of a Ball Screw Feed Drive for Vibration Prediction of Feeding Carriage of a Spindle

An analytical modeling approach for ball screw feed drives is proposed to predict the dynamic behavior of the feeding carriage of a spindle. Mainly considering the rigidity of linear guide modules, a ball-screw-feeding spindle is modeled by a mass-spring system. The contact stiffness of rolling interfaces in linear guide modules is accurately calculated according to the Hertzian theory. Next, a mathematical model is derived using the Lagrange method. The presented model is verified by conducting modal experiments. It is found that the simulated results correspond closely with the experimental data. In order to show the applicability of the proposed mathematical model, parameter-dependent dynamics of the feeding carriage of the spindle is investigated. The work will contribute to the vibration prediction of spindles.

Development of an Ointment Formulation Using Hot-Melt Extrusion Technology.

Ointments are generally prepared either by fusion or by levigation methods. The current study proposes the use of hot-melt extrusion (HME) processing for the preparation of a polyethylene glycol base ointment. Lidocaine was used as a model drug. A modified screw design was used in this process, and parameters such as feeding rate, barrel temperature, and screw speed were optimized to obtain a uniform product. The product characteristics were compared with an ointment of similar composition prepared by conventional fusion method. The rheological properties, drug release profile, and texture characteristics of the hot-melt extruded product were similar to the conventionally prepared product. This study demonstrates a novel application of the hot-melt extrusion process in the manufacturing of topical semi-solids.

Issues related to waste sewage sludge drying under superheated steam

Abstract Sewage sludge was dried in a rotary drum dryer under superheated steam. Particle size and moisture content were shown to have significant influences on sticking and agglomeration of the materials. Pouring partially dried sludge (70–80% moisture content, wet basis) directly into the screw feeder of the drum dryer resulted in a significant sticking to the surface of the drum and the final particle size of the product was greater than 100 mm in diameter. The moisture content of this product was slightly less than its initial value. To overcome this issue, the sludge was mixed with lignite at variety ratios and then chopped before being introduced to the feeding screw. It was found that mixing the sludge with lignite and then sieving the chopped materials through a four millimetre mesh sieve was the key to solve this issue. This technique significantly reduced both stickiness and agglomeration of the material. Also, this enabled for a significant reduction in moisture content of the final product.

Feed fluctuation of ball screw feed systems and its effects on part surface quality

Feed fluctuation plays an important role on the part surface quality during the precision machining. In this paper, an analytical electromechanical model is developed to reveal the essential characteristics of the feed fluctuation for ball screw feed system, where the feedback control and driving circuit are equivalent to a “controlled current-source” and the mechanical transmission is modeled as a two-mass system. The analytical expression of displacement fluctuation is deduced and then the characteristics of feed fluctuation are investigated. Finally the influence of feed fluctuation on machining quality is analyzed. The results show that when the frequency of torque ripple is closer to the natural frequency of feed systems, the amplitude of displacement fluctuation increases significantly while that of the torque ripple has a sharp decrease. The displacement fluctuation along the feed direction contributes to the bright and dark stripes on the surface of workpiece in a precise cylindrical turning.

The Analysis of Influence Factors about Dynamic Characteristics of a Ball Screw Feed Drive System

This paper presents relationships between some vital parameters and the natural frequency of the ball screw feed drive system. A finite element model (FEM) of a machine tool feed drive system is established with joint parameters added in based on the SAMCEF software. Using the finite element model, the influences of the material properties of the worktable, the diameter of the ball screw and joint parameters on the natural frequency of axial vibration are derived. These results provide a reliable basis for the optimization design of the ball screw feed drive system.

Discrete element method (DEM) simulation and validation of a screw feeder system

A computational particle flow simulation of a feeder which transports bulk material through a horizontal cylinder by a turning screw is presented. The objective is hereby the simulation-assisted support of system design. Such systems are used in industry to either create packages of material which have a very accurately determined mass or to produce a continuous flow of the used bulk material. The well known and common problems in practical applications are the missing stability of material flux over time, throughput changes with product quality drifts and a lack in design know how based on theoretical solutions. Therefore a simulation tool is realized by Blender software (v 2.68) to foster straight forward and goal oriented screw and apparatus design. The geometrical and physical properties of the system are adjusted to a real feeder system on which the experimental measurements are performed. Simulation parameters like wall friction, internal shear forces and angle of repose are fitted to the real experimental data. Absolute deviations are smaller than 8%. We demonstrate that a simplified particle simulation tool is able to predict properties of a real machine that progresses bulk material with different types of screws. The mass flow rate in simulation differs from the experimental mass flow rate less than 10% for different screw types and angular velocities of the screw. Qualitative properties like the inflow and outflow behavior of the bulk are compared and the conformity is verified. It is shown that quite a simple particle simulation tool is able to verify and predict properties of a machine that progresses bulk material with different types of screws. The simulation tool allows the modeling of all relevant machine parts without expensive real manufacturing and to test their characteristics.

Expansion and functional properties of extruded snacks enriched with nutrition sources from food processing by-products.

Rich sources of protein and dietary fiber from food processing by-products, defatted soybean meal, germinated brown rice meal, and mango peel fiber, were added to corn grit at 20% (w/w) to produce fortified extruded snacks. Increase of total dietary fiber from 4.82% (wb) to 5.92-17.80% (wb) and protein from 5.03% (wb) to 5.46-13.34% were observed. The product indicated high expansion and good acceptance tested by sensory panels. There were 22.33-33.53 and 5.30-11.53 fold increase in the phenolics and antioxidant activity in the enriched snack products. The effects of feed moisture content, screw speed, and barrel temperature on expansion and nutritional properties of the extruded products were investigated by using response surface methodology. Regression equations describing the effect of each variable on the product responses were obtained. The snacks extruded with feed moisture 13-15% (wb) and extrusion temperature at 160-180°C indicated the products with high preference in terms of expansion ratio between insoluble dietary fiber and soluble dietary fiber balance. The results showed that the by-products could be successfully used for nutritional supplemented expanded snacks.

Study on a novel thermal error compensation system for high-precision ball screw feed drive (2nd report: Experimental verification)

Real-time thermal error compensation of machine tool feed drive in general can be separated into three steps such as modeling, measurement and compensation. In the previous report, as the parts of the thermal error compensation system, component heat generation, compensation method, thermal model, mathematic model and calculation method were studied respectively. And a series of simulations was carried out in several kinds of working condition. And then, in order to discuss the correctness of the developed ball screw thermal error compensation system, a series of tests contains axial deformation, positioning accuracy, temperature variation and temperature distribution was carried out in the same working condition of prediction. As the results, the test data well confirmed the correctness of the developed ball screw thermal error compensation system.

Effect of feed moisture, extrusion temperature and screw speed on properties of soy white flakes based aquafeed: a response surface analysis.

Soy white flakes (SWF) is an intermediate product during soy bean processing. It is an untoasted inexpensive product and contains around 51% of crude protein. It can be a potential source of protein to replace fish meal for developing aquafeed. The extrusion process is versatile and is used for the development of aquafeed. Our objective was to study the effects of inclusion of SWF (up to 50%) and other extrusion processing parameters such as barrel temperature and screw speed on the properties of aquafeed extrudates using a single-screw extruder. Extrudate properties, including pellet durability index, bulk density, water absorption and solubility indices and mass flow rate, were significantly (P < 0.05) affected by the process variables. SWF was the most significant variable with quadratic effects on most of the properties. Increasing temperature and screw speed resulted in increase in durability and mass flow rate of extrudates. Response surface regression models were established to correlate the properties of extrudates to the process variables. SWF was used as an alternative protein source of fish meal. Our study shows that aquafeed with high durability, lower bulk density and lower water absorption and higher solubility indices can be obtained by adding SWF up to 40%.

Fast Pyrolysis of Residues from Paper Mill Industry to Bio-oil and Value Chemicals: Optimization Studies

Biomass is a renewable energy and had been recognized as a promising feedstock for producing bio-fuels. In this work, pyrolysis of black wattle residues was investigated with the aim to study the product distribution and their chemical composition and predicting the optimal condition for maximized bio-oil especially aromatics content by using a two level factorial design of experiment. The pyrolysis were performed at temperature of 380 – 580 oC, Under screw feeder carried the biomass residues and weight of dolomite as catalyst of 1-5 wt% inside pyrolyzer with nitrogen gases flow rate of 20 to 80 cm3/min The detention time was controlled by reactor screw feeder at feeding rate of 120 to 240rpm. Based on the analysis from a design-expert program to determine the appropriated condition of experiment was 515.18 oC, 120.01rpm of feed rate and 20.00 cm3/min of nitrogen flow rate using 5.00wt% of dolomite catalyst. The elemental and physicochemistry analysis of bio-oil were determined, the chemical composition also investigated using gas chromatography-mass spectrometry and 1H NMR. The composition of bio-oil mainly oxygenated compound with high molecular weight and phenol. The results show that the biomass residual can be considered as a potential alternative fuels and relevant to valuable chemical feedstock.

Influence of controller parameters on the life of ball screw feed drives

The ball screws are the machine component most frequently used for transforming rotational into linear motion of a feed drive, to position the machine tool components carrying the cutting tool to the desired location. A failure of the ball screw usually leads to a total breakdown of the axis; therefore, the attainable life of this component is an important issue concerning the availability and productivity of modern machine tools. This article presents an approach to evaluate the influence of control parameters on the fatigue life of ball screws based on simulation, by means of a numerical model of a machine tool servo-axis. Ball screw life was evaluated with different conditions, varying the position loop main proportional gain and the kinematic limit conditions for trajectory generation. Furthermore, the mathematical model was used to evaluate optimal control gain and trajectory conditions for a machine tool based on the achievable life span of the ball screw feed drive system, with regard to the desirable performances, such as position accuracy, promptness, and cutoff frequency.

Study on a novel thermal error compensation system for high-precision ball screw feed drive (1st report: Model, calculation and simulation)

In general, in order to compensate the thermal error or the positioning error of a ball screw feed drive system, the actual temperature or positioning data feedback was needed. The traditional thermal error compensation system of ball screw feed drive is highly dependent on the feedback temperature or positioning data. Because of the overdependence to measuring technique, increasing of compensation system cost and decreasing of productivity level will be an inevitable trend in a machine tool. This paper presents a new approach in ball screw thermal error compensation system which can work without any temperature or positioning feedback. As the parts of the thermal error compensation system, component heat generation, compensation method, thermal model, mathematic model and calculation method were studied respectively. In order to verify correctness and generality of the developed thermal model and the thermal error compensation system, a series of simulations was carried out in several kinds of working condition. Through the series of simulations with the thermal model, calculation method and simulation conditions, deformation characteristics and thermal behavior of the prototype ball screw system have been obtained.

Axial dynamic characteristic parameters identification of rolling joints in a ball screw feed drive system

The dynamic characteristic parameters of mechanical joints are difficult to determine in theoretical modeling, dynamic simulation, and servo controller design for the ball screw feed drive system. Therefore, this study proposes a novel method for identifying the axial stiffness and damping parameters of the rolling joints in an assembled ball screw feed drive system. First, the proposed method deduces the axial vibration equations of the feed drive system with a harmonic excitation force exerted on its worktable. Second, the identification model of the axial stiffness and damping parameters of the rolling joints is established on the basis of the equations. Third, the identification equations are built by measuring the distance between the screw supporting points, the frequency, and the amplitude of the harmonic excitation force, as well as the amplitude of the axial vibration velocity of the screw end section. The axial stiffness and damping parameters of the rolling joints are finally determined by solving the identification equations using the genetic algorithm. With a ball screw feed drive system as the research object, the proposed method is used to identify the rolling joints’ axial stiffness and damping parameters of the ball screw assembly, as well as the left and the right bearing groups. The experiments show that the proposed method is correct, effective, and achieves high identification accuracy.

Investigation into effect of thermal expansion on thermally induced error of ball screw feed drive system of precision machine tools

In order to investigate the effect of thermal expansion on the ball screw feed drive system of a precision boring machine tool, theoretical modeling of and experimental study on thermally induced error along with heat generation characteristics are focused in this paper. A series of thermal experiments are conducted on the machine tool to measure and collect the thermodynamic data with the feed drive system operating at different speeds. Based on the heat generation and transfer analysis of ball screw system, thermal expansion of screw shaft in the axial direction is modeled mathematically. Relationships between the thermal error and axial elongation are established to characterize the thermal error distribution considering the thermal expansion coefficient as a temperature-variant parameter. It turns out that the thermal error varies with different working positions through the ball screw length and working time nonlinearly, and there definitely exists certain transform from the thermal expansion to the thermal error obtained by measurement. In addition, regression analysis is employed to carry out the theoretical modeling of thermal error with the temperature data of the critical heat generation points. The relations between temperature rise and thermal error are formulated directly while taking the thermal expansion as an implicit variable. Experiments under a different condition are preformed and the proposed methods for thermal error modeling prove to be effective and accurate enough to be used in the machining process as well.

Residence Time Distribution of Particles in a Screw Feeder: Experimental and Modelling Study

Experiments were conducted to investigate the effects of screw speed and screw feeder inclination on the residence time distribution (RTD) of particles in a screw feeder via a pulse stimulus response technique. Two models based on Markov chains were developed to simulate particle flows within and between pitches. In upward and horizontal screw feeder inclination cases, a three‐parameter two‐dimensional Markov chain model consisting of parallel active and stagnant zones fitted well with the experimental RTD data, with correlation coefficients (R2) higher than 0.98, and gave a clear physical meaning for the parameters introduced. In these cases, a high screw speed or a horizontal inclination induced a high probability of forward movement from a pitch to the next pitch (f) during each rotation period of the screw, and a low ratio of stagnant zone to active zone (r) in a pitch. The upward screw feeder inclination yielded a higher diffusion probability from stagnant zone to active zone (d). In the downward screw feeder inclination case, a one‐dimensional Markov chain model without a stagnant zone was in agreement with the corresponding experimental data. The analysis showed that during each rotation period of the screw, the particles in a pitch could be transferred not only to the next pitch but also to the following two pitches.