Feed Screw Research Articles

Experiment-based thermal error modeling method for dual ball screw feed system of precision machine tool

In order to investigate the thermal behavior of a dual ball screw feed drive system of a precision boring machine tool, experimental study on and theoretical modeling of thermally induced error along with heat generation characteristics are conducted in this paper. Experiments are carried out on the machine tool to measure and collect the thermodynamic information with its feed drive system operating under different working conditions. Based on the real-time data of the thermal expansion of ball screw in the axial direction, relationships between the thermal error and axial elongation are established to predict the thermal error distribution. The results show that the thermal error varies with different working position through the ball screw length linearly and with working time nonlinearly. In addition, another simplified way to model thermal error is presented to overcome the difficulties existing in the ball screw feed drive system of which the axial elongation is hard to collect. Fuzzy clustering and linear regression methods are employed to carry out the theoretical modeling of thermal error and optimization to sift out the critical heat sources. With the temperature data of these critical heat generation points, the thermally induced error of the ball screw feed drive system can be predicted easily alternatively. Experiments under a different condition are preformed to verify both prediction and modeling methods. It turns out that the proposed prediction methods are effective and practical to be used in the machining process as well.

Physical Properties of Refabricated Rice as Affected by Extrusion: A Response Surface Analysis

The aim of this study was to optimize the extrusion conditions for production of refabricated rice using a response surface modeling approach. The effects of feed moisture content, screw speed, and barrel temperature on the physical properties of rice grains refabricated using a corotating twin-screw extruder were investigated. Rice flour (variety PR-116) obtained from broken grains (smaller than one-eighth of a whole grain) was used in the study. Screw speeds at five levels between 49 and 150 rpm, barrel temperatures between 59 and 110°C, and feed moisture contents between 31 and 45% were tested. All of the physical properties of the refabricated rice grains that were evaluated (thousand kernel weight, length/breadth ratio, bulk density, and breaking strength) were significantly (P < 0.01) affected by these three process variables. Response surface regression models were established to correlate the physical properties of refabricated rice grains to the process variables. Understanding the effects of pro...

목재펠릿보일러의 연료공급 장치의 형태에 따른 연소특성에 관한 연구

This study reports the combustion characteristics, such as burner temperature and the concentration of exhausted gas (, , ) due to the different types and pitches of the fuel supply feeder of the wood pellet boiler. The 1st grade wood pellets composed of mainly larch have been used for the experiment. In case of using the spring feeder, mean temperature of burner was approximately , and the mean concentration of oxygen, carbon monoxide, carbon dioxide and nitrogen oxide were approximately 8.88%, 93.35ppm, 12.15% and 139.83 ppm, respectively. The test result with the spring feeder was shown to approach the condition of complete combustion compared to that of a screw feeder and were in good agreement with authentication judgement standard. Furthermore, the combustion efficiency was improved according to the growth of screw pitch. The control of air flow rate from the blower and ventilator is needed to achieve the complete combustion.

Reduction of aflatoxin B1 in peanut meal by extrusion cooking

This study explored the feasibility of degrading aflatoxin B1 (AFB1) in contaminated peanut meal by extrusion cooking. Peanut meal contaminated with AFB1 (35.8 ± 1.5 μg/kg) was extrusion-cooked in a twin-screw extruder and AFB1 was quantified by ELISA. The effects of barrel temperature, material moisture content, feed rate, and screw speed as well as their interactions on the reduction rate of AFB1 in peanuts meal were evaluated by Response surface methodology (RSM) to optimize the extrusion conditions. Under the optimal conditions (barrel temperature of 150 °C, material moisture content of 40 g/100 g, feed rate of 17 g/min, and screw speed of 152 rpm), 77.6 ± 2.2% of AFB1 was degraded. The barrel temperature and material moisture have significant influences (P < 0.01) on the degradation rate of AFB1, while the feed rate or screw speed has no significant influence.

Some Quality Attributes of High Quality Cassava-Tigernut Composite Flour and Its Extruded Snacks

The chemical properties of the high quality cassava-tigernut composite flour, as well as the physical and quantitative descriptive sensory properties of the extruded snack therefrom, were investigated. Extruded snacks were procesed from different blends of high quality cassava flour (HQCF) and tigernut composite flour at the ratio of 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70 and 20:80, 100% HQCF and 100% tigernut flour. The extrudates were produced using a single screw laboratory extruder at constant feed moisture (27%), screw speed (60 rpm) and barrel temperature (80°C). Addition of tigernut flour improved some chemical and physical qualities of the extrudates and the study concluded that an acceptable extruded snacks can be produced from high quality cassava-tigernut flour blends.

Antioxidant activity, free gamma-aminobutyric acid content, selected physical properties and consumer acceptance of germinated brown rice extrudates as affected by extrusion process

Effects of feed moisture (14, 18, and 22 g/100 g) and screw speed (300, 350 and 400 rpm) on selected physical properties, gamma-aminobutyric-acid (GABA) content, antioxidant activity and consumer acceptance of extruded snacks from germinated brown rice flour (GBRF) were investigated. Changes in feed moisture significantly affected physical properties of extrudates whereas screw speed showed less effects. Decreasing feed moisture caused a decrease in bulk density and hardness, but an increase in expansion ratio. Decreasing feed moisture increased destruction of free GABA in extrudates. DPPH radical-scavenging activities, ferric reducing antioxidant power and total phenolic content of extrudates were significantly lower than those of the non-extruded GBRF. The predicted optimum extrusion condition (16–19 g/100 g feed moisture; 300–320 rpm screw speed) would yield extrudates with 25–30 mg/100 g extrudate (dry-basis) free GABA content and an overall liking score of 6.0 (on a 9-points hedonic scale).

Devulcanization and Recycling of Waste Automotive Epdm Rubber Powder by Using Shearing Action and Chemical Additive

In automotive applications, ethylene-propylene-diene rubber (EPDM) is used to manufacture various components and therefore recycling scrap rubber is a major issue. The primary aim of this study was to develop a new method for devulcanizing waste automotive EPDM rubber powder by using shearing action and chemical additive and recycle the devulcanized powder. A semi-industrial twin screw extruder with a shearing action and reactor along with 2-mercaptobenzothiazole-disulfide (MBTS) chemical were used to devulcanize the waste powder at two different feed screw speeds and main rotor speeds at a constant temperature of 220°C. To recycle the devulcanized powder, different amounts of the devulcanized powder were mixed with a commercial EPDM-based automotive rubber strips compound to produce blends. The blends, commercial compound and devulcanized powder were cured with a semi-efficient (SEV) vulcanization system and their viscosity, cure and mechanical properties measured. For the blends, the Mooney viscosity was unchanged with 40 wt%, crosslink density with 20 wt%, tensile strength and elongation at break with 10 wt%, and compression set with 20 wt% of the devulcanized powder. Interestingly, the hardness benefitted from 50 wt% of the devulcanized powder in the blends. The scorch and optimum cure times shortened and the cure rate index rose when the loading of the devulcanized powder in the blends was raised. This new method offered a major new route for devulcanizing and recycling the waste powder.

옥수수 섬유질로부터 검과 수용성 아라비노자일란의 수율향상을 위한 압출성형 조건의 최적화

본 연구는 압출성형 된 옥수수 섬유질로부터 화학적 추출을 통해 SAX와 CFG 수율을 향상시키기 위해 반응표면분석법을 이용하여 최적의 압출성형조건을 확립하였다. 압출성형공정 조건 중 수분함량(<TEX>$X_1$</TEX>), 스크루 회전속도(<TEX>$X_2$</TEX>), 배럴온도(<TEX>$X_3$</TEX>)를 독립 변수로 하고 옥수수 섬유질의 residual solid, final solution, 그리고 CFG의 수율과 각각의 SAX값을 종속 변수로 하여 화학적으로 추출 하였다. 그 결과, 수율의 경우 final solution은 EDCF가 DCF보다 낮은 경향을 보였고, residual solid와 CFG의 경우, EDCF가 DCF보다 높은 경향을 나타내었다. SAX값은 모든 조건의 EDCF가 DCF보다 높은 경향을 나타냈다. 각각의 결정된 최적의 압출성형 조건에서 분석한 결과 모든 조건에서 예측값과 결과값이 유사하여 반응표면 분석의 결과가 양호한 것으로 나타났다. 이상의 연구결과에서 반응표면 분석법이 압출성형 공정에 의한 CFG의 수율과 총 SAX값의 최적화를 위한 적절한 방법 중 하나라는 것을 보여주었다. The effects of feed moisture content (25, 35, and 45%), screw speed (230, 250, and 270 rpm), and barrel temperature (130, 140, and <TEX>$150^{\circ}C$</TEX>) on the product yield and soluble arabinoxylan (SAX) content from destarched corn fiber (DCF), and its optimization were investigated. The yield and SAX content of corn fiber gum (CFG) from the extruded destarched corn fiber (EDCF) were higher than those of DCF. Statistical analyses revealed that the feed moisture content and barrel temperature had a significant effect on the CFG yield and total SAX content. The optimum extrusion pretreatment conditions were as follows: feed moisture content, 30%; screw speed, 260 rpm; barrel temperature, <TEX>$133^{\circ}C$</TEX>. This study showed that the response surface methodology was suitable for the optimization of the extrusion conditions used to maximize the CFG yield and total SAX content from EDCF.

Mass flow and variability in screw feeding of biomass powders — Relations to particle and bulk properties

Biomass powders often have high cohesiveness, low bulk density and poor material flow characteristics which cause interruptions and variations in feeding systems. In this study, a range of biomasses – commercial charcoal, torrefied Norway spruce stem wood, non-treated Norway spruce stem wood, and reed canary grass – were milled (screen size: 1mm) using two different methods; cutting mill and hammer mill, to form eight types of biomass powders. The powders were analyzed for loose bulk density, Hausner ratio, compression ratio, angle of repose and for size and shape distributions. Size and shape were determined by mechanical sieving and optical particle size and shape analysis. Additionally, yield loci and wall yield loci were determined through standard bulk solid testing methods. Screw feeding properties of the eight biomass powders were determined by feeding the materials in a twin screw feeder — at constant rpm and at a constant feeding rate of 1kg/h. Correlation analysis and principal component loadings were used to describe relations between material properties and feeding characteristics. When materials were fed at a constant rpm, feeding variability was closely correlated to the powder's angle of repose (long time) and Hausner and compression ratios (short time).

Effect of Process Variables on Some System Parameters and Physical Properties of Millet-Soybean Fura Extrudates

A three-factor three level central composite rotatable (CCRD) was adopted to study the effect of feed composition (X1), feed moisture content (X2) and screw speed (X3) on average residence time (ART), mass flow rate (MFR), specific mechanical energy (SME), expansion ratio (ER) and bulk density (BD) during extrusion of pearl millet and soybean flour mixtures for fura production (a Nigerian traditional food).The results shows that linear and quadratic terms showed significant (P Feed Composition (X1) > Screw Speed (X3). Response variables predicted with model equations under optimum conditions were in general agreement with experimental data. The data obtained from the system parameters and physical properties could be used for control of product characteristics and possible projection for the commercial production of millet-soybean based foods like fura.

Interpolating gain-scheduled H∞ loop shaping design for high speed ball screw feed drives

This paper presents a method to design servo controllers for flexible ball screw drives with time-varying dynamics, which are mainly due to the time-varying table position and the workpiece mass. A gain-scheduled H∞ loop shaping controller is designed to achieve high tracking performance against the dynamic variations. H∞ loop shaping design procedure incorporates open loop shaping by a set of compensators to obtain performance/robust stability tradeoffs. The interpolating gain-scheduled controller is obtained by interpolating the state space model of the linear time-invariant (LTI) controllers estimated for fixed values of the scheduling parameters and a linear least squares problem can be solved. The proposed controller has been compared with P/PI with velocity and acceleration feedforward and adaptive backstepping sliding mode control experimentally. The experimental results indicate that the tracking performance has been improved and the robustness for time-varying dynamics has been achieved with the proposed scheme.

The Experimental Study on the Carbon Black Weighing and Discharging Process

In this paper the development trend of mixer feeding system is discussed first. Then against the problem of inaccuracy in automatic weighing and feeding of carbon black and powders which occurs frequently, we suggest that converter motor be used in screw feeder, and that electric heating and variable screw pitch be adopted. We did a series of experiments with the weighing system, and give some recommendations. Discharging is also described in detail. Finally, we provide further suggestions to avoid weighing inaccuracy of discharging system or fluctuations in feeding time and accuracy caused by material adhesion and so on, so that mixing quality can be improved and mixing cycle can be shortened.

Cooking behaviour of re-fabricated rice as affected by extrusion: A response surface analysis

The effect of feed moisture, screw speed and barrel temperature on cooking characteristics of re-fabricated rice grains was investigated in a co-rotating twin-screw extruder using response surface methodology. The rice flour obtained from broken rice (< 1/8th of actual kernel size) of PR-116 after mixing with structural components was used in the study. The screw speed was set at five levels between 49 and 150 rpm, barrel temperature between 59 and 110°C and feed moisture between 31 and 45%. All cooking parameters of the re-fabricated rice grains evaluated—Kernel length before cooking (KLBC), kernel length after cooking (KLAC), volume expansion ratio (VER), water uptake (WU) and cooking coefficient (CC) –were significantly (P<0.01) affected by the three process variables. Barrel temperature was the most significant variable with quadratic effect on KLAC and WU. Response surface regression models were established to correlate the cooking parameters of re-fabricated rice grains to the process variables. The optimized extrusion conditions for preparation of re-fabricated grains were 38% moisture content, 130 rpm screw speed and 89°C barrel temperature. Understanding the effect of process variables on the cooking properties and optimization of extrusion conditions was deemed useful for the development of re-fabricated rice.

The effect of extrusion conditions on the functional properties of defatted cake of sunflower-maize based expanded snacks

The effect of extrusion conditions, including feed moisture content (14–20%), screw speed (300–500 rpm), and barrel temperature (120–180oC) on the functional properties (water absorption index (WAI), and water solubility index (WSI), fat absorption capacity (FAC) and foaming capacity) and sensory properties (color, appearance, flavor, overall acceptability and textural characteristics) of an expanded sunflower snack was investigated. Extruded snacks were prepared by substituting maize flour with developed texturized flour of sunflower at 0–40% levels. Protein content increased to 13.83% in snacks prepared with 10% texturized sunflower meal as compared to the control i.e., 7.55%. Fibre content increased while protein digestibility improved with increased level of incorporation of texturized defatted sunflower flour in extruded snacks making. Increasing feed moisture content results in extrudates with lower expansion, lower WAI, higher WSI, higher hardness and lower sensory acceptability. Increasing screw speed caused slight reduction of density and hardness of sunflower extrudate. Feed moisture had positive while screw speed and barrel temperature had negative influence on WAI. Negative coefficient of linear terms of moisture and screw speed indicated that WSI decreased with increase in these variables. Higher moisture content in extrusion process could diminish protein denaturation which lowered WSI values.

Accuracy Enhancement of Automated System for Multicomponent Batching of Bulk Materials

In the paper the choice of reasonable structure of automated system for multicomponent batching of bulk materials has been substantiated to minimize the batching error of about 3% in case the recipe mixture includes small components of big importance in terms of efficiency and cost. The algorithm of signal adaptation for weight controller of the electric drive control system of screw feeder, which takes into account the material properties changing and the dropping column mass.

Effect of Stiffness of Rolling Joints on the Dynamic Characteristic of Ball Screw Feed Systems in a Milling Machine

Dynamic characteristic of ball screw feed system in a milling machine is studied numerically in this work. In order to avoid the difficulty in determining the stiffness of rolling joints theoretically, a dynamic modeling method for analyzing the feed system is discussed, and a stiffness calculation method of the rolling joints is proposed based on the Hertz contact theory. Taking a 3-axis computer numerical control (CNC) milling machine set ermined as a research object, the stiffness of its fixed joint between the column and the body together with the stiffness parameters of the rolling joints is evaluated according to the Takashi Yoshimura method. Then, a finite element (FE) model is established for the machine tool. The correctness of the FE model and the stiffness calculation method of the rolling joints are validated by theoretical and experimental modal analysis results of the machine tool’s workbench. Under the two modeling methods of joints incorporating the stiffness parameters and rigid connection, a theoretical modal analysis is conducted for the CNC milling machine. The natural frequencies and modal shapes reveal that the joints’ dynamic characteristic has an important influence on the dynamic performance of a whole machine tool, especially for the case with natural frequency and higher modes.

Dynamic Characteristic Analysis of Ball Screw Feed System Based on Stiffness Characteristic of Mechanical Joints

Dynamic Characteristic Analysis of Ball Screw Feed System Based on Stiffness Characteristic of Mechanical Joints

Optimization of Extrusion Process Parameters for Red Lentil-carrot Pomace Incorporated Ready-to-eat Expanded Product Using Response Surface

For optimization of extrusion process for development of red lentil-carrot pomace incorporated ready- to-eat rice based expanded product, experiments were planned in Box-Behnken design using response surface methodology. The independent process variables for extrusion were feed moisture content (14-20%), die temperature (120-180℃), screw speed (300-500 rpm) and formulation (rice flour: pulse flour; 60-80%: 10-30%) with constant proportion of carrot pomace powder (10%). Second order polynomials were used to model the extruder responses, functional and physical properties as a function of extrusion process variables. The extrusion process was optimized for maximum expansion ratio, water absorption index, overall acceptability and minimum bulk density, water solubility index, specific mechanical energy and hardness with in experimental range. The optimum extrusion process conditions obtained were 80:10:10 (rice flour: pulse flour: carrot pomace powder), 14% feed moisture content, 394 rpm screw speed and 120℃ die temperature. An analysis of variance (ANOVA) revealed that among the process variables, feed moisture content followed by screw speed had the most significant effect on all the responses; screw speed had the significantly higher effect on specific mechanical energy. The proportion of red lentil and carrot pomace in rice based expanded product was observed to have significantly lower effect on the selected responses.

A screw-brush feeding system for uniform fine zinc oxide powder feeding and obtaining a homogeneous gas–particle flow

The most important requirements of gas–solid two phase flow feeding are a very uniform mass flow of fine particles and providing a homogeneous dispersed cloud of them. In this study, a screw-brush feeding device has been developed to feed fine zinc oxide powders and to achieve a homogenous gas–particle two phase flow by a minimum gas flow rate. The results of these experiments indicated that the performance of this feeding system without gas flow was better than a screw feeder alone, to stabilize the feeding of fine ZnO powder at low flow rates. Moreover, the results of experimental micrographs showed that the screw-brush system with a minimal amount of gas flow rate is able to reduce the mean aggregate size of the particle size distribution and could provide a homogeneous gas–particle flow.

Production and Quality Evaluation of Noodles From Sweet Potato Starch

The effect of extrusion parameters (feed moisture content, barrel temperature, and screw speed) on the quality of noodles produced from sweet potato starch was investigated. Starch was extracted from the tuber of sweet potato and processed into noodles using single screw cooking extruder. The moisture, protein, and ash contents of the noodles decreased linearly with the feed moisture content and barrel temperature but decreased with increasing screw speed. Increased feed moisture content also led to decrease in water absorption capacity, cooking time, and water solubility index. Lateral expansion increased with increasing barrel temperature. Barrel temperature had significant effect (p < 0.05) on lateral expansion while screw speed and feed moisture content had significant effect (p < 0.05) on cooking time. Significant (p < 0.05) positive correlation was obtained between the overall sensory acceptability, appearance, firmness, and chewiness. The study showed that noodles of desirable functional qualities and sensory acceptability can be obtained from sweet potato starch using barrel temperature of 110°C, screw speed of 100 rpm, and feed moisture content of 47.5%.