Novel Straightening-Machine Design with Integrated Force Measurement for Straightening of High-Strength Flat Wire.

In a punch-bending machine, wire products are manufactured for a wide range of industrial sectors, such as the electronics industry. The raw material for this process is flat wire made of high-strength steel. During the manufacturing process of the flat wire, residual stresses and plastic deformations are induced into the wire. These residual stresses and deformations fluctuate over the length of the semi-finished product and have a negative effect on the final product quality. Straightening machines are used to reduce this influence to a minimum. So far, the adjustment of a straightening machine has been performed manually, which is a lengthy and complex task even for an experienced worker. This inevitably leads to the use of inefficient straightening strategies and causes high rejection rates in the entire production process. Due to a lack of sensor information from the straightening operation, application of modern feedback control methods has not been practicable. This paper presents a novel design for a straightening machine with an integrated, precise straightening force measurement. By simultaneously monitoring the position of the straightening rollers, state variables of the straightening operation can be derived. Additionally, a tension control for feeding the flat wire is introduced. This is implemented to mitigate the disturbing effects caused by irregularities in the wire-feeding process. In the results of this article, the high precision of the developed force measurement design and its possible applications are shown.

Design and Shape Optimization of Strain Gauge Load Cell for Axial Force Measurement for Test Benches.

The load cell is an indispensable component of many engineering machinery and industrial automation for measuring and sensing force and torque. This paper describes the design and analysis of the strain gauge load cell, from the conceptional design stage to shape optimization (based on the finite element method (FEM) technique) and calibration, providing ample load capacity with low-cost material (aluminum 6061) and highly accurate force measurement. The amplifier circuit of the half Wheatstone bridge configuration with two strain gauges was implemented experimentally with an actual load cell prototype. The calibration test was conducted to evaluate the load cell characteristics and derive the governing equation for sensing the unknown load depending on the measured output voltage. The measured sensitivity of the load cell is approximately 15 mV/N and 446.8 µV/V at a maximum applied load of 30 kg. The findings are supported by FEM results and experiments with an acceptable percentage of errors, which revealed an overall error of 6% in the worst situation. Therefore, the proposed load cell meets the design considerations for axial force measurement for the laboratory test bench, which has a light weight of 20 g and a maximum axial force capacity of 300 N with good sensor characteristics.

Design of a vertical Loss-in-Weight feeder prototype with experimental proof of concept validation.

Loss-in-Weights (LiW) feeders are commonly oriented in a horizontal way. In this work, an experimental proof of concept, including mechanical and electrical design, construction, and operation, of a vertical LiW feeder prototype is performed. In a systematic design process, based on functional design specifications, the semi-automated vertical LiW feeder for dosing a wide range of powders, especially cohesive ones, is developed. The new dosing machine is assessed with regard to a number of key features such as high dosing accuracy, first-in-first-out powder discharge, easily interchange of the powder container, and flexibility in controlling the speed of the auger and stirrer motors independently. An experimental sensitivity analysis to study the functionality of the dosing machine and to investigate the weight variability of the weighing platform, i.e. mass flow rate, and quantity of dosed mass, is carried out. The results of the sensitivity analysis and the powder dosing tests of five diverse powders using different auger and stirrer geometries verified the proof of concept prototype.HighlightsA systematic design approach for validating a proof of concept of a vertical loss in weight feeder is appliedA full mechanical CAD design and implementation along with electric installation and software programming are executedSensitivity analysis approach is performed to validate the functionality of the semi-automated machine and successfully dispense dissimilar powders tested with different process parametersThe machine is characterized with a number of key features: first-in-first-out powder discharge, high dosing accuracy, flexible and modular concept design, flexibility in controlling the speed of the auger and the stirrer independently, lightweight and user-friendly design.

Design and development of a machine for continuous popping and puffing of grains.

Popping/puffing have been traditionally practiced for enhancing storage life, improving organoleptic properties and ease of incorporation in ready-to-eat-foods. Currently, batch type sand and electric popping/puffing machines involving conduction mode of heat transfer are employed. The major drawbacks of these methods are high-energy consumption, scorching of grains, non-uniform product quality, contamination (by sand/ash) and problems in scale-up. Since fluidization is known to increase heat and mass transfer, a continuous fluidized popping/puffing machine (capacity 10-20 kg/h) involving convective mode of heat transfer is designed/developed. Hot-flue gas generating from burning of LPG was used as the eco-friendly fuel. Process parameters such as expansion ratio, fluidization velocity, terminal velocity, carry over velocity, bulk density and voidage were estimated for un-popped and popped/puffed rice, maize, jowar (sorghum) and paddy. Fluidization and carry over velocities for these grains were in the range of 4.18-5.78 m/s and 2.15-6.18 m/s, respectively. Based on the terminal velocity of the grains and volumetric air flow rate of the blower, fluidization chamber diameter was arrived. Chamber diameter of 0.15 m was found to be sufficient to generate required air velocity of 6.89 m/s which met the fluidization and carry over velocities of popped/puffed grains. The designed fluidization chamber was analyzed for heat and mass transfer during popping/puffing. Convective heat and mass transfer coefficients were estimated to be in the range of 103-187 W/m2 °C and 0.124-0.162 m/s, respectively. Theoretical values for total heat and mass transfer were similar to the experimental values.

Programmable motion of DNA origami mechanisms.

DNA origami enables the precise fabrication of nanoscale geometries. We demonstrate an approach to engineer complex and reversible motion of nanoscale DNA origami machine elements. We first design, fabricate, and characterize the mechanical behavior of flexible DNA origami rotational and linear joints that integrate stiff double-stranded DNA components and flexible single-stranded DNA components to constrain motion along a single degree of freedom and demonstrate the ability to tune the flexibility and range of motion. Multiple joints with simple 1D motion were then integrated into higher order mechanisms. One mechanism is a crank-slider that couples rotational and linear motion, and the other is a Bennett linkage that moves between a compacted bundle and an expanded frame configuration with a constrained 3D motion path. Finally, we demonstrate distributed actuation of the linkage using DNA input strands to achieve reversible conformational changes of the entire structure on ∼ minute timescales. Our results demonstrate programmable motion of 2D and 3D DNA origami mechanisms constructed following a macroscopic machine design approach.

Development and Performance Analysis of an Automatic Core Cutter for Elephant Apple (Dillenia indica L.) Processing.

Elephant apple, a fruit with numerous bioactive compounds, is rich in therapeutic qualities. However, its use in processed products is limited due to insufficient postharvest processing methods. To address this issue, an automatic core cutter (ACC) was developed to handle the hard nature of the fruit while cutting. The physical characteristics of the elephant apple were considered for designing and development of the cutter. The cutter is divided into four main sections, including a frame, collecting tray, movable coring unit, and cutting base with five fruit holders. The parts that directly contact the fruit are made of food-grade stainless steel. The efficiency of the cutter was analyzed based on cutting/coring capacity, machine efficiency, loss percentage, and other factors, and was compared to traditional cutting methods (TCM) and a foot-operated core cutter (FOCC). The ACC had an average cutting/coring capacity of 270-300 kg/h, which was significantly higher than TCM's capacity of 12-15 kg/h and comparable to FOCC's capacity of 115-130 kg/h. The ACC offered a higher sepal yield of 85.68 ± 1.80% compared to TCM's yield of 65.76 ± 1.35%, which was equivalent to the yield obtained by FOCC. Therefore, the ACC outperforms TCM in terms of quality, quantity, and stress associated and is superior to FOCC in terms of higher efficiency of machine and labor.

Machines that save lives in the intensive care unit: the ultrasonography machine.

This article highlights the ultrasonography machine as a machine that saves lives in the intensive care unit. We review its utility in the limited resource intensive care unit and some elements of machine design that are relevant to both the constrained operating environment and the well-resourced intensive care unit. As the ultrasonography machine can only save lives, if is operated by a competent intensivist; we discuss the challenges of training the frontline clinician to become competent in critical care ultrasonography followed by a review of research that supports its use.

Development of a wind turbine for a hybrid solar-wind power system.

Conventional energy supply has not been able to meet the energy needs of most developing nations. This calls for the need to invest in renewable energy systems which are not only sustainable but clean, abundant, and easily assessable. This research presents a study of wind variability by using wind data got from a weather station to design and fabricate a small-scale horizontal axis wind turbine (HAWT). This was done by using locally sourced materials for a Hybrid Solar-Wind power system for irrigation purposes, as a performance evaluation of the turbine. The materials used in the fabrication of the turbine include wood, polyvinyl chloride plastic, acrylic glass, Teflon, and steel all sourced locally. From the evaluation, the power capacity of the wind turbine was derived to be 40 W, 41 W and 43 W from the voltage and current output reading on the multi-meter from three average wind speed variations of 5 m/s, 10 m/s and 15 m/s measured from handheld digital anemometers respectively. A regression analysis of the relationship between the turbine's power capacity and the wind speed showed that the turbine operates best at low speed of 5 m/s, with an R2 value of 0.9602. The fabricated wind turbine was connected to a hybrid power system with the second energy source consisting of a 40 W solar tracking system to give a more stable power supply. The system was used for soil monitoring irrigation purposes. The design of the HAWT indicates a cheap, alternative and sustainable energy source that is more stable and suitable for smart solar panel irrigation system.

A laboratory-scale binder jet additive manufacturing testbed for process exploration and material development.

Binder jet additive manufacturing (BJAM) is capable of fabricating complex three-dimensional components from a variety of material classes. Understanding the fundamentals of BJAM, including spreading of thin layers of powder, powder-binder interactions, and post-processing is critical to develop robust process parameters for BJAM. Toward meeting these needs, this work presents the design, fabrication, and qualification of a testbed for modular, mechanized, BJAM. The testbed seeks to replicate the operating conditions of commercial AM equipment and features fully programmable motion control including powder spreading using a precision roller mechanism, powder supply via a vibrating hopper, and gantry positioning of an inkjet printhead. The inkjet deposition system allows for the use of variable nozzle diameters, the exploration of novel binder compositions, and full control of jetting parameters. Validation of the accuracy and repeatability of the machine and its subsystems, as well as the fabrication of exemplary stainless steel components, are described. The precision engineered testbed can therefore enable the study of the BJAM process, exploration of novel binder compositions, and processing of custom powders to further scientific research and industrial applicability of BJAM.

Cutting Tests of the Outer Layer of Material Using Onion as an Example.

This paper describes experimental research on cutting the outer layer of onions in the machine peeling process. The authors' own globally innovative modular machine construction was used for this purpose. The onion peeling machine was constructed on a real scale. The effectiveness of the machine's functioning Se was defined as the ratio of the mass of material correctly removed by the scale blower mp to the mass of all material leaving the machine on the test bench mc. In order to carry out the experimental research, a test stand was constructed, a research plan and programme were adopted, and the research methodology was developed. The results obtained during the experimental research and the data obtained from the regression function equations for the developed design of the onion peeling machine were used to build systems of independent variables, for which the dependent variable Se reached extreme values. The effectiveness of the machine's operation Se of modular construction increased with the increase in the depth of the external incisions of the shells dn, the number of scale-blowing nozzles, and the pressure of the air supply to the scale-blowing unit p. Increasing the material feed rate vp and the distance of the air nozzles from the material to be processed hd reduced the machine's efficiency Se. The tests carried out showed a high level of efficiency on the level of Se=0.645-0.780, which is not found in mass-produced machines.

Functional Analysis Validation of Micro and Conventional Injection Molding Machines Performances Based on Process Precision and Accuracy for Micro Manufacturing.

Micro polymer parts can be usually manufactured either by conventional injection moulding (IM) or by micro-injection moulding (µIM). In this paper, functional analysis was used as a tool to investigate the performances of IM and µIM used to manufacture the selected industrial component. The methodology decomposed the production cycle phases of the two processes and attributed functions to parts features of the two investigated machines. The output of the analysis was aimed to determine casual chains leading to the final outcome of the process. Experimental validation of the functional analysis was carried out moulding the same micro medical part in thermoplastic elastomer (TPE) material using the two processes by means of multi-cavity moulds. The produced batches were assessed using a precision scale and a high accuracy optical instrument. The measurement results were compared using capability indexes. The data-driven comparison identified and quantified the correlations between machine design and part quality, demonstrating that the µIM machine technology better meets the accuracy and precision requirements typical of micro manufacturing productions.

Design and construction of a double actuated mechanical speed breaker electricity generator.

The economy runs on energy and quest for development means that more energy is needed. Statistics show that the majority of energy comes from burning fossil fuels, and they pollute our environment. This work is aimed at producing a mechanical speed breaker electricity generator that operates on two actuating strokes. It converts the linear motion of the rack gear that is depressed by the vehicular movement to rotary motion of the pinion gear keyed on the shaft and alternator. The machine gets actuated by compression and release of the springs, thus increasing the output of the machine. It consists of a stable frame, dome-shaped top, rack and pinion mechanism, chain and sprocket mechanism, freewheels, springs, flywheel, shafts, an alternator and a deep cycle battery. The design was carried out using engineering principles with due consideration to cost, serviceability, ease of operation, durability and performance. It is designed to be actuated by vehicles weighing 1,600kg (400kg per wheel) and a prototype rated 100kg was built. Tests were performed to determine the performance of the machine and the results showed that the speed breaker could produce a rotary speed of 1500 rpm at the alternator, thereby generating 204W of electrical power per cycle. The machine conversion efficiency was about 88.7%.

Usage of shape memory alloy actuators for large force active disassembly applications.

Shape memory alloys (SMAs) possess inherent superior properties that make their applications in active disassembly an emerging and interesting field of research. This is because extremely large forces can be generated repeatedly using a small compact-sized element, such as an SMA actuator. To ensure the ability of the SMA actuator to generate a repeated large force or withstand repeated load, several factors should be considered. These include factors that affect the value of the generated recovery forces, such as the amount of strain used, activation temperature, activation time, and cross-sectional area of the SMA element. In general, the compressive strain can be considered as the most influential factor that affects the value of the generated recovery force. The present research investigates the possible use of the SMA actuator in large-force active disassembly applications. To the best of the authors' knowledge, all the studies conducted in this field are concerned with implementing active disassembly in applications requiring small disassembly forces. The present research was conducted in three phases. First, the behaviour of the SMA element upon exposure to different repetitive compressive strains was studied, and the generated recovery force and strain hardening induced in the material were considered to ensure the continuous generation of large recovery forces with the least amount of residual strain induced in the material. Second, the optimum value of the compressive strain required to generate the maximum force with the least amount of residual strain induced in the material was estimated. Third, a practical case study was presented to validate the possible implementation of SMA actuators in large force active disassembly applications. The study successfully estimated the optimum compressive strain value that generated the required recovery force to disassemble the conducted case study using active disassembly technique.

Investigation of process parameters in orthogonal cutting using finite element approaches.

The cutting force in orthogonal cutting of steel AISI 1045 was predicted by applying 2D finite element analysis (FEA) using two methods; (i) Lagrangian (LAG) and (ii) Arbitrary Lagrangian Eulerian (ALE). Johnson-Cook (J-C) models were used for defining plastic and failure properties of simulated materials. The predicted force was validated experimentally by using dynamometer. Comparison held between the simulation methods and experimental work in terms of results accuracy, reading stability, and chip morphology. Furthermore, this study adopted new modeling idea to control the excessive distortion of mesh elements along chip separation line by defining nearly zero damage criterion for these elements. The results demonstrated that LAG and ALE methods could predict the cutting force but with different accuracy, as LAG and ALE results deviated from experimental results with minimum error percentage 3.6% and 0.14% respectively. As well, ALE method showed stable force readings and continues smooth chip during simulation, while LAG method showed unstable force readings and discontinuous realistic chip.

Hybridized fuzzy analytic hierarchy process and fuzzy weighted average for identifying optimal design concept.

In this article, a novel hybridized Multi-Attribute Decision Model (MADM) is developed to identify an optimal design of a Reconfigurable Assembly Fixture (RAF) from a set of alternative design concepts. The model combines the comparative advantage of Fuzzy Analytic Hierarchy Process (FAHP) and the computational strength of the Fuzzy Weighted Average (FWA) based on left and right scores in order to obtain aggregates for the design alternatives considering the relative importance of the design criteria as needed in the optimal design. The model was applied to evaluate four design concepts of a RAF with six design features having numerous sub-features. Results obtained from the evaluation process shows that there are differences in final values of the design alternatives. However, a close variation exists between these values. These differences can be accrued to the interrelationships between the design features and sub-features obtained from the Fuzzy Synthetic Extent (FSE) of the FAHP and an unambiguity judgment of the FWA when aggregating availability of the design features and sub-features in the design alternatives.

Specific energy requirements and soil pulverization of a combined tillage implement.

Reducing energy use in soil preparation has become increasingly important since it is a major cost in planting. Experiments were conducted with a combined tillage implement consisting of a subsoiler and a rotary harrow to reduce the cost due to step reduction in soil preparation. Three tillage operations, two forward speeds, and two rotational rotor speeds were determined as input factors in this study. Soil clod size, performance parameters, and the specific energy requirements of a combined tillage implement were investigated. The field experiments were using two different soil conditions. Increasing the rotor speed from 299 to 526 rpm decreased the mean soil clod diameter at a depth of 0-200 mm from 22.98 to 19.83 mm and from 31.77 to 26.57 mm for fields 1 and 2, respectively. The specific energy requirement was affected significantly by rotor speed and tillage operation. The specific energy requirements for the combined tillage implement with an on-frame pivot joint and an on-pivotable-shank joint were less by 10.4 and 21.1% and by 18.4 and 24.7%, for fields 1 and 2, respectively, compared to the total power requirement for the separate use of a subsoiler and a rotary harrow.

Auto-assessment tools for mechanical computer aided design education.

Traditionally Computer Aided Design (CAD) courses have been carried out in computer classrooms requiring great amount of teaching personnel. Assessment of students' modeling exercises has been both time consuming and error prone. Utilization of the teaching resources could clearly benefit from online auto-assessment. The auto-assessment tools are widely in use in programming and language courses, but suitable tools for assessing 3D models used in CAD are lacking. This paper presents two new online auto-assessment tools to support the development of both command ("what steps are needed to create this shape?") and strategic ("how should I model this shape?") knowledge while learning CAD. The first tool is based on neutral file format (in this case STEP) and can recognize surface differences between student's model and reference model. This tool can assess student's skill to create certain predefined shape (i.e. command knowledge). The second auto-assessment tool utilizes commercial CAD software's API (Application Programming Interface) to test how student's model behaves when modeling parameters are changed. This tool assess student's capabilities to build and design a CAD model's design intent (i.e. strategic knowledge). Developed tools were tested on three mechanical engineering courses. This paper presents both the tools and the feedback received from the students and teachers. Overall, the auto-assessment tools functioned well and feedback from both students and teachers were positive. The most appreciated tool functionality was time and place independent submission and assessment of exercise works. These new tools able focusing teachers' workload from checking the basic exercises to guiding the learning process.

The analysis of shrink-fit connection - the methods of heating and the factors influencing the distribution of residual stresses.

The main aim of this article is to compare various heating methods of the shrink-fit connection and to analyse its shrinkage mechanism. The shrink fit connection consists of the crank and the pin or the ring and the pin, which have negative value of the geometrical clearance. The experimental part of research included the measurement of the temperature at the various points in the surface of the crank, the measurement of the residual stress 5 mm from the crank hole and the measurement of the maximum torsional moment, at which sliding of the shrink-fit connection occurs. Conformity between data from the Finite Element Analysis and the experimental data was obtained in relation to the von Mises stress. The analysis results show that Lamé equations can be successfully used for calculation of the load capacity even for parts with the irregular shape.

Relação entre os fatores de influência no projeto e a estrutura funcional de uma descascadora de mandioca / Relationship between the design influencing factors and the functional structure of a cassava peeling machine

Tipicamente, a mandioca é comercializada na forma in natura, o que requer o descasque manual para posterior consumo humano. Atualmente, é crescente a comercialização da mandioca sem casca, pré-cozida e congelada, no entanto, o beneficiamento é realizado de forma artesanal. Este artigo trata do estudo da operação de retirada da casca e da entrecasca da mandioca, assim como dos demais fatores envolvidos, necessários à construção da base de conhecimentos requeridos para a definição conceitual da estrutura funcional, que expressa um equipamento a ser desenvolvido, destinado a este fim. Assim, o trabalho se delimita às fases iniciais do processo de projeto de produtos industriais. Nesse contexto, o objetivo é verificar se existe relação entre os fatores de influência na operação de descasque e a estrutura funcional de uma descascadora de mandioca. A metodologia empregada baseia-se no modelo de referência para o processo de desenvolvimento de máquinas agrícolas, com foco nas atividades concernentes às fases de projeto informacional e conceitual. Os resultados obtidos definem que a análise da operação de descasque, o conhecimento do sistema de cultivo e do processo operacional, as interferências e limites, os requisitos energéticos, o clima, ambiente e a planta são fatores de influência determinantes para a definição completa da estrutura funcional do equipamento. A função global "retirar a casca e a entrecasca da mandioca" se desdobra em quatro funções parciais, as quais decompõem-se em treze funções elementares. Destas, dez funções derivam-se diretamente dos fatores de influência identificados inicialmente. Com isso, verifica-se a existência de relação entre os fatores de influência no projeto e a estrutura funcional do descascador de mandioca, demonstrando dependência entre as definições feitas no início da fase de projeto informacional e as atividades da fase de projeto conceitual, responsáveis pela definição linguística do funcionamento do equipamento e de suas interdependências.

Cassava is marketed in fresh form, which requires manual peeling for later human consumption. Currently, there is a growing commercialization of peeled cassava, however the processing is done by hand. This article presents the study of the operation to remove the external shell and the inner shell of cassava, as well as others factors involved, necessary to build the knowledge base required for the conceptual definition of functional structure of a cassava peeling machine. This research is delimited to the early stages of the design of industrial products. The objective is to check whether there is a relationship between factors of influence in the operation of peeling and the functional structure of a cassava peeling machine. The methodology is based on a reference model for agricultural machinery development process, with a focus on activities pertaining to the phases of informational and conceptual design. The results establish that the analysis of the operation of peeling are determinants influencing factors for the complete definition of the functional structure. The global function "to remove the external shell and inner shell of cassava" consists in four partial functions that divide into thirteen elementary functions. Of these, ten functions are derived from the influence of the factors initially identified. Thus, it is possible to verify the existence of a relationship between the design influence factors and the functional structure of cassava peeling machine, demonstrating the dependence of the settings made in the informational design phase and the tasks established during the conceptual design phase.

Avaliação técnica de um transportador pneumático de grãos por aspiração / Technical evaluation of a suction pneumatic grain conveyor

Este trabalho apresenta os resultados da avaliação técnica do protótipo do transportador pneumático de grãos por aspiração ASP 200. O equipamento foi construído para uso em instalações armazenadoras agrícolas, na limpeza de pés de elevadores, moegas e renovação do ar em galerias de silos. Os testes avaliaram características mecânicas do equipamento, descargas de material e ar, perdas de carga, vedação do equipamento, eficiência dos captores e o diâmetro das mangueiras. Os resultados subsidiaram diversas recomendações para melhoria no projeto do equipamento, que aumentarão a sua eficiência operacional. Embora o transporte pneumático seja considerado uma ciência experimental, os autores notaram a falta de procedimentos, parâmetros e orientações para testes e comparações na literatura, que são fundamentais para o desenvolvimento do projeto desses transportadores.

This research shows the results that were obtained from technical evaluation of ASP 200 prototype that is a suction pneumatic grain conveyor. This equipment was built to use in agricultural storage facilities to clean bucket elevator feet, loading hoppers and air renovation in silo galleries. The tests have evaluated mechanical characteristics of conveyor, air and material discharges, pressure losses, air infiltration, intake nozzle efficiency and piping diameters. The results have allowed several recommendations to improve equipment design that will increase its operational efficiency. Although pneumatic conveying is considered an experimental science, the authors have perceived the lack of procedures, parameters and orientations to conduct tests and comparisons in literature, that are fundamental to develop a design of this conveyor type.