Abstract
In order to solve the flange and dent defects in the end face of the cold extrusion of the connecting screw, the Deform3D software is used to simulate the extrusion forming process of the ...connecting screw, and the velocity vector is used to study the metal flow law of the part in the cold extrusion process. According to the velocity field and deformation law obtained by the simulation, the end face depression defect in the forming process is predicted. An improved production process is proposed, and the simulation results show that the new process scheme effectively eliminates the “sag” defect on the end face of the part. Finally, the extruded parts with qualified dimensional accuracy are obtained through experiments, and the results are basically consistent with the simulation results.
Cold extrusion 3D food printing is an emerging technology which enables the manufacture of food in different shapes and structures and offers huge potential for personalised food products. This study ...investigates rheological properties and printability (shape fidelity) of food-grade hydrocolloid pastes. From this study, it was found that if the phase angle is in the range of 3°–15° and the relaxation exponent is in the range of 0.03–0.13 the paste material is printable, which means that it can support its own-weight if printed. As the demand for inks for 3D printing increases, rheological measurements can rapidly assist with the development of new ink feedstocks.
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•3D printing of hydrocolloids is influenced by their rheological properties.•Thixotropic hydrocolloid systems were used as a model for food 3D printing.•Over 50 combinations (concentration/type) of hydrocolloids were analysed and their rheological properties were reported.•Phase angle and relaxation exponent are used to get insight on 3D printing of hydrocolloids.•This design rule can be used to identify food formulations with tailored made properties for use in food 3D printing.
In the process of internal thread cold extrusion, the extrusion tap is an indispensable tool. Therefore, it is important to improve the service life of the extrusion tap and reduce the tool wear. In ...this paper, using Central Composite Design response surface test, the influence of the parameters (including the guide cone angle, backhoe capacity, guide cone length and working cone length) of the extrusion tap on the forming quality of internal cold extrusion are investigated, so as to obtain the minimum extrusion torque and the minimum extrusion temperature. A polynomial regression response model of the minimum extrusion torque and minimum extrusion temperature is obtained. Using the regression model, the objective function is optimized, and a group of optimal parameters is obtained (guide cone angle: 10°, backhoe capacity: 0.32, guide cone length: 4 mm, and working cone length: 13 mm). Numerical simulation of the optimal parameters is also carried out. The results show that the measured extrusion torque and extrusion temperature are close to the predicted values with errors of 2 and 2.55%, respectively, which are well fitted by the model.
Abstract The installation process for the dynamic cold extrusion of Al/Al interference-fit bolted joint applied by electromagnetic force was investigated by numerical simulation. The simulation ...results show that the deformation distribution of the bore wall at joint installed by the electromagnetic force is more uniform than that of the traditional installation technologies. And in the axial direction of bore wall without pin, the maximum stress region occurs at its outlet regardless of the values of interference-fit. Additionally found that the critical interference-fit value for a joint to reach yield strength is about 1 %, and when the amount of interference-fit is less than 1%, the joint mainly exhibits elastic deformation, and when the interference is more than 1 %, the plastic deformation is its main manifestation.
In order to improve the fatigue performance of the internal thread of the connecting rod for marine diesel engine, the internal thread cold extrusion technology is introduced into the bolt hole ...position. Based on the three-dimensional finite element model, the residual stress distribution around the cold extrusion internal thread of 42CrMo4 high-strength steel plate hole structure under different edge distance ratios is analyzed in detail. The multiaxial fatigue life prediction model of thread is established based on the stress-strain method; the accuracy and feasibility of the prediction model are further verified by fatigue experiments. The thread surfaces are examined by utilizing the scanning electron microscope and coordinate with the X-ray diffraction method to measure the residual stress of thread. The relationship between the residual stress distribution, surface structure, and fatigue life of the extrusion thread is revealed. The research shows that the improved fatigue prediction model gives a satisfactory accuracy in predicting the fatigue life. Both the tangential residual stress fields around the extrusion thread and the surface structure have a certain influence on its fatigue life, especially when the edge distance ratio is less than 2. The tangential residual compressive stress of the cold extrusion internal thread decreases with the edge distance ratio being smaller, while the depth of the stress zone increases firstly and then decreases. Higher load will greatly reduce the fatigue life and dispersion of the thread; the fatigue life increases linearly with the increase of the edge distance ratio under lower stress level.
•Kodo millet analogue rice was developed by substituting rice flour•The rice analogue was loaded with dietary fibre, protein and mineral•It can be personalized for obese, diabetic and ...health-concerned individuals•Cooking didn't break the analogue rice prepared but gruel loss was more
Rice analogue is an artificial rice formulated and extruded from a non-rice carbohydrate source. This concept was started with the aim of providing highly nutritious compounds in the form of rice to targeted individuals to address malnutrition and therapeutic and health needs. In the current study, Kodo Millet (KM) was used as a substitute for rice flour to produce personalized KM rice analogues for diabetic, obese and health-conscious individuals. KM semolina and rice flour at different ratios were cold extruded to produce rice analogues. The developed analogue rice was disclosed to contain more amounts of protein, dietary fibre, and mineral content. In addition, it was revealed that the nutrients increased in the rice analogue based on the percentage of KM semolina used in the formulation. Further, the cooking time required for the rice analogue was less (6 to 8 mins) than the original rice. Based on the nutritional profile and the sensory analysis the formulation with 78.5 % KM semolina, 20 % rice flour, 0.5 % xanthan gum and 1 % glycerol monostearate was optimized to be a perfect formulation to produce kodo millet-based rice analogue.
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In the internal thread extrusion forming, if the process parameters are not selected properly, the extrusion torque will increase, the extrusion temperature will be too high, or even the tap will ...break. In order to obtain effective process parameters under certain working conditions, this paper uses a combination of numerical simulation and process experiment to analyze the influence of the bottom hole diameter, extrusion speed, and friction factor on the extrusion torque and extrusion temperature. Through an orthogonal experiment, the significant influence law of different process parameters on the extrusion torque and extrusion temperature was studied, and the order of their influence was determined. Based on the optimal process parameters, numerical simulations and process tests were carried out, and the extrusion effect and related parameters were compared and analyzed. The results show that the extruded thread has clear contour, uniform tooth pitch, complete tooth shape, and good flatness. Compared with before optimization, the maximum extrusion torque has been reduced by 37.15%, the maximum temperature has been reduced by 29.72%, and the extrusion quality has been improved. It shows that the optimized method and optimized process parameters have good engineering practicability.
•Linkage site of disulfide peptides was located by LC/MS/MS with pLink software.•Cysteine increased disulfide cross-linkage between cold-extruded whey proteins.•Cysteine raised viscoelasticity and ...cell vitality of cold-extrusion whey proteins.
Polymer chemistry, rheology and cytotoxicity of cysteine initiated S-S redistribution in cold-extruded whey protein (TWPI) molecules were investigated. The locations of disulfide bonds in whey protein isolate (WPI), WPI dried without being extruded (OWPI) and cold-extruded WPI (TWPI), Cysteine (Cys)-treated WPI (WPI-Cys), OWPI (OWPI-Cys) and TWPI (TWPI-Cys) were precisely analyzed using liquid chromatography electrospray ionization tandem mass spectrometry (LC/MS/MS) combined with pLink software approaches. The numbers of intermolecular disulfide cross-linked peptides identified in Cys-treated samples increased by 4, 6 and 1, respectively, in the order of TWPI-Cys, OWPI-Cys and WPI-Cys. Fourier Transform infrared spectroscopy (FTIR) showed cysteine treatment loosed secondary structure of protein samples. Meanwhile, size exclusion chromatography (SEC) assay demonstrated the extensive polymerization in TWPI-Cys. Furthermore, Cys-treatment decreased the gelling temperature of TWPI to 57 °C sharply. Cys-treated TWPI has 19.11 times storage modulus (G’) and 25.86 times loss modulus (G”) of Cys-untreated TWPI at 85 °C. Additionally, cell viability with Cys addition indicate modified whey proteins are not toxic to human umbilical vein endothelial cells (HUVECs).
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