Research on Improvement of Cold Extrusion Technology of Connecting Screw

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 stamping of a cartridge case blank for 40x53 mm caliber grenade launcher ammunition

Problems. The choice of a rational method for stamping blanks with two hollows is usually carried out according to the permissible degree of deformation, the coefficient of material utilization, and the productivity of the process without taking into account the effect of the deformation pattern on the final mechanical properties of the stamped semi-finished product. Purpose of the study. Determination of a rational method for stamping a blank of a 40x53 mm grenade launcher cartridge case based on the results of computer modeling using the finite element method. Cartridge case material - AD35 aluminum alloy. The workpiece has two hollows with different diameters and depths. Implementation technique. By means of computer modeling using the finite element method, two options for stamping of a workpiece are researched - double-sided extrusion and sequential reverse extrusion with tilting of the workpiece. Research results. Based on the results of the research, the features of deformation according to the given schemes, as well as the energy-force parameters and parameters of the stress-strain state of the processes, are determined. It has been established that both methods make it possible to obtain blanks with specified geometric dimensions. At the same time, sequential back extrusion provides a more uniform and predictable deformation of the material along the cross-section of the workpiece, but loses in productivity to double-sided extrusion. Conclusions. The obtained research results can be used as criteria when choosing the optimal option for stamping of a workpiece with two hollows by cold extrusion.

Numerical Simulation and Experimental Study on Rotary Cold Extrusion Forming of Screw Rod

The rotary cold extrusion forming process is a plastic forming process with very low material loss, especially in the production of hollow screw rods with equal wall thickness. In this work, the rotary cold extrusion forming process of a hollow T2 copper screw rod with a wall thickness of 4 mm and solid T2 copper screw rod was verified by experimental method. The finite element simulation software Deform-3D was also used to simulate the rotary cold extrusion forming process of the screw rod. The effects of the die with different heights of the working belt and the different wall thickness of the billet on the eccentricity, extrusion force, and forming torque in the forming process of the screw rod were studied. The results show that it is feasible to process hollow and solid T2 copper screw rods with equal wall thickness by rotary cold extrusion. With the increase of die working belt height, the eccentricity of the screw rod becomes smaller and closer to the ideal eccentricity. With the increase of the wall thickness of the billet, the amplitude fluctuation range of the eccentricity of the screw rod gradually decreases. The higher the height of the die working belt, the greater the extrusion force and torque required in the extrusion process, and the more intense the change of torque. These results also provide theoretical guidance for the production practice and lightweight transformation of the screw pump rotor.

Incorporation of coconut milk residue in pasta: Influence on cooking quality, sensory and physical properties

A study was conducted to explore the potentiality of coconut milk residue (CMR) for cold extrusion (pasta preparation). Proximate analysis revealed that coconut milk residue is a rich source of crude fibre (24.03%) in addition to crude fat (41.55%), crude protein (5%), total carbohydrates (26.24%) and ash content (0.97%) at 2.23 per cent moisture. The effect of coconut milk residue upon replacing durum wheat semolina on cooking qualities, colour parameters, textural property and overall sensory acceptability of pasta samples were evaluated. Incorporation of coconut milk residue significantly influenced the observed parameters (P<0.01). Cooking time was unaffected by incorporating milk residue up to 10 per cent (P<0.05). Though the addition of residue increased the gruel loss (0.84 to 1.34%), the per cent loss was below the technologically acceptable limit (<8%). A similar effect was visualized in water absorption. Conversely, the firmness gets reduced with an increased concentration of coconut milk residue beyond 10 per cent. Pasta with 5 per cent and 10 per cent coconut milk residue were accepted as that of control by the sensory panel. Free fatty acid content was not affected by the period of storage (P>0.05). Thus, the study recommends incorporating 10 per cent coconut milk residue in durum wheat semolina for pasta preparation. Moreover, the entrepreneurs engaged in the coconut milk/milk powder and virgin coconut oil industry would be benefitted by adopting this venture, wherein they would be able to fetch huge additional income by placing their residue product on an upgraded fast-moving consumer good (FMCG) value chain.

Finite Element Analysis and Life Prediction of Pre-stressed Composed Dies in Cold Extrusion Process

Improving and stabilizing the life of the die has always been the key to increasing the output of cold precision forging products and reducing the production cost of forgings. The stress state in pre-stressed composed dies during cold extrusion process is investigated in this paper, it shows that the combined die can greatly reduce the tangential tensile stress of the inner wall of the die and reduce the strain energy density of the die, thereby improving the strength of the die and extending the life of the die. By increasing the number of pre-stressed rings, the amount of interference can be changed, which indirectly changes the pre-stress applied to the die. The relationship between the die fatigue life and the number of pre-stressed rings indicates that the design of the pre-stressed composed structure above the inflection point is an excess design, and the optimal design should be near the inflection point.

The Influence of the Bottom Hole of Cold Extruding Internal Thread on Thread Quality

The diameter of the threaded bottom hole determines whether the extrusion can proceed smoothly and the fullness of the tooth shape after extrusion. The tooth height rate is an important indicator of the strength of the threaded connection. In order to establish the relationship between the diameter of the bottom hole and the tooth height of the extruded internal thread, this paper takes the aluminum alloy M8×1.25 mm internal thread as an example, and uses a method of combining numerical simulation and process test. Obtained the changing law of internal thread profile and tooth height rate of extruded workpieces with different bottom hole diameters. Using MATLAB to fit the numerical simulation results, the relationship between the tooth height of the internal thread and the diameter of the prefabricated bottom hole of the workpiece was obtained. The reliability of the numerical simulation results and the feasibility of the fitting formula are verified through experiments. The results show that the diameter of the prefabricated bottom hole of the workpiece is controlled within 7.33~7.39 mm when the M8×1.25 mm internal thread is processed by the cold extrusion process. The high rate of the internal thread after extrusion meets the requirements of thread connection strength, and the internal thread has high forming quality and good surface quality.

Production and Evaluation of Breakfast Meals from Germinated and Ungerminated Blends of Sorghum and Soybean by Cold Extrusion Process

Breakfast meal was formulated from blends of sorghum and soya beans. The mixed blends of (ungerminated and germinated sorghum/soyabean flour blends) was produced into S-shaped granules using a cold extruder in the following formulation ratio of 100:0, 90:10, 80:20, 70:30,and 60:40 ratio. Proximate composition, total mineral (Magnesium, phosphorous, potassium calcium, iron and Zinc), extractable mineral and mineral bio-availability were carried out on the finished product of different blends. Germinated products showed lowest moisture(7.99 %) and carbohydrate(59.43 %) contents, and high values of Ash (3.64 %), Protein(18.19 %) and fat (8.99 %) contents. The highest value Fiber and Energy were obtained in the ungerminated products with values of 11.22 % and 355.72 %, respectively.Bioavailability of germinated product blends showed higher values for all the minerals analyzed.Onsensory evaluation, the ungerminated sorghum product (100:0) recorded highest values among the samples analyzed and was most preferred in term of colour (4.35) and taste (4.10) while the germinated products received preference in the texture with a highest value of 4.35. The overall acceptability was recorded in the ungerminated products with the highest value of 4.15. The results showed that germination and substitution with soya bean up to 60:40 increased the nutrient content of breakfast meal.

Statistical analysis of the reproducibility of residual stress measurements in cold extruded parts

Cold extruded components are characterized by residual stresses, which originate from the experienced manufacturing process. For industrial applications, reproducibility and homogeneity of the final components are key aspects for an optimized quality control. Although striving to obtain identical deformation and surface conditions, fluctuation in the manufacturing parameters and contact shear conditions during the forming process may lead to variations of the spatial residual stress distribution in the final product. This could lead to a dependency of the residual stress measurement results on the relative axial and circumferential position on the sample. An attempt to examine this problem is made by the employment of design of experiments (DoE) methods. A statistical analysis of the residual stress results generated through X-Ray diffraction is performed. Additionally, the ability of cold extrusion processes to generate uniform stress states is analyzed on specimens of austenitic stainless steel 1.4404 and possible correlations with the pre-deformed condition are statistically examined. Moreover, the influence of the coating, consisting of oxalate and a MoS2 based lubricant, on the X-Ray diffraction measurements of the surface is investigated.

Designing a kinematic module with rounding to model the processes of combined radial-longitudinal extrusion involving a tool whose configuration is complex

It is advisable that parts whose shape is complex and which are made from solid or hollow blanks should be made by means of transverse and combined radial-longitudinal extrusion. The variation of manufacturing modes, tool configurations (in the form of chambers and rounding of the transitional sections of matrices) requires an adequate preliminary assessment of the force regime and the features of part shape formation. This paper has proposed a curvilinear kinematic module of the trapezoidal form for modeling radial-longitudinal extrusion processes in the presence of matrix rounding. Given the impossibility of using a quarter-circle boundary for the kinematically assigned possible velocity field, it has been proposed to use approximate curves in the form of z1(r) and z2(r). Taking into account the slightest deviation in the length of the arc of the approximate curve z1(r) and the area of the curvilinear trapezoid bounded by it relative to a quarter of the circle (not exceeding 0.8 % for any ratio), it has been recommended using this particular replacement. We have performed calculations of the value of the reduced deformation pressure inside the kinematic module with rounding taking into consideration the power of cutting forces at the border with adjacent kinematic modules. As an example, the devised module with rounding embedded in the estimation scheme of radial extrusion was analyzed. A significant impact of friction conditions on the force mode and the corresponding optimal value of the rounding radius have been identified. The resulting kinematic module makes it possible to expand the capabilities of the energy method for modeling cold extrusion processes involving the tools of complex form according to new deformation schemes. That could contribute to preparing recommendations on the optimal tool configuration and more active industrial implementation of these processes