Optimization of AL6061-T6 Tube End Forming Process Using Response Surface Method

Tube end closing is a metal forming process that replaces welding processes while closing tubes ends. It depends on deforming a rotating tube using a roller, and therefore, it is also called tube end spinning. The process involves many parameters like contact depth, roller inclination angle, roller diameter, mandrel curvature, and tube rotational speed. This study develops a finite element model (FE-model) for this process and validates it through experimental results. The numerical and experimental results have shown minor deviation of 1.87%. The FE-model is then employed to carry out a statistical analysis based on the response surface method (RSM). The analysis of variance (ANOVA) and regression analysis have proved the accuracy of the obtained mathematical model. The contact depth has proved to have the most significant effect in the process responses, while the roller diameter has the least effect. Finally, an optimization analysis is carried out to select the finest conditions for the process.

Design Requirements Substantiation for an Automated Planting Unit for Potato Minitubers

The authors showed that the transition to the technology of virus-free minitubers mass production changed the machines requirements for planting original seed potatoes.(Research purpose) To develop a technological scheme and substantiate the design parameters of the planting apparatus of an automatic planter of potato minitubers.(Materials and methods) The development was based on an elevator-type planting apparatus. The authors decided to create a spoon design with the ability to grip and move into the guide casing one minituber in each spoon, eliminating the minitubers jumping from one spoon to another or pinching them when moving along the guiding casing to the furrow bottom. The diameters of the lower guide and upper drive rollers were theoretically substantiated in order to exclude the influence of the planting tubers sizes difference on the uniformity of their submitting into the furrow.(Results and discussion) The authors determined the minimum permissible elevator belt speed, which depended on the distance between the spoons on the elevator belt and the planting unit speed. The size of the upper driving reel diameter was justified from the condition that the spoon unfolded 180 degrees in at least 1.5 seconds, which ensured a tuber smooth transition to the back side of the spoon.(Conclusions) The authors developed a technological scheme of an automatic planting elevator type device for planting potato minitubers with a working speed of 6-9 kilometers per hour. It was found that the upper driving reel diameter was not less than 44 centimeters, and the lower guide roller diameter was not more than 12 centimeters. They showed that the double-sided design of scooping spoons with the possibility of installing replaceable bowls in them would ensure a high-quality planting of not only minitubers, but also subsequent reproductions of seed and ware potatoes with a tuber mass of 5-80 grams.

Influence of tooth profile on rotation error of eccentric gearing satellite

In the article a cycloid internal engagement of gears that form an eccentric gearing, is considered. This engagement is investigated in point of insensitivity to assembly error. Only one type of assembly error – error of center distance i. e. eccentricity – is considered. It is expanded that workability of gearing with center distance error is provided on the assumption of decrease of diameter of roller that acts as central gear tooth. Roller diameter decrease and center distance error lead to breach of condition of conjugation of gears of eccentric gearing that in turn governs the output member rotation error. IThe output member and rotation transmission mechanism are not considered. Thus output member rotation error is equated to rotation error of eccentric gearing satellite. The influence of tooth profile on rotation error of eccentric gearing satellite is estimated when center distance error. On the base of matrix kinematic the methodology that takes in account the multiple-tooth contact is worked out. On basis of the developed methodology the research of influence of satellite tooth profiles formed on the base of shortened and extended epicycloids on rotation error is carried out. It is determined that in the eccentric gearing the use of satellite tooth profiles, formed on the base of extended epicycloid, makes it possible to decrease the rotation error. At that makes possible the operation of eccentric gearing in general manufacturing settings. Thus, the possibility of extending of eccentric gearing application fields to driving devices with higher requirements to overall sizes, mass, as well as cost, is come.

Determination of permissible contact stress of case hardened raceway of roller slewing bearing

The permissible contact stress for the rolling bearing made of the through hardened bearing steel has been established based on experience, while there is no definite value or calculating formula of the permissible contact stress for the slewing bearings which are hardened only on the raceway surface yet. To determine the permissible contact stress of the case hardened raceway of roller slewing bearing, finite element analysis for the contact elasto-plastic characteristics between the loaded roller and the case hardened raceway was performed, and the contact plastic deformations corresponding to different roller diameter, roller load, and case depth were obtained. The contact stress produced by the roller load was calculated by using Hertz contact theory. Based on the nonlinear regression analysis between the input parameters and the output plastic deformations of the model, the relation equation between the contact plastic deformation and the roller diameter, contact stress, case depth was established. The formula for calculating the permissible contact stress of the case hardened raceway was obtained according to the regression equation further. The permissible contact stresses calculated by using the obtained formula show that the permissible contact stress of the case hardened raceway depends mainly on the case depth. Loaded compression tests between the roller and the case hardened specimens were conducted to verify the validity of the established calculation method for the permissible contact stress of the case hardened raceway. Permissible contact stress decreases slightly with the increase of the roller diameter and increases with the increase of the case depth significantly. As the case depth reaches 6 mm, the maximum permissible contact stress is 3758 MPa. As the case depth reaches 7 mm, the maximum permissible contact stress of the case hardened raceway is 3889 MPa.

Experimental and Numerical Study of Internal Gear Manufacturing by Flowforming Processand Investigation of Effective Parameters on Teeth Height

Manufacturing of internal gears using flowforming process is a difficult to achieve but very interesting process in which the gear may be produced without the need for high forming forces and the need for high cost tooling. In this study, manufacturing of internal gears using flowforming process is studied. The process was numerically analyzed and simulated. Several controlled test were performed to evaluate the validity of simulation.A comparison ofsimulation and experimental results indicates pretty good agreement between these results. Once thesimulationis verified,theeffects of roller diameter, thickness reduction percentage, feed rateand attack angle on teeth height wereobtained using design of experiments (DOE) procedure.

Analysis of the Influence of Segmented Rollers on Slab Bulge Deformation

The bulge deformation of the continuous casting slab must be controlled in order to improve the slab quality. In this study, a coupled three-dimensional thermomechanical model is suggested based on dynamic contact between the slab and the rollers, so as to investigate the influence of the rollers in reducing slab bulge deformation. Moreover, the rigid casting rollers in this model are replaced by elastic casting rollers in order to improve the calculation accuracy. Further, the influence of two-segment and three-segment rollers on the slab bulge deformation is systematically studied. The results indicate that the bulge deformation of the slab increased by 74.3% when elastic casting rollers were adopted instead of rigid casting rollers. This deformation was reduced by 29.7% when three-segment rollers were used instead of two-segment rollers. Moreover, the influence of the roller spacing and the roller diameter of the segmented roller on the deformation was studied in detail. In order to achieve the purpose of controlling the bulge deformation, improved segmented roller spacing and diameter were proposed, leading to a 75.4% reduction in the bulge deformation.

Pengaruh diameter roller terhadap jumlah hasil tangkapan bagan di Perairan Selat Lembeh Kota Bitung (The effect of roller diameter on the fish catch of aerial traps in Lembeh Strait Waters, Bitung)

Lembeh Bay waters possess sufficient potency of small pelagic fish resources that could be managed for people prosperity, particularly fisheries communities. One of the fishing gears operated in Lembeh Strait is aerial traps. The success of aerial traps operation is the availability of target fish resources, the control of target fish behavior, and hauling time. One of the influencing factors of net hauling time isroller that functions to lower and lift the net in light fishing. This study utilized 3 different roller diameters, 10 cm, 15 cm, and 20 cm,installed over each aerial traps and simultaneously operated. Fishing operations were done 7 times once a day, from October 21th, 2017, and October 23th to 28th, 2017. Results found that the roller size highly significantly affected the time of net hauling and catches, 262 seconds for 10 cm diameter, 215.86 seconds for 15 cm diameter, and 178.86 seconds for 20 cm diameter, respectively. Total catches obtained in 3 aerial traps using different rollers were 4450 kg (18.43 %) of mackerel (Decapterus sp), 5250 kg (21.74 %) of yellowstripe scad (Selaroides sp), 5500 kg (22.77 %) of bullet tuna (Auxisrocii), 5750 kg (23.81 %)of sardines (Sardinella sp), and 3200 kg (13.25 %) of squids (Loligo sp).Keywords: roller diameters, aerial traps. ABSTRAKPerairan Selat Lembeh memiliki potensi sumberdaya ikan pelagis kecil yang cukup potensial untuk dikelola bagi kemakmuran masyarakat pada umumnya dan khusunya masyarakat nelayan. Salah satu alat tangkap yang diusahakan oleh nelayan yang berkegiatan di perairan Selat Lembeh adalah bagan. Keberhasilan pengoperasian bagan adalah tersedianya sumberdaya ikan target, pengendalian tingkah laku ikan target serta waktu pengangkatan atau penarikan jaring (cang). Salah satu faktor yang mempengaruhi waktu pengangkatan jaring yaitu roller. Pada bagian atas rumah bagan terdapat alat penggulung (roller) yang berfungsi sebagai katrol untuk menurunkan dan mengangkat jaring bagan pada malam hari (light fishing) terutama pada hari yang gelap dengan menggubakan lampu sebagan alat bantu penangkapan. Perlakuan yang digunakan dalam penelitian ini adalah 3 (tiga) penambahan diameter roller dengan ukuran berbeda yaitu: 10 cm, 15 cm, dan 20 cm yang dipasang pada tiap bagan (1 bagan 1 ukuran roller) dan dioperasikan secara bersamaan. Pengoperasian dilakukan sebanyak 7 (tujuh) kali pada hari-hari yang berbeda, yaitu dilakukan pada bulan Oktober 2017, dimulai pada hari Sabtu tanggal 21, Senin tanggal 23 – Sabtu tanggal 28. Perbedaan beberapa ukuran roller pada bagan apung, berpengaruh sangat nyata terhadap waktu penarikan jaring dan hasil tangkapan yaitu lebih cepat, dengan rincian waktu pada penambahan diameter 10 cm 262 detik, diameter 15 cm 215,86 detik, dan diameter 20 cm 178,86 detik. Hasil tangkapan total yang diperoleh selama pelaksanaan penelitian pada 3 alat tangkap bagan dengan ukuran penambahan sampul roller yang berbeda sebanyak 4450 kg (18,43 %) malalugis (Decapterus sp), 5250 kg (21,74 %) tude (Selaroides sp), 5500 kg (22,77 %) deho (Auxisrocii), 5750 kg (23,81 %) sardin (Sardinella sp) dan 3200 kg (13,25 %) cumi (loligo sp).Kata-kata kunci: diameter roller, bagan apung.