Design of Precision Finishing Method for Cold Extruded Sun Gear With Internal External Tooth Shapes

Due to the complex metal flow in the cold extrusion of sun gear, the teeth accuracy of formed sun gear is poor. In order to improve the accuracy of the extruded sun gear, a novel precision f inishing method was proposed in this study. A new finite element ( prediction strategy was developed to obtain an in-depth understanding of the deviation distribution laws of the finished sun gear. Then, the forming laws of internal-external gears such as material flow, tooth deformation, forming load and tooth accuracy were analyzed using FE simulation and verified experiment. The investigation results show that the single deviations in profile and helix both first diminished remar ka bly , and then rose gradually while the single M value deviation decreased remarkably with increasing the tooth width The simulation results of teeth deviations are well agreed with the experimental ones, which verifies the reliability of the FE prediction strategy Moreover, the profile accuracy of external gear can be improved from ninth to seventh class, lead accuracy can be enhanced from tenth to eighth class, and total M value deviation of internal spline is reduced to 72.3 μm which proves the feasibility and effectiveness of t he precision finishing method

Evaluation of Different Tools of Precision Finishing for Cold Extruded Sun Gear With Internal-External Tooth Shapes

Due to the complex metal flow in the cold extrusion of sun gear, the teeth accuracy of formed sun gear is poor. In order to improve the accuracy of the extruded sun gear, a novel precision finishing method with different tools was proposed in this study. Finite element simulations were performed using DEFORM, and a new finite element (FE) prediction strategy was developed to obtain an in-depth understanding of the deviation distribution laws of the finished sun gear. Then, the influences of different finishing tools on tooth deformation, tool stress, forming load and tooth accuracy were examined. The investigation results show that the profile accuracy of external gear can be improved from ninth to seventh class, lead accuracy can be enhanced from tenth to eighth class, and total M value deviation of internal spline is reduced to 72.3 μm by the precision finishing method with interference mandrel. Therefore, the interference mandrel is recommended as the optimal reshaping tool for commercial production of sun gears. The simulation results are well agreed with the experimental results, which verifies the feasibility of the precision finishing method and the reliability of the FE prediction strategy.

Premium lamb production of South African sheep breed types under feedlot conditions

An increasing number of producers opt to finish their lambs in on-farm feedlots. Therefore, detailed production information is required to implement precision finishing of lambs of different genotypes. Precision finishing monitors growth, feed intake and efficiency to optimize management. In this study, feedlot production characteristics of Dohne Merino, Dormer, Dorper, Meatmaster, Merino, Namaqua Afrikaner, and South African Mutton Merino (SAMM) lambs were evaluated. The lambs were reared in a feedlot and fed a diet with 10.41 MJ metabolizable energy (ME)/kg feed and 19.06% crude protein. Feed intake and body weight were recorded weekly from an initial weight of 30 kg until they had the subcutaneous fat cover needed to produce an A2 carcass. Subcutaneous fat was measured on the Longissimus lumborum muscle with an ultrasound scanner. Dorper, Meatmaster and Namaqua Afrikaner had the shortest rearing periods in the feedlot, and were market ready at a lower live weight (P <0.05). As a result, these lambs consumed less feed in the feedlot. Namaqua Afrikaner and Merino lambs were least efficient: 7.08 and 5.63 kg feed/kg gain, respectively. Dohne Merino, Dormer, Dorper, and Meatmaster rams and Dorper ewes were more efficient; approximately 3.58 kg feed/kg gain. Dohne Merino and Dormer rams had the highest growth rates: approximately 465 g/day. The end weights described in this study could be used as an indication for producers of the ideal slaughter weights for breeds of different maturity types.Keywords: average daily gain, fat deposition, feed efficiency, rearing period

Detailed Review of Ball End Magnetorheological Fluid Finishing Process

For precision finishing of various newly and difficult of finish materials like optical glasses, metals, 3D-printed workpieces etc. Ball End Magnetorheological Finishing (BEMRF) finishing processes has been recently developed. This method utilizes a paste like fluid consisting of a base fluid which can be either water or oil, both magnetic and non-magnetic particles and stabilizing agents if necessary. Rheological behavior of this mixture of magnetorheological (MR) fluid with abrasives changes under the influence of magnetic field which in turn regulates the finishing forces during finishing processes. Present study critically reviews the BEMRF process used for achieving nano-level finishing variety of materials like mild steel, EN-31, copper etc. and the factors influenced this process so far which led to further advancements in this method.

Effects of Water Supply Using Ultrasonic Atomization on the Working Life of MCF Slurry in MCF Polishing

The magnetic compound fluid (MCF) polishing process is a precision finishing method that has been applied to a large variety of materials, from soft optical polymers to hard ceramics. The purpose of this study is to extend the working life of MCF slurry. In this paper, we focus on the drying phenomenon of MCF slurry during polishing, and we develop a new water supply system that uses an ultrasonic atomization mechanism. This system can moisturize the MCF polishing area locally. Polishing experiments involving supplying water to MCF slurry are carried out, and extending the working life of MCF slurry is discussed.

Magnetorheological Fluid Finishing of Soft Materials: A Critical Review

Magnetorheological Finishing (MRF) is one of the precision finishing processes and recently commercialized method for finishing of various materials like optical glasses, metals, non-metals etc. This method utilizes a suspension consisting of a fluid carrier which can be water or oil, both magnetic and non-magnetic particles and stabilizing agents. Rheological behavior of this mixture of magnetorheological (MR) fluid with abrasives changes under the influence of magnetic field which in turn regulates the finishing forces during finishing processes. Present study critically reviews the MRF process used for achieving nano-level finishing of soft materials and the advancements made in this process

Study of Ultra-precision Finishing Techniques for Brittle Materials

Wide application of hard and brittle advanced ceramics, glasses and semiconductors in Mechanical, Optical and Electronic industry has led to the development of new ultra-precision finishing processes. With an increase in the applications of these materials, the need of finishing these materials has also become a great challenge. Dimensional and finish accuracies are the parameters that needs to be focused and improved with minimum time and cost. Another crucial parameter is the subsurface damages that are quiet common with these materials during finishing process. New processes have been developed to overcome the drawbacks of the existing processes for Nano finishing. These processes can be classified as Conventional, Precision and Ultra-precision finishing based on the degree of dimensional accuracy and final surface finish. Both loose and bonded abrasives have been used for these processes. This paper deals with the study of some of the significant advances in ultra-precision finishing processes of hard and brittle materials.