A comparative analysis of hot and cold flashless forging of a stepped shaft using vertically-parted dies

Flashless forging is classified as a precise metal forming technology. The main advantages of this technology are the reduction of the flash allowance and the shortening of the manufacturing time by eliminating the flash trimming operation. The article presents the process of one-step forging of a stepped shaft made of aluminum with the use of split dies. The process was carried out in cold and hot metal-forming conditions. The forging process was analyzed numerically using the Simufact Forming 15.0 software. The geometrical parameters of the obtained product were analyzed, and the distribution of effective strain, temperature, and the standardized cracking criterion was determined. The process force parameters were also determined. Numerical tests were verified in real conditions with the use of a specially designed device for forging in vertical split dies. Comparison of hot and cold forging in vertical split dies is presented. The comparative analysis results have demonstrated that the hot forging process has more advantages than the cold forging process. The hot forging process ensures higher accuracy of forged parts.

Hot Forging Process Design and Initial Billet Size Optimization for Manufacturing of the Talar Body Prosthesis by Finite Element Modeling

In hot forging industry, the process design and the billet size determination are very crucial steps because those steps directly influence both the product quality and material utilization. The purpose of this paper was to propose a technique used to design the hot forging process for the manufacturing of the talar body prosthesis. The talar body prosthesis is one of the artificial bones, which its geometry is a free form shape. In this study, the Finite Element Modeling (FEM) was used as a tool to verify the proposed design before implementation in a production line. In addition, an initial billet was determined the optimum size in the FEM by varying the mass ratio factor, the diameter, and the length. It was found that the mass ratio factor is a very useful guideline since the optimum size is quite close to the provided size from the guideline. The FEM results showed that the dimensions of the initial billet significantly affect the complete metal filling in the die cavity. Moreover, the optimum size between the diameter and length can reduce the material waste in the hot forging process of the talar body prosthesis. Finally, the experimental results of the hot forging process showed that the proposed process design with the optimum size of the initial billet is achieved in order to manufacture the talar body prosthesis and the material utilization of the new proposed process is improved from the traditional process by 2.6 times.

Parametric optimization of hot forging process: a six sigma based approach

One of the major concerns for industries in the modern world is to focus efforts on producing high quality products with minimal costs. Various quality improvement philosophies have emerged in recent times, Six Sigma being one of the most practical and efficient techniques for quality improvement of processes. In this work, Six Sigma based DMAIC (Define, Measure, Analyze, Improve, Control) approach is used to enhance productivity and quality performance, and to make the hot forging process robust to quality variations. Finite element method has been employed for the simulation of hot forging of the connecting rod. The influence of design and process parameters is investigated for the response ‘forging die load’. Analysis of various critical parameters and the interaction among them has been carried out with the help of Taguchi’s method of experimental design. To further optimize the response and make the analysis more precise and robust, response surface methodology has been incorporated. Parameters have been optimized, leading to the accomplishment of a minimized forging die load which is verified using a confirmation experiment. Confirmatory results reveal the potential of the DMAIC approach of Six Sigma in optimizing the process parameters successfully and thereby present significant applicability in the industry.