Papers by Keyword: Press-Forming Process

Abstract: A growing demand for lightweight products has been brought about by the rapid development of new automobiles in order to reduce fuel consumption, since the global environment conservation meeting at Kyoto. One of the keys to reduced fuel consumption is to utilize high-strength, light materials like stainless-steel, high-tensile strength steels and magnesium alloys, which are difficult to form due to their material characteristics compared to normal steel tubes. The purpose of this paper discuses the development of our new pressing technology that forms a relatively high-strength and light weight stainless-steel tube which is SUS436 with surface screw threads. Our new press-forming process was tested in order to obtain accurate screw threads on stainless-steel tubes. Finite element simulation and a 3-D digitizer were used to measure the accuracy of tubes manufactured by the proposed pressing method. It was proved from FEM simulation and a 3-D digitizer measurement that the proposed press-forming method decrease tube thickness more effectively than conventional roll-forming technology. As a result, the maximum decrease in material thickness produced by conventional roll-forming process was 40%, but the maximum decrease in material thickness produced by our press-forming process was 20%. Especially the processing by four outer dies and two inner dies is better as for material thickness than the processing by six outer dies and three inner dies.

Abstract: Prior knowledge of local increase in sheet metal thickness due to forming of products would contribute to decreasing total product weight by giving the product designer an advance notice of the appropriate sheet metal thickness distribution in a product. A method using simulation to accurately predict such increases would greatly aid the designer in this task. The designer can then distribute thicker parts where a large area moment of inertia is needed from the viewpoint of structural strength in a given section. In terms of optical designing for variable thickness distribution in products, the sheet thickness in a product need not be considered constant. This paper presents the forming prediction during deep drawing. To clarify the mechanism of increase in sheet thickness, a 3-D forming simulation is performed during deep drawing by using the finite element method (FEM). The effects of tool shapes—angle of contact with the original material and the contacting length of the punch with the material—that mainly affect the change in thickness of the original material are investigated. The thickness distribution of drawn cups is measured for comparing the simulation results obtained by FEM with the experimental results. It is shown that controlling the distribution of sheet metal thickness is possible if the original material is relatively thick, and when an appropriate manufacturing method is selected.

Abstract: The approach to total weight reduction has been a key issue for car manufacturers as they cope with more and more stringent requirements for fuel economy. In sheet metal forming, local increases in product-sheet thickness effectively contribute to reducing the total product weight. Products could be designed more efficiently if a designer could predict and control the thickness distribution of formed products. This paper describes a numerical simulation and evaluation of the material flow in local thickness increments of products formed by an ironing process. In order to clarify the mechanism of the local increase in sheet thickness, a 3-D numerical simulation of deep drawing and ironing was performed using finite-element simulation. The effects of various types of finite elements that primarily affect thickness changes in original materials and thickness prediction were investigated. It was found that the sheet-thickness distribution could be predicted if the original material was relatively thick and if an appropriate type of finite element is selected.

Abstract: A growing demand for lightweight products has been brought about by the rapid development of new automobiles in order to reduce fuel consumption. One of the keys to reduced fuel consumption is to utilize high-strength, light materials like stainless-steel that are difficult to form due to their strength. This paper discusses the development of pressing technology that forms a relatively high-strength stainless-steel tube with surface screw threads. Our new press-forming process was tested to obtain accurate screw threads on stainless-steel tubes. A 3-D digitizer was used to measure the accuracy of tubes manufactured by the proposed pressing method. The proposed press-forming method decreases tube thickness more effectively than conventional roll-forming technology. The maximum decrease in material thickness produced by conventional roll forming was 40%, but the maximum decrease in material thickness produced by our press-forming process was 20%. Stress and strain were clarified by using a finite-element simulation to expand the effectiveness of the new press-forming technology.

Abstract: Growing demand for lightweight products has been increased by the rapid development of automobiles since the global environment conservation meeting at Kyoto. Lighter products have been necessary when considering in taking action to reduce fuel consumption. One of the key is the utilization of high strength and light materials, such as stainless, high-tensile strength steels and magnesium alloys, which are difficult to be formed due to their high strength compared to normal steel pipes. This paper is concerned with the development of pressing technology that copes with forming relatively high strength stainless pipe with screw threads on the surface of pipes. Our new press-forming process in order to obtain accurate screw threads on the stainless pipe was tested. A 3-D digitizer was used for the measurement of the accuracy of manufactured pipes by the proposed pressing method. It is found that the proposed our press-forming was effective to improve decrease of pipe thickness compared to conventional roll forming technology. The maximum decrease in material thickness was 20% using our press-forming process for screw threads in the formed pipe.

Abstract: To lighten total product weights, the local increases in sheet thickness of products effectively contribute to decreasing product weights, when appropriate sheet thickness distribution in product by a designer could be performed by using an accurate prediction method by simulation. The designer only could distribute thick part where needed a large moment inertia of area from the view points of the strength of the section. In the sense of the such optical designing for the variable thickness distribution in the products, we do not need to consider that sheet thickness should be constant in a product. This paper is concerned with a forming prediction during deep drawing process. To clarify the mechanism of increase of sheet thickness, a 3-D forming simulation during deep drawing by finite element method was performed. Effects of tool shapes (contacting angles to the original materials, contacting length of punch with a material) which mainly affects the results on thickness change of original materials were investigated. The thickness distribution of drawn cups was measured in order to compare simulation results obtained by the finite element method. It has been found that controlling sheet thickness distribution was possible if an original material was relatively thick, when in choosing an appropriate manufacturing condition could be selected.

Abstract: The growing demand for lightweight products has been increased by the rapid development of automobiles in order to reduce fuel consumption. One of the keys to reduced fuel consumption is to utilize high-strength, light materials like stainless steel that are difficult to form due to their high strength. This paper discusses the development of pressing technology that forms relatively high-strength stainless-steel pipe with surface screw threads. Our new press-forming process was tested to obtain accurate screw threads on stainless-steel pipe. A 3-D digitizer was used to measure the accuracy of pipes manufactured by the proposed pressing method. Our proposed press-forming method decreases pipe thickness more effectively than conventional roll-forming technology. The maximum decrease in material thickness produced by conventional roll forming was 40%. The maximum decrease in material thickness produced by our press-forming process was 20%.

Abstract: Local increases in product sheet thickness effectively contribute to reducing total product weight. Products could be designed efficiently if a designer could predict and control the thickness distribution of formed products. This paper presents a numerical simulation and evaluation of the local thickness increment of products formed during the ironing process. To clarify the mechanism of the local increase of sheet thickness, a 3-D numerical simulation during ironing was performed by the Finite-Element Method. Tool shapes (contact angles with the original materials and contact length of the punch with the material) that primarily affect thickness changes of original materials were evaluated. It was found that the sheet thickness distribution could be controlled if the original material were relatively thick, when appropriate manufacturing conditions could be selected.