Simulation and experiment researches on rubber pad forming of two-step channels by different dies

Rubber pad forming is one of advance processing technologies. With both rubber pad and die, the sheet metal is stamped into the required shapes. The shapes of the die directly affect the final shapes of the channels on the sheet. With the developments of micro-channels, a new kind of two-step channels is concerned gradually in many fields. Since there are waved structures in these channels, many beneficial functions are caused. However, the manufacturing of this new kind channels by rubber pad forming are still not meticulously researched. This article is focused on the rubber pad forming process of different two-step channels. Different two-step channels are designed and made. Based on both FEM and physical experiments, the forming processes of these new channels are researched. The forming results are discussed and compared with each other, the best design strategy is also proposed through results.

3D printed prototyping tools for flexible sheet metal drawing

Due to the change from mass production to mass personalized production and the resulting intrinsic product flexibility, the automotive industry, among others, is looking for cost-efficient and resource-saving production methods to combining global just-in-time production. In addition to geometric manufacturing flexibility, additive manufacturing offers a resource-saving application for rapid prototyping and small series in predevelopment. In this study, the FDM process is utilized to manufacture the tooling to draw a small series of sheet metal parts in combination with the rubber pad forming process. Therefore, a variety of common AM polymer materials (PETG, PLA, and ABS) is compared in compression tests, from which PLA is selected to be applied as sheet metal forming die. For the rubber pad forming process, relevant processing parameters, i.e., press force and rubber cushion hardness, are studied with respect to forming depth. The product batch is examined by optical evaluation using a metrological system. The scans of the tool and sheet metal parts confirm the mechanical integrity of the additively manufactured die from polymer and thus the suitability of this approach for small series in sheet metal drawing processes, e.g., for automotive applications.

Shape and position design of two-step micro-channel on plate during rubber pad forming process based on simulation

Rubber pad forming is an advanced processing technology. The micro-channel is formed on the plate by both rubber pad and the metal mold. With the development of micro-channel, a two-step micro-channel has been applied in more and more fields. However, little attention was given to the design during rubber pad forming process for these unique channels. In this paper, the rubber pad forming process of an entire plate with two-step channels is studied. In order to find the suitable design, the main parameters of the two-step micro-channel are discussed. Not only for the geometric ones for structures like: length, width, edge chamfer and the height ratio of first to second step, but also for the spatial distribution like: the number and distance of two-step micro-channels in the entire plate. Matlab is used to study the influences on the final forming results because of the various parameters. Moreover, a better design of the plate with two-step micro-channels are provided. Finally, based on the FEM and forming experiments, a design strategy is provided by forming results in conclusions.

Fabrication of aluminum bipolar plates with Archimedes' screw-shaped channels: a rubber pad forming process assessment

Bipolar plates are one of the most important components of polymer membrane fuel cells. In this manuscript, the rubber pad forming of aluminum bipolar plates with Archimedes' screw-shaped channels and draft angle of 90$$^\circ$$ ∘ has been investigated. Hence, all possible combinations of the process parameters were determined and corresponding experimentations performed in order to investigate the effects of the rubber hardness, punch speed and the hydraulic press force. In this regard, three rubber pads including polyurethane, silicone and natural rubber were used. Channel depth and thinning percentage in the corner of the channel are measured and the effect of each parameter is analyzed. Based on the results, the maximum channel depth was achieved using a silicone pad with a hardness of 60 Shore A. Using a rubber pad with a very high and low hardness number, both, reduces the depth of channel. Furthermore, as the punch speed increases, the channel depth increases and the thinning percentage, as well.

3D printed prototyping tools for flexible sheet metal drawing

Due to the change from mass production to mass personalized production and the resulting intrinsic product flexibility, the automotive industry, among others, is looking for cost-efficient and resource-saving production methods to combining global just-in-time production. In addition to geometric manufacturing flexibility, additive manufacturing offers a resource-saving application for rapid prototyping and small series in pre-development. In this study, the FDM process was utilized to manufacture the tooling to draw a small series of sheet metal parts in combination with the rubber pad forming process. Therefore, a variety of common AM polymer materials (PETG, PLA and ABS) is compared in compression tests, from which PLA is selected to be applied as sheet metal forming die. For the rubber pad forming process, relevant processing parameters, i.e. press force and rubber cushion hardness, are studied with respect to forming depth. The product batch was examined by an optical evaluation using a metrological system. The scans of the tool and sheet metal parts confirm the mechanical integrity of the additively manufactured die from polymer and thus the suitability of this approach for small series in sheet metal drawing processes, e.g. for automotive applications.

Shape and Position Design of Two-Step Micro-Channel on Plate During Rubber Pad Forming Process Based on Simulation

Rubber pad forming is an advanced processing technology. The micro-channel is formed on the plate by both rubber pad and the metal mold. With the development of micro-channel, a two-step micro-channel has been applied in more and more fields. However, little attention was given to the geometric design and forming process of this unique channel. In this paper, the process of forming multi-row two-step micro-channels on plate by rubber pad forming is studied. At the same time, the length, width, height ratio and the edge chamfer of two-step micro-channel are discussed as the main parameters of geometry. The number and distance of the second-step structures are also studied in this paper. The influence of these geometric parameters on the forming results is analyzed in the finite element simulation. The plates are designed according to these geometric parameters and structures. Moreover, a novel shape and position design of two-step micro-channel are provided. In addition, forming experiments are also carried out for further study. Finally, a design strategy is provided by forming results in conclusions.

Thickness analysis of complex two-step micro-groove on plate during rubber pad forming process

The surface groove structure has numerous functions based on their shapes. In order to make these functions developed, both new shapes and processing forms of the surface structures are being innovated. In this paper, not only the advanced rubber pad forming process is used, but also a new kind of micro-groove with two-step structures is designed. A model based on multi-plane slab method is proposed to analyze the process. According to the stress acting condition, a half of two-step micro-groove structure is divided into seven areas in the width direction. The thickness variation of plate in each area is obtained. When the shape, depth, width, and height ratio of the first and second-step micro-groove are different, the thickness variations of the plate are analyzed. In order to verify the accuracy of the model, both finite element method and pressing experiment are done. Based on the results provided by both finite element method and experiment, the accuracy of results calculated by analytical model is verified.

Analysis of Thickness Distribution in Cup Produced by Rubber Pad Forming

In many manufacturing fields such as the aeroplanes and automobiles industries, the control of the thinning variations in produced parts is a major point to investigate since good thickness distribution mean the reliability of these products. In this framework, several experimental and numerical modeling tests have been developed for the purpose of studying phenomenon of thinning during rubber pad forming process. The low carbon steel (AISI 1080) has been used as the blank material. Three forming block shapes had been used (flat, hemispherical and complex), rubber pad with three different hardness (50, 60 and 70 Shore A) also the rubber pad thickness have (40, 60 and 80 mm). The results have showed that improvement in thickness distribution occurred with decrease in rubber hardness and thickness distribution is various from one deformation style to other.