Manufacturing of Geared Sheet Metal Components Using Flexible Rolled Tailored Blanks

Abstract

Manufacturing of functional sheet metal products with integrated gear teeth by form-ing can be realised with the application of bulk forming operations on sheet metals. Due to the desired part geometry simultaneous 2D and 3D stress and strain states occur during the forming operations. The main challenges of sheet-bulk metal form-ing are high resulting forming forces and the demand on a specific control of the material flow. In addition, there is a distinctive interaction between blank thickness and resulting part quality. To meet these challenges at high material efficiency, the application of tailored blanks with a defined sheet thickness distribution is a promising way. The process adapted semi-finished used in the presented work are formed by a flexible rolling process. First of all, the forming concept for the realization of geared sheet metal components using flexible rolled tailored blanks is presented. Afterwards, the developed rolling machine to produce rotational symmetric tailored blanks is shown, as well as the fundamental process influences during rolling. Based on that, the development of suitable process strategies to produce tailored blanks with a thickened sheet edge is presented. The further processing of those tailored blanks for the realization of external geared sheet metal components will show the advantages compared to the application of conventional sheet metals of constant sheet thickness. Therefore the concept of a combined deep drawing and ironing process is presented. The results show, that on the one hand the material efficiency is increased in comparison to the usage of conventional sheets of the same maximum thickness. On the other hand, the application of flexible rolled tailored blanks improves the accuracy of shape of the gear teeth. Both approaches prove that the application of flexible rolled is an appropriate procedure to enhance the limits of using conventional sheet metals within sheet-bulk metal forming.

Flexible Rolling of Process Adapted Semi-Finished Parts and its Application in a Sheet-Bulk Metal Forming Process

“…Process description. Tailored blanks manufactured by the presented flexible rolling process can be processed within sheet-bulk metal forming processes like a single-stage deep drawing and upsetting, presented in [8]. Hereby, thin-walled cups are deep-drawn and the cup wall is upset with the concurrent forming of an external gearing.…”

“…However, flow forming only enables the production of hollow, axial symmetrical components [7]. By using the flexible rolling process presented in [8] and used for this paper, rotational symmetric tailored blanks of different materials with circular sheet thickness transitions can be manufactured with a higher strength of the material [3]. rolling tool is pivoted on an x-axis to provide a free rotary movement during the process.…”

“…The entry angle α of both rolls is 15° whereas the smoothing angle β is 5° for the right roll, the forming roll, and β = 0° for the left roll, the smoothing roll. Using two different rolls, a smoother and less rough surface in the thickening zone can be achieved [8]. Tailored blank geometry and process strategy.…”

Fringe Projection Profilometry in Production Metrology: A Multi-Scale Comparison in Sheet-Bulk Metal Forming

“…After the blank is clamped by the upsetting punch, the drawing die moves downwards to draw the cup. In the final step, the cup is upset by the upsetting punch under the adjusted maximum press force [ 10 ]. As for the previous process, tailored approaches were developed to extend identified process limits.…”

Plate forging of drawn cup with flange including thickening of corners

“…Although the wheel disk formed from the axisymmetric tailor welded blank has optimum strength and thickness distributions [16], the welding of three or more pieces of sheet for obtaining the local thickening is not only practical but costly. The use of the tailor rolled blanks is not easy for axi-symmetric parts, however a compression and flexible rolling process was developed to form axi-symmetric tailored blanks [17]. One the other hand, a stamping process of tailor blank having locally thickening was developed [18,19] and then the tailor blanks were applied to increase the wall thickness around the bottom corner in the mild steel [18] and high strength steel disks [20].…”