Vibrations in engineering and technology

Babyn Ihor – Candidate of Technical Sciences, Associate Professor of the Department of machinery and equipment for agricultural production of Vinnytsia National Agrarian University (St. Soniachna, 3, Vinnytsia, Ukraine, 21008, e-mail: ihorbabyn@gmail.com, https://orcid.org/0000-0002-7070-4957). 

Luts Pavlo – Candidate of Technical Sciences, Senior Lecturer of Department of machines and equipment of agricultural production of Vinnytsia National Agrarian University (St. Soniachna, 1, Vinnytsia, Ukraine, 21008, e-mail: luts@vsau.vin.ua). ORCID 0000-0002-3776-8940.

Shtuts Andrii – Candidate of Technical Sciences, Associate Professor, Head of Department of machines and equipment of agricultural production of Vinnytsia National Agrarian University (3, Solnechna str., Vinnitsa, 21008, Ukraine, email: shtuts1989@gmail.com, https://orcid.org/0000-0002-4242-2100). 

Springback is one of the key factors that significantly reduce the achievement of geometric accuracy of parts obtained by sheet bending, especially in the case of forming profiles with two bending angles. The magnitude of springback is determined by the combined effect of the elastic and plastic characteristics of the material, the thickness of the workpiece, the degree and pattern of deformation, the geometric parameters of the tool, as well as the contact conditions in the bending zone.

In industrial practice, accurate prediction of the magnitude of springback remains a difficult but priority task, which necessitates the use of additional technological measures to achieve the specified accuracy: calibration operations, the use of complex adjustable dies, special temperature regimes (for example, preheating of the tooling) or modified deformation conditions. Such approaches lead to a complication of the technological process and an increase in the cost of production.

The article investigates the effectiveness of springback compensation during double-angle bending by using a special design of a die equipped with spring-loaded clamping strips. The proposed solution provides continuous controlled pressing of the workpiece to the punch surface throughout the bending cycle and creates additional controlled plastic deformation aimed at compensating for angular deviation after load removal.

The spring-loaded strips are made of carbon steel and have a geometry optimized in accordance with the expected value of springback of a specific workpiece material. The punch is made with a corresponding compensation notch, which contributes to the formation of the target angle taking into account the predicted deviation. The design is designed to form right angles of bending.

The results of theoretical modeling and experimental research of the double-angle bending process using the developed die equipment are presented. It has been established that the use of spring-loaded clamping strips allows to significantly reduce, and in many cases – to practically completely eliminate, elastic return, ensuring the production of parts with specified angular parameters in one technological operation without the need for subsequent calibration.

The proposed method is distinguished by its structural simplicity, economic feasibility and high prospects for application in single and small-scale production.

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