Development of an innovative hydraulic press for incremental forming: machine and process evaluation using a hybrid two-step process

Sevšek, Luka (author), Šimic, Marko (author), Herakovič, Niko (author), Pepelnjak, Tomaž (author)

Developing individual/personalised products requires flexible forming processes, which are limited by insufficient sheet thickness distribution and inadequate mechanical properties of the formed material. One group of forming processes with greater flexibility are incremental sheet metal forming (ISF) processes, the simplest representative of which is single-point incremental forming (SPIF). In order to improve the sheet thickness distribution, a pre-bulging process with subsequent SPIF is carried out in this study. Experimental results show that the integration of a pre-bulging step in a hybrid forming process leads to a more uniform final sheet thickness and reduces tip thinning compared to SPIF. This study focuses on the development of a hybrid machine based on a servo-hydraulic press to achieve sufficient forming accuracy with SPIF on difficult-to-form materials. SPIF is performed by increasing the flexibility of the hydraulic machine through the use of ball runner blocks mounted on the press bed, which allow movements in the horizontal plane. The developed hydraulic forming setup enables a significantly higher vertical force capacity, extending the application of SPIF to high-strength materials such as DP590 steel. This approach demonstrates a novel, scalable path for SPIF for industrially relevant materials and overcomes significant limitations of conventional CNC-based SPIF systems.

• Language: English
• Keywords: hybrid two-step forming, single-point incremental forming, sheet metal bulging, advanced hydraulic press concept, high energy incremental forming machine, dual-phase steel
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 18 str.
• Numbering: Vol. 258, art. 114602
• PID: 20.500.12556/RUL-171230
• UDC: 621.226:621.98
• ISSN on article: 0264-1275
• DOI: 10.1016/j.matdes.2025.114602
• COBISS.SI-ID: 246058755
• Publication date in RUL: 20.08.2025

Record is a part of a journal

• Title: Materials & design
• Shortened title: Mater. des.
• Publisher: Scientific and Technical Press
• ISSN: 0264-1275
• COBISS.SI-ID: 10626075

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.

Secondary language

• Language: Slovenian
• Keywords: hibridno dvo-stopenjsko preoblikovanje, enotočkovno inkrementalno preoblikovanje, izbočevanje pločevine, napredni koncept hidravlične stiskalnice, visokoenergijski stroj za inkrementalno preoblikovanje, dvofazno jeklo

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0248
• Name: Inovativni izdelovalni sistemi in procesi

• Funder: EC - European Commission
• Project number: 101058693
• Name: Sustainable Transition to the Agile and Green Enterprise
• Acronym: STAGE