Theory of single point incremental forming

https://home.kpn.nl/i.w.c.emmens/pdf/36.pdf

An overview of stabilizing deformation mechanisms in incremental sheet forming

The paper deals with the testing and modelling of metals response when subjected to sheet forming operations. The focus is both on the modelling of hardening behaviour and yield criteria and on the description of the sheet metal formability limits. Within this scope, the paper provides a critical review of the models available today for predicting the material behaviour at both industrial and scientific level, and the tests needed to identify the models’ material parameters. The most recent advances in the field are also presented and discussed with particular emphasis on the challenges the sheet metal forming community is now facing.

Testing and modelling of material behaviour and formability in sheet metal forming

Mechanics of fracture in single point incremental forming

A review on forming techniques for manufacturing lightweight complex—shaped aluminium panel components

Process window of tube-end inversion: experimentation and numerical analysis

Strain Paths and Fractures in Rotational Symmetric Multi Stage Single Point Incremental Forming

This paper is focused on injection by upsetting of sheet-formed side walls. The presentation draws from fundamental aspects of material flow to typical failures caused by buckling and by the development of material flaws. Results show that the utilization of two-piece blank holders in conjunction with an adequate selection of the die cavity thickness and the creation of relief-holes to allow divided material flow are effective and easy-to-implement strategies to increase process formability and ensure the production of sound sheet-bulk parts. The work is carried out in two completely different materials (polyvinylchloride and aluminium AA1050) and its originality stands not only for the investigation on sheet injection but also for the utilization of thermoplastics in sheet-bulk forming. Numerical modelling with finite elements gives support to the overall results and discussion.

Injection by sheet-bulk forming

Metallic additive manufacturing processes have been significantly developed since their inception with modern systems capable of manufacturing components for structural applications. However, successful processing through these methods requires extensive experimentation before optimised parameters can be found. In laser-based processes, such as direct energy deposition, it is common for single track beads to be deposited and subjected to analysis, yielding information on how the input parameters influence characteristics such as the output’s adhesion to the substrate. These characteristics are often determined using specialised software, from images obtained by cross-section cutting the line beads. The proposed approach was based on a Python algorithm, using the scikit-image library and optical microscopy imaging from produced 18Ni300 Maraging steel on H13 tool steel, and it computes the relevant properties of DED-produced line beads, such as the track height, width, penetration, wettability angles, cross-section areas above and below the substrate and dilution proportion. 18Ni300 Maraging steel depositions were optimised with a laser power of 1550 W, feeding rate of 12 gmin−1, scanning speed of 12 mm s−1, shielding gas flow rate of 25 Lmin−1 and carrier gas flow rate of 4 Lmin−1 for a laser spot diameter of 2.1mm. Out of the cross-sectioned beads, their respective height, width and penetration were calculated with 2.71%, 4.01% and 9.35% errors; the dilution proportion was computed with 14.15% error, the area above the substrate with 5.27% error and the area below the substrate with 17.93% error. The average computational time for the processing of one image was 12.7s. The developed approach was purely segmentational and could potentially benefit from machine-learning implementations.

/pdf/automation-of-property-acquisition-of-single-track-30bhb0nr.pdf

Automation of Property Acquisition of Single Track Depositions Manufactured through Direct Energy Deposition

The “Observar e Aprender” Project (Observing and Learning - O&L) is a peer-observation program for the teaching community in Universidade de Lisboa. The project aims to promote spaces for experimentation and support of the Universidade de Lisboa teachers, constituting itself as an interdisciplinary training forum. This paper presents the project, its main results and management activities.

Maria Beatriz Silva

Papers

Process window of tube-end inversion: experimentation and numerical analysis

Strain Paths and Fractures in Rotational Symmetric Multi Stage Single Point Incremental Forming

Injection by sheet-bulk forming

Automation of Property Acquisition of Single Track Depositions Manufactured through Direct Energy Deposition

Peer Observation Project at the University of Lisbon - Implementation and Management