Laser-Assisted Bending of Sharp Angles With Small Fillet Radius on Stainless Steel Sheets: Analysis of Experimental Set-Up and Processing Parameters

Abstract

Achievement of sharp bending angles with small fillet radius on stainless steel sheets by mechanical bending requires sophisticated bending device and troublesome operational procedures, which can involve expensive molds, huge presses and large loads. In addition, springback is always difficult to control, thus often leading to final parts with limited precision and accuracy. In contrast, laser-assisted bending of metals is an emerging technology, as it often allows toperform difficult and multifaceted manufacturing tasks with relatively small efforts. In the present work, laser-assisted bending of stainless steel sheets to achieve sharp angles is thus investigated. First, bending trials were performed by combining laser irradiation with an auxiliary bending device triggered by a pneumatic actuator and based on kinematic of deformable quadrilaterals. Second, laser operational parameters, that is, scanning speed, power and number of passes, were varied to identify the most suitable processing settings. Bending angles and fillet radii were measured by coordinate measurement machine. Experimental data were elaborated by combined ANalysis Of Mean (ANOM) and ANalysis Of VAriance (ANOVA). Based on experimental findings, the best strategy to achieve an aircraft prototype from a stainless steel sheet was designed and implemented

Laser-assisted bending of Titanium Grade-2 sheets: Experimental analysis and numerical simulation

“…Kinematic of the bending device is schematized in Fig. 2 and, elsewhere, described in detail [9]. Briefly, it consists of a pneumatic piston and bending elements.…”

“…The following steps are involved during external force laser-assisted bending process of the titanium alloys: (1) cleaning of the substrates in an ultrasonic bath of a solution of isopropyl alcohol; (2) workpiece positioning on the bending device and its clamping inside the dowels of the system; (3) positioning of the punch below the bending line (i.e., the laser scanning pattern); (4) triggering the compressed air system with a constant pressure of 8 bar; (5) setting of laser working distance on the substrate surface; (6) setting the operational parameters of laser processing; (7) checking alignment between clamping system and laser beam; (8) starting the experimental apparatus and data recording; (9) starting the processing of the substrate; (10) turning off the laser system and the compressed air system; (11) cooling off the experimental apparatus and retrieving the workpiece; (12) measuring the bending parameters. The operational parameters of the experiment (laser power, scan speed and number of passes) are summarized in Table 1.…”

“…It is a thermo-mechanical, non-contact and easy-to-control process, which is able to deform metal sheets by irradiating them with a concentrated laser beam. Recently, applications of laser bending assisted by external forces and, vice versa, external force laser-assisted bending have been attracting a remarkable interest [9]. It is a hybrid manufacturing technique where simple combination of laser irradiation patterns with a basilar holding/pressing device can allow the achievement of tridimensional shape on many metal alloys, included those characterized by sharp bending angles with small filet radii.…”

Effect of Pre-Stress on Laser-Induced Thermoplastic Deformation of Inconel 718 Beams

“…In order to increase the forming efficiency, the application of external forces is studied with growing interest [22][23][24][25][26]. In this way, the research on laser forming meets investigations on heat-assisted metal forming processes [27,28].…”

An integrated FEM-ANN model for laser bending process with inverse estimation of absorptivity

“…Kant and Joshi (2013) proposed a laser assisted bending with moving mechanical load for bending of large sized worksheets. Gisario et al (2015a) studied laser assisted bending of AISI 304 stainless steel sheets of 1 mm thickness to obtain a large bend angle upto 140°with a small fillet radius of 2 mm. Gisario et al (2015b) studied laser assisted origami bending of the stainless steel sheets for shaping the sheets into three dimensional items such as cubes and chairs.…”