Hybrid processes in manufacturing

Considerable changes have occurred in metal forming in the last decade. A record of these changes can be found in keynote papers presented by the members of the Scientific Technical Committee—Forming, at the CIRP Annual General Meeting each year. The keynote papers are excellent references on important developments in metal forming and are used as a reference, globally. Not only is this paper a compendium of most of the keynotes presented, but from 2001 onward, it has updates on new information on five keynote subject areas. The authors of each keynote have written an update with new information that has developed since the writing of the keynote. The authors of each section are shown in order of presentation.

Metal forming progress since 2000

Today, hybrid manufacturing technology has drawn significant interests from both academia and industry due to the capability to make products in a more efficient and productive way. Although there is no specific consensus on the definition of the term ‘hybrid processes’, researchers have explored a number of approaches to combine different manufacturing processes with the similar objectives of improving surface integrity, increasing material removal rate, reducing tool wear, reducing production time and extending application areas. Thus, hybrid processes open up new opportunities and applications for manufacturing various components which are not able to be produced economically by processes on their own. This review paper starts with the classification of current manufacturing processes based on processes being defined as additive, subtractive, transformative, joining and dividing. Definitions of hybrid processes from other researchers in the literature are then introduced. The major part of this paper reviews existing hybrid processes reported over the past two decades. Finally, this paper attempts to propose possible definitions of hybrid processes along with the authors’ classification, followed by discussion of their developments, limitations and future research needs.

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A review of hybrid manufacturing processes – state of the art and future perspectives

In the current work, a new method is proposed for hot incremental forming. The method is based on simple tooling and is easy to employ. It makes use of electric current for heating hard-to-form sheet metals at the tool–sheet interface in order to fully utilize the formability of these materials. The potential effect of processing parameters, namely current, tool size, feed rate and step size, on the formability are investigated using AZ31 magnesium. In addition to this, the shape distortion of TiAl2Mn1.5 titanium workpiece after hot forming has also been addressed herein. Experimental results demonstrate that this technique is feasible and easy to control.

Electric hot incremental forming: A novel technique

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

Laser Assisted Incremental Forming: Formability and Accuracy Improvement

The limited accuracy of the single point incremental forming process [J. Jeswiet, F. Micari, G. Hirt, A. Bramley, J. Duflou, J. Allwood, Asymmetric single point incremental forming of sheet metal, Annals of CIRP 54(2) (2005) 623–650] has been identified as its major deficiency [J.M. Allwood, G.F. King, J. Duflou, A structured search for applications of the Incremental Sheet Forming process by product segmentation, Proceedings of the Institute of Mechanical Engineers, Part B, Journal of Engineering Manufacture 219(2) (2005) 239–244]. Improving the process by introducing either fixed [J.R. Duflou, B. Lauwers, J. Verbert, F. Gelaude, Y. Tunckol, Medical application of single point incremental forming: cranial plate manufacturing, in: Proceedings of the VRAP 2006 Conference, Leiria, September 2006, pp. 161–166] or programmable support structures [J.M. Allwood, N.E. Houghton, K.P. Jackson, The design of an incremental sheet forming machine, in: Proceedings of the Shemet 2005 Conference, Erlangen, April 2005, pp. 471–478; H. Meier, O. Dewald, J. Zhang, incremental forming of sheet metal by two industrial robots, in: AMST’05 Advanced Manufacturing Systems and Technology 2005, vol. 486, Springer, Wien, New York, pp. 437–444], tends to reduce the flexibility of the process and increases the complexity of the control system. In the presented research, the authors have opted for an alternative approach in which the material properties are differentiated by localised temperature variations. In this way, different zones can be created in the sheet metal part being processed. By means of a dynamic heat, input in the direct vicinity of the stylus, a ductile area with low-yield strength is generated. By synchronising the movement of the heat source over the sheet metal surface with the stylus feed rate and direction, and by using appropriate cooling of the surrounding area, a temperature gradient can be assured between this area and the workpiece zone where no deformation is envisaged. Effects of such strategy are reduced forces on the stylus and, in consequence, a better localised deformation and thus a higher precision. Furthermore, higher forming limit angles have been demonstrated for materials with low strainability at room temperature. An experimental setup has been built to test this dynamic, local heating principle and is described in the paper. The effects on the process performance are demonstrated by means of experimental results.

H. De Baerdemaeker

Papers

Laser Assisted Incremental Forming: Formability and Accuracy Improvement

Improved SPIF performance through dynamic local heating