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Advanced manufacturing processes

The main activity is focused on the production and processing of metallic materials through advanced manufacturing processes, mainly based on laser technology.

The skills, present in the secondary unit of Lecco, concern: (i) study of the laser beam/matter interaction and characterization of the obtained modifications of the material properties and performances; (ii) development of materials processing technologies.

Nowadays, the following activities, based on unconventional material processes, are in progress:

  • Laser welding for making high technological content joints (for instance, welding among a massive element and a foam in brass – work done in collaboration with Sitec-Politecnico di Milano).

  • Laser cutting for producing micro-elements, mainly in Nitinol but not only, for biomedical and microactuation applications.

  • Laser surface modification for inducing morphological change (though laser ablation or thermal effects for producing nanostuctured texturing) or compositional changes through selective vaporization of specific elements.

  • Laser thermal treatments performed both on massive and surface samples for microstructural modifications; an example can be the development of thermal treatments for reaching microstructural gradients or local microstructural changes.

  • Self-propagating high temperature synthesis (SHS) with laser ignition for the preparation of bulk or porous samples, starting from the elemental powders. The process has been studied on some metallic systems, such as both binary and ternary NiTi (work done in collaboration with CNR, ICMATE, Milano).
Figure 1: Cross section of a laser welded bead, made between foam and plate in CuZn alloy

Figure 2: Detail of a Nitinol element realized with a femtosecond laser

Moreover, additive manufacturing has been selected as prospective of future activities in this field. The secondary unit of Lecco of the institute is going to acquire a selective laser beam melting facility. This technology can open new studies on: (i) evaluation of the interaction between the laser beam and the powder; (ii) synthesis of materials, starting from powders, by means of high power density thermal beam; (iii) production of components with complex geometries.

Figure 3: Laser drilled hole, having high aspect ratio, on TiCr alloy for hidrogen storage applications. Hole diameter of about 120 120 μm, machined on a thickness of 2 mm (the corresponding depth/diameter ratio values 15:1).
Figure 4: Nanometric structure induced by means of femtosecond laser pulses on Nitinol sample
Figure 5: Laser equipment used for making the laser shape setting on thin Nitinol wires
Figure 6: Porous sample in Nitinol produced via laser actived SHS
  • RECENT PUBLICATIONS:
    • C.A. Biffi, D. Colombo,A. Tuissi
      Laser Beam Welding of CuZn open cell foams
      Laser and Optics in Engineering Volume 62, November 2014, Pages 112–118; DOI: 10.1016/j.optlaseng.2014.05.005
    • C.A. Biffi, A. Tuissi
      Fiber Laser Drilling of Ni46Mn27Ga27 Ferromagnetic Shape Memory Alloy
      Optics and Laser Technology. 63C (2014), pp. 1-7 DOI information: 10.1016/j.optlastec.2014.03.010
    • C.A. Biffi, R. Casati, A. Tuissi
      Laser shape setting of NiTinol thin wires
      Smart Materials and Structures. 2016, 25 01LT02; doi:10.1088/0964-1726/25/1/01LT02
    • P. Bassani, E. Bassani, M. Coduri, P. Giuliani, A. Tuissi, C. Zanotti
      Influence of TiHx addition on SHS porous shape memory alloys
      Materials Today Proceedings. International Conference on Martensitic Transformations, ICOMAT-2014, Materials Today: Proceedings 2S ( 2015) S715 - S718
    • 5. A. Nespoli, C. A. Biffi, B. Previtali, E. Villa, A. Tuissi
      Laser and surface processes of NiTi shape memory elements for micro-actuation
      Metallurgical and Materials Transaction A, 45(2014) 2242-2249