Thermal Modeling of Polyamide 12 Powder in the Selective Laser Sintering Process Using the Discrete Element Method.

Selective laser sintering (SLS) is one of the key additive manufacturing technologies that can build any complex three-dimensional structure without the use of any special tools. Thermal modeling of this process is required to anticipate the quality of the manufactured parts by assessing the microstructure, residual stresses, and structural deformations of the finished product. This paper proposes a framework for the thermal simulation of the SLS process based on the discrete element method (DEM) and numerically generated in Python. This framework simulates a polyamide 12 (PA12) particle domain to describe the temperature evolution in this domain using simple interaction laws between the DEM particles and considering the exchange of these particles with the boundary planes. The results obtained and the comparison with the literature show that the DEM frame accurately captures the temperature distribution in the domain scanned by the laser. The effect of laser power and projection time on the temperature of PA12 particles is investigated and validated with experimental settings to show the reliability of DEM in simulating powder-based additive manufacturing processes.

[CAD/CAM assisted facial epithesis: Clinical and technical aspects]. / Épithèse faciale par CFAO : aspects cliniques et techniques.

The face is an important part of the human body from an anatomical, functional, aesthetic and psychosocial point of view. It can be the site of several mutilations resulting from trauma, treatment of neoplasms and congenital malformations. The plastic facial prosthesis is therefore indicated to restore these facial deformities and to compensate for the various consequences. Recently, digital technologies have shown an increasing impact on the future of maxillofacial rehabilitation. Computer-aided design and manufacturing technique enabled practitioners to acquire numerical data, perform three-dimensional reconstructions, and then materialize and manufacture the facial epithesis through various manufacturing processes, by addition or subtraction. The aim of this article is to describe, through a clinical case, the steps of realization of a nasal epithesis by CAD/CAM, in a patient who underwent a surgical exeresis of the nasal pyramid following a squamous cell carcinoma. Thus, the clinical and technical aspects are highlighted, as follows, the taking of the impression, the materials used, the set-up and the make-up, as well as the software and the useful concepts for the computer-assisted realization of a facial plastic prosthesis of the nasal epithesis type. Our therapy will also focus on the interest of the multidisciplinary approach in Maxillofacial Prosthodontics.