Optimization of WAAM Deposition Patterns for T-crossing Features

AbstractAmong emerging additive manufacturing technologies for metallic components, WAAM (Wire and Arc Additive Manufacturing) is one of the most promising. It is an arc based technology characterized by high productivity, high energy efficiency and low raw material cost. Anyway, it has some drawbacks limiting its diffusion in the industry. One is the open issue about the layer deposition strategy that must be manually optimized in order to reduce as possible the residual stress and strains, efficiently matching the geometrical characteristics of the component to build and assure a constant height for each layer. This work deals with the definition of deposition paths for WAAM. The choice of a path must be carried out as a compromise between productivity and material usage efficiency. In the present paper, the process to select an optimized strategy for the manufacturing of T-crossing features will be shown

Speed-varying Machine Tool Dynamics Identification Through Chatter Detection and Receptance Coupling

AbstractTool-tip Frequency Response Function (FRF) represents one of the essential inputs to predict chatter vibration and compute the Stability Lobe Diagram (SLD). Tool-tip FRFs are generally obtained for the stationary (non-rotating) condition. However, high speeds influence spindle dynamics, leading to a reduced accuracy of the SLD prediction. This paper presents a comprehensive method to identify speed-varying tool-tip FRFs and improve chatter prediction. First, FRFs for a screening tool is identified by a novel technique based on a dedicated experimental test and analytical stability solution. Then, a tailored receptance coupling technique is used to predict speed-varying tool-tip FRFs of any other tool. Proposed method was experimentally validated: chatter prediction accuracy was demonstrated through chatter tests

Cutting Forces Analysis in Additive Manufactured AISI H13 Alloy

AbstractCombining Additive Manufacturing (AM) and traditional machining processes is essential to meet components functional requirements. However significant differences arise in machining AM and wrought parts. Previous works highlighted the increasing of tool wear and worse surface finish. In this paper cutting forces are investigated as an indicator of material machinability. Milling cutting force coefficients are identified using mechanistic approach, comparing AISI-H13 wrought and AM specimen. Cutting force behaviour was investigated for two AM technologies: laser deposition (LENS) and wire-arc additive manufacturing (WAAM). Results show a general increase of cutting forces and coefficients of both AM materials, suggesting AM parts reduced machinability. Therefore, different cutting parameters should be selected for the AM material to achieve a sustainable production

The temporalis muscle flap for reconstruction of soft palate and lateral oropharyngeal wall after transoral robotic surgery

Trans Oral Robotic Surgery (TORS) is a prominent surgical approach for the resection of oropharyngeal tumors without division of the lip and mandible. Some defects following TORS are large and complex enough to benefit soft-tissue coverage. The pedicled temporalis muscle flap is a versatile and reliable flap and may be a valid option to reconstruct defects of the lateral pharyngeal wall and partial soft palate