Session: 02-01-01: Product and Process Design

Paper Number: 149504

149504 - Modelling and Validation of Cf-Smc Uncured Composite Shapes Grasping Behavior for Effective Design of Needle Grippers Modules for Robotic End-Effector 

Automation of "Compression Molding" processes to produce automotive components in carbon fiber, CF-SMC (Carbon Fiber-Sheet Molding Compound), represents a topic of great importance to increase key performance indicators related to composited products manufacturing, such as process efficiency, accuracy and safety of the operations, as well the reduction of overall fabrication costs. To this aim, the manual layup of CF-SMC layers can be effectively supported by means of pick and place robotic solutions.
Properties alterations due to premature cross-linking of the composite matrix can be prevented thanks to automatic transfer of CF-SMC uncured shapes toward the warmed moulds under the press. To this aim, the robot end-effectors adopted have modular structures that integrate needle grippers, returning a good grasping behavior thanks to mechanical connection between the grippers modules and the CF-SMC uncured shape.
Nevertheless, the uncured state leads to shortened life cycles of the needles, due to viscosity and tackiness of the composite material. A topic of interest for an effective design of pick and place robotic end-effectors is therefore the identification of the geometric parameters that are related to grasping performance of needle gripper modules.
Consequently, the objective of this work is to propose a design methodology to optimize the single gripping module to grasp uncured CF-SMC "charges". The proposed method is based on the use of a functional model of the elementary gripping module, which is acquired as a reference for the characterization of the physical behavior, through a first analytical formulation of the four phases of the grasping process (needle inserting, shape detachment, shape handling, shape release). Given the complexity of the analyses, the method in question, which uses analytical, numerical and experimental tools, was implemented with respect to the first phase of the process, i.e. the needle inserting phase. A first analytical study of the need inserting process highlighted the characteristic parameters and the existing relation between the uncured CF-SMC needle-sheet interaction forces, the needle speed, and the inclination angle with which the composite drilling process is carried out. The numerical model was implemented with the Abaqus software using a Finite Element Modelling and Smoothed Particle Hydrodynamics modelling, namely FEM-SPH modeling. The mesh-free SPH algorithm, which in the literature is outlined as the most suitable method for modeling problems involving large deformations, has made it possible to simulate the dynamic of needle inserting process of the composite material, knowing how the material properties only Young's Modulus and Poisson's Ratio. Given the greater computational load of this mesh-free method, the strategy adopted to reduce the calculation time involves the use of FEM for the remaining components of the model and the setting of the "Mass Scaling" parameter. Finally, the design of specific experimental set-ups and the definition of the needle inserting lay-up made it possible to collect data on the forces and proceed with an initial evaluation of the model and correlation between exchanged forces and characteristic geometric parameters.

Presenting Author: Fabio Pini "Enzo Ferrari" Department of Engineering - University of Modena and Reggio Emilia

Presenting Author Biography: Tenure track Professor at the “Enzo Ferrari” Engineering Department - Università degli Studi di Modena e Reggio Emilia (University of Modena and Reggio Emilia - UNIMORE), in the Academic Discipline ING-IND/15 “Design Methods for Industrial Engineering”. Research scientist at the IDEALab on Computer Aided Design for Product Lifecycle Management -integrated development of industrial products and processes, design by simulation of mechanical systems, knowledge-based engineering - and on the Desing of Collaborative and Industrial robotics solutions and devices: design by simulation of robotic equipment for manufacturing and assembly operations. Teacher for the Inter-University International Degree Course in Advanced Automotive Engineering, for the Inter-University Bachelor Degree Course in Human Centered Medical System Engineering, as well as for the Bachelor Degree courses in Vehicle Engineering, and Computer Engineering of UNIMORE.

Authors:

Fabio Pini "Enzo Ferrari" Department of Engineering - University of Modena and Reggio Emilia
Nicolò Galati "Enzo Ferrari" Department of Engineering - University of Modena and Reggio Emilia
Francesco Leali "Enzo Ferrari" Department of Engineering - University of Modena and Reggio Emilia
Valeria Tropiano "Enzo Ferrari" Department of Engineering - University of Modena and Reggio Emilia