Session: 02-01-02: Product and Process Design 2

Paper Number: 165912

Design and Optimization Integrated Approach for Robotic Welding Processes of Car Chassis 

The main issues with defining sequences to weld car chassis are related to targeting the expected tolerances. To keep deformation within the expected specification, refinement loops on prototypal chassis are required to achieve the expected specifications. Moreover, the processing time is also a parameter to be kept as low as possible to meet the expected production costs.
To reduce refinement loops and anticipate the behavior of the selected sequence, this work aims to define an integrated design approach of robotic welding processes to support the selection of the best robot welding sequence and weld jigs design trade-off. Specifically, the goal is to identify the solution that returns the minimum deformation of the car chassis and minimum process times and costs. The approach relies on using a PLM platform to recreate a digital twin of the potential solution through the integration of design tools, product analysis, and process simulation in a single environment. The phases involved in traditional welding process design approaches can be summarized in three main steps, such as product design, definition of component positioning and fixing fixtures, and determination of welding operations.
Adopting an integrated solution on the platform, a collaborative and interconnected workflow is defined to minimize uncertainties and time for validating the welding solution.
CAD model of the selected car frame, related material, and the defined fixing points are the inputs for the suggested approach. The next step focuses on modeling the weld seams, locking mechanisms, and fixture. The robot arm, related welding torch, and the auxiliary equipment to define the welding cell complete the layout. A preliminary analysis of the encumbrances and collisions returns the first assessment of the geometry and size of the model for selected components. A loop back to the design phase occurs in case of potential impacts or unreachable points. The next phase is related to the definition of the simulation plan. Local robot trajectories are defined for all the weld seams. Subsequently, the simulation plan is derived by combining the potential sequences through the weld seams. The next phase loops a thermomechanical simulation for each sequence to return the deformation; robot simulations are performed to collect the processing time required for the selected sequence. Dedicated parameters have been defined to assess the most effective sequence.
A chassis subassembly is selected to demonstrate the suggested approach's feasibility. Thanks to the symmetry of the structure, twelve sequences have been identified. The platform-based integrated approach returns the data for each sequence to enable the assessment phase. One potential sequence returns the lowest deformations and lowest process time.
Nonetheless, the method highlights that the thermomechanical phase requires a long time, which might impact the adoption of the approach for cases with many seams.

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

Presenting Author Biography: Fabio Pini - Associate 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 University of Modena and Reggio Emilia - Engineering Department "Enzo Ferrari"
Alessandro Dimauro University of Modena and Reggio Emilia - Engineering Department "Enzo Ferrari"
Enrico Dalpadulo University of Modena and Reggio Emilia - Engineering Department "Enzo Ferrari"
Francesco Leali University of Modena and Reggio Emilia - Engineering Department "Enzo Ferrari"