Prediction of Path Deviation in Robot Based Incremental Sheet Metal Forming by Means of a New Solid-Shell Finite Element Technology and a Finite Elastoplastic Model with Combined Hardening

2011 ◽  
Author(s):  
Yalin Kiliclar ◽  
Roman Laurischkat ◽  
Ivaylo N. Vladimirov ◽  
Stefanie Reese
Keyword(s):  
Finite Element ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Solid Shell ◽  
Elastoplastic Model ◽  
Finite Element Technology ◽  
Incremental Sheet Metal Forming ◽  
Combined Hardening ◽  
Shell Finite Element ◽  
Path Deviation

The Simulation of Robot Based Incremental Sheet Metal Forming by Means of a New Solid-Shell Finite Element Technology and a Finite Elastoplastic Model with Combined Hardening

2011 ◽  
Vol 473 ◽  
pp. 875-880 ◽  
Author(s):  
Yalin Kiliclar ◽  
Roman Laurischkat ◽  
Stefanie Reese ◽  
Horst Meier
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Kinematic Hardening ◽  
Industrial Robots ◽  
Solid Shell ◽  
Forming Process ◽  
Incremental Sheet Metal Forming ◽  
Shell Finite Element

The principle of robot based incremental sheet metal forming is based on flexible shaping by means of a freely programmable path-synchronous movement of two tools, which are operated by two industrial robots. The final shape is produced by the incremental infeed of the forming tool in depth direction and its movement along the geometry’s contour in lateral direction. The main problem during the forming process is the influence on the dimensional accuracy resulting from the compliance of the involved machine structures and the springback effects of the workpiece. The project aims to predict these deviations caused by resiliences and to carry out a compensative path planning based on this prediction. Therefore a planning tool is implemented which compensates the robot’s compliance and the springback effects of the sheet metal. Finite element analysis using a material model developed at the Institute of Applied Mechanics (IFAM) [1] has been used for the simulation of the forming process. The finite strain constitutive model combines nonlinear kinematic and isotropic hardening and is derived in a thermodynamical setting. It is based on the multiplicative split of the deformation gradient in the context of hyperelasticity. The kinematic hardening component represents a continuum extension of the classical rheological model of Armstrong–Frederick kinematic hardening which is widely adopted as capable of representing the above metal hardening effects. The major problem of low-order finite elements used to simulate thin sheet structures, such as used for the experiments, is locking, a non-physical stiffening effect. Recent research focuses on the large deformation version of a new eight-node solid-shell finite element based on reduced integration with hourglass stabilization. In the solid-shell formulation developed at IFAM ([2], [3]) the enhanced assumed strain (EAS) concept as well as the assumed natural strain (ANS) concept are implemented to circumvent locking. These tools are very important to obtain a good correlation between experiment and simulation.

Prediction of Path Deviation in Robot Based Incremental Sheet Metal Forming by Means of an Integrated Finite Element – Multi Body System Model

2009 ◽  
Vol 410-411 ◽  
pp. 365-372 ◽  
Author(s):  
Horst Meier ◽  
Roman Laurischkat ◽  
C. Bertsch ◽  
Stefanie Reese
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Tool Path ◽  
Body System ◽  
True Path ◽  
Incremental Sheet Metal Forming ◽  
Path Prediction ◽  
Multi Body

The main influence on the dimensional accuracy in incremental sheet metal forming results from the compliance of the involved machine structures and the springback effects of the workpiece. This holds especially for robot based sheet metal forming, as the stiffness of the robot’s kinematics compared to a conventional machine tool is low, resulting in a significant deviation of the planned tool path and therefore in a shape of insufficient quality. To predict these deviations, a coupled process structure model has been implemented. It consists of a finite element (FE) approach to simulate the sheet forming and a multi body system (MBS) modeling the compliant robot structure. The forces in the tool tip are computed by the FEA, while the path deviations due to these forces can be obtained using the MBS model. Coupling both models gives the true path driven by the robots. Built on this path prediction, mechanisms to compensate the robot’s kinematics can be implemented. The current paper describes an exemplary model based path prediction and its validation.

Incremental sheet metal forming of Ti–6Al–4V alloy for aerospace application

2020 ◽  
Vol 44 (1) ◽  
pp. 56-64 ◽  
Author(s):  
R. Mohanraj ◽  
S. Elangovan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Sheet Metal ◽  
Process Parameters ◽  
Experimental Work ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Geometric Accuracy ◽  
Element Analysis ◽  
Incremental Sheet Metal Forming

Driven by an increasing demand from the aerospace industry, thin sheet forming of titanium and its alloys is gaining prominence in scientific research. The design and manufacture of aerospace components requires the utmost precision and accuracy. It is essential to have good control over the process parameters of the forming process. Processes such as incremental sheet metal forming (ISMF) are highly controlled in the current manufacturing environment, but improvements in geometric accuracy and thinning are still needed. Although ISMF has greater process competence for manufacturing airframe structures with minimal costs, the process has its own negative effect on geometric accuracy due to elastic springback and sheet thinning. In this study, finite element analysis and experimental work are performed, considering process parameters such as spindle speed, feed rate, step depth, and tool diameter, to study the geometric accuracy and thinning of Ti–6Al–4V alloy sheet, while incrementally forming an aerospace component with asymmetrical geometry. The results are useful for understanding the geometric accuracy and thinning effects on parts manufactured by single point incremental forming (SPIF). Results from finite element analysis and experimental work are compared and found to be in good agreement.

Sign in / Sign up

Export Citation Format

Share Document