Design of a Novel End-Effector for Kinematic Support in Incremental Sheet Forming

2016 ◽  
Vol 716 ◽  
pp. 395-401 ◽  
Author(s):  
Jan Brüninghaus ◽  
Yan Volfson ◽  
Jobst Bickendorf ◽  
Sigrid Brell-Cokcan
Keyword(s):  
Rotation Axis ◽  
Sheet Forming ◽  
Center Of Gravity ◽  
Incremental Sheet Forming ◽  
Vertical Position ◽  
End Effector ◽  
Support Tool ◽  
Geometrical Accuracy ◽  
Force Magnitude ◽  
Support Tools

The formability and geometrical accuracy in incremental sheet forming can be increased using a force-controlled support tool. The main problems in using such a kinematic support tool is the positioning of forming and support tools, while maintaining force magnitude and alignment. A new tool for this was developed systematically using a morphological box. It uses a spring controlled rotation of the tool tip to maintain the force. Since the rotation axis is not in line with the tool tip axis and the tool tip can freely rotate around its axis, roll friction conditions can be achieved. The center of gravity of the rotating part of the tool is placed in the rotating axis and the force is therefore independent from the alignment of the tool in space. It has a mechanical stop with locking option in the vertical position and is therefore also fully usable as a forming tool. While the prototype is manually controlled, concepts for a fully automated version have been designed, as well. First tests are in line with results described in literature, showing that direction and magnitude of force have an influence on the formability.

scholarly journals On the Influence of the Tool Path and Intrusion Depth on the Geometrical Accuracy in Incremental Sheet Forming

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 661
Author(s):  
Roman Ulrich Christopher Schmitz ◽  
Thomas Bremen ◽  
David Benjamin Bailly ◽  
Gerhard Kurt Peter Hirt
Keyword(s):  
Sheet Metal ◽  
Tool Path ◽  
Sheet Material ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Forming Process ◽  
Geometrical Accuracy ◽  
Metal Forming Process ◽  
Short Time ◽  
Intrusion Depth

Incremental sheet forming (ISF) is a flexible sheet metal forming process to realize products within short time from design to the first produced part. Although fundamental research on ISF has been carried out around the world, ISF still misses commonly required tolerances for industrial application. In this study, the influences of tool path as well as intrusion depth of the forming tool into the sheet material on the geometrical accuracy were investigated. In the conducted experiments, both flat and stretch-formed sheet metal blanks with different tool paths and intrusion depths were examined. Experimental and numerical investigations showed that changes in the range of a tenth millimeter of the intrusion depth with a consistent tool path lead to different resulting part geometries. A better understanding of the sensitive influence of the tool path and the intrusion depth on the resulting geometry might lead to more accurate parts in the future.

FlexDie: A Flexible Tooling-Concept for Incremental Sheet Forming

2012 ◽  
Vol 504-506 ◽  
pp. 883-888 ◽  
Author(s):  
Gerd Sebastiani ◽  
Arthur Wawrosch ◽  
Volker Franzen ◽  
Alexander Brosius ◽  
A. Erman Tekkaya
Keyword(s):  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Geometric Accuracy ◽  
Support Tool ◽  
Part Geometry ◽  
Complex Process ◽  
Critical Zones ◽  
Similar Accuracy ◽  
Flexible Die ◽  
The Given

Forming tasks in Sheet Metal Prototyping are currently a balancing act between part flexibility and accuracy. In view of Asymmetric Incremental Sheet Forming (AISF), the part support is the decisive factor: Die-based processes such as TPIF are restricted to the given geometry of the part. On the other hand, the die-less variant (SPIF) is prone to a much more complex process-layout – once a similar accuracy needs to be obtained. Consequently, this requires a flexible die concept, supporting the part in the critical zones only. Within this article we meet this challenge by introducing the configurable tooling concept "FlexDie". This support tool comprises a construction kit for skeleton dies allowing for an adjustment of its geometry to almost any desired shape. Based on the solar cooker benchmark by Jeswiet et al., we show both the tooling-concept and the feasibility. The latter we discuss, based on the quality features geometric accuracy as well as surface quality. Both features are assessed with respect to the forming results obtained by use of a full-die. The accuracy resulting by applying the FlexDie is only slightly inferior to the parts formed by use of a full-die. However, the FlexDie allows for simple optimization of both, die and part geometry. In addition, compensation strategies by adapting the toolpath are still possible. In summary, the results show the feasibility of the FlexDie concept for industrial ISF tasks - even at very low production volumes.

scholarly journals Closed-loop control of product geometry by using an artificial neural network in incremental sheet forming with active medium

2020 ◽  
Author(s):  
S. Thiery ◽  
M. Zein El Abdine ◽  
J. Heger ◽  
N. Ben Khalifa
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Active Medium ◽  
Closed Loop ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Closed Loop Control ◽  
Loop Control ◽  
Geometrical Accuracy ◽  
Artificial Neural

AbstractA strategy to adjust the product geometry autonomously through an online control of the manufacturing process in incremental sheet forming with active medium is presented. An axial force sensor and a laser distance sensor are integrated into the process setup to measure the forming force and the product height, respectively. Experiments are conducted to estimate the bulging behavior for different pre-determined tool paths. An artificial neural network is consequently trained based on the experimental data to continuously predict the pressure levels required to control the final product height. The predicted pressure is part of a closed-loop control to improve the geometrical accuracy of formed parts. Finally, experiments were conducted to verify the results, where truncated cones with different dimensions were formed with and without the closed-loop control. The results indicate that this strategy enhances the geometrical accuracy of the parts and can potentially be expanded to be implemented for different types of material and geometries.

Kinematic Calibration and Data-Based Error Compensation of a Parallel Robot-Based Incremental Sheet Forming Machine

2020 ◽  
Author(s):  
Shuheng Liao ◽  
Kornel Ehmann ◽  
Jian Cao
Keyword(s):  
Error Compensation ◽  
Incremental Forming ◽  
State Of The Art ◽  
Parallel Robot ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Control Law ◽  
End Effector ◽  
Linear Encoder ◽  
Rapid Manufacture

Abstract Incremental sheet forming is a state-of-the-art manufacturing process for the rapid manufacture of sheet metal components without the use of geometry-specific dies. In this paper, a novel ISF machine, based on a unique overconstrained parallel robot called the Tri-pyramid robot, is introduced. The inverse and forward kinematics of the machine are first analyzed and calibrated based on experimental measurements. In turn, to compensate the kinematic and compliance errors of the machine, a linear encoder system, developed to directly measure the end-effector positions, in conjunction with a neural network, trained to map encoder readings and spatial end-effector positions, is used. A feedback control law is then implemented to compensate the errors in real-time. Experimental results demonstrate that after calibration and error compensation the accuracy of the machine is improved tenfold, making it adequate for incremental forming applications.

On the Geometrical Accuracy in Incremental Sheet Forming

2021 ◽  
pp. 507-521
Author(s):  
Gerhard Hirt ◽  
Roman Kordtomeikel ◽  
Thomas Bremen ◽  
Marvin Laugwitz ◽  
David Bailly
Keyword(s):  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Geometrical Accuracy

Multiobjective optimization of process variables in single-point incremental forming using grey relational analysis coupled with entropy weights

2021 ◽  
pp. 146442072110204
Author(s):  
Abdulmajeed Dabwan ◽  
Adham E Ragab ◽  
Mohamed A Saleh ◽  
Atef M Ghaleb ◽  
Mohamed Z Ramadan ◽  
...  
Keyword(s):  
Grey Relational Analysis ◽  
Incremental Forming ◽  
Single Point ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Numerical Control ◽  
Single Point Incremental Forming ◽  
Process Variables ◽  
Relational Analysis ◽  
Grey Relational

Incremental sheet forming is a specific group of sheet forming methods that enable the manufacture of complex parts utilizing computer numerical control instead of specialized tools. It is an incredibly adaptable operation that involves minimal usage of sophisticated tools, dies, and forming presses. Besides its main application in the field of rapid prototyping, incremental sheet forming processes can be used for the manufacture of unique parts in small batches. The goal of this study is to broaden the knowledge of the deformation process in single-point incremental forming. This work studies the deformation behavior in single-point incremental forming by experimentally investigating the principal stresses, principal strains, and thinning of single-point incremental forming products. Conical-shaped components are fabricated using AA1050-H14 aluminum alloy at various combinations of fundamental variables. The factorial design is employed to plan the experimental study and analysis of variance is conducted to analyze the results. The grey relational analysis approach coupled with entropy weights is also implemented to identify optimum process variables for single-point incremental forming. The results show that the tool diameter has the greatest effect on the thinning of the SPIF product, followed by the sheet thickness, step size, and feed rate.

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