Closed-loop feedback control of product properties in flexible metal forming processes with mobile tools

Allwood, Julian M.; Music, Omer; Raithathna, Ankor; Duncan, Stephen R.

doi:10.1016/j.cirp.2009.03.065

Cited by 76 publications

(35 citation statements)

References 9 publications

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“…The ISF toolpath can be corrected by using error compensation based on trial fabrications [11], a feature-based toolpath generation strategy [12], a Multivariate Adaptive Regression splines (MARS) correction strategy [13], iterative algorithms based on a transfer function [14], and an artificial cognitive system [15]. Moreover, some in-process toolpath correction approaches were performed in SPIF based on a control strategy using spatial impulse responses of the process [16] and a MPC strategy [17]. In particular, the MPC control strategy reported in [17] only dealt with the optimisation of the step depth, which is one of the two critical toolpath parameters in ISF.…”

Section: Introductionmentioning

confidence: 99%

Part accuracy improvement in two point incremental forming with a partial die using a model predictive control algorithm

Kearney

Wang

et al. 2017

Precision Engineering

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.Part accuracy improvement in two point incremental forming with a partial die using a model predictive control algorithm.Precision Engineering http://dx.doi.org/10. 1016/j.precisioneng.2017.02.006 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Research highlights: Flexible forming technologies are becoming increasingly significant with the rise of small batch and customised production in the market. work. The enhanced control algorithm is able to correct the toolpath in both the vertical and horizontal directions. In the newly-added horizontal control module, intensive profile points in the evenly distributed radial directions of the horizontal section were used to estimate the horizontal error distribution along the horizontal sectional profile during the forming process. The toolpath correction was performed through properly adjusting the toolpath in two directions based on the optimised toolpath parameters at each step. A case study for forming a non-axisymmetric shape was conducted to experimentally validate the developed toolpath correction strategy. Experiment results indicate that the two-directional toolpath correction approach contributes to part accuracy improvement in TPIF compared with the typical TPIF process that is without toolpath correction.

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Section: Introductionmentioning

confidence: 99%

Part accuracy improvement in two point incremental forming with a partial die using a model predictive control algorithm

Kearney

Wang

et al. 2017

Precision Engineering

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“…This method is also studied by Kopac and Campus (2005), Kim and Park (2003), Ceretti et al (2004), Micari et al (2007), Ham and Jeswiet (2007), Silva et al (2009) and Ambrogio et al (2009). Allwood et al (2009) designed a close-loop system by integrated a vision system into the CNC ISMF system. Callegari et al (2007) compared the advantages of ISMF forming method by using robot cells and CNC machines.…”

Section: Introductionmentioning

confidence: 99%

A New Rapid Prototyping Process for Sheet Metal Parts

Luo¹,

He²,

Du³

2011

Rapid Prototyping Technology - Principles and Functional Requirements

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“…Compared with previously reported control models for ISF [68,100,108] that were built based the measured process information from the forming process with no feedback control, the simplified MPC algorithm for SPIF uses an analytical predictive model built based on the incremental deformation nature of the SPIF process and can be directly applied for in-process toolpath control/correction. The experimental verification of the simplified MPC algorithm for SPIF provides experimental data for the toolpath control/correction in ISF.…”

Section: Thesis Contributionsmentioning

confidence: 99%

“…Based on the shape feedback, a simplified linear forming process model was firstly derived and then modified to tackle the "tool contact" issue and after that a full MPC formulation was established. In a contour Both Allwood's and Wang's control methods could lead to great accuracy improvement at the base of the formed shapes while the errors in the wall areas of the test shape were still relatively large.What's more, the error distribution map of the whole part, a significant indicator for fully evaluating the accuracy of the whole part, was not reported in these studies [68,100,108].Similarly, Han et al[109] developed a closed loop control model, shown in Figure 2-30, to compensate for springback and enhance the work piece precision. A closed loop algorithm of the trajectory profile for incremental sheet forming based on the wavelet transform combined with fast Fourier transform was constructed and a finite element method (FEM) was developed to simulate and correct the springback of incremental sheet forming.…”

mentioning

confidence: 99%

Investigation of control of the incremental forming processes

Lu¹

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Incremental Sheet Forming (ISF) is a new-emerging sheet forming process that promises high flexibility and formability because it does not need any dedicated dies or tooling. This makes ISF well suited for small scale and customised production. ISF uses a simple tool with a smooth end to deform sheets along a toolpath typically generated from CAM software. In ISF, the part is fabricated incrementally by orderly accumulation of plastic deformations localised around the ball end of the tool. Without using dedicated tooling, ISF can quickly adapt to new and modified product shapes via toolpath alteration. Hence, ISF is a promising sheet forming process for quick and low-cost production for small batch manufacturing. In spite of these outstanding characteristics, ISF still suffers from some drawbacks including long processing time and low geometric accuracy. The latter one is the major cause of low take-up of ISF in the forming industry. Therefore, the work presented in this thesis is mainly focused on the improvement of geometric accuracy of the formed parts via inprocess toolpath correction using feedback control. In this thesis, Model Predictive Control (MPC), an advanced model-based control technology, was adopted to develop feedback control strategies for ISF toolpath control and correction to improve geometric accuracy.The first research aspect of this thesis is focused on the development of a simple MPC algorithm to optimise the step depth, a critical toolpath parameter defined by the user in the toolpath generation.Firstly, a parameter investigation was performed to experimentally study the influences of the step depth on geometric accuracy, surface finish, and thickness distribution. Two sets of experimental tests with varying step depth values were conducted in the typical Single Point Incremental Forming (SPIF) process that is without toolpath control. The results showed that a smaller step depth led to better geometric accuracy and part surface quality in the ISF process, while the material formability decreased with the step depth value. Too small step depth values would lead to material failure. The parameter investigation work provided significant fundamental information for the development of feedback control strategies for toolpath correction. Then, a simple MPC algorithm was developed for in-process toolpath control/correction in SPIF. During the forming process using the simple MPC algorithm, the step depth of the contour toolpath was optimised at each forming step by solving a receding optimal problem based on the measured shape feedback during the forming process. The developed algorithm was experimentally verified in two case studies to form two different shapes.Results show that the geometric accuracy in ISF with feedback control has been greatly improved (from ±3 mm to ±0.3 mm) at the bottom area of the formed parts compared with a standard ISF approach without control. Improved geometric accuracy has been achieved on the wall of the parts as well, but the errors in the wall areas are...

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Closed-loop feedback control of product properties in flexible metal forming processes with mobile tools

Cited by 76 publications

References 9 publications

Part accuracy improvement in two point incremental forming with a partial die using a model predictive control algorithm

Part accuracy improvement in two point incremental forming with a partial die using a model predictive control algorithm

A New Rapid Prototyping Process for Sheet Metal Parts

Investigation of control of the incremental forming processes

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