Closed-loop control of product properties in metal forming: A review and prospectus

A Hybrid Data-Based and Model-Based Approach to Process Monitoring and Control in Sheet Metal Forming

“…Process control, in simple terms, is the activity of regulating a process using an automated control system based on process measurements. Several publications have reviewed the state of the art in the advancements of a manufacturing process control at a generic level spanning multiple process control techniques [17,18,28] or within specific application areas [6,29]. Part quality and dimensional integrity are two important factors governing the productivity of machine tools especially in high-speed regimes [17,28] and, hence, several strategies for control of servo-systems, estimating contour error, tool path profile planning, feed-rate scheduling for cycle time optimization, tool condition monitoring, and overall productivity optimization have been developed [17].…”

“…The sheet metal forming (SMF) process involves non-stationary conditions and complicated phenomena such as non-linearities, temperature variation, batch-to-batch fluctuations in material properties, and complex product geometries, which makes it challenging to achieve desired product specifications and ensure process performance [1][2][3][4][5]. Due to the high tooling costs associated with SMF, justified by large-volume and efficient production runs, product quality control is of high importance [6]. Timely detection, diagnosis (identification of root-cause), and correction of a fault are paramount to enhance process performance, which leads to improved product quality and reduced production costs.…”

“…Although these approaches have gained significant popularity within sophisticated manufacturing processes such as in semiconductor production or chemical plants, their potential within other manufacturing domains such as metal forming remains underexploited [18]. Most control approaches within metal forming aim to control and optimize machine parameter settings instead of the product properties, which is usually the property of interest for the end customer [6,19]. Furthermore, the control actions in such approaches are generally based on either offline models or online process models, which involve several approximations to be computationally feasible [19].…”

Numerical Comparison of Three Different Feedback Control Schemes Applied on a Forming Operation

“…One approach to reduce the scrap rate is introducing an in-process feedback control. Polyblank et.al gives an extensive review of the area covering more than two decades of research activities, within the field of feedback control applied on various metal-forming processes [9]. In the current paper the plant (model of the control system) is based on a finite element model and the feedback constants (gain factors) are identified solving a non-linear optimal control problem.…”

Model-based control of strip bending in mass production

“…Closed-loop control is widely used to ensure the robustness of the production processes, but is hardly used to control the state of the product itself. That is, metal forming machines are controlled to accurately perform a certain task, such as to follow a certain ''tool-path'', but fail to control the actual production target: the desired final properties of the product (such as geometry, residual stresses or surface quality) [1].…”