New press deflection measuring methods for the creation of substitutive models for efficient die cambering

Sheet metal forming (SMF) simulations are traditionally carried out with rigid active forming surfaces. This means that the elasticity and dynamics of presses and die structures are ignored. The only geometries of the tools included in the simulations are the active forming surfaces. One reason for this simplification is the large amount of computational power that is required to solve finite element (FE) models that incorporates elastic stamping dies. Another reason is the lack of die CAD models before the later stages of stamping projects. Research during the last couple of decades indicated potential large benefits when including elastic dies in SMF simulations. For example, for simulating die try-out or for Digital Twins of presses and dies. Even though the need and potential benefits of elastic dies in simulations are well known it is not yet implemented on a wide scale. The main obstacles have been lacking data on presses and dies, long simulation times, and no standardized implementation in SMF software. This paper presents an overview of existing methods for SMF simulations with elastic dies and discuss their respective benefits and drawbacks. The survey of methods shows that simulation models with elastic tools will be needed for detailed analyses of forming operations and also for purposes like digital twins. On the other hand, simplified and robust models can be developed for non-FEA users to carry out simple one-step compensation of tool surfaces for virtual spotting purposes. The most promising and versatile method from the literature is selected, modified, and demonstrated for industrial sized dies.

Section: Methods For Smf Simulations With Elastic Diesmentioning

confidence: 99%

An overview of Methods for Simulating Sheet Metal Forming with Elastic Dies

Pilthammar,

Sigvant,

Islam

et al. 2023

“…Key parameters for assessing the process quality as well as for digitizing the tryout process entail the process force distribution and the elastic deflection of the tool clamping surfaces of press table and slide. In various research projects and works, solutions and methods to monitor the quality of formed components in production, during tool development and tryout have been developed and investigated [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…Alaluss et al [7] analyzed underlying interdependencies and mechanism of action. An assessment of the various sensors systems [2,3,[8][9][10] associated with tool clamping interfaces regarding different applications requirements (capability for inline monitoring, complexity, robustness, adaptability and state of development) is documented. Here, these sensor systems can be divided into three main groups depending on the mechanism of action and the target parameters:…”

Section: Introductionmentioning

confidence: 99%

“…• Sensor systems based on optical, fiber-optic or eddy current-based measurement sensors, which are arranged either on the rear sides of the clamping plates or in the T-slots of the press [3,8,9]: This measuring method promises high sensitivity concerning small process fluctuations, since components subjected to reaction forces are sensed. In addition, a local resolution of the deflection (and thus also of the acting force distribution) can be achieved.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Process Monitoring using Digital Twin-Based Sensors integrated in Tool Clamping Surfaces

Kurth

Alaluss

Wagner

et al. 2023

Process monitoring in forming technology can serve as a basis for transparent manufacturing and closed-loop control systems. Particularly, sensor systems associated with tool clamping interfaces offer great potential for robust inline process monitoring but are hardly investigated. In this paper, a concept to monitor a sheet metal forming process combined with a digital twin-based approach for virtual sensors is introduced. Here, sensors integrated into the T-slots of tool clamping surfaces in forming machines are enhanced by a mathematical representation of the elasto-mechanical behavior of the tool clamping interfaces. Moreover, the potential of the certain sensor system for inline process monitoring is highlighted. The resulting approach is substantiated by simulative analysis and by experimental investigation.

“…The objective is automation of the stamping die spotting process and stamping optimising contact patterns for the forming surfaces. Research efforts have also been aimed at developing measurement technology to detect stamping press deflections, both portable solutions and imbedded sensors in the presses [7]. The deflection strain has been measured by optical fibers with Fiber Bragg Gratings (FBG).…”

Section: Introductionmentioning

confidence: 99%

Substitutive models of press deflections for efficient numerical die cambering

Ottosson

Pilthammar

Wiklund

et al. 2023

Cost and time for stamping die tryouts are significant within the car industry. A major contributing factor is that elastic deflections of stamping dies and presses are usually not considered during the virtual die design and forming simulation phase. Active surfaces of stamping dies are only cambered based on previous experiences of tool types and stamping presses. However, almost all stamping dies and presses are unique, and available experiences are not valid for new sheet materials. This leads to component deviations and often several loops of tool adjustments are needed. Previously partners within the SMART Advanced Manufacturing research project CAMBER have developed advanced deflection measuring devices to quantify the elastic deformations of stamping presses. Using these measurements, cambering methodologies can be utilized in sheet metal forming simulations. In this paper numerical substitutive stamping press models are described which are capable of compensating for measured stamping press dynamics. The result show that a numerical compensated tool can improve the contact by over 80% compared to the corresponding contact without compensation.