MODEL-BASED DESIGN OF SELF-CORRECTING FORMING PROCESSES

Transcription

1 MODEL-BASED DESIGN OF SELF-CORRECTING FORMING PROCESSES M. Krüger, M. Borzykh, W. Schaermann Chair of Forming and Machining Technology University of Paderborn Sheet 1

2 Project Group Mechatronic Systems Design Fraunhofer Project Group Mechatronic Systems Design Project Group of Fraunhofer Institute for Production Technology Start in March employees Competences Product engineering Control engineering Software engineering Sheet 2

3 it s owl one of 15 Leading-Edge Clusters in Germany Aviation Cluster Hamburg Intelligent Technical Systems OstWestfalenLippe (it s OWL) Efficiency Cluster Logistics Ruhr BioEconomy Cluster Software Cluster Cool Silicon Saxony Cluster Individual Immunintervention CI3 Biotech-Cluster Rhein-Neckar BioRN Solarvalley Mitteldeutschland Medical Valley EMN Forum Organic Electronics Munich Biotech Cluster m4 MicroTec South-West Sheet 3 Electric Mobility South-West MAI Carbon

4 Leading-Edge Cluster it s owl Innovation Leap Towards Technical Systems with Inherent Partial Intelligence Mechanics Mechatronics Intelligent Systems Intelligent Networks Industry 4.0 Self-Optimization Cyber-Physical Systems Sheet 4

5 Introduction Manufacturing of metal parts for the electrical connection technology Punch-bending machine with NC servo drives Source: Bihler Source: Bihler Reference dimension: opening Source: Weidmüller Sheet 5

6 Introduction Challenges of punch-bending Geometrical deviations appear during manufacturing leading to high scrap rate long setup time time consuming interruptions of the process for setting new process parameters Trend in the electrical-connection technology moves towards decreasing part size tighter tolerances use of high-strength materials Self-Correcting punch-bending tool Model-based Analysis Design closed-loop control Realize Self- Correction Sheet 6

7 MODEL-BASED DESIGN OF SELF-CORRECTING FORMING PROCESSES 1. Introduction 2. Modeling of Forming Processes 3. Feedback Control and Implementation 4. Conclusion Sheet 7

8 Machine- and Technology Models Dynamical behavior Thermal effects driving motors Machine Technology models Control / Automation Architecture Control strategy Interfaces Process Interaction tool / workpiece Measurement technology Sheet 8

9 Modeling of bending process Punch Bending Process F Work Piece F Clamp Requirements for the model System dynamics Elastic-plastic deformation Implementation of control architecture FEM-simulation possible but has long computational period and is expensive to create and/or change Die Reduction of model complexity Build up in RecurDyn Media Transport Toolkit 2D (MTT2D) Sheet 9

10 Modeling of bending process Multi-Body-System Model of the work piece Damper M pl Torsion spring Element Fixed bearing Work piece is built up as a chain of (n) sheet-bodies Sheet-bodies are connected by a spring-damper system Representation of elastic material behavior Stiffness corresponds to material constants Implement the plastic deformation as external axial torque M pl Torque of plastic deformation Sheet 10

11 Modeling of plastic deformation Bending theory after Ludwig which depends on: Angle between two sheet-bodies Stress-strain curve Profile geometry s plastic deformation elastic deformation e Sheet 11

12 Modeling of bending process Result Sheet 12

13 MODEL-BASED DESIGN OF SELF-CORRECTING FORMING PROCESSES 1. Introduction 2. Modeling of Forming Processes 3. Feedback Control and Implementation 4. Conclusion Sheet 13

14 y plast, mm Self-correcting Strategy General idea Due to the manufacturing process and results of model-based analysis, the following information will be used: changes in material from the current work piece geometrical deviation of the prior work piece Current part Material properties Computing correction factor y Plast von y Richtstempels nach dem Kontakt y Prior part Deviation Richtstempelposition, mm Corrective Action Sheet 14

15 Self-correcting strategy Implementation Closed-loop control for corrective action in runtime is realized by: discrete I-controller for opening dimension measured by prior part Consideration of the change of thickness by measuring the force on the punch Simulation results: Leaving of tolerances is avoided Zero defects tendency Quality is increased Sheet 15

16 Experimental Tool & Measurement Devices Experimental tool is installed on universal testing machine Zwick Z020, max force 20 kn Bending punch Clamping Bending Punch 1 Side mounted auxiliary punch Bending Punch 2 Workpiece Sheet 16

17 Experimental Tool & Measurement Devices Setup of optical measurement method Flat LED-backlight Objective lens with bellows CCD-sensor Objective LED Workpiece B A Measurement object CCD-sensor: Length: 29 mm with 2088 pixels Pixel size: mm Measurement accuracy: 0.02 mm Bellows Evaluation electronic for the CCD-sensor Measurement device installed on the experimental tool Sheet 17

18 Opening dimension [mm] Opening dimension [mm] Results 0, , , ,2 0-0,2-0, , , , , ,4 Upper tolerance Lower tolerance 1 Opening dimension in uncontrolled process Current opening dimension Nominal opening dimension Opening dimension in controlled process Upper tolerance Current opening dimension Lower tolerance Part number Nominal opening dimension Part number Sheet 18

19 MODEL-BASED DESIGN OF SELF-CORRECTING FORMING PROCESSES 1. Introduction 2. Modeling of Forming Processes 3. Feedback Control and Implementation 4. Conclusion Sheet 19

20 Conclusion MBS-model for bending process Elastic & plastic deformation Feedback control to realize self correction decreasing geometrically deviations Outlook Transfer self-correction approach to other processes (e.g. roll forming) different modeling approach? increase robustness / usability Self-correction for high production rates Sheet 20