LASERS IN LASYS 2018

Transcription

1 Thermal direct joining of metal to fiber reinforced thermoplastic components June 7th, 2018, Stuttgart P. Götze 1,3,A. Klotzbach 1, D. Lezock 2, J. Seitenglanz 2, M. Langer 1, F. Zimmermann 1, A. Jahn 1, J. Standfuß 1, E. Beyer 1, 3 1 Fraunhofer-Institut für Werkstoff- und Strahltechnik Dresden 2 Scherdel Marienberg GmbH 3 Technische Universität Dresden

2 Content Motivation Joining Process Part construction and design Proof of concept Spot-shaped joining with HPCI Conclusion Fraunhofer IWS Content

3 Motivation Motivation Using composites in car bodies? Material costs Production costs Integration to metal structure Trends: - local stiffening/ partial part exchange for model upscaling - hybridization BMW Task: Fast and efficient joining of thermoplastic composites with metal

4 Process chain Process chain Functionality, (load configuration) Environmental/ Economic aspects (weight savings) Function optimized part construction multi-material design Mechanical load simulation Proof of concept Joining techniques Joint configuration Input stress data Environmental tests Production technology

5 Joining process Thermal direct joining Thermoplastic or hot melt required Short term heating by laser or induction Combination of adhesion bond + mechanical interlocking Adhesive bonding + Strain and tolerance compensation - Adhesive application - Curing time Thermal direct joining + No additional material + Fast joining - Residual stresses - No tolerance compensation Pre-treatment of metal surface!

6 Laser structuring with brilliant cw fiber laser High speed laser scanning (v > 10 m/s) Ablation efficiency: > 2 kw laser power Ablation structure depends on composite mixture Function Surface extension Surface cleaning Chemical surface modification Form-fit structures & undercuts Fraunhofer IWS Joining process

7 Joining process Thermal direct joining Initial state Organosheet Metal Fraunhofer IWS Clamp & heat Cool & solidify

8 Joining process Thermal direct joining - summary Successful process development at coupon level Tensile strengths over 25 MPa Fast joining by laser and induction Strength decrease after 1000 h climate testing (up to 40%) Input data for FEM simulation process laser induction material heating [sec.] tensile strength [MPa] E AA > 23 E AA Composite: Tepex dynalite 102-RG600(x), 2 mm Metal: variable, 1.5 mm Pre-treatment: laser structuring Testing conditions: DIN EN 1465

9 Joining process Thermal direct joining by laser by induction laser spot diameter laser power joining pressure scanning modus heating time YLS2000-SM 5 mm 1 2 kw 0,25 10 N/mm² 2-dimensional 1-5 sec. Specimen for multiaxial testing Pancake inductor with concentrator and ceramic ram power up to 60 kw frequency khz coupling distance up to 5 mm joining pressure 0,25 6 N/mm²

10 Joining process

11 Joining process Thermal joining of slot tab joints Laser structuring of metal Laser heating of composite from two sides Mechanical forming with roll Combination of form-fit and adhesion Breaking forces up to 7000 N Input data for FEM simulation!

12 Part design Design and simulation of structural part Technology demonstrator: middle arm-rest Design change: Metallic weld structure metal-composite hybrid part Demonstration of developed joining processes Serial construction MAL Daimler BR205 (carrying structure) Design study 1 Outlook Design study 2 Further development

13 Part design Design study 1 A - A E355 Organo sheet Tepex dynalite 102-RG600(x) Laser welding E355 Thermal direct joining Slot tab joint organo sheet / E355 Mild steel (E355)

14 Proof of concept Proof of concept: Demonstrator fabrication Laser surface pre-treatment Thermal direct joining Part fixing 1 mm - Laser power: 1 kw 125 µm distance 150 µm depth 3 cycles Fraunhofer IWS - Dynamic beam forming - Laser power: 1 kw - Spot: appr. 5 mm

15 Proof of concept Multi-Remote Station MuReA Laser sources: 3 kw SM fiber laser 3.5 kw CO2 laser 650 w CO2 sealed-off laser Laser beam movement by: Scanner optics, up to 15 m/s XY table (1.5 x 1.5 m²), up to 100 m/min laser welding, heating, ablating Pre-treatment by laser and/or atmospheric pressure plasma Processing on the fly Fraunhofer IWS

16 Conclusion Part simulation model with realistic material and joint data was developed Successful evaluation for defined load conditions Thermal direct joining has potential for use in mass production (handling, process time, tolerances,...) Future demonstrator design (study 2) will provide 30% weight savings and an acceptable economic assessment Industrialisation concepts are under investigation Fraunhofer IWS Proof of concept

17 Heat-Press-Cool-Integrative (HPCI) Method and equipment for point-shaped joining of metal to thermoplastics Concept Local surface pre-treatment of metal parts Multi - heating Clamping and insitu heating of metallic joining partners Induction heating Local melting of thermoplastic matrix or hotmelt at the interface Cooling and declamping Laser-induced heating Process routine Clamp heat cool declamp

18

19 Modular joining gun HPCI Flange widths Clamping distance Clamping pressure Heating rate Tensile shear strength Joining time per point > 15 mm < 50 mm up to 10 N/mm² up to 500 K/sec. > 20 MPa GFPA6-E355/AW6082 < 1,5 sec. (E355) < 3,5 sec. (AW6082) Advantages State-of-the-art system technology Robot guided processing One-sided treatment Closed-loop processing Fraunhofer IWS Alu/CF-PEKK

20 Part of the work was supported by: BMBF project: LaserLeichter Development of laser based joining technologies for dissimilar lightweight constructions Annett Klotzbach Working Group Bonding and Composite Technology Phone Philipp Götze Working Group Bonding and Composite Technology Phone