Textechno Testing Solutions for the Carbon Fibre Industry

Textechno Testing Solutions for the Carbon Fibre Industry Dr. Stefan Fliescher rethink Travelling Conference CFRP Recycling and Sustainability 1

About Textechno Herbert Stein GmbH & Co. KG Founded in 1949 in Mönchengladbach, Germany Family business, operating world-wide Since the 1960ies market- and technology leader in testing instruments for man-made fibres and yarns In 2004 Textechno founded Lenzing Instruments in Austria as specialist for online testing equipment Since 2010 additional focus on testing solutions for composite materials Founder: Herbert Stein Textechno s Headquarter in Germany 2 Lenzing Instruments in Austria

Textechno: 100% Made in Germany 3

FAVIMAT+ Single Fibre Testing Situation Precise determination of modulus and breaking stress of CFs is also possible on single filaments Requires precise determination of the cross-section per filament Microscopic determination of cross-section is time-consuming and cumbersome Vibroscopic head 4

FAVIMAT+ Single Fibre Testing Approach Integrate measurement of cross section and breaking force into one device: FAVIMAT+ Speed up the test with an automatic single-fibre feeding device: ROBOT 2 Use vibroscopic method to determine cross section Vibroscopic head 5

FAVIMAT+ Cross Section from Vibroscopic Method Search the resonance frequency f of the fibre Given a know tension F, gauge length L and density of the fibre ρ the cross section A is calculated as: Jaws of FAVIMAT+ A = F 4ρL 2 f 2 Vibroscopic head 6

FAVIMAT+ Determination of Modulus Example: 20 tested Carbon Fibres Force is translated to stress using the individual fibre cross sections Precise determination of modulus as derivative of the stress-elongation diagram Here: Modulus = 275 GPa 7

Fast Fibre Diameter Distribution: Situation Approach Diameter distribution is important e.g. to check homogeneity of rovings Regular microscopic determination is cumbersome and time-consuming Even with FAVIMAT+ limited statistics Cut fibres into short sections Dissolve and disperse in water Scan with microscopic camera and high-speed image analysis Equipment developed and produced in Australia Measures up to 20.000 fibres per minute Fast and easy to use 8

Fast Fibre Diameter Distribution: Example: Distribution within a CF roving Measured: 10000 fibres Mean diameter: 5.8 µm Approach Cut fibres into short sections Dissolve and disperse in water Scan with microscopic camera and high-speed image analysis Equipment developed and produced in Australia Measures up to 20.000 fibres per minute Fast and easy to use 9

FIMATEST: Fibre-Matrix Adhesion Testing A single CF composite: Epoxy matrix A single carbon fibre Performance of composites: Strongly depends on fibre-matrix adhesion, influenced by: surface structure sizing of the fibre the matrix material Macroscopic tests (e.g. ILSS) have limited precision due to large influence of the operator Up to now tests on micro-level are time consuming and not commercially available 10

FIMATEST: Fibre-Matrix Adhesion Testing A single CF composite: Epoxy matrix A single carbon fibre Approach: Pull-out tests based on single fibre composites have been researched at IPF Dresden for the past 20 years Pull-out most versatile of all micromechanical tests suited for all kinds of fibres and matrices Make microscopic pull-out test into a commercial system Cooperation with IPF Dresden and Faserinstitut Bremen (FIBRE) for knowledge transfer and automation Use FAVIMAT+ for pull-out tests AND cross-section AND tensile properties 11

FIMATEST: Fibre-Matrix Adhesion Testing FIMATEST consists of: The FIMABOND embedding station A pull-out testing device as accessory to FAVIMAT+ fibre-matrix adhesion and diameter, breaking strength, modulus of fibres Many important measurements for CF in one system 12 FIMATEST has won the JEC WORLD Innovation Award 2016

FIMATEST: Embedding Station FIMABOND Insert a fibre into the FIMABOND 13

FIMATEST: Embedding Station FIMABOND As seen by FIMABOND (time lapse) Matrix is placed in an aluminum crucible Freely-programmable heater (max. 400 C) Adjustable embedding speed and depth Inert atmosphere possible (flushing with nitrogen, argon etc.) Example: Embedding a fibre in PP 14 Melting Embedding Cooling

FIMATEST: Pull-out Test in FAVIMAT+ As seen by FAVIMAT+ Direct clamping of the fibre huge speed up in comparison to previous lab setup Measure the forcedisplacement curve using FAVIMAT+ s excellent force and path resolution (1µN, 0.1µm) 17

FIMATEST: Pull-out Test Evaluation Example: Pull-out from a epoxy resin F max F F d E. Mäder F b l e The FIMATEST analysis software automatically determines the relevant parameters from the force-displacement curve and calculates the sought-after τ d : 18 quantities τ f, τ app, τ d and G ic Local interfacial shear strength based on F d absolute measure of the fibre-to-matrix adhesion, independent from friction, corrected for deformation of fibre and matrix during the pull-out test

FIMATEST: Pull-out Test Evaluation Calculated parameters: Apparent interfacial shear strength..τ app [MPa] Local interfacial shear strength τ d [MPa] Interfacial frictional stress..τ f [MPa] Critical interfacial energy release rate... G ic [J/m 2 ] Meaning of the most important parameters: τ app : based on the maximum force F max. Good for a first relative comparison of the fibre-to-maxtrix adhesion (influence of fibre-to-matrix friction) τ d : based on the debonding force F d. Absolute measure of the fibre-to-matrix adhesion, independent from friction and corrected for deformation of fibre and matrix during the pull-out test G ic : Describes the energy required to debond the fibre per unit contact surface area. 19

DRAPETEST: Drapability Testing Situation: Defects in fabric structure occur in draping and forming and lead to bad performance of composite parts. Classical drapability testing as for textile applications is not suited for reinforcement fabrics Picture-frame test is used, but not standardized, not suited for other than 0/90 geometries, no automatic/objective detection of defects. Partners: SAERTEX, FIBRE Bremen, Schilgen Typical defects during draping: waviness undulations and loops gaps 20

DRAPETEST: Drapability Testing Approach: Cricular sample deformed by reference body Clamping mechanism with computer-controlled pressure holds back the sample Force to deform the sample is recorded Defects are detected and analyzed: Gaps, undulation, loops, waves, wrinkles Example: Gaps in a NCF DIN-SPEC 8100 established since November 2015 Project has been introduced to ISO committee 22

NOS 200: Fibre Orientation in Nonwovens Situation Strength of the nonwoven web is directly connected to the fibre orientation Fiber orientation along and across the machine direction is crucial indicator for strength, tenacity and working capacity of the nonwoven Demand for non-destructive and fast control of the MD-CD ratio Approach High-speed CCD camera and intense LED light combined with real-time image analysis Continuous online feedback about the present fibre orientation Constant quality level with minimum waste loss 23

STATIMAT 4U: Automatic Tensile Testing Situation Features Textechno is manufacturing automatic tensile tester for more than 50 years STATIMAT 4U latest evolutionary stage for high-tenacity materials Fully automatic tensile tests on up to 48 yarn ends / packages Linear-density range from 1 to 5000 tex Patented force-reduction cams Integrated twister for better force-distribution between the filaments Reliable and objective No user influence on results Sealed version and dust suction for save operation with carbon fibres 24

Summary Textechno s testing solutions for carbon fibres fibre yarn fabric composite Methods apply to both CF and rcf FIMATEST fibre-to-matrix adhesion FAVIMAT+ mechanical properties NOS 200 fibre orientation in nonwovens DIAMSCOPE diameter- and length distribution DRAPETEST drapability of fabrics STATIMAT 4U automatic tensile testing Textechno offers in house testing services 25

Textechno: 100% Made in Germany 26