MIKAEL BERG, KJELL JANSSON USE OF AREA-INTEGRATING LIGHT SCATTERING AND X-RAY FLUORESCENCE SPECTROSCOPY FOR SURFACE CONDITION MONITORING IN A MECHANOCHEMICAL SURFACE FINISHING PROCESS Tribology Days 2014, 15 – 16 October, Gothenburg. Applied Nano Surfaces (ANS) • Founded in 2008 as a spin-off from the Ångström Laboratory in Uppsala • Innovative and award winning technology • Clients ex: Volvo Powertrain, Scania, BMW, Daimler, Audi, Ford, GM, Chrysler, Mahle, and Gnutti Powertrain • Presence in Sweden (Uppsala HQ), Germany and USA Investors Awards 2 ANS Triboconditioning® Lowfriction TRIBO layer 3 Effect on the surface Original surface Triboconditioned surface Triboconditioning improves surface finish and produces a low-friction tribolayer in one machining operation 4 Surface topography 5 Tooling – for treatment of cylinder liners Feed Stroke Rotation 6 Technical results Ref: B. Zhmud, E. Tomanik, F.-A. Xavier, Lubrication Science 2013. Test conditions: 3.5 mm wide CrN PVD-coated ring Lubrication: 20 mL of SAE 30 oil; Load: 50 N; Stroke: 10 mm; Frequency: 25 - 375 min-1. • Significant friction and wear reduction when simulating boundary/mixed friction in a reciprocating rig test 7 QC techniques Requirements: • Robust • Fast • Suitable for use in shop floor Wanted information: • Surface roughness Contact methods - profilometers Non-contact methods - optical – Scattered light • Elemental composition – tungsten content – XRF equipment 8 Supplying the industry with test, control and measurement instrument METROLOGY NON-DESTRUCTIVE TESTING (NDT) MATERIAL TESTING Surface parameters Friction Surface friction is one of the most important characteristic of engineering surfaces. The profile slope angles have a strong impact on the friction behavior. Friction force F = FN ⋅ tanθ F = µ (H,G) ⋅ FN (Coulomb law) Material, Lubricant, Roughness A parameter which describes the profile slope is Rdq which is the mean square value of the profile angle distribution. Unfortunately Rdq is difficult to measure because the necessary differentiation of the profile is strongly impact by system noise. © OptoSurf GmbH 10 Scattering light principle Frequency φ φ=2∙δ δ For technical surfaces the angles of scattered light correlates very well with surface slope angles © OptoSurf GmbH 11 What is Aq? Η(ϕ) φ Ηi δ ϕi φ φ=2∙δ δ ( © OptoSurf GmbH ϕ (x) ) 12 OptoSurf – Real-time QA Output from measurements: • Surface roughness, Aq-value. • Waviness, Form • Intensity of reflected light. Features: • Machine process monitoring. • Robust use in shop floor. • Vibration insensitive. • Up to 2,000 measurements per second. • Process data capture to an SQL database. © OptoSurf GmbH 13 Measurement of Roundness, Waviness and Roughness © OptoSurf GmbH 14 OptoSurf – Result cylinder liner 40 mm Before treatment Profilometer measurements Aq 360° The roughness mapping shows a variation of the Aq-value between 30 and 55. Ra Rz Rk Rpk Rvk Untreated 0,40 4,59 0,53 0,27 1,70 Treated 0,17 2,72 0,29 0,09 0,79 40 mm After treatment Aq After the treatment the Aq-Values decrease to a very low level between 5 and 10. 360° 15 OptoSurf – Result Scania rollers Aq - value Before treatment • The Aq-value is around 40 for the untreated roller and around 10 for the treated roller. • The OptoSurf sensor can easily separate the treated from the untreated roller. • The surface of the treated roller appears to be smooth and even. After treatment 16 Handheld XRF X-ray fluorescence is the emission of characteristic “secondary” X-rays from a material. Advantages: • Relatively good sensitivity. • Suitable for quantitative analysis. • Doesn't need vacuum. • Rapid analysis – about 30 seconds. • All materials, even fluids. Disadvantages (for Triboconditioned surfaces): • Not always suitable for thin films, the signal of interest might be below the detection limit of the instrument. 17 XRF – During production trials 0,14 W-measurements on cylinder liners W - reading 0,12 0,10 0,08 0,06 0,04 0,02 0,00 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Component • The XRF-equipment was able to consistently identify tungsten on the treated cylinder liners from the production trials. • The distribution between the readings in the same series was relatively small. • The XRF-equipment was easy to use and seems to by suitable for process monitoring. 18 XRF – Treatment parameters W - reading Treatment time/W-presence • W-signal as a function of time gives logical values. 0,08 0,07 0,06 0,05 0,04 0,03 0,02 0,01 0 • W-signal as a function of load gives logical values. 0 1 2 3 4 Time [min] Treatment load/W-presence 0,16 W - reading 0,14 0,12 0,1 0,08 0,06 0,04 0,02 0 0 10 20 30 40 Load [% of maximum] 50 60 19 Conclusions OptoSurf • The OptoSurf sensor can easily separate treated from untreated components. Aq < x • The measurements are stabile and gives good results on different components made from different materials. XRF • The XRF-equipment can consistently identify the tungsten content in the tribofilm. W% > y • The values seems to be stable and follows logic. Together the two techniques seems suitable for monitoring the Triboconditioning process while in production. 20 THANK YOU! Mikael Berg, Development Engineer Phone: +46 70 461 40 53 Email: [email protected] Kjell Jansson, Application Engineer Phone: +46 70 636 99 92 Email: [email protected] QUESTIONS?