inspection for texture and lead in dynamic sealing systems · 2016. 2. 25. · afm confocal, wli,...

Inspection for Texture and Lead in Dynamic Sealing Systems

Agenda

• Introduction• Bruker, BNANO Group

• 3D Metrology, Engineered Surfaces• Overview, Intro to 3D WLI• Application to sealing surface metrology

• Summary/Questions

Introduction - BNANO GroupServing a Wide Range of Analytical Instrument Needs

• Academic / Government Research• Material science

• Life science

• Industrial Materials Research• Metals / Ceramics

• Polymers / Composites

• Electronic materials

• Microelectronics• Semiconductor wafer

• Semiconductor packaging

• Display

• Data storage

• Green Technology• HBLED

• Solar

• Battery

• Heavy Industries Processing• Metals processing /

refractories

• Cement

• Metal scrap

• Materials finishing• Metals finishing

• Polymer coatings

• Minerals / Mining / Petrochem

• Medical Materials

• Pharmaceutical

BNANO is a part of Bruker

Bruker headquarters in Billerica, Massachusetts, USA

~$1.7B Revenues, 80% outside US

IntroductionSpeaker

Matt Novak, Ph.D.Director, ApplicationsTribology, Stylus and Optical Metrology, [email protected]

Agenda




Overview, Various InspectionsEngineered surfaces - wide range of requirementsWide range of measurement technologies

nano-meter micro-meter milli-meter centi-meter meter

Surface Finish Waviness Shape and Form

AFM Confocal, WLI, etc. CMMStylus Fringe Projection,Photogrammetry,

Lidar, Laser Scanning, etc.

Very fine scale Mid-range scale Large scale“2.5 D” True 3D

SEM, Spectroscopy, other methods as well

• Microscope with special objectives used to create images + height map

Interference-Based Optical ProfilerAccurate Local (X,Y) + Z Images Texture (including Lead) Well Resolved

Coherence Scanning/Vertical Scanning Interferometry

Interference signal functions as a focus sensorResolution of height is independent of magnification/FOV

VSI

3D Optical Profiler – Image + HeightImaging Example

Stepped Surface

~ 40 µm

~ -110 µm

~ 150 µm range

Images traditionally displayed as a color look up table (e.g., red high, blue low)

…or displayed in grayscale to look like SEM as well

3D Optical Profiler Surface ImagingVarious Display Options

Can provide enhanced images showing varioussurface texture differences or defects

3D Optical Profiler Surface ImagingVarious Display Options

Agenda




Functional Sealing SystemsMany Inputs, Complex Interactions

Seal, Shaft Materials

Dynamic Sealing System

Operating Conditions

Assembly, Alignment

Manufacturing Process, Surface Finish

Additives, Lubricants

Manufacturing Process, Surface Finish

Machining Influence on TextureExamples of 3D Areal Images – NB Directionality

• Flat lapping/Reaming • Grinding

• Horizontal Milling

• Vertical Milling

• Turning

3D Image of Journal Sealing SurfaceShows micro-structural nature of surface

Cylinder stitch showing sealgroove ~ 4 µm depth and microstructures on the overall surface

Wide area, high resolution images are obtained with 3D optical profiling - enable detailed study of surfaces

Industry Case StudyWhat Differentiates Sealing System Function, Accounts for Performance Change?

• Six shafts (sealing journal surfaces), used in dynamic application

• Bruker approached (independently) by system end-user and shaft manufacturer/supplier – (initially regarding shaft lead)

• Two of six systems fail initial functional test (fixed temperature, pressure, sealed fluid test)

Grinding Process A

Grinding Process B

Controls Made for All InputsWhat About Shaft Surfacing, Resulting Finish?

• Process control cannot always guarantee functional differences• What about resulting surface finish (given other controls)?

Shaft Texture PreparationImportant to Function of Sealing Systems

• Burr, pore, scratch/ defect free surfaces

• Ra, Rz, Rpm of surface play a part

• Good topography, non-oriented lead (zero lead)

• Good concentricity of shaft to seal housing

Detail: RSS Tech Manual – Freudenberg-NOK Sealing Technologies

• Standard 2D texture, 3D Areal Parameter Analyses• … per ISO (4287/4288 or 25178-2) standards

• Variety of parameters (height, spatial, functional, hybrid)

• Micro lead analysis capability• Bruker-designed algorithm, non-contact lead

angle measurement of rotary shaft surfaces

• Macro twist analysis per MBN 37001-7• Licensed algorithm to compute macro lead per

MBN 31007-7 standard

Shaft Surface TextureComputations Made for Comparison using 3D WLI

Shaft Surface Texture: S Parameters2D and 3D Data Collection

• 2D Example: 20mm scan = 2.5 minutes = 500pts; 40um resolution

• 3D: 20mm scan = 2.5 minutes = 9,900,000pts; 7.92um resolution

Ra = 0.262 micron

Rz = 1.689 micron

Rp = 0.813 micron

Ra = 0.265 micron

Rz = 1.668 micron

Rp = 0.801 micron

Ra Rz Rp

Sample A – 2D Cross Section from 3D data

Sample A – Industrial Stylus

Shaft Surface TextureCorrelation Non-Contact/Contact MetrologyProper Sampling and Filtering are Key!

3Di view ofmicro lead angle

Shaft Surface Texture Surface Lead, Lead Angle, or Twist (Drall)

Bruker Nano Surfaces Division- Stylus and Optical Metrology

“Macro” vs. “Micro” Lead

Macro lead: Here this means periodic features imparted to sealing surface due to machining

preparation – if too deep or prevalent, seal mayleak right away

Micro lead: Aperiodic, main feature is a perpendicularity variation with respect to the shaft axis - seal will possibly leak in longer timeframe

What is Lead Angle?A word on Macro vs. Micro Lead…

Zero Lead AngleDid Not Explain System Functional Test Difference

Surface Texture, GeometryRoughness, Form Don’t Explain System Functional Test Difference

All shafts in spec for form and surface roughness per drawings

Rz 2.7 um Ra ~ 300 nm

Shaft- UnwornSa 368nm

Sds 1130 /mm2

Ssc 49 mm-1 (radii 20m)

Sa 769 nm

Sds 247 /mm2

Ssc 6 mm-1 (radii 166 m)

Shaft- worn600 m

Shaft Surface Texture: S ParametersSds, Ssc other indicators of function

S Parameter - Skewness

Skewness – Are peaks or valleys predominant?

Surface with positive Ssk – peaks predominant

Ssk Over Wide Area ImagesBrings Insight…

A1 A2 A3 A4 B1 B2

• B2 shaft micro lead higher than others..

• Possible benefit - reverse pumping, preventing leak

• If too powerful, debris/grit may be pulled into sealing region (problematic)

Agenda




Summary

• Introduced Bruker, Bruker Nano Group, TSOM

• Introduced 3D white light interference based optical microscope (optical profiler)

• Showed utility of 3D WLI system for lead and texture metrology – problem resolution• Industry case study - dynamic functional sealing system

• Macro / Micro lead angle alone cannot explain performance • Interaction between measured parameters – insight to

performance • 3D data are very useful for gaining broad insights to surface

inspection for texture and lead in dynamic sealing systems · 2016. 2. 25. · afm confocal, wli,...

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