smartWLI Cylinder Inspector 3D

Non-contact measurement of the cylinder surface based on white light interferometry.

Now with higher resolution and high-speed camera to scan more details in shorter time - Designed for the control of inner cylinder surfaces for the automotive industry.


  • Massive parallel data processing on GPU's
  • Extreme fast scanning
  • Real time 3D evaluation
  • Optimized for steep structures
  • Integrated data quality parameter for sample optimized  filtering processes

Single objectives

  • manual exchangeable
  • magnifications from 2.5x to 100x

Push button scan and evaluation macros using SmartVis 3D as system - and Mountains Map as evaluation software

Simplifies handling

  • 360° rotation
  • manual insertion axis
  • optional motorized insertions axis with automated stitching


PDF icon smartWLI Cylinder Inspector Brochure346.32 KB
Intention of the cylinder inspection

Lapping/structuring of inner cylinder running surfaces

  • Structures have an essential influence on the friction:
    • the oil retaining volume is essential for the necessary lubrication of the friction partner piston and cylinder surface
    • smooth contact areas reduce the wear and friction special on lower revolution speed
    • pores can reduce the oil consumption still providing the necessary oil retaining volume for the lubrication of the friction partners
    • honing structures - angle, furrows... have a big influence on the oil transport and the hydrodynamic lubrication
  • the optimization of the structures can reduce the consumption of engines as well as extend the live time
  • there are various positive effects as reduction of the environmental pollution and reduction of the  operation costs - this increase  the value of cars and has a significant impact on purchase decisions

 Typical operation areas of the Cylinder Inspector 3D

  • Research and development
    • Optimization of production processes
    • Assessment of functional behaviour on basis of the 3D structures without extended tests
    • Wear evaluation after running tests
  • Quality control
    • Survey of production processes
    • Optimization of tool exchanges ... in the production
Areas of applications
  • 3D inspection of cylinder surface and cylindrical honing structures
  • Comprehensive geometric analysis (lengths, angles, heights & depths, volume, etc.)
  • 2D roughness and waviness analysis of components (accord. ISO 16610, 13565, 12085)
  • 3D parameters according to ISO 25178 (roughness, functional characteristics: bearing ratio and volume)
  • Optimized for use in the development, manufacturing and quality assurance
  • Optional software upgrade can add pore analysis
Modern technologies require a detailed quality control

There are many competitive technologies used, new on the market or under development. All technologies have several production steps and adapted quality control.

Aluminum engine blocks

  • Monolithic
    • Hypereutectic Al-Si Alloy
  • Quasi-monolithic Coated Bores
    • Galvanic Ni-Sic dispersion
    • Plasma coating
    • PVD thin layer, TiN, TiAlN
  • Quasi monolithic local material engineering
    • Al matrix compound
    • Laser Alloying with Si
  • Heterogenous-liner Dry cast-in
    • Grey iron machined
    • AlSi/PM
    • Grey iron as cast with rough outer surface
    • Grey iron coated
    • Plasma sprayed
  • Heterogenous-liner Dry pressed-in
    • Grey iron
    • Hypereutectic Al-Si
    • AlSi/PM
  • Heterogenous-liner wet slip-in
    • Galvanic Ni-Sic dispersion
Evaluation parameters for inner cylinder running surfaces

Structure Evaluation

Honing structures

  • Honing angle
  • Honing grooves
    • directional classification (rising, falling, across..)
    • numbers, depth, area, volume
    • Distance between groove
    • Cross grooves


  • Contact roughness

Cavities / Pores

  • numbers / distances
  • volume
  • area
  • depth
  • distribution of cavities (according volume, area and depth)


  • % over surrounding surfaces

Surface roughness

Functional 2D parameters

  • Rk, Rpk, Rvk

Functional 3D parameters

  • Sk, Spk, Svk


Different surfaces and a wide range of priorities for measurements

Technologies get optimized in the same directions:

  • lower friction
  • wear resistance
  • lower oil consumption
  • weight reduction

...but measuring devices are used for different purposes


  • detailed analysis for technology optimization

Quality control:

  • fast survey of predetermined parameters
  • different priorities for the used technology
Scans with various magnifications

More structures per scan - More details from each structure

2,5 x - 10x, 50x magnifications
5 x - 20x, 100x magnifications
Sample: many cavities but not enough details of honing structures

FOV: 7,2 X 4,5 mm2
time: <10s
z-res: 1 nm
xy-res: 3,5 um

Larger honing structures are still visible but the point density of 3,5 um isn't enough to evaluate small structures starting from app. 10 um. Using of an higher point density is recommended

Partial area of a single scan using the 2.5x Objective
Sample: many details but only a single (large) groove inside

FOV: 0,28 x 0.21 mm2
time: <10s
z-res: 1 nm
xy-res: 0,2 um

All details are very good visible, but the significance from single structures for the rating of complete cylinder liners is very limited. Larger areas are recommended.

Single scan using the 50x objective
Sample: local variation of cavities, multiple scans necessary

FOV: 7,2 x 4,5 mm2
time: <10s
z-res: 1 nm
xy-res: 3,5 um

the cavities show a local variation of areas with higher and lower densities. It is recommended to use multiple evaluation fields. In addition to the average it is recommended to check the local variation of the cavities in different positions.

Local variation of cavities
Recommendation for the correct field of view

Check the table here below to select the correct system configuration:

  • min. 10x higher resoluzion in xyz than the feature which sould be measured
  • min. 10 evaluation features inside the scanning area
  • min. 10 measuring positions for statistical analysis
FeaturesParametersReality* SeizeReality* DepthReality* DensityRSP** - xy res.RSP** - z res.RSP** - area
cavitiesarea500 um2> 1 um10 / mm2< 2 um< 100 nm> 1 mm2
honingdepth10 um0,1 um>1 / mm< 1 um< 10 nm> 1 mm2
marblingarea %0,01 mm20,1 um10 / mm2< 1 um< 10 nm> 1 mm2
plateaus - peaksSpk / Rpk0,01 mm220 nm100 / mm2< 1 um< 2 nm> 0,1 mm2
* These parameters typically are subject to individual adaptation ** Required System parameter The 10x Objective can fulfill all the requirements - Several scans from differen positions are necessary for significant and trustworthy evaluation
Robust form filtering

Robust filters (polynomial, gaussian, and combinations) are the basis for all the following evaluation processes. "Robust" are filters which eliminate the influence of cavities and avoid local waves on the filtered surface.

Cylinder Surface
Filtered surface (z-range reduced)
Surface without marked cavities
Robust filtered surface (z-range reduced)
Structure separation

Structure characteristics (directional orientation, depth, height, size) can be used to separate the structures from each other and evaluate them separately.

Superficie del cilindro con filtro robusto
Superficie levigata
Honing Structure FFT Analysis

The GBS programmed Honing Structure FFT Analysis allowed a separate analysis of rising and falling structures. The sample on the right shows a higher percentage of closed structures because of the cavities (positive) but also more cross structures. The scan on the left side shows more falling structures and on the right side more rising structures.

Honing Structure FFT Analysis - Samples
Key cavities

Separated cavities could be counted and statistically evaluated.

Many classificatory operators - as depth, volume, form factors, etc.. -  can be used to analyze many partial aspects from the cavities.

Key cavities
Cumulative volume distribution
Cumulative area distribution
Key aspect "marbling"

Marbling - The camera image shows a texture as could be seen on marble surfaces. the black lines are cracks in the surface. Inner tensions could cause that surface plateaus standing out of the surrounding areas.

Photorealistic 3D plot
Grey coded 3D plot
Key aspect - Marbling

Areas which are standing up can be detected and evaluated.

Technical Features

Technical Product Specification
smartWLI Cylinder Inspector 3D
Cylinder Diameter70 - 125 mm (standard configuration)
Measurement TechniqueWhite-Light Interferometry
Height resolution / nm1nm (all objectives / field of view)
ScannerPrecision piezo drive with gauge control
Scan Range 200 um
Speedup to 20 um/s
System SoftwaresmartVIS 3D / Speedytec on GPU
Evaluation softwareMountains Map with GBS programmed extensions
Array1624 x 1324 measuring points
Weight12-14 Kg
Power Supply100 to 240 VAC, 50/60 Hz
Optional Configuration
Insertion System
StandardManual down to app. 188 mm
ExtendedManual down to app. 270 mm
MotorizedAutomated z axis down to app. 200 mm
Optical configuration
Field of view / mm2.8 x 2.081.4 x 1.040.7 x 0.520.28 x 0.21
Point Distance / um1.

Application Fields