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Category: Profilometry | Volume and Area

 

Styrofoam Surface Boundary Measurement Profilometry

Surface Boundary Measurement

Surface Boundary Measurement Using 3D Profilometry

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SURFACE BOUNDARY MEASUREMENT

USING 3D PROFILOMETRY

Prepared by

Craig Leising

INTRODUCTION

In studies where the interface of surface features, patterns, shapes etc., are being evaluated for orientation, it will be useful to quickly identify areas of interest over the entire profile of measurement. By segmenting a surface into significant areas the user can quickly evaluate boundaries, peaks, pits, areas, volumes and many others to understand their functional role in the entire surface profile under study. For example, like that of a grain boundary imaging of metals, the importance of analysis is the interface of many structures and their overall orientation. By understanding each area of interest defects and or abnormalities within the overall area can be identified. Although grain boundary imaging is typically studied at a range surpassing Profilometer capability, and is only 2D image analysis, it is a helpful reference to illustrate the concept of what will be shown here on a larger scale along with 3D surface measurement advantages.

IMPORTANCE OF 3D NON CONTACT PROFILOMETER FOR SURFACE SEPARATION STUDY

Unlike other techniques such as touch probes or interferometry, the 3D Non Contact Profilometer, using axial chromatism, can measure nearly any surface, sample sizes can vary widely due to open staging and there is no sample preparation needed. Nano through macro range is obtained during surface profile measurement with zero influence from sample reflectivity or absorption, has advanced ability to measure high surface angles and there is no software manipulation of results. Easily measure any material: transparent, opaque, specular, diffusive, polished, rough etc. The technique of the Non Contact Profilometer provides an ideal, broad and user friendly capability to maximize surface studies when surface boundary analysis will be needed; along with the benefits of combined 2D & 3D capability.

MEASUREMENT OBJECTIVE

In this application the Nanovea ST400 Profilometer is used to measure the surface area of Styrofoam. Boundaries were established by combining a reflected intensity file along with the topography, which are simultaneously acquired using the NANOVEA ST400. This data was then used to calculate different shape and size information of each Styrofoam “grain”.

NANOVEA

ST400

RESULTS & DISCUSSION: 2D Surface Boundary Measurement

Topography image(below left) masked by reflected intensity image(below right) to clearly define grain boundaries. All grains below 565µm diameter have been ignored by applying filter.

Total number of grains: 167
Total projected area occupied by the grains: 166.917 mm² (64.5962 %)
Total projected area occupied by boundaries: (35.4038 %)
Density of grains: 0.646285 grains / mm2

Area = 0.999500 mm² +/- 0.491846 mm²
Perimeter = 9114.15 µm +/- 4570.38 µm
Equivalent diameter = 1098.61 µm +/- 256.235 µm
Mean diameter = 945.373 µm +/- 248.344 µm
Min diameter = 675.898 µm +/- 246.850 µm
Max diameter = 1312.43 µm +/- 295.258 µm

RESULTS & DISCUSSION: 3D Surface Boundary Measurement

By using the 3D topography data obtained, the volume, height, peak, aspect ratio and general shape information can be analyzed on each grain. Total 3D area occupied: 2.525mm3

CONCLUSION

In this application, we have shown how the NANOVEA 3D Non Contact Profilometer can precisely characterize the surface of Styrofoam. Statistical information can be gained over the entire surface of interest or on individual grains, whether they are peaks or pits. In this example all grains larger than a user defined size were used to show the area, perimeter, diameter and height. The features shown here can be critical to research and quality control of natural and pre fabricated surfaces ranging from bio medical to micromachining applications along with many others. 

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Contour Measurement using Profilometer by NANOVEA

Rubber Tread Contour Measurement

Rubber Tread Contour Measurement

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RUBBER TREAD CONTOUR MEASUREMENT

USING 3D OPTICAL PROFILER

Rubber Tread Contour Measurement - NANOVEA Profiler

Prepared by

ANDREA HERRMANN

INTRODUCTION

Like all materials, rubber’s coefficient of friction is related in part to its surface roughness. In vehicle tire applications, traction with the road is very important. Surface roughness and the tire’s treads both play a role in this. In this study, the rubber surface and tread’s roughness and dimensions are analyzed.

* THE SAMPLE

IMPORTANCE

OF 3D NON-CONTACT PROFILOMETRY

FOR RUBBER STUDIES

Unlike other techniques such as touch probes or interferometry, NANOVEA’s 3D Non-Contact Optical Profilers use axial chromatism to measure nearly any surface. 

The Profiler system’s open staging allows for a wide variety of sample sizes and requires zero sample preparation. Nano through macro range features can be detected during a single scan with zero influence from sample reflectivity or absorption. Plus, these profilers have the advanced ability to measure high surface angles without requiring software manipulation of results.

Easily measure any material: transparent, opaque, specular, diffusive, polished, rough etc. The measurement technique of the NANOVEA 3D Non-Contact Profilers provides an ideal, broad and user friendly capability to maximize surface studies along with the benefits of combined 2D & 3D capability.

MEASUREMENT OBJECTIVE

In this application, we showcase the NANOVEA ST400, a 3D Non-Contact Optical Profiler measuring the surface and treads of a rubber tire.

A sample surface area large enough to represent the entire tire surface was selected at random for this study. 

To quantify the rubber’s characteristics, we used the NANOVEA Ultra 3D analysis software to measure the contour dimensions, depth, roughness and developed area of the surface.

NANOVEA

ST400

ANALYSIS: TIRE TREAD

The 3D View and False Color View of the treads show the value of mapping 3D surface designs. It provides users a straightforward tool to directly observe the size and shape of the treads from different angles. The Advanced Contour Analysis and Step Height Analysis are both extremely powerful tools for measuring precise dimensions of sample shapes and design

ADVANCED CONTOUR ANALYSIS

STEP HEIGHT ANALYSIS

ANALYSIS: RUBBER SURFACE

The rubber surface can be quantified in numerous ways using built-in software tools as shown in the following figures as examples. It can be observed that the surface roughness is 2.688 μm, and the developed area vs. projected area is 9.410 mm² vs. 8.997 mm². This information allows us to examine the relationship between surface finish and the traction of different rubber formulations or even rubber with varying degrees of surface wear.

CONCLUSION

In this application, we have shown how the NANOVEA 3D Non-Contact Optical Profiler can precisely characterize the surface roughness and tread dimensions of rubber.

The data shows a surface roughness of 2.69 ­µm and a developed area of 9.41 mm² with a projected area of 9 mm². Various dimensions and radii of the rubber treads were measured as well.

The information presented in this study can be used to compare the performance of rubber tires with di­fferent tread designs, formulations, or varying degrees of wear. The data shown here represents only a portion of the calculations available in the Ultra 3D analysis software.

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Fish Scale Surface Analysis Using 3D Optical Profiler

Fish Scale Surface Analysis Using 3D Optical Profiler

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FISH SCALE SURFACE ANALYSIS

using 3D OPTICAL PROFILER

Fish Scales profilometer

Prepared by

Andrea Novitsky

INTRODUCTION

The morphology, patterns, and other features of a fish scale are studied using the NANOVEA 3D Non-Contact Optical Profiler. The delicate nature of this biological sample along with its very small and high angled grooves also highlights the importance of the profiler’s non-contact technique. The grooves on the scale are called circuli, and can be studied to estimate the age of the fish, and even distinguish periods of different rates of growth, similar to the rings of a tree. This is very important information for the management of wild fish populations in order to prevent overfishing.

Importance of 3D Non-Contact Profilometry FOR BIOLOGICAL STUDIES

Unlike other techniques such as touch probes or interferometry, the 3D Non-Contact Optical Profiler, using axial chromatism, can measure nearly any surface. Sample sizes can vary widely due to open staging and there is no sample preparation needed. Nano through macro range features are obtained during a surface profile measurement with zero influence from sample reflectivity or absorption. The instrument provides an advanced ability to measure high surface angles with no software manipulation of the results. Any material can be easily measured, whether it’s transparent, opaque, specular, diffusive, polished or rough. The technique provides an ideal, broad and user friendly capability to maximize surface studies along with the benefits of combined 2D & 3D capabilities.

MEASUREMENT OBJECTIVE

In this application, we showcase NANOVEA ST400, a 3D Non-Contact Profiler with a high-speed sensor, providing comprehensive analysis of the surface of a scale.

The instrument has been used to scan the entire sample, along with a higher resolution scan of the center area. The outer and inner side surface roughness of the scale was measured for comparison as well.

NANOVEA

ST400

3D & 2D Surface Characterization of Outer Scale

The 3D View and False Color View of the outer scale show a complex structure similar to a finger print or the rings of a tree. This provides users a straightforward tool to directly observe the surface characterization of the scale from different angles. Various other measurements of the outer scale are shown along with the comparison of the outer and inner side of the scale.

Fish Scale Scan 3D View Profilometer
Fish Scale Scan Volume 3D Profilometer
Fish Scale Scan Step Height 3D Optical Profiler

SURFACE ROUGHNESS COMPARISON

Fish Scale Profilometer 3D Scanning

CONCLUSION

In this application, we have shown how the NANOVEA 3D Non-Contact Optical Profiler can characterize a fish scale in a variety of ways. 

The outer and inner surfaces of the scale can be easily distinguished by surface roughness alone, with roughness values of 15.92μm and 1.56μm respectively. Additionally, precise and accurate information can be learned about a fish scale by analyzing the grooves, or circuli, on the outer surface of the scale. The distance of bands of circuli from the center focus were measured, and the height of the circuli were also found to be approximately 58μm high on average. 

The data shown here represents only a portion of the calculations available in the analysis software.

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Machined Parts QC

Machined Parts Inspection

Machined Parts Inspection from CAD models using 3D profilometry

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MACHINED PARTS

inspection from CAD model using 3D profilometry

Author:

Duanjie Li, PhD

Revised by

Jocelyn Esparza

Machined Parts Inspection with a Profilometer
Machined Parts Quality Control Profilometry

INTRODUCTION

The demand for precision machining able to create complex geometries has been on the rise across a spectrum of industries. From aerospace, medical and automobile, to tech gears, machinery and musical instruments, the continuous innovation and evolution push expectations and accuracy standards to new heights. Consequently, we see the rise of the demand for rigorous inspection techniques and instruments to ensure the highest quality of the products.

Importance of 3D Non-Contact Profilometry for Parts Inspection

Comparing properties of machined parts to their CAD models is essential to verify tolerances and adherence to production standards. Inspection during the service time is also crucial as wear and tear of the parts may call for their replacement. Identification of any deviations from the required specifications in a timely manner will help avoid costly repairs, production halts and tarnished reputation.

Unlike a touch probe technique, the NANOVEA Optical Profilers perform 3D surface scans with zero contact, allowing for quick, precise and non-destructive measurements of complex shapes with the highest accuracy.

MEASUREMENT OBJECTIVE

In this application, we showcase NANOVEA HS2000, a 3D Non-Contact Profiler with a high-speed sensor, performing a comprehensive surface inspection of dimension, radius, and roughness. 

All in under 40 seconds.

NANOVEA

HS2000

CAD MODEL

A precise measurement of the dimension and surface roughness of the machined part is critical to make sure it meets the desired specifications, tolerances and surface finishes. The 3D model and the engineering drawing of the part to be inspected are presented below. 

FALSE COLOR VIEW

The false color view of the CAD model and the scanned machined part surface are compared in FIGURE 3. The height variation on the sample surface can be observed by the change in color.

Three 2D profiles are extracted from the 3D surface scan as indicated in FIGURE 2 to further verify the dimensional tolerance of the machined part.

PROFILES COMPARISON & RESULTS

Profile 1 through 3 are shown in FIGURE 3 through 5. Quantitative tolerance inspection is carried out by comparing the measured profile with the CAD model to uphold rigorous manufacturing standards. Profile 1 and Profile 2 measure the radius of different areas on the curved machined part. The height variation of Profile 2 is 30 µm over a length of 156 mm which meets the desired ±125 µm tolerance requirement. 

By setting up a tolerance limit value, the analysis software can automatically determine pass or fail of the machined part.

Machine Parts Inspection with a Profilometer

The roughness and uniformity of the machined part’s surface play an important role in ensuring its quality and functionality. FIGURE 6 is an extracted surface area from the parent scan of the machined part which was used to quantify the surface finish. The average surface roughness (Sa) was calculated to be 2.31 µm.

CONCLUSION

In this study, we have showcased how the NANOVEA HS2000 Non-Contact Profiler equipped with a high speed sensor performs comprehensive surface inspection of dimensions and roughness. 

High-resolution scans enable users to measure detailed morphology and surface features of machined parts and to quantitatively compare them with their CAD models. The instrument is also capable of detecting any defects including scratches and cracks. 

The advanced contour analysis serves as an unparalleled tool not only to determine whether the machined parts satisfy the set specifications, but also to evaluate the failure mechanisms of the worn components.

The data shown here represents only a portion of the calculations possible with the advanced analysis software that comes equipped with every NANOVEA Optical Profiler.

 

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Avoid Critical Wear Damage By Using Block-On-Ring Tests

IMPORTANCE OF BLOCK-ON-RING WEAR EVALUATION

Sliding wear is the progressive loss of material that results from two materials sliding against each other at the contact area under load. It occurs inevitably in a wide variety of industries where machines and engines are in operation, including automotive, aerospace, oil & gas and many others. Such sliding motion causes serious mechanical wear and material transfer at the surface, which may lead to reduced production efficiency, machine performance or even damage to the machine.
 
Sliding wear often involves complex wear mechanisms taking place at the contact surface, such as adhesion wear, two-body abrasion, three-body abrasion and fatigue wear. The wear behavior of materials is significantly influenced by the work environment, such as normal loading, speed, corrosion and lubrication. A versatile tribometer that can simulate the different realistic work conditions will be ideal for wear evaluation. Block-on-Ring (ASTM G77) test is a widely used technique that evaluates the sliding wear behaviors of mate-rials in different simulated conditions, allows reliable ranking of material couples for specific tribological applications.
 


MEASUREMENT OBJECTIVE

In this application, the Nanovea Mechanical Tester measures the YS and UTS of stainless steel SS304 and aluminum Al6061 metal alloy samples. The samples were chosen for their commonly recognized YS and UTS values showing the reliability of Nanovea’s indentation methods.


The sliding wear behavior of an H-30 block on an S-10 ring was evaluated by Nanovea’s tribometer using the Block-on-Ring module. The H-30 block is made of 01 tool steel of 30HRC hardness, while the S-10 ring is steel type 4620 of surface hardness 58 to 63 HRC and ring diameter of ~34.98 mm. Block-on-Ring tests were performed in dry and lubricated environments to investigate the effect on wear behavior. Lubrication tests were performed in USP heavy mineral oil. The wear track was examined using Nanovea’s 3D non-contact profilometer. Test parameters are summarized in Table 1. The wear rate (K), was evaluated using the formula K=V/(F×s), where V is the worn volume, F is the normal load, s is the sliding distance.

 


RESULTS AND DISCUSSION

Figure 2 compares the coefficient of friction (COF) of the Block-on-Ring tests in dry and lubricated environments. The block has significantly more friction in a dry environment than a lubricated environment. COF fluctuates during the run-in period in the first 50-revolution and reaches a constant COF of ~0.8 for the rest of the 200-revolution wear test. In comparison, the Block-on-Ring test performed in the USP heavy mineral oil lubrication exhibits constant low COF of 0.09 throughout the 500,000-revolution wear test. The lubricant significantly reduces the COF between the surfaces by ~90 times.


Figures 3 and 4 show the optical images and cross-section 2D profiles of the wear scars on the blocks after dry and lubricated wear tests. The wear track volumes and wear rates are listed in Table 2. The steel block after the dry wear test at a lower rotational speed of 72 rpm for 200 revolutions exhibits a large wear scar volume of 9.45 mm˙. In comparison, the wear test carried out at a higher speed of 197 rpm for 500,000 revolutions in the mineral oil lubricant creates a substantially smaller wear track volume of 0.03 mm˙.

 

The images in ÿgure 3 show severe wear takes place during tests in the dry conditions compared to the mild wear from the lubricated wear test. High heat and intense vibrations generated during the dry wear test promotes oxidation of metallic debris resulting in severe three-body abrasion. In the lubricated test the mineral oil reduces friction and cools the contact face as well as transporting abrasive debris created during wear away. This leads to signiÿcant reduction of wear rate by a factor of ~8×10ˆ. Such a substantial di˛erence in wear resistance in di˛erent environments shows the importance of proper sliding wear simulation in realistic service conditions.

 

Wear behavior can change drastically when small changes in test conditions are introduced. The versatility of Nanovea’s tribometer allows wear measurement in high temperature, lubrication, and tribocorrosion conditions. The accurate speed and position control by the advanced motor enables wear tests to be performed at speeds ranging from 0.001 to 5000 rpm, making it an ideal tool for research/testing labs to investigate the wear in di˛erent tribological conditions.


The surface condition of the samples was examined by Nanovea’s non-contact optical proÿlometer. Figure 5 shows the surface morphology of the rings after the wear tests. The cylinder form is removed to better present the surface morphology and roughness created by the sliding wear process. Signiÿcant surface roughening took place due to the three-body abrasion process during the dry wear test of 200 revolutions. The block and ring after the dry wear test exhibit a roughness Ra of 14.1 and 18.1 µm, respectively, compared to 5.7 and 9.1 µm for the long-term 500,000 – revolution lubricated wear test at a higher speed. This test demonstrates the importance of proper lubrication of piston ring-cylinder contact. Severe wear quickly damages the contact surface without lubrication and leads to irreversible deterioration of the service quality and even breakage of the engine.

 

 



 


CONCLUSION


In this study we showcase how Nanovea’s Tribometer is used to evaluate the sliding wear behavior of a steel metal couple using the Block-on-Ring module following the ASTM G77 Standard. The lubricant plays a critical role in the wear properties of the material couple. The mineral oil reduces the wear rate of the H-30 block by a factor of ~8×10ˆ and the COF by ~90 times. The versatility of Nanovea’s Tribometer makes it an ideal tool for measuring wear behavior under various lubrication, high temperature, and tribocorrosion conditions. Nanovea’s Tribometer o˛ers precise and repeatable wear and friction testing using ISO and ASTM compliant rotative and linear modes, with optional high-temperature wear, lubrication, and tribo-corrosion modules available in one pre-integrated system. Nanovea’s unmatched range is an ideal solution for determining the full range of tribological properties of thin or thick, soft, or hard coatings, ÿlms, and substrates.

Dynamic Load Tribology

Introduction

Wear takes place in virtually every industrial sector and imposes costs of ~0.75% of the GDP1. Tribology research is vital in improving production efficiency, application performance, as well as conservation of material, energy, and the environment. Vibration and oscillation inevitably occur in a wide range of tribological applications. Excessive external vibration accelerates the wear process and reduces service performance which leads to catastrophic failures to the mechanical parts.

Conventional dead load tribometers apply normal loads by mass weights. Such a loading technique not only limits the loading options to a constant load, but it also creates intense uncontrolled vibrations at high loads and speeds leading to limited and inconsistent wear behavior assessments. A reliable evaluation of the effect of controlled oscillation on the wear behavior of materials is desirable for R&D and QC in different industrial applications.

Nanovea’s groundbreaking high load tribometer has a maximum load capacity of 2000 N with a dynamic-load control system. The advanced pneumatic compressed air loading system enables users to evaluate the tribological behavior of a material under high normal loads with the advantage of damping undesired vibration created during the wear process. Therefore, the load is measured directly with no need for buffer springs used in older designs. A parallel electromagnet oscillating loading module applies well-controlled oscillation of desired amplitude up to 20 N and frequency up to 150 Hz.

Friction is measured with high accuracy directly from the side force applied to the upper holder. The displacement is monitored in situ, providing insight into the evolution of the wear behavior of the test samples. The wear test under controlled oscillation loading can also be performed in corrosion, high temperature, humidity, and lubrication environments to simulate the real work conditions for the tribological applications. An integrated high-speed non-contact profilometer automatically measures the wear track morphology and wear volume in a few seconds.

 

Measurement Objective

In this study, we showcase the capacity of the Nanovea T2000 Dynamic Load Tribometer in studying the tribological behavior of different coating and metal samples under controlled oscillation loading conditions.

 

 

 

Test Procedure

The tribological behavior, e.g. coefficient of friction, COF, and wear resistance of a 300 µm thick wear-resistant coating was assessed and compared by the Nanovea T2000 Tribometer with a conventional dead load tribometer using a pin on disk setup following ASTM G992.

Separate Cu and TiN coated samples against a 6 mm Al₂0₃ ball under controlled oscillation were evaluated by Dynamic Load Mode of the Nanovea T2000 Tribometer.

The test parameters are summarized in Table 1.

The integrated 3D profilometer equipped with a line sensor automatically scans the wear track after the tests, providing the most accurate wear volume measurement in seconds.

 

 

Results and Discussion

 

Pneumatic loading system vs. Dead load system

 

The tribological behavior of a wear-resistant coating using Nanovea T2000 Tribometer is compared to a conventional dead load (DL) tribometer. The evolution of the COF of the coating are shown in Fig. 2. We observe the coating exhibits a comparable COF value of ~0.6 during the wear test. However, the 20 cross-section profiles at different locations of the wear track in Fig. 3 indicate that the coating experienced much more severe wear under the dead load system.

Intense vibrations were generated by the wear process of the dead load system at high load and speed. The massive concentrated pressure at the contact face combined with a high sliding speed creates substantial weight and structure vibration leading to accelerated wear. The conventional dead load tribometer applies load using mass weights. This method is reliable at lower contact loads under mild wear conditions; however, under aggressive wear conditions at higher loads and speeds, the significant vibration causes the weights to bounce repeatedly, resulting in an uneven wear track causing unreliable tribological evaluation. The calculated wear rate is 8.0±2.4 x 10-4 mm3/N m, showing a high wear rate and large standard deviation.

The Nanovea T2000 tribometer is designed with a dynamic control loading system to dampen the oscillations. It applies the normal load with compressed air which minimizes undesired vibration created during the wear process. In addition, active closed loop loading control ensures a constant load is applied throughout the wear test and the stylus follows the depth change of the wear track. A significantly more consistent wear track profile is measured as shown in Fig. 3a, resulting in a low wear rate of 3.4±0.5 x 10-4 mm3/N m.

The wear track analysis shown in Fig. 4 confirms the wear test performed by the pneumatic compressed air loading system of the Nanovea T2000 Tribometer creates a smoother and more consistent wear track compared to the conventional dead load tribometer. In addition, the Nanovea T2000 tribometer measures stylus displacement during the wear process providing further insight into the progress of the wear behavior in situ.

 

 

Controlled Oscillation on Wear of the Cu sample

The parallel oscillating loading electromagnet module of the Nanovea T2000 Tribometer enables users to investigate the effect of controlled amplitude and frequency oscillations on the wear behavior of materials. The COF of the Cu samples is recorded in situ as shown in Fig. 6. The Cu sample exhibits a constant COF of ~0.3 during the first 330-revolution measurement, signifying the formation of a stable contact at the interface and relatively smooth wear track. As the wear test continues, the variation of the COF indicates a change in the wear mechanism. In comparison, the wear tests under a 5 N amplitude-controlled oscillation at 50 N exhibits a different wear behavior: the COF increases promptly at the beginning of the wear process, and shows significant variation throughout the wear test. Such behavior of COF indicates that the imposed oscillation in the normal load plays a role in the unstable sliding state at the contact.

Fig. 7 compares the wear track morphology measured by the integrated non-contact optical profilometer. It can be observed that the Cu sample under a controlled oscillation amplitude of 5 N exhibits a much larger wear track with a volume of 1.35 x 109 µm3, compared to 5.03 x 108 µm3 under no imposed oscillation. The controlled oscillation significantly accelerates the wear rate by a factor of ~2.7, showing the critical effect of oscillation on wear behavior.

 

Controlled Oscillation on Wear of the TiN Coating

The COF and wear tracks of the TiN coating sample are shown in Fig. 8. The TiN coating exhibits significantly different wear behaviors under oscillation as indicated by the evolution of COF during the tests. The TiN coating shows a constant COF of ~0.3 following the run-in period at the beginning of the wear test, due to the stable sliding contact at the interface between the TiN coating and the Al₂O₃ ball. However, when the TiN coating starts to fail, the Al₂O₃ ball penetrates through the coating and slides against the fresh steel substrate underneath. A significant amount of hard TiN coating debris is generated in the wear track at the same time, turning a stable two-body sliding wear into three-body abrasion wear. Such a change of the material couple characteristics leads to the increased variations in the evolution of COF. The imposed 5 N and 10 N oscillation accelerates the TiN coating failure from ~400 revolutions to below 100 revolutions. The larger wear tracks on the TiN coating samples after the wear tests under the controlled oscillation is in agreement with such a change in COF.

 

Conclusion

The advanced pneumatic loading system of the Nanovea T2000 Tribometer possesses an intrinsic advantage as a naturally quick vibration damper compared to traditional dead load systems. This technological advantage of pneumatic systems is true compared to load-controlled systems that use a combination of servo motors and springs to apply the load. The technology ensures reliable and better-controlled wear evaluation at high loads as demonstrated in this study. In addition, the active closed loop loading system can change the normal load to a desired value during wear tests to simulate real-life applications seen in brake systems.

Instead of having influence from uncontrolled vibration conditions during tests, we have shown the Nanovea T2000 Dynamic-Load Tribometer enables users to quantitatively assess the tribological behaviors of materials under different controlled oscillation conditions. Vibrations play a significant role in the wear behavior of metal and ceramic coating samples.

The parallel electromagnet oscillating loading module provides precisely controlled oscillations at set amplitudes and frequencies, allowing users to simulate the wear process under real-life conditions when environmental vibrations are often an important factor. In the presence of imposed oscillations during wear, both the Cu and the TiN coating samples exhibit substantially increased wear rate. The evolution of the coefficient of friction and stylus displacement measured in situ are important indicators for the performance of the material during the tribological applications. The integrated 3D non-contact profilometer offers a tool to precisely measure the wear volume and analyze the detailed morphology of the wear tracks in seconds, providing more insight into the fundamental understanding of wear mechanism.

The T2000 is equipped with a self-tuned, high-quality, and high torque motor with a 20-bit internal speed and a 16-bit external position encoder. It enables the tribometer to provide an unmatched range of rotational speeds from 0.01 to 5000 rpm that can change in stepwise jumps or at continuous rates. Contrary to systems that use a bottom located torque sensor, the Nanovea Tribometer uses a top located high-precision load cell to accurately and separately measure friction forces.

Nanovea Tribometers offers precise and repeatable wear and friction testing using ISO and ASTM compliant rotative and linear modes (including 4ball, thrust washer, and block on ring tests), with optional high-temperature wear, lubrication and tribo-corrosion modules available in one pre-integrated system. Nanovea T2000’s unmatched range is an ideal solution for determining the full range of tribological properties of thin or thick, soft or hard coatings, films, and substrates.

Learn more about all the features our Nanovea Tribometer offers.

Tribology of Polymers

Introduction

Polymers have been used extensively in a wide variety of applications and have become an indispensable part of everyday life. Natural polymers such as amber, silk, and natural rubber have played an essential role in human history. The fabrication process of synthetic polymers can be optimized to achieve unique physical properties such as toughness, viscoelasticity, self-lubrication, and many others.

Importance of Wear and Friction of Polymers

Polymers are commonly used for tribological applications, such as tires, bearings, and conveyor belts.
Different wear mechanisms occur depending on the mechanical properties of the polymer, the contact conditions, and the properties of the debris or transfer film formed during the wear process. To ensure that the polymers possess sufficient wear resistance under the service conditions, reliable and quantifiable tribological evaluation is necessary. Tribological evaluation allows us to quantitatively compare the wear behaviors of different polymers in a controlled and monitored manner to select the material candidate for the target application.

The Nanovea Tribometer offers repeatable wear and friction testing using ISO and ASTM compliant rotative and linear modes, with optional high-temperature wear and lubrication modules available in one pre-integrated system. This unmatched range allows users to simulate the different work environments of the polymers including concentrated stress, wear, and high temperature, etc.

MEASUREMENT OBJECTIVE

In this study, we showcased that the Nanovea Tribometer is an ideal tool for comparing the friction and wear resistance of different polymers in a well-controlled and quantitative manner.

TEST PROCEDURE

The coefficient of friction (COF) and the wear resistance of different common polymers were evaluated by the Nanovea Tribometer. An Al2O3 ball was used as the counter material (pin, static sample). The wear tracks on the polymers (dynamic rotating samples) were measured using a non-contact 3D profilometer and optical microscope after the tests concluded. It should be noted that a non-contact endoscopic sensor can be used to measure the depth the pin penetrates the dynamic sample during a wear test as an option. The test parameters are summarized in Table 1. The wear rate, K, was evaluated using the formula K=Vl(Fxs), where V is the worn volume, F is the normal load, and s is the sliding distance.

Please note that Al2O3 balls were used as the counter material in this study. Any solid material can be substituted to more closely simulate the performance of two specimens under actual application conditions.

RESULTS AND DISCUSSION

Wear rate is a vital factor for determining the service lifetime of the materials, while the friction plays a critical role during the tribological applications. Figure 2 compares the evolution of the COF for different polymers against the Al2O3 ball during the wear tests. COF works as an indicator of when failures occur and the wear process enters a new stage. Among the tested polymers, HDPE maintains the lowest constant COF of ~0.15 throughout the wear test. The smooth COF implies that a stable tribo-contact is formed.

Figure 3 and Figure 4 compare the wear tracks of the polymer samples after the test is measured by the optical microscope. The In-situ non-contact 3D profilometer precisely determines the wear volume of the polymer samples, making it possible to accurately calculate wear rates of 0.0029, 0.0020, and 0.0032m3/N m, respectively. In comparison, the CPVC sample shows the highest wear rate of 0.1121m3/N m. Deep parallel wear scars are present in the wear track of CPVC.

CONCLUSION

The wear resistance of the polymers plays a vital role in their service performance. In this study, we showcased that the Nanovea Tribometer evaluates the coefficient of friction and wear rate of different polymers in a
well-controlled and quantitative manner. HDPE shows the lowest COF of ~0.15 among the tested polymers. HDPE, Nylon 66, and Polypropylene samples possess low wear rates of 0.0029, 0.0020 and 0.0032 m3/N m, respectively. The combination of low friction and great wear resistance makes HDPE a good candidate for polymer tribological applications.

The In-situ non-contact 3D profilometer enables precise wear volume measurement and offers a tool to analyze the detailed morphology of the wear tracks, providing more insight into the fundamental understanding of wear mechanisms

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Honeycomb Panel Surface Finish with 3D Profilometry

INTRODUCTION


Roughness, porosity, and texture of the honeycomb panel surface are critical to quantify for the final panel design. These surface qualities can directly correlate to the aesthetics and functional characteristics of the panel surface. A better understanding of the surface texture and porosity can help optimize the panel surface processing and manufacturability. A quantitative, precise, and reliable surface measurement of the honeycomb panel is needed to control surface parameters for application and painting requirements. The Nanovea 3D Non-Contact sensors utilize unique chromatic confocal technology capable of precisely measuring these panel surfaces.



MEASUREMENT OBJECTIVE


In this study, the Nanovea HS2000 platform equipped with a high-speed Line Sensor was used to measure and compare two honeycomb panels with different surface finishes. We showcase the Nanovea non-contact profilometer’s ability to provide fast and precise 3D profiling measurements and comprehensive in-depth analysis of the surface finish.



RESULTS AND DISCUSSION

The surface of two honeycomb panel samples with varied surface finishes, namely Sample 1 and Sample 2, were measured. The false color and 3D view of the Samples 1 and 2 surfaces are shown in Figure 3 and Figure 4, respectively. The roughness and flatness values were calculated by advanced analysis software and are compared in Table 1. Sample 2 exhibits a more porous surface compared to Sample 1. As a result, Sample 2 possesses a higher roughness Sa of 14.7 µm, compared to an Sa value of 4.27 µm for Sample 1.

The 2D profiles of the honeycomb panel surfaces were compared in Figure 5, allowing users to have a visual comparison of the height change at different locations of the sample surface. We can observe that Sample 1 has a height variation of ~25 µm between the highest peak and lowest valley location. On the other hand, Sample 2 shows several deep pores across the 2D profile. The advanced analysis software has the ability to automatically locate and measure the depth of six relatively deep pores as shown in the table of Figure 4.b Sample 2. The deepest pore amongst the six possesses a maximum depth of nearly 90 µm (Step 4).

To further investigate the pore size and distribution of Sample 2, porosity evaluation was performed and discussed in the following section. The sliced view is displayed in Figure 5 and the results are summarized in Table 2. We can observe that the pores, marked in blue color in Figure 5, have a relatively homogeneous distribution on the sample surface. The projected area of the pores constitutes 18.9% of the whole sample surface. The volume per mm² of the total pores is ~0.06 mm³. The pores have an average depth of 42.2 µm, and the maximum depth is 108.1 µm.

CONCLUSION



In this application, we have showcased that the Nanovea HS2000 platform equipped with a high-speed Line Sensor is an ideal tool for analyzing and comparing the surface finish of honeycomb panel samples in a fast and accurate manner. The high-resolution profilometry scans paired with an advanced analysis software allow for a comprehensive and quantitative evaluation of the surface finish of honeycomb panel samples.

The data shown here represents only a small portion of the calculations available in the analysis software. Nanovea Profilometers measure virtually any surface for a wide range of applications in the Semiconductor, Microelectronic, Solar, Fiber Optics, Automotive, Aerospace, Metallurgy, Machining, Coatings, Pharmaceutical, Biomedical, Environmental and many other industries.

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Understanding Coating Failures using Scratch Testing

Introduction:

Surface engineering of materials plays a significant role in a variety of functional applications, ranging from decorative appearance to protecting the substrates from wear, corrosion and other forms of attacks. An important and overriding factor that determines the quality and service lifetime of the coatings is their cohesive and adhesive strength.

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Rotative or Linear Wear & COF? (A Comprehensive Study Using the Nanovea Tribometer)

Wear is the process of removal and deformation of material on a surface as a result of mechanical action of the opposite surface1. It is influenced by a variety of factors, including unidirectional sliding, rolling, speed, temperature, and many others. The study of wear, tribology, spans many disciplines, from physics and chemistry to mechanical engineering and material science. The complex nature of wear requires isolated studies towards specific wear mechanisms or processes, such as adhesive wear, abrasive wear, surface fatigue, fretting wear and erosive wear2. However, “Industrial Wear” commonly involves multiple wear mechanisms occurring in synergy.

Linear reciprocating and Rotative (Pin on Disk) wear tests are two widely used ASTM compliant setups34for measuring sliding wear behaviors of materials. Since the wear rate value of any wear test method is often used to predict the relative ranking of material combinations, it is extremely important to conrm the repeatability of the wear rate measured using different test setups. This enables users to carefully consider the wear rate value reported in the literature, which is critical in understanding the tribological characteristics of materials.

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