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Pharmaceutical Tablets Surface Roughness Inspection


Pharmaceutical Tablets

Inspecting Roughness using 3d profilometers


Jocelyn Esparza


Pharmaceutical tablets are the most popular medicinal dosage used today. Each tablet is made up by a combination of active substances (the chemicals that produce pharmacological effect) and inactive substances (disintegrant, binder, lubricant, diluent – usually in the form of powder). The active and inactive substances are then compressed or molded into a solid. Then, depending on the manufacturer specifications, the tablets are either coated or uncoated.

To be effective, tablet coatings need to follow the fine contours of embossed logos or characters on tablets, they need to be stable and sturdy enough to survive handling of the tablet, and they must not cause the tablets to stick to each other during the coating process. Current tablets typically have a polysaccharide and polymer-based coating which include substances like pigments and plasticizers. The two most common types of table coatings are film coatings and sugar coating. Compared to sugar coatings, film coatings are less bulky, more durable, and are less time-consuming to prepare and apply. However, film coatings have more difficulty hiding tablet appearance.

Tablet coatings are essential for moisture protection, masking the taste of the ingredients, and making the tablets easier to swallow. More importantly, the tablet coating controls the location and the rate in which the drug is released.


In this application, we use the NANOVEA Optical Profiler and advanced Mountains software to measure and quantify the topography of various name brand pressed pills (1 coated and 2 uncoated) to compare their surface roughness.

It is assumed that Advil (coated) will have the lowest surface roughness due to the protective coating it has.



Test Conditions

Three batches of name brand pharmaceutical pressed tablets were scanned with the Nanovea HS2000
using High-Speed Line Sensor to measure various surface roughness parameters according to ISO 25178.

Scan Area

2 x 2 mm

Lateral Scan Resolution

5 x 5 μm

Scan Time

4 sec


Results & Discussion

After scanning the tablets, a surface roughness study was conducted with the advanced Mountains analysis software to calculate the surface average, root-mean-square, and maximum height of each tablet.

The calculated values support the assumption that Advil has a lower surface roughness due to the protective coating encasing its ingredients. Tylenol shows to have the highest surface roughness out of all three measured tablets.

A 2D and 3D height map of each tablet’s surface topography was produced which show the height distributions measured. One out of the five tablets were selected to represent the height maps for each brand. These height maps make a great tool for visual detection of outlying surface features such as pits or peaks.


In this study, we analyzed and compared the surface roughness of three name brand pressed pharmaceutical pills: Advil, Tylenol, and Excedrin. Advil proved to have the lowest average surface roughness. This can be attributed to the presence of the orange coating incasing the drug. In contrast, both Excedrin and Tylenol lack coatings, however, their surface roughness still differ from each other. Tylenol proved to have the highest average surface roughness out of all the tablets studied.

Using the NANOVEA HS2000 with High-Speed Line Sensor, we were able to measure 5 tablets in less than 1 minute. This can prove to be useful for quality control testing of hundreds of pills in a production today.


Microparticles: Compression Strength and Micro Indentation




Jorge Ramirez

Revised by:
Jocelyn Esparza


Compression strength has become vital to quality control measurement in developing and improving new and existing microparticles and micro features (pillars and spheres) seen today. Microparticles have various shapes, sizes and can be developed from ceramics, glass, polymers, and metals. Uses include drug delivery, food flavor enhancement, concrete formulations among many others. Controlling the mechanical properties of microparticles or microfeatures are critical for their success and requires the ability to quantitatively characterize their mechanical integrity  


Standard compressive measurement instruments are not capable of low loads and fail to provide adequate depth data for microparticles. By using Nano or Microindentation, the compression strength of nano or microparticles (soft or hard) can be accurately and precisely measured.  


In this application note we measure  the compression strength of salt with the NANOVEA Mechanical Tester in micro indentation mode.




maximum force

30 N

loading rate

60 N/min

unloading rate

60 N/min

indenter type

Flat Punch

Steel | 1mm Diameter

Load vs depth curves

Results & Discussion

Height, failure force and strength for Particle 1 and Particle 2

Particle failure was determined to be the point where the initial slope of the force vs. depth curve began to noticeably decrease.This behavior shows the material has reached a yield point and is no longer able to resist the compressive forces being applied. Once the yield point is surpassed, the indentation depth begins to exponentially increase for the duration of the loading period. These behaviors can be seen in Load vs Depth Curves for both samples.


In conclusion, we have shown how the NANOVEA Mechanical Tester in micro indentation mode is a great tool for compression strength testing of microparticles. Although the particles tested are made of the same material, it is suspected that the different failure points measured in this study were likely due to pre-existent micro cracks in the particles and varying particle sizes. It should be noted that for brittle materials, acoustic emission sensors are available to measure the beginning of crack propagation during a test.

NANOVEA Mechanical Tester offers depth displacement resolutions down to the sub nanometer level,
making it a great tool for the study of very fragile micro particles or features as well. For soft and fragile
materials, loads down to 0.1mN are possible with our nano indentation module


Ball Bearings: High Force Wear Resistance Study


A ball bearing uses balls to reduce rotational friction and support radial and axial loads. The rolling balls between the bearing races produce much lower coefficient of friction (COF) compared to two flat surfaces sliding against each other. Ball bearings are often exposed to high contact stress levels, wear and extreme environmental conditions such as high temperatures. Therefore, wear resistance of the balls under high loads and extreme environmental conditions is critical for extending the lifetime of the ball bearing to cut down cost and time on repairs and replacements.
Ball bearings can be found in nearly all applications that involve moving parts. They are commonly used in transportation industries such as aerospace and automobile as well as the toy industry that manufactures items such as fidget spinner and skateboards.


Ball bearings can be made from an extensive list of materials. Commonly used materials range between metals like stainless steel and chrome steel or ceramics such as tungsten carbide (WC) and silicon nitride (Si3n4). To ensure that the manufactured ball bearings possess the required wear resistance ideal for the given application’s conditions, reliable tribological evaluations under high loads are necessary. Tribological testing aids in quantifying and contrasting the wear behaviors of diff­erent ball bearings in a controlled and monitored manner to select the best candidate for the targeted application.


In this study, we showcase a Nanovea Tribometer as the ideal tool for comparing the wear resistance of different ball bearings under high loads.

Figure 1:  Setup of the bearing test.


The coefficient of friction, COF, and the wear resistance of the ball bearings made of different materials were evaluated by a Nanovea Tribometer. P100 grit sandpaper was used as the counter material. The wear scars of the ball bearings were examined using a Nanovea 3D Non-Contact Profiler after the wear tests concluded. The 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 and s is the sliding distance. Ball wear scars were evaluated by a Nanovea 3D Non-Contact Profiler to ensure precise wear volume measurement.
The automated motorized radial positioning feature allows the tribometer to decrease the radius of the wear track for the duration of a test. This test mode is called a spiral test and it ensures that the ball bearing always slides on a new surface of the sandpaper (Figure 2). It significantly improves the repeatability of the wear resistance test on the ball. The advanced 20bit encoder for internal speed control and 16bit encoder for external position control provide precise real-time speed and position information, allowing for a continuous adjustment of rotational speed to achieve constant linear sliding speed at the contact.
Please note that P100 Grit sandpaper was used to simplify the wear behavior between various ball materials in this study and can be substituted with any other material surface. Any solid material can be substituted to simulate the performance of a wide range of material couplings under actual application conditions, such as in liquid or lubricant.

Figure 2:  Illustration of the spiral passes for the ball bearing on the sandpaper.
Table 1:  Test parameters of the wear measurements.



Wear rate is a vital factor for determining the service lifetime of the ball bearing, while a low COF is desirable to improve the bearing performance and efficiency. Figure 3 compares the evolution of COF for di­fferent ball bearings against the sandpaper during the tests. The Cr Steel ball shows an increased COF of ~0.4 during the wear test, compared to ~0.32 and ~0.28 for SS440 and Al2O3 ball bearings. On the other hand, the WC ball exhibits a constant COF of ~0.2 throughout the wear test. Observable COF variation can be seen throughout each test which is attributed to vibrations caused by the sliding movement of the ball bearings against the rough sandpaper surface.


Figure 3:  Evolution of COF during the wear tests.

Figure 4 and Figure 5 compare the wear scars of the ball bearings after they were measured by an optical microscope and Nanovea Non-Contact optical profiler, respectively, and Table 2 summarizes the results of the wear track analysis. The Nanovea 3D profiler precisely determines the wear volume of the ball bearings, making it possible to calculate and compare the wear rates of different ball bearings. It can be observed that the Cr Steel and SS440 balls exhibit much larger flattened wear scars compared to the ceramic balls, i.e. Al2O3 and WC after the wear tests. The Cr Steel and SS440 balls have comparable wear rates of 3.7×10-3 and 3.2×10-3 m3/N m, respectively. In comparison, the Al2O3 ball shows an enhanced wear resistance with a wear rate of 7.2×10-4 m3/N m. The WC ball barely exhibits minor scratches on the shallow wear track area, resulting in a significantly reduced wear rate of 3.3×10-6 mm3/N m.

Figure 4:  Wear scars of the ball bearings after the tests.

Figure 5:  3D morphology of the wear scars on the ball bearings.

Table 2: Wear scar analysis of the ball bearings.

Figure 6 shows microscope images of the wear tracks produced on the sand paper by the four ball bearings. It is evident that the WC ball produced the most severe wear track (removing almost all sand particle in its path) and possesses the best wear resistance. In comparison, the Cr Steel and SS440 balls left a large amount of metal debris on the wear track of the sand paper.
These observations further demonstrate the importance of the benefit of a spiral test. It ensures that the ball bearing always slides on a new surface of the sandpaper, which significantly improves the repeatability of a wear resistance test.

Figure 6:  Wear tracks on the sand paper against different ball bearings.


The wear resistance of the ball bearings under a high pressure plays a vital role in their service performance. The ceramic ball bearings possess significantly enhanced wear resistance under high stress conditions and reduce the time and cost due to bearing repairing or replacement. In this study, the WC ball bearing exhibits a substantially higher wear resistance compared to the steel bearings, making it an ideal candidate for bearing applications where severe wear takes place.
A Nanovea Tribometer is designed with high torque capabilities for loads up to 2000 N and precise and controlled motor for rotational speeds from 0.01 to 15,000 rpm. It 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 different severe work environments of the ball bearings including high stress, wear and high temperature, etc. It also acts as an ideal tool to quantitatively assess the tribological behaviors of superior wear resistant materials under high loads.
A Nanovea 3D Non-Contact Profiler provides precise wear volume measurements and acts as a tool to analyze the detailed morphology of the wear tracks, providing additional insights in the fundamental understanding of wear mechanisms.

Prepared by
Duanjie Li, PhD, Jonathan Thomas, and Pierre Leroux


Dental Tools: Dimensional and Surface Roughness Analysis



Having precise dimensions and optimal surface roughness are vital to the functionality of dental screws. Many dental screw dimensions require high precision such as radii, angles, distances, and step heights. Understanding local surface roughness is also highly important for any medical tool or part being inserted inside the human body to minimize sliding friction.





Nanovea 3D Non-Contact Profilers use a chromatic light-based technology to measure any material surface: transparent, opaque, specular, diffusive, polished or rough. Unlike a touch probe technique, the non-contact technique can measure inside tight areas and will not add any intrinsic errors due to deformation caused by the tip pressing on a softer plastic material.  Chromatic light-based technology also offers superior lateral and height accuracies compared to focus variation technology. Nanovea Profilers can scan large surfaces directly without stitching and profile the length of a part in a few seconds. Nano through macro range surface features and high surface angles can be measured due to the profiler’s ability to measure surfaces without any complex algorithms manipulating the results.





In this application, the Nanovea ST400 Optical Pro­filer was used to measure a dental screw along flat and thread features in a single measurement. The surface roughness was calculated from the flat area, and various dimensions of the threaded features were determined.


dental screw quality control

Sample of dental screw analyzed by NANOVEA Optical Profiler.


Dental screw sample analyzed.




3D Surface

The 3D View and False Color View of the dental screw shows a flat area with threading starting on either side. It provides users a straightforward tool to directly observe the morphology of the screw from different angles. The flat area was extracted from the full scan to measure its surface roughness.



2D Surface Analysis

Line profiles can also be extracted from the surface to show a cross-sectional view of the screw. The Contour Analysis and step height studies were used to measure precise dimensions at a certain location on the screw.





In this application, we have showcase the Nanovea 3D Non-Contact Profiler’s ability to precisely calculate local surface roughness and measure large dimensional features in a single scan.

The data shows a local surface roughness of 0.9637 μm. The radius of the screw between threads was found to be 1.729 mm, and the threads had an average height of 0.413 mm. The average angle between the threads was determined to be 61.3°.

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


Prepared by
Duanjie Li, PhD., Jonathan Thomas, and Pierre Leroux

Ceramics: Nanoindentation Fast Mapping for Grain Detection



Nanoindentation has become a widely applied technique for measuring mechanical behaviors of materials at small scalesi ii. The high-resolution load-displacement curves from a nanoindentation measurement can provide a variety of physicomechanical properties, including hardness, Young’s modulus, creeping, fracture toughness and many others.



Importance of Fast Mapping Indentation


One significant bottleneck for further popularization of the nanoindentation technique is time consumption. A mechanical property mapping by conventional nanoindentation procedure can easily take hours which hinders the application of the technique in mass production industries, such as semiconductor, aerospace, MEMS, consumer products such as ceramic tiles and many others.

Fast mapping can prove to be essential in the ceramic tile manufacturing industry, Hardness and Young’s modulus mappings across a single ceramic tile can present a distribution of data that indicates how homogeneous the surface is. Softer regions on a tile can be outlined in this mapping and show locations more prone to failure from physical impacts that happen on a day to day basis in someone’s residence. Mappings can be made on different types of tiles for comparative studies and on a batch of similar tiles to measure tile consistency in a quality control processes. The combination of measurements setups can be extensive as well as accurate and efficient with the fast mapping method.




In this study, the Nanovea Mechanical Tester, in FastMap mode is used to map the mechanical property of a floor tile at high speeds. We showcase the capacity of the Nanovea Mechanical Tester in performing two fast nanoindentation mappings with high precision and reproducibility.


Test Conditions


The Nanovea Mechanical Tester was used to perform a series of nanoindentations with the FastMap Mode on a floor tile using a Berkovich indenter. The test parameters are summarized below for the two indent matrices created.


Table 1:  Test parameter summary.




Figure 1:  2D and 3D view of 625-indent hardness mapping.




Figure 2:  Micrograph of 625-indent matrix showcasing grain.



A 625-indent matrix was conducted on a 0.20mm2 area with a large visible grain present. This grain (Figure 2) had an average hardness lower than the overall surface of the tile. The Nanovea Mechanical Software allows the user to see the hardness distribution map in 2D and 3D mode which are depicted in Figure 1. Using the high-precision position control of the sample stage, the software allows users to target areas such as these for in depth mechanical properties mapping.

Figure 3:  2D and 3D view of 1600-indent hardness mapping.



Figure 4:  Micrograph of 1600-indent matrix.



A 1600-indent matrix was also created on the same tile to measure the homogeneity of the surface. Here again the user has the ability to see the hardness distribution in 3D or 2D mode (Figure 3) as well as the microscope image of the indented surface. Based on the hardness distribution presented, it can be concluded that the material is porous due to the even scattering of high and low hardness data points.

Compared to conventional nanoindentation procedures, FastMap mode in this study is substantially less time-consuming and more cost-effective. It enables speedy quantitative mapping of mechanical properties including Hardness and Young’s Modulus and provides a solution for grain detection and material consistency which is critical for quality control of a variety of materials in mass production.





In this study, we showcased the capacity of the Nanovea Mechanical Tester in performing speedy and precise nanoindentation mapping using FastMap mode. The mechanical property maps on the ceramic tile utilize the position control (with 0.2µm accuracy) of the stages and force module sensitivity to detect surface grains and measure homogeneity of a surface at high speed.

The test parameters used in this study were determined based on the size of the matrix and sample material. A variety of test parameters can be chosen to optimize the total indentation cycle time to 3 seconds per indent (or 30 seconds for every 10 indentations).

The Nano and Micro modules of the Nanovea Mechanical Tester all include ISO and ASTM compliant indentation, scratch and wear tester modes, providing the widest and most user-friendly range of testing available in a single system. Nanovea’s unmatched range is an ideal solution for determining the full range of mechanical properties of thin or thick, soft or hard coatings, films and substrates, including hardness, Young’s Modulus, fracture toughness, adhesion, wear resistance and many others.

In addition, optional 3D non-contact profiler and AFM Module are available for high resolution 3D imaging of indentation, scratch and wear track in addition to other surface measurements such as roughness.


Author: Duanjie Li, PhD        Revised by Pierre Leroux & Jocelyn Esparza