Profilometer / Roughness
Capturing the features of the target as a surface enables instant measurement of 3D figures over a wide area. This non-contact roughness meter / profile measurement system can measure surface roughness as well as burrs and other microscopic shapes in as little as 1 second. The system automatically determines settings such as the sensitivity according to the target height, size, material, and color. It eliminates measurement mistakes, saves time, and allows inexperienced users to start capturing data immediately.
VR Series Wide-Area 3D Measurement Systems are capable of non-contact, high-resolution 3D measurement. The VR Series captures full surface data, instead of point or line data typically captured by CMMs or profilometers, allowing small features to be measured with the highest level of confidence. The automatic place-and-measure capability allows any user to capture accurate data across the entire surface of their part, with no fixturing or adjustments required. The VR Series excels at measuring precise 3D features, profiles, flatness, and roughness.
A profilometer/roughness gauge is a measuring device used to capture 2D or 3D data on the surface of a sample in order to measure roughness, flatness, or other critical 2D and 3D dimensions. The terms "profilometer" and "roughness gage" are often used interchangeably and come in several types, however, they are primarily divided into contact and non-contact systems.
Contact systems physically trace a stylus probe over the target surface in order to capture 2D line data, while non-contact profilometers (also called "optical profilometers") project light onto the target surface and capture 3D surface data.
Benefits of Optical Profilometers / Roughness Gages
Conventionally, contact profilometers were the standard for profile and roughness measurements. However, in recent years, optical profilometers are increasingly being adopted by companies to overcome typical limitations of contact profilometers.
Unlike contact profilometers, optical profilometers project light onto the target surface and are able to capture 3D data across the entire surface. This allows for true 3D measurements to be performed, such as volumetric measurements and area surface roughness.
Since data is captured across the entire surface, it is possible to calculate the highest and lowest points, as well as to measure targets with complex surface features, such as PCBs, both of which are impossible with contact-type measuring systems.
Contact profilometers must physically drag a probe across the surface of a part, which can introduce scratches and dents onto the target surface, potentially rendering the sample unusable. Soft surfaces, such as rubber, cannot be measured because the pressure from the stylus probe will deform the surface.
Optical profilometers capture data by projecting light onto the surface, so no sample damage occurs. Additionally, soft surfaces can be accurately measured with no sample deformation.
With contact profilometers, precise fixturing of the target is required in order to capture data. Due to the nature of the device, the stylus must be positioned visually by the operator and can be difficult to determine if the probe is aligned correctly. If the probe is misaligned, the feature of interest could be missed, or incorrect measurement values may be obtained.
Optical profilometers do not require fixturing, as automatic alignment can be performed after capturing the surface data. Since the full surface data is obtained, users can ensure they are measuring in the proper place, and through the use of templates, different operators will obtain the same measurement results.
Optical Profilometers / Roughness Gages Case Studies
Profilometers measure the Ra (arithmetic mean roughness) and Rz (max. height) of the sliding surface of steering parts. Ra measures the smoothness of sliding surfaces, and Rz measures the surface height. Using Ra alone might cause some points, such as single protrusions, to be overlooked, so it is important that Ra and Rz be used together. This type of analysis enables users to compare changes in surface properties that arise from different metal processing methods. Sa (arithmetic mean height) and Sz (max. height) analysis look at the finishing condition, and Str (aspect ratio of surface properties) analysis checks whether processing traces can be found in external appearances.
The VR Series acquires 3D data of surfaces in as little as one second and is capable of calculating different roughness parameters at the same time. These advantages contribute to a major improvement in measurement efficiency.
Electrical machinery and electronics industry
The Sa (arithmetic mean height) value of the PCB copper foil significantly affects the spread of solder when soldering electronic components. If the Sa value indicates high roughness, the solder will spread over a larger surface area, causing a higher likelihood of leaks. Sdr (developed interfacial area ratio) and Sa of the etching on copper can also be measured to understand the impact soldering and other processes have on the surface.
The VR Series expands roughness capabilities from not just measuring a single line, but across an entire area so the surface conditions can be better understood.
Surface roughness and profile measurements on engine components are extremely critical, as any defects or non-conforming products could lead to catastrophic failures. Contact profilometers risk damaging the surface of the part, or if the stylus is not placed in the perfect position defects may be missed.
The VR Series is commonly used to quantify the shape and surface roughness of engine components without damaging the sample. Spc (arithmetic mean peak curvature) is often used to determine the sharpness of the peaks on the surface. Surfaces with sharper peaks are more likely to have small amounts of material break off when they come into contact with another surface, which could cause damage to other components within the engine. The VR Series is capable of performing profile and roughness inspections in as little as 1 second, contributing to enhanced quality control.
Quick measurement of flatness/warpage
Deep drawing is a forming process for which it is very difficult to define the correct conditions. Unexpected deformation of materials can occur due to mechanical stress. Care must be taken to prevent warpage and other forming errors.
With the VR Series, you only need to place and scan the target on the stage to measure its 3D profile. No positioning or fixturing is required. The surface of the target is measured, and the overall height is visualized with a color-coded display. As profile measurement is also possible in any area of the target, the VR Series can detect defective parts and provide detailed values for defective areas. This can contribute to identifying the cause of defects, which may be the die or forming conditions, as well as making adjustments simpler. The warpage can also be quantified for inspection purposes.
Measuring the shank and threads of bolts and screws
The shank and threads of screws and bolts are key measurement points, as a smoother surface can improve fatigue strength.
KEYENCE revised the VR Series with a focus on measurement algorithms and hardware, achieving measurement times as short as 1 second. Operators can perform nearly any measurement, such as the underhead fillet radius and thread pitch. With automated scanning and templates, measurement results do not vary between operators.
These improvements in measurement task efficiency lead to higher processing volume and shorter operating time, as well as improved allocation of personnel and resources and an increase in production performance.
Solving issues in coplanarity inspection
Measuring and inspecting coplanarity not only requires a lot of time and effort but is also prone to variations in measured values when using standard measuring instruments and microscopes. It is also difficult to measure small electronic devices with contact-type measuring instruments, and they may even damage targets during measurement.
With the VR Series, you only need to place the target on the stage, the system can automatically move the stage to position the target and instantaneously scan its profile. Variations in measurement results do not occur, even if different operators measure the part. With no need for fixturing, the VR Series can collectively measure the coplanarity and profile of multiple pins, leads, and solder balls, which helps significantly shorten the time spent on measurement.
Frequently Asked Questions About Profilometers / Roughness Gages
Contact profilometers are limited to capturing line data across the target surface. Because of this, the surface profile cannot be measured across the entire surface and minute surface details may not be captured.
The VR Series can scan the entire surface of the target. Surface measurements are performed over a 200 × 100 × 50 mm (7.87" × 3.94" × 1.97") area, which makes it possible to accurately visualize the surface warpage using a color-coded display. Surface maximum and minimum points can be measured, and small surface irregularities can be identified and analyzed.
Ra measures the mean height of a line of data captured on the target surface, and is commonly used to express the overall "roughness" of the surface. Sa is an extension of Ra; instead of measuring the mean height of the surface across a single line of data, Sa measures the mean height of the surface across an entire area. In recent years, many industries have transitioned to using Sa for its increased accuracy and ability to identify non-conforming products.
Profilometers are commonly used for measuring the roughness, or finish of a surface. Additionally, optical profilometers are capable of taking 3D shape measurements, such as flatness, waviness, warpage, radii, step heights, etc.
Types and Characteristics of Profilometers / Roughness Gages
This type of measuring system touches the target on the stage with a probe to accurately measure the surface profile. The stylus traces the surface of the target, and the vertical displacement of the stylus is detected electronically. Dimensional measurements as well as line roughness can be measured.
This type of measuring system projects light onto the target and uses the reflected light to accurately measure the surface profile. 2D and 3D dimensional measurements are possible, as well as line roughness and surface roughness.
While the working principle is the same as that of the contact type, this type can be used while holding the controller in your hand. Although there are some restrictions on measurement functions and accuracy, it can be carried and used anywhere.
This guide introduces two points to consider before adopting profilometers or roughness gages. It explains the problems encountered when using conventional measurement systems and how to work around them. Recommended for potential users considering profilometers and roughness gages.
Measure large and small targets with our 3D measurement systems. Micron-order roughness and profile data as well as warpage analysis are possible. This guide covers the functions useful for measuring large components.
The VR Series offers non-contact, high-speed, high-accuracy surface measurements. This guide details where it is used and why the series is a preferred choice for our customers. Download the document and discover for yourself the benefits the VR Series offers to your industry.
This guide is a collection of cases where the VR Series provided solutions to problems that were unsolvable by conventional measuring instruments, such as dealing with warpage, deformation, dents, burrs, and viscous targets. A must-read for measurement operators.