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Screen shot of M3 software showing field of view measurement

Field of View (FOV) measurement… a new way of measuring small flat parts

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Measuring within the field of view is an entirely new way to accurately measure small, flat components, providing unrivalled speed and simplicity compared to alternative methods such as profile projectors, video measuring machines, or measuring microscopes.

But what is field of view measurement, how does it work and how could it help me?

What is Field of View measurement?

Field of view (FOV) measurement, or measuring within the field of view, is an entirely new way of measuring small components accurately, with amazing speed and simplicity. FOV measurement uses a specially designed high resolution video camera to measure a component within the optical field of view. Compare this to alternative methods such as:

Profile projectors – projects a magnified silhouette of a component onto a screen, with a measuring stage moving the component part so all of it can be measured.

Video measuring machines and measuring microscopes employ a magnified image, and like a profile projector, utilise a measuring stage to move the component around. With a small field of view, traditional optical measuring systems utilise a stage since only a small area of the component can be seen by the optics at any given time. Moving the stage allows different parts of the component to be ‘seen’ and therefore measured.

Xpress 70
(57mm x 43mm field of view)
Example 1x objective
(14.2mm Ø field of view)
Example 2x objective
(7.1mm Ø field of view)
Fig 1. Diagram illustrating the relative size of the field of view.

 

FOV measuring systems do not require a moving stage, since the entire sample is viewed within a large field of view (57mm x 43mm with Xpress 70). Compare this to the size of a traditional optical measuring system – approximately 0.5mm to 20mm. (Fig 1.)

A larger field of view allows the whole component to be seen and therefore measured, without the need for a measuring stage, providing some significant advantages, including dramatically increased speed and unrivalled simplicity.

 

 

How does it work?

‘Flat-field’ optics
Field of view measurement employs a high resolution video camera, coupled with a large ‘flat-field’ telecentric lens system. The telecentric lens provides a flat image, across the full field of view, without any curvature or distortion, so you can place and measure your component anywhere within the field of view, without affecting the measurements.

Fig 2.Flat field of a telecentric lensCurved field of a standard lens

No need to focus *
Moreover, the ‘flat-field’ telecentric lens system has been designed with an exceptionally large depth of field, meaning your subject is always in focus*. Typically a depth of field (focus) with a comparable measuring device varies between a couple of microns and a couple of millimetres. Typically, a FOV measuring system has a depth of focus of 40mm or more (lens dependant).

*Note: Once the system is focused, no further focusing is required for components of similar height.

Why measure within the field of view?

A wide-field telecentric lens allows the whole component to be seen within its large field of view, enabling all the features to be measured in seconds. Compare this to alternative measuring systems, which require a mechanical stage to be moved to capture all of the measured points, therefore taking considerably longer. Not only can the whole components be seen and measured, but multiple components can also be measured at the same time.

Fig 3. Single or multiple parts can be measured in seconds, using the same measurement programme.

No moving stage
Since the entire component is ‘seen’ within the field of view, you therefore do not need a moving stage to measure the whole component.

Immediately, this fact brings numerous benefits. No moving stage means …

  • There are no moving parts, therefore no mechanical variance affecting the measurement.
  • There is no operator variance due to different habits or skills in taking the measurement.
  • Time. There is nothing to move, saving you time. Lots of time.


View whole components

This significant development opens up numerous highly advantageous possibilities. Viewing whole components means …

  • You can view and therefore measure all the visible ‘features’ in seconds, not minutes.
  • You can even measure multiple parts at the same time, saving you more time.
  • You do not need to align or skew the part/s, saving you yet more time.

 

Simply place your part anywhere within the field of view.
The software automatically recognises the part. Just press RUN.
All the features are measured in seconds.

Speed
Measuring within the field of view saves you significant amounts of time, across every stage of the measurement process. No need to focus*. No need to position or align the part. No need to move a measuring stage. No need to take multiple measurement points …

Accuracy
Since there are no manual operations required by the user – such as point selection, edge alignment and focus adjustment* – differences between individual operators are completely eliminated.

Simplicity
Exceptional simplicity is the key. No need to focus*, or position the component. Just place your part/s, then press RUN. The software automatically recognises the part, taking all the measurements at the touch of a button, with Go, No Go results. And the exceptional simplicity means that operator training takes minutes, not hours.

*Note: Once the system is focused, no further focusing is required for components of similar height.

 

What can I measure?

2D (X,Y) measurement within the field of view offers significant advantages over alternative dimensional measuring solutions. In order to benefit the speed and simplicity offered by FOV measurement, the major consideration is that your component must fit within the field of view (57 x 43mm). Typically, FOV measurement is ideal for 2D (X,Y) measurement of small flat parts, such as …

GasketsO-ringsStamped parts
CirclipsPressed partsLaser-cut / water-cut parts
   
Small plastic partsExtruded materialsCutting tools
ConnectorsOther small flat partsAnd much more …

 

Full range of non-contact measurement solutions

Measuring applications vary greatly. Vision Engineering’s measurement range consists of a full range of non-contact measurement solutions, ideally suited for a wide range of 2-axis and 3-axis measurement. The Xpress field of view measurement systems represent the latest development in this range.

To discuss how Xpress or any other of Vision Engineering’s products can help save you time and money, why not contact one of our Metrology Application Specialists to discuss your measurement requirements?

Stereo microscope eyepiece SX45

How to correctly set-up and focus a stereo microscope

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Quickly and easily set-up and focus your stereo microscope.

  • Turn on the illumination – adjust the light source so that it illuminates the subject.
  • Set the dioptre setting(s) to zero.

  • With the eyes about 10mm away from the eyepieces, adjust the distance between the eyepieces (interpupillary distance) until you see a single image.
  • Adjust the illumination brightness to the desired levels.
  • Zoom up to the highest magnification.
  • Closing the right eye (or the same eyepiece as the dioptre adjustment), adjust the focus until you get a sharp image.
  • Closing the left eye, adjust the eyepiece dioptre until you obtain a sharp image.
    (Make a note of your dioptre setting for future convenience.)

Note: Dioptre adjustment is performed on just one of the eyepieces.

  • Your stereo microscope is now correctly focused. Your sample will be in focus throughout the zoom range.
CamZ handheld digital inspection magnifier

CamZ digital magnifier vs. iPhone 4S camera

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Which takes better pictures?

CamZ is a handheld digital magnifier, providing magnification options (up to 14x) and is in worldwide use for a wide range of tasks, from documenting faults to inspecting immobile subjects. The iPhone 4S is great, people love it. Smartphones are now the common choice for taking pictures, so should be considered as a real alternative to the stand alone digital camera.

Why don’t I just take pictures with my iPhone?

These days, we all have smartphone cameras, or digital cameras with 5Mp, 10Mp, or more. So why would you need a CamZ digital magnifier?

To explain the difference, we decided to pitch CamZ versus an iPhone 4S, as well as a Canon PowerShot A650 digital camera.

Here are the top-level specifications:

CamZiPhone 4SCanon PowerShot A650
Image sensor3Mp*8Mp12.1Mp
Image size480 x 272 pixels3264 x 2448 pixels4000 x 3000 pixels

* Part sensor application

How CamZ works

Taking and storing magnified images is made easy with LED illumination specifically configured for close-up imaging. But, before we get started, there is a fundamental difference between CamZ and a digital camera to explain.

With a digital camera, you stand back from the subject being photographed and take a high resolution picture. The large size of the image means that you can zoom in to view more detail.

CamZ is a digital magnifier… meaning that the image you view is already magnified (up to 14x). When viewing a subject, you position CamZ around 2cm from the subject, much like a magnifying glass. You can then ‘freeze’ the image to view the image, or save it on CamZ’s internal memory.

Saved images are 480 x 272 pixels in dimension, which does not seem large compared to a digital camera, however since the images are already magnified and the LED illumination optimised for magnified (close-up) imaging, it is easy to take high quality pictures with CamZ.

Lets look at the results…

CamZ handheld digital magnifier
Image sensor3Mp (part sensor application)
Image size480 x 272 pixels

4x magnification

9x magnification

14x magnification

 

iPhone 4S
Image sensor8Mp
Image size3264 x 2448 pixels

Maximum zoom (without flash)
View full size original image

With flash

Enlarged and cropped image

 

Canon PowerShot A650
Image sensor12.1Mp
Image size4000 x 3000 pixels

Maximum zoom (without flash)
View full size original image

With flash

Enlarged and cropped image

 

The Conclusion

 

Both the iPhone 4S and Canon PowerShot A650 are very capable cameras. With a steady hand, the Canon PowerShot A650 is capable of taking surprisingly good close-up photos, but since there is no easy way to suitably illuminate close-up subjects, it is very difficult to capture a good image. To illustrate the point, here is another image from the iPhone 4S, but this time with a separate external light source (LED ring light illumination).

The image quality is significantly improved. Neither the iPhone 4S nor the Canon PowerShot A650 were designed for close-up imaging, so it is not surprising that they did not perform too well, which of course illustrates the point. To take close-up pictures, you need the correct illumination, as well as a good camera. If you need to capture magnified images, in any location, without having to fiddle with camera or illumination settings, then CamZ is ideal. For everything else, there is your smartphone or digital camera.

Optical magnification of drill bit

Optical Metrology Spotlight…Size IS everything

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When we start looking for that all important measuring kit, it’s tempting to go for the all singing and all dancing metrology system, that can’t fail but to give the accurate measurement needed to get that instant pass or fail.

But it’s not all down to the cost of the system and this doesn’t always reflect on the accuracy you can expect to achieve.

What are you measuring

It’s all about what we are trying to measure. Investing in a good optical measuring microscope could allows us to measure those small sub ten micron accuracy features, AND save our budget, without having to compromise on accuracy.

As the components on our books get smaller and smaller, Co-ordinate Measuring Machines (CMMs) are becoming less efficient, not only because they struggle to measure features quickly with cumbersome probes, but because they don’t allow us to inspect surface features or provide that important non-contact measurement, absolutely pivotal to critical components such as medical devices.

Inspection not possible with CMM

Optical measuring microscopes allow us to inspect surface features that would not be able to do using CMMs. This is down to the high magnification which enables us to inspect features and surface features that can’t be seen with just the naked eye.

Having the ability to inspect surface features during measuring routines means we can check for surface defects such as the quality of coatings or machining defects such as burrs and scratches.

Optical measuring microscopes use a microscope-resolution, pure optical image, and this together with the best image recognition system known to man – the human brain.  Combined together, it provides highly accurate measurement, particularly for difficult to view components or complex features.

Is video measuring an alternative?

The alternative would be to orientate towards a video measuring system, but even video systems do not give us the fidelity we can obtain from an optical systems.

Even with the higher density chips now available for video systems, closing the ever decreasing threshold between optical and video resolution, video systems will never simulate what you can see through an optical system.

Although the image quality of the video system is improving with higher density chips, the chips will always be limited by how small the chips can be by the wavelength of light they require to produce an image.

Similarly with an optical image we don’t need to adjust or calibrate a screen to see accurate colour rendition, like we would for a video system, it’s already there in front of us.

White balance can also be a problem, especially if there is a one video system measuring a catalogue of component parts. Highly reflective alloys require the white balance to be finely tuned and if we are not careful we can spend an unprecedented amount of time adjusting the camera controls to obtain a highly defined edge for measuring, rather than simply using a cross hair to take out points from what we see immediately through the use of an optical system.

In brief

In summary, a good optical system has a smaller foot print than a CMM and often costs less too.

For those of us looking for accuracy of sub ten microns and measuring features that are not always visible to the naked eye, an optical system is a good starting point.

If we need to inspect surface features and our critical components are in danger of deformation an optical system should be considered. If in addition to these factors the components are complex with little contrast, no easily defined edges, and colour rendition is equally as important, then an optical system maybe the only option. If you can see it, you can measure it!

Falcon 3 axis video measuring system CNC

Spotlight on the Falcon 3-Axis Video Measuring Machine

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Measurement and inspection have become increasingly critical in the manufacturing process with pressure on increasing throughput and turnaround times. Smaller components with tighter tolerances means greater size to performance ratios, but the adverse effect of all these demands requires meticulous inspection and accurate measurement, often sub 10 microns.

Even with new solutions being introduced to the market to meet with current manufacturing / quality requirements, departments often lose valuable time training staff on new systems, with initial setup and appliance frequently slow and laborious.

With accuracy sub 10 microns and ease of use minimising training necessities, Vision Engineering introduced the new Falcon,
3-axis video measurement system, to complement their wide range of optical measurement solutions and award winning stereo inspection range of microscopes.

Designed with video essentials and additional valuable features, the Falcon has already been a success in a wide range of markets because of its accuracy and outstanding image quality.

Falcon vision system addresses the demands of manufacturing today with features and capabilities allowing high throughput to be maintained without compromising on accuracy and therefore quality.

Falcon is available as a manual option and a CNC (Computer Numerical Control) option depending on measurement requirements.

As a key feature, Vision Engineering has produced the capable Falcon to be easy to use, designed to allow a wide range of components to be measured accurately, while maintaining consistent measurement which are both repeatable by the same individuals, measuring the same components and reproducible by others measuring the same components.

Ease of use means minimum time is required for both training and set-up and even initial application.

Non-contact – no deformation of component parts or probe damage

Compact enough to squeeze into the corner of a quality control department, the Falcon’ compact size is deceptive, it boasts a zoom magnification range up to 100x and its high precision stages (calibrated with Non-Linear Error Correction or NLEC) provide accurate and repeatable measurement with one micron encoder resolution.

The system is a non-contact measuring solution which means there are no probes which can be damaged, or more importantly, critical components such as medical devices can be measured and inspected without deformation occurring.

Manual or automated, the Falcon addresses the throughput by offering an automated measuring solution for measuring components, and with high precision stages, the smaller components with tighter tolerances can be measured to ± 4µm in both x and y axes.

Additionally, the Falcon video system measures in z-axis which is motorised for fine and rapid movement with a repeatable 5-position indexed zoom.


Fig. 1.0. Shows the cutting edge of a tool tip, zoomed in using a 10x objective. The cutting edge can be inspected and measured simultaneously.

 

 

Quadrant Illumination – no angle is too difficult

Designed to give engineers increased flexibility for the range of component parts on their books, the Falcon is designed with quadrant illumination to enhance the visibility for both the inspection and measurement of component parts.

Depending on their features, some components such as tool tips can be difficult to measure and inspect due to the angle of the cutting edge.  However, quadrant illumination means there is additional control over the direction of the surface illumination.  For example: Figure 2.1., below shows the surface of the tool tip with one quadrant illuminated.  Each quadrant benefits from a set of four bright, white LEDs.  In contrast Figure 2.1., below shows all of the quadrants illuminated, where inspection requires larger surface areas to be illuminated for quicker processing.

Shows the cutting edge of a tool tip illuminated by a single quadrant at 6 o’clock

 

 

Fig. 2.1. Shows the cutting edge of a tool tip illuminated by a single quadrant at 6 o’clock.

 

 

Fig. 2.2. Shows the tool tip illuminated by all of the quadrants – 16 LEDs.

 

 

Equally, the versatility of the quadrant illumination assists is the documentation process through digital image capture, where it can be utilised to enhance specific areas and features.

Unique Camera Iris Feature – the advantage of changing the depth of field.

Digital image capture is often a prerequisite for today’s quality systems, and so Falcon has been designed with an innovative camera iris. The camera iris can be opened up or closed down depending on your intention, for example, closing the iris one will obtain a greater depth of field, ideal for digital image capture and therefore reporting purposes; however, opening  the iris will obtain a sharp edge but decreased depth of field for accurate feature measurement – see below.

 

Fig. 3.1. Shows the cutting edge of a tool tip with the iris fully open allowing for a reduced depth of field for accurate measurement.

 

 

 

 

Fig. 3.2. Shows the cutting edge of a tool tip with the iris closed allowing for an increased depth of field for digital image capture.

 

 

 

Digital image capture and a wide range of features are designed to be easy to use and include a programming measurement sequence to measure the same points per feature, part after part; easy-to-view graphical representation instantly views pass / fail performance details for critical part dimensions.

The advanced Falcon option with QC5000 software allows for CAD import and export as well as data integration with PC software such as Excel.

With a wide range of capabilities, the Falcon is an intelligent system, yet has been designed to be easy to use and to fit into a wide range of manufacturing processes, either just for measurement of key features and digital image capture, or more advanced programming and geometric tolerancing and analysis.

CNC Automated Capability

Falcon also incorporates an automated measurement option, making the measurement process effortless. The Falcon’s automated CNC (computer numerical control) option allows measurements to be made automatically, saving significant amounts of time.

Once the component’s programme has been implemented, the same component can be measured over and over again, with impressive repeatability and reproducibility.

Even with the current demands on manufacturing such as tighter tolerances and faster turnaround times, simultaneously there is an evolution of inspection and measurement systems continuing to support changing requirements.

The Falcon from Vision Engineering has already proven to be a success within manufacturing companies around the world requiring such advanced capabilities, and with ease of use requiring minimum training, bundled together at a competitive price, the Falcon is often a highly considered solution.

Lynx VS8 pcb stereo microscope inspection work station

The role of optical inspection in today’s demanding electronics industry

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Reliable automated systems for populating PCBs are a common sight on most of today’s assembly lines. With this in mind, to what extent are manual processes implemented into the production of PCBs, in today’s demanding electronics industry?

The development of automated inspection routines has been fuelled in part by the changes in electronics manufacturing processes.

Firstly the departure from through-hole components to surface mount components meant that traditional in-circuit tests no longer had the electrical connectivity to provide high levels of fault coverage. It has further been accelerated by the use of smaller and smaller geometry devices forcing the requirement for a high connection count automated solution.

PCB inspection systems come in a number of guises: automated optical inspection [AOI]; automated X-ray inspection [AXI]; automated Infra-red inspection; manual video and manual optical inspection – positioned at post paste, post place, post solder and finished goods stages.

With all of the technological developments of automated inspection solutions, there remains the fundamental reliance on human intervention to program and train the automated inspection system to achieve the level of fault coverage that is required for a particular product.

A high quality manual inspection process is essential in the generation and stabilization of an automated inspection programs. This is particularly important where a variety of boards are assembled and tested.

Use of manual inspection in today’s industry

Optical inspection is often used by research and development engineers, especially where the prototypes of boards are inspected for accuracy and design for fit. At this point automated routines have not been programmed and with no defect history, quality procedures rely on the experience of their engineers and the accuracy of the tools allowing them to manually inspect the boards.

Often, alongside automated inspection systems there will be spot checks on production solder quality. This will usually be implemented to stringent quality procedures making sure the boards are being inspected by the automated systems consistently.

With a balance of cost and quality always in mind, new components are often sourced from competing suppliers and new suppliers are often sourced to provide new and improved components. When this occurs, it is paramount that these components are checked for quality and this can only be achieved by inspection, where often manual inspection is preferential.

Where bespoke boards are designed and manufactured, optical inspection is an ideal solution where a large investment of automated inspection is not always necessary.

Manual inspection systems come in a number of guises. Ranging from simple bench magnifiers to high resolution video cameras, the humble stereo microscope has become the mainstay of manual inspection solutions, since whilst the resolution of video systems has increased dramatically over the decade, they are only able to present 2D images to the operator.

However the design of the microscope dictates that operators must sit in an uncomfortable position, often for prolonged periods, which can result in operator fatigue, leading to a risk of error.

Ergonomics and manual optical inspection

Where manual optical inspection is required, a high level of ergonomics is essential to maximize comfort to operators, minimising associated fatigue from a strained body posture, optimizing both accuracy and productivity.

Traditionally, optical microscopes have two eyepieces, look like a microscope and act like a microscope. The resulting combination of a human operator with a microscope provides a powerful and highly flexible inspection solution for any size of electronics manufacturing operation, yet for many, the issue of operators fatigue and the resulting errors provides a real-life and everyday obstacle.

Eyepiece-less microscope technology

Vision Engineering’s patented optical technology is designed to overcome the fundamental problem of a conventional microscope – the small image that exits from the microscope eyepieces.

With ‘eyepiece’ microscopes, the size of the image exiting the eyepieces (the exit pupil) is around 3mm in diameter. This means that the operator must precisely align their eyes with the eyepieces, otherwise just a small movement of the head will result in a loss of image.

The result is an operator fixed rigid in and uncomfortable position. ‘Eyepiece-less’ technology enlarges the image exiting the microscope eyepieces.

Vision Engineering’s patented range of stereo inspection microscopes utilise a technology to optimize ergonomics is the sophisticated Dynascope™ viewing head used on the Lynx – an advanced stereo zoom microscope – as well as Vision Engineering’s range of optical measuring microscopes.

The patented Dynascope™ optical technology used in Lynx systems utilize a 148mm diameter multi-lenticular (multi-lens) disc surface comprising of over 3.5 million individual lenticules (lenses), each measuring just 70 microns in size.

The Dynascope™ disk spins at 3,400rpm to merge the millions of individual optical paths into a smooth, expanded stereo image with a generous depth of focus and a wide field of view.

In use, the multi-lenticular disc serves to expand the intrinsic pupil of the system. The resultant image is reflected through the field lenses to the operator’s eyes and the high resolution image is projected onto a large viewing area for maximum viewing comfort.

Reducing eyestrain and fatigue

As operators frequently alternate their views from the magnified object image to the actual object (especially during rework or when manipulating parts), the long distance to the apparent magnified image eliminates the need for the eyes to refocus each time.

In fact, the magnified image is almost exactly the same distance from the operator’s eyes as the actual sample is – a tangible advantage in reducing eyestrain and fatigue.

In addition, employing a viewer rather than eyepieces permits much greater positional head freedom and an upright body posture for the operator, plus allows the use of spectacles.

Operators who require reading glasses remove them for microscope viewing and must then re-focus at a different distance, which again quickly leads to eye fatigue. Operators with astigmatism fare worse: removing spectacles immediately spoils their vision.

The significant ergonomic advantages contribute to increased production rates and reduced scrap as the operator is able to work longer without experiencing eyestrain and fatigue.

Even better ergonomic viewing of PCBs

Vision Engineering Limited is launching an updated Lynx LED stereo microscope with oblique and direct viewer. Now employing LED illumination and an oblique and direct viewer, the Lynx provides a full 360° view around the PCB for 34° angled inspection of solder joints and pad alignment that can often be hard to reach by usual stereo inspection methods.

The Lynx is widely used in the electronics industry providing unrivalled ergonomic performance and optimum clarity with superb optics.

In addition, the Lynx now benefits from LED illumination, projecting brighter, whiter, long-life illumination on the PCB. Consumable costs have also been greatly reduced with costs decreasing by more than 80% and lamp life lasting up to an impressive 10,000 hours. The dimmable LEDs allow for every application to benefit from the precise intensity of illumination.

The LED illumination can now be used in conjunction with the impressive oblique and direct viewer.

Coupled with the switchable direct view and the benefits of stereo viewing offered by the Lynx, surface features can be easily inspected in three dimensions without moving the workpiece. It is ideal for inspecting device leads, PCB via holes, connectors, solder joints, solder bumps on SMT, TAB and ball-grid array devices, and precision wafer bumping characteristics.

It is this technology that is used in parallel to automated processes, maximizing the quality of PCBs. Manual inspection plays an important role alongside automated systems or where automated systems are not a cost-effective option and since technology is constantly changing and components are evolving, optical inspection provides a magnified view for engineers so they apply their expertise and knowledge to individual case by case scenarios and imperfections.

Now celebrating their 50th anniversary, Vision Engineering’s patented optical technology brings the stereo microscope into the 21st century, breaking the mould of the traditional, uncomfortable microscope.

The latest evolution of Vision Engineering’s patented ‘eyepiece-less’ technology not only removes the need for the restrictive eyepieces of a conventional microscope, but provides the user with the ability to see high detail, in complete comfort.

Vision’s continuing research and development program is set to produce more award-winning, innovative products.