Robotic Metrology: The Future Is Now

Article by Jay Elepano, Business Development Manager – Large Scale Products

Robots have been playing an important role in automated manufacturing for decades. However, the larger question has always been, if the robot is smart enough to move the parts around, can we measure with it, as well?

When we think of robots, iconic images such as C3PO and R2D2 from Star Wars often come to mind, or perhaps even Rose, the Jetsons’ housekeeping robot. These images are of trusty sidekicks who will always work to get the job done – often providing a laugh as they do so. But what do they all have in common? They’re fictional.

The fact of the matter is, robots exist in the real world and have been playing an important role in automated manufacturing for decades. Historically, robots in metrology have been used to shuttle parts into and out of precision measuring devices, such as coordinate measuring machines (CMMs). However, the larger question has always been, if the robot is smart enough to move the parts around, can we measure with it as well?

Nikon Metrology  has worked hard to answer this challenging question.

Nikon Metrology’s Center of Excellence (CoE)—Metrology and Integrated Robotics (Derby, England)— conducted a study on the accuracy versus repeatability of robots in the measurement function. What it found—and there should be little surprise here—is that robots are extremely repeatable, but not very accurate. Specifically, they are not accurate enough for aerospace metrology applications in general. This explains why robots have been used in repetitive manufacturing tasks for years now, but not widely deployed for use as metrology equipment. In the business of metrology and measurement, accuracy is core to the business. Without guarantees of accuracy, there cannot be a guaranteed results.

Nikon found that the main issues with robot accuracy pertain largely to the stiffness and rigidity of the structure itself. To wit, when conducting experiments, one must assume stiffness in the unit. Then, as the count encoder pulses at the joints, one can calculate the end-of-arm robot position. The problem lies in the assumption of stiffness in a robot being valid. A robot will get to a location but will have no idea if it is actually, where it needs to be. In a CMM, one makes the same assumption of stiffness, and ensures it by making each axis linear in a simplified structure of X, Y and Z, producing a better assumption and result than with a robot.

Nikon Metrology has found a way around the robot issue by simply removing the assumption. To this end, its K-Series metrology system is optically based and fully integrated into the robot as an end-of-arm tool.

It begins with three linear CCD cameras. When light from an active infrared LED is detected, the three cameras triangulate its position in space.

The KROBOT Probe is pictured here, mounted on a robotic arm. Source: Nikon Metrology

Then, Nikon extrapolated the concept by surrounding a laser scanner with 40 LEDs strategically placed around the laser for redundancy and accuracy. Thus, Nikon can track the position of that laser scanner with extreme accuracy.

Nikon Metrology takes this concept even further with the KSCAN metrology system. The LED enclosure of the system not only tracks the position of the laser scanner, but also protects and ruggedizes it, creating a laser scanner that performs within the harsh reality of a manufacturing environment.

This hand-held laser scanning system uses Nikon’s MMDx laser scanner and is proving functional and popular in multiple applications and industries such as aerospace, automotive, and heavy machinery, globally.

Similarly, Nikon also produces the KROBOT probe, which is a modified KSCAN probe. The main difference between the two is that the KROBOT is not a hand-held device; instead, it functions as an end of arm robotic metrology device. However, because of the repeatable nature of robotic motion, it actually becomes more accurate than its hand-held counterpart.

This makes robot stiffness irrelevant because robot location is not used at all. Instead, the robot quickly, repetitively and robustly moves the laser scanner around the part to be measured. This way, Nikon leverages the robot’s strengths and mitigates its weaknesses as a metrology system.

In essence, the KROBOT system is a fully external metrology loop. With this, Nikon Metrology has greatly expanded metrology solutions for highly automated, repetitive applications, that greatly reduce your time and labor costs, while improving repeatability and accuracy. These systems are available from us now and are as easy to deploy as an off-the-shelf solution, but with the value we add. As for robots that make us laugh while cleaning our homes, well, we will leave that to others to develop. We’re happy just improving your quality, productivity and bottom line.

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Nikon Metrology takes non-contact multi-sensor 3D metrology to the next level

Nikon Metrology takes non-contact multi-sensor 3D metrology to the next level, realizing faster investigation and serial inspection by capturing full-part geometry with a single system.

By: Rob Snoeijs

As components get smaller and more complex, and the demand for high precision rises, manufacturing companies are challenged to produce high-quality products in a shorter time. Relying solely on tactile inspection requires excess overhead in terms of measurement preparation and execution, and it covers only a small portion of the entire part surface. This makes it necessary to use other metrology systems to gather additional geometry information; not exactly the ideal recipe for error-free data consolidation and fast, automated inspection. To overcome this obstacle Nikon Metrology incorporated several of its leading non-contact 3D technologies into one brand-new HN-6060 system.

Instead of getting partial inspection results from different metrology systems, Nikon Metrology combines multiple non-contact 3D technologies in a single inspection system. Equipped with a newly developed high-precision laser scanner measurement head, the HN-6060 system digitizes components at a rate of 120,000 points per second. To access the complex geometry of a spiral bevel gear or any other sophisticated part, the five-axis Coordinate Measuring Machine (CMM) can position the head and tilt and turn the specimen exactly as desired. Furthermore, the multi-sensor head incorporates proven optical image processing with built-in LED illumination, Shape From Focus (SFF), laser autofocus and zoom, and tactile probing. The HN-6060 is designed to acquire and process the full point cloud data of the diverse surface colors and textures of complex automotive molded and machined components, toothed wheels, gears, and medical devices, etc. Figure 1

Higher Accuracy
To ensure its laser scanner met the highest-precision standards required by advanced part manufacturers, Nikon further enhanced its non-contact sensor optics. It achieved unprecedented measuring accuracy by the use of a new cylindrical lens for the laser emitter, and an image-side telecentric optical system which, with high precision, directs the object image to a detector. The hardware mechanism is designed to suppress magnification variations resulting from temperature changes. The hinged optical system allows surface data to be acquired by the CCD with a constant focus. The enhanced CCD, in tandem with the bright optical system, allows glossy as well as low-reflectivity part surfaces to be captured without spraying or other manual preparation. Figure 2

Nikon engineers designed HN-6060 laser scanning optics and motion control with highest precision as the prime objective. Every second the laser scanner captures up to 120,000 points, each at 4 micron accuracy and with a line pitch of 20 micron, to accurately describe the waviness of freeform surfaces and the shape of geometric features. Capturing a multitude of scanned inspection points provides more valuable data than touch-probing a handful of points.

Powerful Video Measuring
To complement 3D laser scanning, the Nikon Metrology HN-6060 features the proven high numerical aperture zoom optical system from the Nikon NEXIV VMR series CNC video measuring systems. This enabling vision technology now exclusively uses LED illumination as well as image processing developed in-house by Nikon. Advanced edge detection by image processing increases measuring speed and confidence. Figure 3

In addition, the system is equipped with the very latest Shape From Focus (SFF) inspection sensor. Using an active texture pattern projection mechanism, the system can perform high-precision shape acquisition for surfaces that are devoid of texture, such as the surface of a mirror, while TTL laser AF enables level difference and profile measurement. To catch the finest details, Nikon optics provide crystal-clear and pinpoint-sharp 15x image magnification.

Managing Measurements
Regardless of the technology used to collect the data, the Nikon HN Metrology software manages the acquisition of point clouds through laser scanning and the SFF sensor. It also integrates a whole range of image-processing and touch-probe-related measurement tasks. HN Metrology software is an evolution in multi-sensor metrology software, based on the dimensional inspection software used on the NEXIV VMR. The software’s intuitive graphics support straightforward setup, macro-based teach-in, quick shape and distance measurement, and insightful 3D part-to-CAD comparison. The optional Focus Inspection software offers the edge in point cloud processing, providing the most detailed analysis and reporting capabilities.

After setting up an inspection routine that involves sampling complex shapes, the HN Metrology software offers a practical way to simulate system operation prior to taking actual measurements. The operation function simulator reads in the CAD model data, and completes the taught measuring process within the software. It is a unique feature that shows how geometry data capturing will proceed, predicts potential collisions, and checks whether full surface coverage will be obtained. The simulator may be run either in on-line mode or off-line mode. Figure 4

Since the HN Metrology software deals with 3D point cloud data, the data can also be used for reverse engineering purposes. This technology is typically utilized to create CAD from handmade clay models, to generate CAD data from existing parts when the original CAD data is missing, to update designs from part surface data produced by high-yield dies and molds, or to serve as input for rapid prototyping of freeform parts and products.

Synchronized Motion Control
The HN-6060 reaches the full potential of non-contact 3D inspection by having a two-axis rotary stage present the part for inspection. The high precision and rigid unit can dynamically apply the optimum rotation and tilt angles to scan around ribs and flanges, and to fully capture pockets, slots and notches. Important in this regard is the concurrent movement of the measuring head, which is optimized by a newly developed high-precision orthogonal drive system. A system console provides easy control over full five-axis synchronized head and specimen motion. It features a straightforward configuration that includes switches for changing between sensors and buttons for carrying out simple inspection. Figure 5

The adoption of five-axis synchronized hardware control is particularly useful for spur, helical, spiral, and other gears. By continuously adapting the orientation of a gear, the HN-6060 is able to fully digitize the faces and flanks of all gear teeth as well as the geometry in between them. Figure 6 As it successfully deals with the most complex gears, the system can accurately and fully digitize any intricate component. This makes the HN-6060 the preferred inspection system for machined (toothed) rotating parts, composites and smaller stamped or cut sheet metal components. It is equally suitable for plastic and metal devices made using (injection) molding or additive technologies, which covers an extensive number of parts used in automotive, aerospace, medical, and manufacturing industries.

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Visit Nikon Metrology at the Medical Design and Manufacturing Show 2011

 

Anaheim, CA – February 8-10
Booth #2094

Nikon Metrology will be featuring the following products at the show. Contact us today to set up a demonstration. 

 

The XT V 160 is a versatile tool that allows an operator to easily make use of the system’s manual and programmable inspection capabilities.

The iNEXIV VMA-2520 is a new multi-sensor measuring system that’s lightweight and compact enough to be used in the factory on the bench top, with fast, fully automatic and high accuracy features that make it ideally suited for a wide variety of industrial measuring, inspection and quality control applications.

Nikon’s new MM-200 Measuring Microscope is compact and lightweight with an affordable price for all who require precision and accuracy for measuring a variety of metal, plastic, and electronic parts in all industries; especially automotive and electronics.

 

Featuring one of the highest zoom magnifications in its class at 7.5x zoom, the new SMZ-745T trinocular stereo microscope offers powerful imaging capabilities at an economical price.

Visit www.nikonmetrology.com for more details.

Nikon Metrology and Deva integrate Focus Scan with Deva CMM controller

Deva Electronic Controls recently teamed up with Nikon Metrology to integrate the Deva CMM Controller with Nikon Metrology digital laser scanning probes and Focus Scan software.

Laser scanning is a developing technology well suited to today’s quality control and reverse engineering challenges providing CMM users with greater versatility, shortened development cycles and increased productivity.  Nikon Metrology’s latest scanning probes take the technology a step further by tripling traditional scan rates and eliminating user interaction when scanning components with varying colour or high reflectivity.
 
The highly popular CMM System Pack from Deva includes the fully featured 004 CMM Controller, 030 Servo Amplifier and the 031 Colour Touch screen Joystick.  This complete CMM hardware solution already offers support to a number of third party CMM software packages.
 
Users familiar with Nikon Metrology Focus Scan software will already appreciate the many features offered by this powerful application including the 2D preview window, which facilitates laser set up and operation.  Using the Deva 031 joystick PC View feature, this information and other PC information can be viewed remotely on the joystick screen enhancing ease of use and leading to more effective operation.
 
 “Deva are proud to partner with Nikon Metrology who share our commitment to product innovation” said Simon Moruzzi, Managing Director of Deva.
 
This Deva-Nikon solution is available on new CMMs from Aberlink Innovative Metrology and from Nikon Metrology as an upgrade package to retrofit to any CMM using the Deva CMM controller.  In addition Nikon Metrology offers  a range of new machines and upgrade packages available for other controllers.

Visit www.nikonmetrology.com for more details.

Cost-Effective 3D X-Ray Inspection

	Revolution X-ray inspection system. In the fast-moving and highly competitive electronics manufacturing market, long-term survival increasingly depends on developing relationships with customers and establishing a basis for repeat business. As a result, the ability to gain a reputation as a reliable and trustworthy supplier through the continual delivery of defect-free products has never been more important. Customers are also becoming increasingly price-sensitive, so gaining cost advantages through reduced waste while using competitively priced machinery is imperative. In response to this need, Nikon Metrology offers the XT V160 Inspection System, also known as the “Revolution.” A fundamental part of X-ray inspection is the ability to view a product from different angles. Further, identification of product defects depends on the magnification the inspection equipment can offer. And to increase the likelihood of identifying product defects, inspection images need to be of the highest possible resolution. Meeting all of these requirements, the smaller footprint and lower price micro-focus X-ray inspection system from Nikon Metrology provides the highest resolution and magnification possible within a compact system for quality control, research and failure analysis. With the ability to inspect substrates at steep angles of up to 75°, it is designed for 100 percent BGA and µBGA inspection, multilayer board inspection and PCB solder joint inspection in production lines and failure analysis laboratories in many manufacturing areas. True Concentric Imaging The XT V160 uses true concentric imaging that enables the operator to choose a Region of Interest (ROI) to inspect, which is then positioned in the center of the screen. To stay focused on this region, the X-ray source and detector rotate, rather than the product. The Region of Interest therefore remains completely locked into the center of the field of view under any combination of rotate, tilt and magnification, regardless of the sample’s position on the manipulator table. A further positioning feature is provided to view the region from any rotation (360° continuous freedom) and tilt angle of up to 75°. The XT V160 is therefore able to inspect around single or multiple BGA balls as the true concentric imaging feature operates over the entire scan area of the manipulator. Inspecting the rows of BGA balls is also less labor intensive than with standard manipulators as the XT V160’s true parallel tracking maintains the X and Y axes parallel to the BGA. This allows the rows to be scanned using a single X or Y axis instead of requiring the simultaneous operation of 3 axes. X-ray of ball-grid array. If a sample is to be declared defect-free, internal structures also require thorough inspection. The XT V160 employs Computed Tomography (CT) which is the process of imaging an object from many different directions using penetrating radiation and a computer to calculate the interior structure of that object from the images. Many industries make use of CT including electronics, aviation, medical, advanced materials research, casting and a host of other manufacturing areas. The CT function allows the complete structure of an object to be stored and examined to give a reading of all internal dimensions and the precise size, shape and location of any internal feature or defect. The CT system can be upgraded for real 3D analysis of components. The upgrade simply plugs into the existing manipulator controller without the need for future re-wiring or other modifications. Finding Product Defects Identification of product defects depends on the magnification the inspection equipment can offer. The transmission target design fitted to the XT V160’s X-Ray source has an ultra thin output window that enables samples to be safely placed within 250µ of the focal spot providing up to 13000x system magnification at all angles over the entire 410 x 410mm manipulator scan area. This facilitates 100 percent BGA, µBGA, multilayer board and PCB solder joint inspection, with quick analysis of BGA ball wetting, attachment, cracks and delaminations. In addition, the patented Nikon Metrology Xi “Open Tube” X-ray source is smaller than any other design and allows X-ray images of fine detail in thick and dense samples to be seen with ease. This high energy vacuum de-mountable unit enables views at steep angles through solder joints and heatsinks without ever running out of energy. Another attribute of this technology is the combination of the vacuum tube and the voltage generator. This has resulted in increased reliability and reduced maintenance costs as the extra charges typically associated with servicing separate voltage generators, cables and connections are avoided. Inspecting PC board on sample tray. To increase the likelihood of identifying product defects, inspection images need to be of the highest possible resolution. The XT V160 employs a tightly controlled microfocus X-ray spot and the latest digital imaging technology including a NanoTech target capable of feature recognition to approximately 500nM. The advanced electromagnetic lens is computer-controlled to ensure that the image remains in focus at all kV settings and the target does not burn when using high power. This enables the production of sharp images of micron level features of even the most challenging substrates. Inspecting PC Boards The photography equipment incorporates a dual field image intensifier with a digital camera. This combination (Impix) provides a large field of view, high sensitivity and high dynamic range (16 bit image processing). Combined with the On Chip Integration (OCI) feature, this equipment allows the user to take advantage of low energy X-ray photons for imaging low density features such as aluminum bond wires, thin copper traces, epoxy voids and more. This is achieved by a very sensitive image intensifier and by gating the digital camera to accumulate a greater signal. The production of high resolution images is supported by Inspect-X, an advanced image capture and analysis software with special functions for inspection of semiconductor package voids, wire bonding and BGA solder bumps. Inspect-X runs under Windows XP Pro on the latest specification processing hardware which enables the resulting data to be saved or exported directly to any COM compliant package, such as MS Word, Excel, Access and SPC systems. A range of inkjet, laser or thermal printers can then be used to produce photo quality printouts. Inspect-X allows rapid software customization to suit specific inspection requirements and has been designed to enable quick transfer and sharing of information so that anyone can open and view the information from their PCs. CT reconstruction of ball-grid array. The need for user-friendly and flexible equipment in inspection requires common technology and platforms that are best suited for the purpose. The XT V160 is a versatile tool that allows an operator to easily make use of the system’s manual and programmable inspection capabilities. The Windows control screen is laid out logically with all regularly used functions in view on single click buttons. Joysticks are also provided for very fine positioning and control to enable a direct and logical response from both sample manipulator and X-ray images. This enables operators to pick up on even the most demanding defects. Inspection equipment should be designed for ease of use without compromising performance. To meet this need, the XT V160 provides advanced viewing capabilities including dual monitors that separate images from the software control and the Quad View that allows 4 images to be displayed at once. This process is useful for image comparison or reference for operators. The XT V160 is highly intuitive to operate and as a result, operator training time is significantly reduced. In addition, the XT V160 features advanced ergonomics including fully adjustable shelves that ensure all system controls are at the operator’s fingertips whether standing or sitting and irrespective of the person’s height. During the inspection process of the manufacturing line there is a high risk of samples being damaged by static as sample trays are often made of anodized aluminum which is not ESD safe. To ensure this is avoided, the XT V160 has a carbon fiber static dissipative sample tray with an ESD-safe side control desk and an additional ESD clip in point. With the ESD control desk there is no need to worry about placing a sample on a work desk and risk static damage.