Hexagon’s Manufacturing Intelligence division has launched Captura, an entry-level optical coordinate measuring machine (CMM) that offers an intuitive and cost-effective solution for multisensor measurement of small to medium parts.
Captura supports measurements using vision sensors, laser sensors and confocal sensors, and is designed to offer good price to performance ratio for the entry-level market. The basic machine is supplied with a vision sensor and can be expanded with additional sensors. The dynamic machine concept offers high positioning accuracy, fast measuring point acquisition, and high-performance vision capturing. Captura CMMs run the Metus metrology software, a Hexagon-developed package for 2.5D multisensor measurement. Metus has its roots Hexagon’s flagship PC-DMIS metrology software, and delivers the highest standard of precision measurement in an easy-to-use software package.
“Multisensor and optical CMMs are ideal for manufacturers who are working with very small or fragile parts, or with materials that can’t be measured with touch probes – for example in the electronics sector,” said Kah Khoon Goh, Business Development Director Asia-Pacific.
“As manufacturing in the Asia-Pacific region diversifies, we’re seeing more manufacturers selecting this kind of system. Together with the user-friendly Metus software, Captura has been designed to meet the specific requirements of entry-level users without compromising on overall performance.”
How does the aerospace industry manage to optimise its manufacturing processes and produce more parts of the highest quality in less time? Simon Côté, product manager at Creaform, explains.
The aerospace industry is known for manufacturing parts with critical dimensions and tight tolerances, all of which must undergo high-demanding inspections. Given the scale of the controls to be carried out on these parts, it is hardly surprising that quality people prefer to turn to coordinate measuring machines (CMMs). After all, this highly accurate measuring instrument has their full confidence.
However, directing all inspections to the CMM may cause other non-negligible problems: CMMs are hyper-loaded, generating bottlenecks during inspections, slowing down the manufacturing processes, and causing production and delivery delays.
Is it possible to unload the CMMs so that they are fully available for the final quality controls? How can we improve manufacturing processes to produce more parts faster and, above all, of better quality? And in the event of a quality issue occurring during production, is it possible to identify the root cause more quickly in order to minimise the delays that could impact schedules and production deliveries?
This article aims to explain how important players in the aerospace industry have managed to unload their CMMs and improve their manufacturing processes without ever neglecting the quality of parts with critical dimensions and tight tolerances, such as castings, gears, pump covers, stators, and bearing housings. Solutions developed by the aerospace industry can serve as a guide for other industries because, after all, the entire industrial sector aims to optimise its manufacturing processes and produce more parts of better quality in less time.
Challenges
Bottlenecks at the CMMs
Aerospace companies, and many other industries, require that manufactured parts be inspected with the CMM, because they have full confidence in the accuracy of its measurements. This exclusive trust, however, creates certain challenges.
Indeed, the CMM is a highly accurate metrology tool that is often used to inspect non-critical dimensions, leaving little availability for final inspections and important dimensions. Therefore, quality controls are delayed due to these bottlenecks at the CMMs. Moreover, the CMM is a measuring instrument that requires a specialised workforce to build and execute the programming. If the company does not have the human resources to do the inspection programs, the parts will accumulate as they wait to be inspected. Therefore, buying more CMMs will not solve the bottleneck issue; what is needed is the specialised manpower to operate them.
But that is not easy to find these days.
Quality problem detected at the end of the manufacturing process
Too often, manufacturing companies wait until the end of the manufacturing process to perform quality controls on manufactured parts. Moreover, not only critical dimensions are inspected at the CMM, but also all other dimensions, which lengthens the process, often resulting in delivery delays.
So, what happens if a quality problem is detected only at the end of the manufacturing process? The quality assurance team must then go through the whole process to investigate and find the root cause. This analysis may generate downtime and production delays, which will impact the part delivery and customer satisfaction.
Solution
Incorporate an alternative measurement method to detect quality problems faster
Rather than inspecting all dimensions at the CMM, which requires long programming time and involves qualified resources, the aerospace industry uses a faster and simpler alternative measurement method to inspect less critical dimensions. One example of this alternative method is a metrology-grade 3D scanner called the HandySCAN BLACK.
The HandySCAN BLACK 3D scanner excels due to its scan quality, accuracy, and measurement reliability. Certified to ISO 17025 and compliant with the German standard VDI/VDE 2634 Part 3, the accuracy of the HandySCAN BLACK is 25μm. Using a safety factor of 5x, for instance (i.e., five times more accurate than the smallest tolerance to be measured), the aerospace industry uses the HandySCAN BLACK for inspecting features with tolerances starting at 125μm (5x 25μm) or more.
With its 11 blue laser crosses, combined with new high-resolution cameras and custom optical components, the HandySCAN BLACK can perform up to 1,300,000 measurements per second in addition to generating an automatic and instant mesh. This means that, unlike a cloud file, the generated mesh is already lightened and processed, which reduces the need for data filtering and lessens the variability on data processing. Thus, the aerospace industry regains the same confidence it has in the CMM, because the data obtained with the HandySCAN BLACK are consistent and repeatable.
Moreover, since the HandySCAN BLACK is a portable device, it can be moved to any stage of the manufacturing process to perform an intermediate check without having to move parts. For example, it allows a pump to be inspected before machining to ensure that there is enough material and after machining to validate that the dimensions are accurate. The HandySCAN BLACK can also be used to check the dimensions of gears before and after their heat treatment. Only a portable metrology tool enables quality and production teams to perform these intermediate checks quickly and easily during the manufacturing process.
Benefits
Unload the CMMs for the final quality controls
CMMs will always be the preferred measuring instruments for final inspections. However, these highly accurate devices must be available to perform the final quality controls. In other words, they must not be loaded down by all kinds of intermediate controls during the manufacturing process or by various investigations while troubleshooting production issues.
This is precisely what the HandySCAN BLACK is doing for the aerospace industry: unloading the CMMs by diverting less critical inspections to an alternative measurement tool. An in-house survey quantified that 50 percent to 90 percent of the dimensions could be measured with the scanner, allowing the CMMs to be available and used to their full potential and full accuracy for critical dimensions with tighter tolerances.
Improve manufacturing process
The more the parts are inspected during their manufacturing process, the less tedious the final inspection will be. Indeed, if the parts—whether pumps, gears, or casting—have already been inspected before and after their machining and before and after their heat treatment, the risk of detecting unexpected problems is lessened.
The final inspection on the CMM, now widely available, will only serve to control the critical dimensions, as all other features will have already been validated during the manufacturing process. These intermediate checks, performed during production, not only accelerate the manufacturing process, but also improve the quality of parts while producing parts in higher quantity. The same in-house survey quantified that intermediate checks with the HandySCAN BLACK improved the manufacturing process by 30 percent, either by producing 30 percent more parts during the same production time or producing the same number of parts 30 percent more quickly.
Find the root cause in quality assurance
Finally, the HandySCAN BLACK helps identify the root cause of quality issues that arise during production. Since it is accurate, fast, and portable, it can find the source of problems faster in order to minimise delays that could impact schedules and production deliveries.
Conclusion
The aerospace industry values the CMM for quality controls because of its high accuracy and repeatability. However, aerospace companies agree that the performance of portable scanners, such as the HandySCAN BLACK, positions this alternative method as a must to optimise its manufacturing processes. This fast, portable, metrology-grade measurement tool is increasingly proving itself to be an indispensable tool for performing quality controls during the manufacturing process in order to unload the CMMs and detect problems more quickly.
The time saved on measurements helps MAPAL Dr. Kress KG develop innovative tool solutions even more quickly for trends that will play such a pivotal role in the future. Contributed by Carl Zeiss Pte Ltd.
These days, employees from the development department at MAPAL Dr. Kress KG generally know within an hour if new tools will offer the level of precision their customers require. Instead of having to wait days for a service provider to deliver the measurement results, the company started performing onsite measurements at the beginning of 2018.
With the high-precision coordinate measuring machine (CMM) ZEISS PRISMO ultra, MAPAL inspects the workpieces machined with the new tools it manufactures. The time saved on measurements helps this global company develop innovative tool solutions even more quickly for trends that will play such a pivotal role in the future like e-mobility.
With the high precision coordinate measuring machine ZEISS PRISMO ultra, MAPAL inspects in-house the workpieces machined with the new tools it manufactures and generally gets results within one hour.
How a Workpiece Ensures a Precise Tool
“We need extremely exact measurement results to develop high-precision, innovative tools and tool solutions,” says Dr. Dirk Sellmer, vice president of R&D at MAPAL. For years, the company had an external service provider measure its workpieces and tools. Seller compares MAPAL’s tools to “Lego blocks that are combined to create complex solutions.” To deliver these bespoke products to the customers more quickly, the company invested in an extremely precise CMM from ZEISS.
In January 2018, two employees began working with the ZEISS PRISMO ultra. Almost a year later, Sellmer has reached the conclusion, “The investment has paid off.” The measuring machine provided MAPAL with the necessary precision and was immediately running at full capacity. The two employees from the development department, who alternate between the measuring system and the production machines every two weeks, inspect the department’s tools on the CMM.
Most importantly, however, MAPAL employees measure workpieces that are machined in the development area with the company’s own tools, thereby determining the workpieces’ precision and stability under manufacturing conditions. Precision is on everyone’s mind because most MAPAL tools and tool solutions are used when components need to be machined with a very high level of accuracy.
The stator housing for an electric motor is one example of how MAPAL is successfully meeting its customers’ requirements. The challenge with this cast part is to create the primary, large-diameter borehole that runs through the entire component—all with an accuracy of just a few microns. For perpendicularity, the tolerance is just 30 microns (0.03mm) and, for coaxiality, 50 microns.
The Right Tool for Stator Housings
These are extremely narrow tolerances for such large boreholes. Yet, a closer look at the design of the electric motor illustrates why these stringent requirements are necessary. Take for example the permanent magnet synchronous motor, the most frequently used motor design in new energy vehicles (NEVs). The stator is the stationary component within the motor. Coils or copper wires known as hairpins are attached. These generate a current that creates a rotating magnetic field. The rotor is located within the stator and, thanks to its own constant magnetic field, follows the magnetic field of the stator. The three-phase current of the rotor causes it to rotate in synch with the magnetic field.
The rotor cannot move unless there is a gap between it and the stator. However, the rotor is subject to considerable magnetic resistance, which in turn reduces the magnetic flux density and with it the power of the motor. Thus, designers make this gap as narrow as possible.
To ensure that the manufacturing process does not compromise the component’s design, MAPAL offers its customers a high-precision tool which is also very light for its size.
First, a borehole is made in the cylinder for the stator housing. This means that a tool approximately 30cm long creates a hole in the outer die-cast layer of the housing. Then, the surface is carefully ground down. Tools for the highly precise machining of primary boreholes for stator housings have been part of MAPAL’s product portfolio for one-and-a-half years. And since not all housings are identical, these tools are customised for each customer.
On-site Measurements for Reduced Wait Times
Automotive manufacturers generally provide 10 to 30 housings that MAPAL must then machine with the corresponding tools in its testing area. The measurements performed after multiple rounds of machining serve as the basis for optimising the highly complex tool solutions in line with the customer’s needs.
Before purchasing their own CMM, MAPAL had an external service provider measure its workpieces and tools. However, the company’s measuring expenses rose significantly within the span of just 10 years. MAPAL increasingly manufactures the tools for its customers and takes on pre-series production. Numerous measurements are performed to ensure that the customer has all the information they require. The need for more measurements also increased outlay.
Yet as the company considered whether or not to invest in a CMM, it was not the costs that ultimately tilted the balance, but time.
“We used to have to wait two to three days for measuring results. This is no longer the case,” explains Sellmer. Now, these are generally available within an hour.
Since the employees performing measurements at MAPAL have also received metrology training, there are fewer artefacts. “Since our team also works with the machines used in production, they have a highly developed intuition and know, for example, where contaminants might have impacted the measurement result,” says Sellmer.
Moreover, the components are now clamped in the machining fixtures for measurements and measured on the company’s premises. This reduces potential artefacts caused by removing the workpieces from the fixtures or preclamping them. Another significant benefit for MAPAL is the ability to intermittently perform unplanned measurements, such as with thin-walled components like a stator housing. This way, the company can see how fixturing impacts machining.
Dr. Sellmer highlights yet another key advantage: the improved communication between engineers and technicians. They can now discuss the results at the measuring machine, rather than relying solely on measurement reports. And this promotes knowledge sharing. “We now achieve our goals significantly faster,” concludes Sellmer.
Here’s how Wenzel’s SF 87 shop floor CMM helps improve quality and productivity at Ferratec GmbH. Article by Wenzel Group.
Since 1989, Ferratec GmbH has stood for quality and reliability in the fields of tool and mould making and plastics technology. The company offers complete solutions from a single source—from the conception and development of tools to sample parts and series production readiness, through to the assembly of the finished components. The range of activities includes mould construction for the company’s own plastic injection moulding shop as well as tool construction for special machines, jigs and fixtures, cutting tools, series production, assembly and contract manufacturing.
To guarantee the highest quality standards, Ferratec constantly invests in new technologies, including in the area of quality control. One of the latest acquisitions by the company for its workshop is the SF 87 coordinate measuring machine (CMM) from Wenzel Group. Featuring a large measuring volume, a small footprint and a wide operating temperature range, the SF 87 meets all the requirements for successful measurements in the direct production environment.
Wenzel’s SF 87 CMM is a universal measuring machine for the production environment. It requires little floor space and offers an optimized measuring volume of 800x700x700mm—making it ideal for a large part of the metal cutting and forming industry.
Featuring high measuring volumes, Wenzel’s SF 87 CMM has a compact design with a small footprint and is flexible and mobile for use in the workshop.
More Efficient Measuring And Testing Process
The machine concept offers a very good price-performance ratio with low space requirements. Its high traversing speeds and accelerations ensure high productivity. The combination of powerful probes and optical sensors also leads to a considerable increase in efficiency in the measuring and testing process.
According to René Kunkel, product manager for CMM at Wenzel, the system’s measuring volume is three times that of competing products with comparable footprints. “Further increases in efficiency can be achieved by using more powerful probes and optical sensors,” he adds.
The Wenzel SF 87 can also be operated at temperatures of up to 30 deg C. In contrast, conventional CMMs can only operate at up to 20 deg C—making them unsuitable for use in production halls. At Ferratec, the SF 87 is primarily used for the evaluation of dimensional accuracy and shape and position tolerances of plastic parts from a wide variety of areas.
SF 87’s bionic structure and unique low centre of gravity design make it efficient, ergonomic, productive, and insensitive to shop floor vibrations. In addition, it is multi-sensor capable and supports both optical and Renishaw tactile sensors. This includes the PH10MQ PLUS, which can be equipped with extensions and SP25M analogue scanning probes. SF 87 can also be configured with a tool-change rack to switch probes and extensions automatically, without requiring time-consuming requalification.
Another notable benefit of SF 87 is that it uses an active damping system and does not need air bearing technology, which eliminates the need for expensive clean air. Additionally, it can operate using only a 230V power supply.
“In order to be able to guarantee our customers’ quality products, we manufacture almost all tools ourselves. It doesn’t matter whether you want single pieces or small series. The measurement solutions from Wenzel contribute to product quality, productivity and satisfied customers,” said Kunkel.
The decision for this measuring solution was easy. “We have been working successfully for many years with Wenzel, using its LH series of bridge measuring device,” explains Gerhard Rosenberger, head of QS at Ferratec. The high quality of the Wenzel products, and the fast and good service, convinced him.
Wenzel complements its strong product offering with an optional comprehensive service package, wherein customers receive up to 60 months of maintenance, calibration, and inspection, as well as preventative replacement of worn parts, insurance machine coverage, exchange service, and online support.
Supporting Seamless Integration into Automation Solutions
While the LH series is in the measuring room for precision measurements, the SF 87 is integrated into the machine tool workflow. “The SF 87 stands in a typical shop floor environment with direct sunlight, for which it was designed,” reports Kunkel. In the next step, automated assembly and an initial visual check by optical sensors are planned.
The SF 87 is a directly usable production line and automation solution, and it can be integrated through the optional WENZEL Automation Interface (WAI) for material handling without expanding its footprint. The accessibility of the measuring volume from three sides is optimal for automated assembly by robots and can be flexibly adapted for more complex tasks, according to Kunkel. The ability to seamlessly integrate into automation solutions was also a key factor in Frost & Sullivan awarding the SF 87 its 2018 Global New Product Innovation Award last March.
The advent of new, high-performance measuring technologies could have posed an existential threat; but instead, the CMM has proven its resilience and remains key to metalworking manufacturers’ long-term strategies. Article by Sea Chia Hui, Hexagon Manufacturing Intelligence.
The DEA TORO CMMs can be employed as metrology stations in the development and engineering departments for supporting industrial design of complex contoured shapes, as well as flexible gages for process control in a shop environment.
For more than 40 years, the accuracy of coordinate measuring machines (CMMs) has guaranteed them a central role in metalworking companies’ quality control processes. The advent of new, high-performance measuring technologies could have posed an existential threat. But instead, the CMM has proven its resilience and remains key to metalworking manufacturers’ long-term strategies. This is because rather than replacing CMMs, new measuring technologies are complementing their strengths as quality control capabilities expand across the production cycle.
Adapting to Accelerated Evolution
A whole gamut of machines from smartphones and cars through to PCs have benefited from rapid technology advances that include lower cost of processing, higher performance software, and faster network connectivity. CMMs are no exception. But what makes CMMs different is their unique robustness and adaptability. A sizeable number of CMMs in use today have been in operation in excess of 20 years, kept up to date by retrofitting software and sensor systems.
At the heart of the CMM’s longevity are its unparalleled accuracy and durability, combined with an ability to be upgraded for new applications and working methods. Unlike many other machines, there is no need to replace a CMM in order to gain access to new functionalities. Manufacturers simply change a CMM’s controllers, software or sensors, while keeping their principal investment intact for years.
Increased Versatility and Cost-Effectiveness
Recent advances in measuring software, sensors and data analysis systems have played a crucial role in transforming the ease-of-use of CMMs, opening them up to new applications while increasing their measurement throughput.
One of the consistent benefits of a CMM has been its ability to provide 2-D touch probe-based measurement of unparalleled accuracy, precision and repeatability. But today’s metalworking companies often want to combine the accuracy of a 2-D probe sensor with the fast 3-D data capture offered by optical sensors.
Contactless measurement, for example, makes sense for sheet metal parts where throughput and speed of measurement are of the essence, or for metal parts on which a probe would leave an undesired mark. And because laser scanners can be used to create solid models from surface profiles, they are the ideal tool for reverse engineering and rapid prototyping.
Improvements in multisensor systems mean CMMs are ideally placed to support both tactile and 3D non-contact measurement. Crucially, manufacturers are able to opt for CMM software and machine controllers that enable seamless transfers between different non-contact or tactile sensors within a single inspection program. This enables a CMM to automatically switch between different sensors to capture a full metrological report even for complex parts.
And because software systems can be programmed to instruct the CMM to automatically change over sensors, multisensor systems can be left to run untended, whether they’re using touch trigger, optical, chromatic white light, laser point, or laser line sensors. The supporting software also makes it easy to create a graphical analysis of the captured CMM measuring data and overlay it on three-dimensional CAD models to compare the real data with the nominal data. This visual representation makes anomalies easy to identify, allowing operators to take decisions quickly on the shop floor.
And since the advent of intuitive software systems and greater levels of automation have made CMMs simpler to operate accurately, their use has been opened up to a wider range of employee skill sets and levels of experience.
Dealing with the Task in Hand
Not every application will need the same software package—much will depend on parts to be inspected and the complexity of their geometry, and the extent to which manufacturers want to analyse captured data and use it to inform their design, engineering, and production processes.
Similar factors shape the choice of a CMM, which is determined by the volumes of the workpieces to be measured, the tolerances required, and the desired throughput speed. Gantry CMMs, for example, continue to be a popular choice in the automotive, shipbuilding, and aerospace industries, because they are designed to accommodate the measurement of very large sheet metal parts. And they can be adapted to meet different accuracy and productivity requirements.
Parts such as aeroblades or car powertrain gears, for example, need to attain very tight tolerances, which requires the use of high precision CMMs. In contrast, the manufacturers of car bodies or aircraft fuselage are likely to seek a CMM optimised for throughput rather than precision.
When it comes to smaller parts, manufacturers in the metalworking industry have a choice of bridge CMMs that again provide differing levels of throughput, accuracy and flexibility, depending on the application need. Manufacturers can also consider gaining productivity benefits by installing CMMs on the shop floor.
As we have seen, the CMM’s versatility is at the root of its ongoing success, offering manufacturers the possibility to closely match a CMM’s measuring capabilities with their application needs. Whether a manufacturer is looking for an entry-level CMM or the most accurate measuring machine on the market, with the right supplier they can be confident of deploying a cost-effective CMM solution that future proofs their business for years to come.
With the DEA MERCURY FX solution, Hexagon’s Manufacturing Intelligence division has simplified the retrofitting of horizontal arm coordinate measuring machine (CMM), enabling automotive and other large part manufacturers to adopt smarter, more automated manufacturing practices while reusing their existing horizontal arm CMM guideway assets. Hexagon’s DEA MERCURY FX meets customers’ demands to combine the accuracy of horizontal arm CMMs with technology advances, such as automation and multisensor capabilities, so they can switch easily between tactile probe and non-contact measurement while capturing data that helps them improve manufacturing processes.
To help manufacturers shift to smarter working more quickly, Hexagon’s DEA MERCURY FX allows them to upgrade to the latest metrology tools and software features, while reusing their existing base tables, even if it is not a Hexagon system. Eliminating the need to replace base tables from a wide range of suppliers minimises disruption and downtime. DEA MERCURY FX is also available as a new standalone horizontal arm CMM solution for manufacturers.
“The horizontal arm CMM’s accuracy means many manufacturers want it to be part of their future automation strategy. By designing the DEA MERCURY FX for installation on existing base tables, Hexagon helps manufacturers upgrade to a horizontal arm CMM that supports features such as multisensor capabilities and the latest metrology software,” said Paolo De Bortoli, product line director, Horizontal Arm CMMs. “The move reflects our strategy to help manufacturers maximise the use of their existing metrology assets as they adopt new technologies that make their factories smarter and more productive.”
The DEA MERCURY FX is a multisensor horizontal arm CMM that supports both tactile and non-contact scanning. It enables OEMs and suppliers in the automotive, aerospace, defence and railway sectors, as well as manufacturers of large mechanical parts and earth moving machinery to continue to benefit from the precision of horizontal arm CMMs while adopting new, more automated and smarter metrology software and tools.
Hexagon will demonstrate how it is innovating to meet the fast-evolving needs of the aerospace and defence industries with a range of connected software and hardware systems at the Paris Air Show 2019, which is being held on June 17–23.
Visitors to the aerospace exhibition will see first-hand how discrete software and hardware solutions from Hexagon’s Manufacturing Intelligence division connect to form tool chains that lay the foundations for data-driven aerospace manufacturing ecosystems. On Hexagon’s stand, a continuous digital process, using digital twin and equipment monitoring technology, will show the development of an aeroengine blade from the design and engineering stages, through production, to the final quality inspection of the finished blade by the GLOBAL S HTA CMM solution.
Hexagon’s software and hardware systems underpin aerospace manufacturing at every level of design, production and final assembly on all sizes of parts and types of aircraft. They also support aircraft maintenance repair and overhaul. A Leica Absolute Tracker ATS600 on the stand will display the benefit of using large-volume 3D measurement for large structural assembly.
At the Paris Air Show, there will also be an opportunity to see Hexagon’s Geospatial division’s demonstration of a 3D flight training simulator based on Luciad technology. It combines static flight plans and dynamic aeronautical data, and provides real-time and post-training feedback and evaluation of any deviations from the designated flight plan and the disruptions that might cause.
The co-ordinate measuring machine (CMM) has become an indispensable tool in the process control regimes of modern production lines. Whether in-line or off-line, CMMs provide the most accurate measurements of parts ranging from turbine blades to engine piston rings.
This case study explores how DUKIN designs CMMs that minimise measurement errors through robust mechanical design and position feedback and how the recent expansion of the DUKIN product range to cover a variety of different accuracy and capacity requirements has been supported by Renishaw.
Background
DUKIN Co., Ltd., based in Korea, designs and manufactures a wide range of coordinate measurement machines (CMMs) that meet standard to ultra-high precision levels of metrology requirements in the electronics, automotive, aerospace and other industries.
These CMMs are used to capture three-dimensional measurement data on high precision, machined components such as car engine cylinders and aircraft engine blades as part of a quality control process.
The CMMs integrate either Renishaw optical or laser encoder systems to meet varying metrology challenges.
Linear position encoders are used in conjunction with Renishaw contact and vision probing systems to measure discrete points on a workpiece. This data is then used to ensure that parts meet predetermined tolerances.
Challenge
Manufacturers require CMMs that achieve high performance and system stability, which is affected by temperature fluctuations and greatly impacts overall accuracy. The instability in linear position measurements taken on the gantry axis affects inspection throughput and measurement accuracy.
Even when deploying Renishaw’s high speed 5-axis systems, which synchronise the movement of the 3 axes of the CMM and the 2 axes of the measuring head to inspect the part, the stability of the linear position measurements is important.
Solution
DUKIN uses Renishaw’s PH20 and REVO 5-axis probe systems on their CMMs with the understanding that robust CMM design is essential to realise the full performance potential of these measurement systems.
System designers at DUKIN deploy robust design principles and use high quality materials and components to minimise the amount of measurement error. These mechanical design approaches are applied in conjunction with software that compensate for errors caused by thermal expansion.
A combination of statistical and theoretical modelling and accurate live measurements of position and acceleration are used for force feed-forward control of the CMM’s motor driven axes.
For example, in a CMM bridge design; the X-axis (along the bridge) is driven along two guideways in the Y-axis direction where each shoulder of the bridge is driven by a linear system equipped with a separate servo motor.
To prevent a torque moment in the Z-axis direction and thereby distortion of the bridge structure, force feed-forward control is applied by the controller. This depends on the detected position of the measurement head as it moves along the X-axis guideway and the setpoint acceleration along the Y-axis.
Alternatively, comparison of the accelerations of the Y-axis guideways may provide additional feedback control of the bridge moment. Dependable, high-accuracy, position encoders are vital for these complex control regimes to work. A combination of a priori data and position and acceleration feedback in the X-, Y- and Z- axis directions are used to give the highest-levels of metrology performance.
Results
Renishaw encoders and scales are used across the full range of CMMs offered by DUKIN and the TONiC incremental encoder system with RTLC linear scale is installed on DUKIN’s gantry and bridge-type models.
RTLC is a low profile stainless steel tape scale featuring a 20 µm pitch. It is accurate to ±5 µm/m and may be ordered in lengths of up to 10 m. Any thermal expansion of RTLC scale is independent of the substrate as it is suspended in a carrier track, which maintains an air gap underneath the scale. As temperature changes occur in the CMM operating environment, the RTLC scale does not follow the same degree of deformation as the granite base. Thermal compensation is therefore greatly simplified – particularly in temperature controlled environments with the encoder scales and workpiece(s) in thermal equilibrium.
TONiC’s dynamic signal processing gives improved signal stability with ultra-low Sub-Divisional Error of typically <±30 nm to help realize superior motion control performance.
Regarding the role of Reinshaw’s innovations in DUKIN’s product lines, DUKIN Technical Manager, Tae Young Ku, has emphasized the important contribution of Renishaw’s encoder products by stating that: “We offer a wide range of CMM product lines, including standard, high precision and ultra-high precision models, depending on the type of position feedback. We have adopted Renishaw’s TONiC encoder series and the ultra-high precision RLE interferometry laser encoder system. The high-performance TONiC encoder is the most widely used and has been integrated into our CHAMP, HERO and VICTOR CMMs.”
Hexagon’s Manufacturing Intelligence division has launched its first blue laser scanning sensor for creating point clouds. The HP-L-5.8 joins Hexagon’s comprehensive range of tactile and non-contact sensors for CMMs and is designed for companies who need a versatile, affordable, fixed-line laser sensor.
The HP-L-5.8 performs equally well when taking point cloud measurements from dark or shiny surfaces. Designed to be rugged and compact, it protects the sensor from collisions and vibrations and is ideal for use in areas where accessibility is restricted as well as on smaller CMMs.
“Increasingly our customers want to add the speed and wide measurement coverage of laser scanning to their CMM’s capabilities,” says Christian Schorr, Hexagon’s Product Manager for Laser Scanners on CMMs. “The HP-L-5.8 meets our customers’ demand for an accurate, affordable laser scanner that turns a CMM into a multisensor machine that can switch easily between tactile probing or laser scanning in a single part program.”
The HP-L-5.8 is seamlessly compatible with Hexagon CMMs that use PC-DMIS 2018 R2 and subsequent versions of the software and works with an automatic indexing probe head or continuous wrist, making it easy to operate for users of tactile probing tools.
Manufactured parts need to be measured to ensure they meet the original design intent. Modern manufacturing techniques allow complex parts to be designed with numerous critical dimensions. A key element in precision metrology is having the right measurement tool for the job. Modern measurement machines use a variety of sensors to collect measurement data. Metrology software analyzes the measurement data, and through numerical and graphical reports, allows the user to make confident decisions about the part design and manufacturing processes. By Terry Herbeck, Vice-President of Asian Operations at OGP
