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Laser & Waterjet Profiling
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Austrian 3D surface measurement specialist Alicona has come a long way since its inception 11 years ago. When Dr Stefan Scherer and Dr Manfred Prantl started the company, the product portfolio was entirely software-based and used mainly in laboratory/R&D environments. Today, Alicona manufactures a range of optical 3D measurement solutions that are equally at home in production environments as they are in the lab.
Initially, Alicona’s software was used in conjunction with a Scanning Electron Microscope (SEM) to produce 3D models but as the company evolved, hardware was introduced resulting in an all-encompassing range of standalone optical measuring systems. What is fundamentally different about Alicona’s products however is that essentially they’re dual purpose – allowing the measurement of both complex forms and surface roughness on features and geometries on a single machine.
Globally, all R&D and manufacturing takes place at Alicona’s headquarters in Austria – supported by a global network of subsidiaries and distributors. UK sales director Brian Kyte heads up the UK operation which currently consists of six sales, service and support staff – three of which are direct Alicona employees and three are employees of Optimax, a Northampton-based company well-versed in the operation and support of Alicona products. This is a result of a recent partnership formed between the two companies to enhance and expand service and support levels in the UK.
Integral to all Alicona products is its own Focus-Variation technology which combines the functionalities of a micro CMM with those of a surface measurement system to enable vertical resolutions of up to 10nm – even across large vertical and lateral measurement areas. Alicona’s products are designed to operate within a measurement area of approximately 100mm square although the object size can be much larger.
“We’ve always approached measurement as a 3D process,” explains Mr Kyte. “Whilst an SEM can provide excellent chemical composition data and 2D images and can show, for example, that a feature is 50µm wide, it is unable to reveal any data concerning a feature’s depth. The algorithms used in our software have been 3D from the very start and initially were developed to give a Z dimension to an SEM image. Today all our systems are based on 3D optical metrology.”
Although early installations of Alicona’s systems were largely research-based, the requirement for the precise measurement of complex geometries and surface roughness has increased dramatically as miniaturisation has advanced. For this reason, Alicona’s equipment can be found in a wide variety of applications – from the shopfloor or inspection room of a manufacturing company needing to be able to accurately measure micro features and finish on components, to the development area of a cutting tool manufacturer. In fact, Alicona’s customer base is very approximately divided 50/50 between manufacturing companies and cutting tool manufacturers.
“It’s important to understand that the Focus-Variation technology used in our products is not intended to replace a CMM or an XY coordinate measuring system,” Mr Kyte emphasises. “But what it does do – uniquely we believe – is allow the detailed measurement of features that have up until now been almost impossible to measure. In addition, the technology also provides robust and repeatable data – particularly in establishing surface finish characteristics.
“For tooling manufacturers, the technology allows the accurate measurement of cutting tool edges, angles, radii, form and flanks as well as roughness – all vital aspects which can ultimately affect tool life and productivity. Many leading tooling manufacturers use our equipment extensively.”
The word ‘unique’ is widely used these days – often misleadingly – as companies clamber to gain a competitive edge, but Mr Kyte is clear in his definition of the word and how it applies to Alicona’s products. “Focus-Variation is a technology developed by, and exclusive to, Alicona and we have no direct competition,” he explains. “There are competing technologies such as interferometry and confocal microscopy but it’s not really comparing like for like as these methods are very limited in the Z range and consequently in the slope of angles that can be measured.”
The ability to measure both form and surface finish means that Alicona’s equipment is used extensively in often critical applications. The company has customers in a wide range of industries spanning motorsport for the measurement of engine and gearbox features to aero-engine manufacture where systems are used to detect stress-raising defects that could lead to catastrophic failure. Medical is an up and coming market too with a fascinating array of applications including roughness measurement on both dental and body implants.
As Mr Kyte illustrates however, although the measurement field is relatively small, the actual parts measured can be comparatively large; “If we take a component such as a large cylinder with stringent surface finish requirements on the OD – this would be very difficult to measure,” Mr Kyte affirms. “But what we’re able to do is construct an exact physical replica of the surface via a silicon model – incorporating any specific surface features – and measure that. You simply couldn’t do this with a conventional tactile measurement system.”
In good health
Current business levels for Alicona are healthy. 2011 was a record year and 2012 looks set to be even better. Encouragingly, sales are a fruitful mix of new and existing customers with two recent successes being the sale of two systems to a leading diesel pump manufacturer and the sale of an InfiniteFocus G4 system to the AMRC in Rotherham to assist with its research into cutting tool geometries.
“The AMRC is using the system for the measurement of cutting edges on cutting tools,” Mr Kyte advises, “and we supplied the machine with an additional rotational fourth axis for the ‘all round’ measurement of contours and surface finish. Edge preparation and controlled radii on cutting tools are areas currently being researched by the AMRC to establish optimum cutting geometries and the InfiniteFocus is being used to not only to measure the tool features themselves – but also to measure the effects of real life machining on those cutting edges in terms of tool life and performance.”
Focus-Variation – the core ingredient
Central to all Alicona products is Focus-Variation technology. Developed exclusively by Alicona it provides the foundation for the entire InfiniteFocus product range. “In basic terms, Focus-Variation involves moving the focal plane of an optical system over a surface,” Mr Kyte explains. “The process captures the data to produce a 3D model which is subsequently measured. It’s highly repeatable and the data captured is fully traceable but equally as important, particularly for shopfloor applications, is the fact that it’s very insensitive to both vibration and external light. Also the data can be exported to CAD.”
The Alicona product portfolio takes the Focus-Variation concept and adapts it for use in a wide spectrum of applications. The InfiniteFocus G4 for example is the base model but there are a number of variants including: IF-Edgemaster for automatic cutting tool edge measurement; IF-Edgemaster HOB for the 3D measurement of hob cutters; IF-ToolPrecision for the measurement of taps and; IF-Real 3D for the 360º measurement of drills and cutters. There is also IF-Portable for the mobile measurement of large components and IF-Robot, which, as the name suggests, brings a degree of robotic automation to the process.
An important new addition to the range is InfiniteFocusSL. It’s important because it’s Alicona’s first real attempt to bring Focus-Variation capability to the masses in an affordable, functional package. With this in mind, it’s intended very much for shopfloor use in real world manufacturing environments.
Essentially it’s a cost-effective optical 3D profile measurement system for the simple, fast and traceable 3D measurement of form and finish on micro-structured surfaces. High contrast colour images and high depths of focus are inherent features of the machine – as is a rigid and robust construction. The long working distance of up to 33mm in combination with the above average measurement field of 50mm by 50mm allows for a wide range of applications. Measurements are achieved within seconds and features, such as a coaxial laser for rapid focusing enhance its usability.
The system can measure surfaces with Ra values down to 0.08µm in seconds and all measurements are traceable with high repeatability and a known level of uncertainty that, when combined, with the ease of use the system meets the requirements from industry to perform 3D measurements in a near production environment.
“New products such as the SL are making Alicona products ever more flexible and versatile,” Mr Kyte advises, “and the great thing is that the data produced from all machines is fully interchangeable. In practical terms, this means that a machine installed in an R&D facility can communicate – and use the data from – a machine in production and vice versa.”
Times they are a-changing
Mr Kyte believes that Alicona is at the forefront of technology – but in terms of the future, his predictions go much further. “When customers invest in Focus-Variation technology they’re investing in the future,” he claims. “I believe that tactile-based systems will ultimately become obsolete – and that’s simply because as a measurement medium, they’re largely inconsistent and don’t tell the whole story.”
He continues: “Traditional Ra measurements are line-based and only provide data between two points – they say absolutely nothing about the overall surface finish of the area being measured. Draw six lines and you’ll get six different readings.
“Area-based measurement, such as that provided by Focus-Variation is the way forward and produces Sa values rather than Ra. Sa values are effectively functional parameters and provide much more meaningful and comprehensive information regarding surface finish than a line, stylus-based system ever can.
“In fact,” he adds, “a committee has been set-up to integrate Sa values into ISO 21578 which details areal texture parameter guidelines. Some very eminent figures in the industry are predicting that Ra values will be obsolete within five years in favour of Sa,” he concludes. “Area-based measurement is the future and removes any subjectivity.”