Renishaw is pleased to announce the launch of a new vision measurement probe (RVP) for use with the REVO 5-axis measurement system on co-ordinate measuring machines (CMMs). RVP increases the multi-sensor capability of REVO by adding non-contact inspection to the existing touch-trigger, high-speed tactile scanning and surface finish measurement capability of the system.

For certain applications, non-contact inspection provides clear advantages over traditional tactile probing techniques. Thin sheet metal parts or components with large numbers of holes as small as 0.5 mm, and parts which are not suited to tactile measurement, can be fully inspected with the RVP system. RVP also gives exceptional improvements in throughput and CMM capability by utilising the 5-axis motion and infinite positioning provided by the REVO head.

The RVP system comprises a probe and a range of modules that are automatically interchangable with all other probe options available for REVO. Data from multiple sensors is automatically referenced to a common datum. This flexibility means that the optimum tool can be selected to inspect a wide range of features, all on one CMM platform.

When using RVP, part illumination is provided by integrated programmable LED lighting inside each module. Background feature enhancement is also available using backlighting combined with bespoke part fixturing.

The RVP system is managed by the same I++ DME compliant interface as REVO and full user functionality is provided by Renishaw’s MODUS metrology software. New MODUS vision software capability includes RVP configuration, image processing with application specific options and automatic image storage for review and further analysis.

“REVO® has reduced inspection times by up to 80% per part.” Mecanizados Escribano has reduced bottlenecks while maintaining rigorous part inspection.

A Madrid, Spain-based precision engineering business specialising in complex parts for aerospace and defence applications has invested in a Renishaw REVO® five-axis measuring head and probe system. The change has resulted in a reduction in inspection time by as much as a factor of 5, ensuring quality control and inspection keep up with its high-productivity CNC machine tools.

It’s true that in many ways making things is getting easier, at least as far as the technology is concerned. For example, machine tools are simpler to program and operate, rapid prototyping means that product development is faster and cheaper than ever, and user-friendly CAD software may even negate the need for physical prototypes entirely. All of this assumes that what you are actually making, or trying to make, is relatively uncomplicated. It’s a different matter, however, if you are building complex multi-million dollar aerospace systems, like those engineered by Mecanizados Escribano.

“When we buy a machine tool we specify all the options,” says company project manager Juan A. Humanes. “But, having the best machines is only part of the equation. Our customers demand very rigorous part inspection, which means there’s always the chance that the metrology department can become a bottleneck, especially when the parts are complex and machined to very tight tolerances.”

He continues, “Depending on what the customer requests, we inspect between 10% and 100% of machined parts. The Renishaw REVO system, recently fitted to a Metris CMM, measures non-prismatic surfaces very quickly, many of which would be difficult or impossible to measure with touch trigger systems. In some cases, such as a complex avionics chassis for the Typhoon, the REVO has increased our inspection throughput by a factor of 5; typically, up to 80% reduction in time per part.”

Exceptional scanning speed and accuracy
The key attribute of the REVO five-axis head is its ability to overcome the limitations of three-axis scanning methods, where any attempt to rapidly move the large mass of a CMM results in inertial errors caused by accelerations and decelerations. Therefore, the only possible way to maintain acceptable accuracy in three-axis scanning has been at the expense of measuring speed. However, REVO uses synchronised head and machine motion when scanning, rapidly following changes in part geometry without introducing its own dynamic errors. The CMM is able to move at a constant velocity whilst measurements are being taken, without impacting accuracy.

REVO also benefits CMM users with infinite head positioning and innovative tip-sensing probe technology, which further improves measurement accuracy by sensing close to the measured surface. This combination of speed, flexibility and accuracy has proven to give exceptional performance in a wide range of scanning measurement applications, including circle, helix, sweep and gasket scanning, plus, if required, rapid single-touch routines.

Expanding to meet increased demand
Any visitor lucky enough to tour the Escribano factory can see the size and significance of the investment required for such production. Juan A. Humanes (pictured right) reveals it to be between €1million and €1.5million a year, and most of the company’s CNC machines are top-end, Japanese or Swiss-built multi-pallet and multi-axis: Makino, Matsuura, Mazak; Sodick wire EDMs and CNC precision grinders from Jung.  All of them are the latest models, meticulously maintained and configured to minimise set-up and non-machining time, mostly using Renishaw OMP40 spindle-mounted touch probes and NC4 non-contact laser tool setting systems.

Escribano has outgrown its current building and has designed and built a new facility, where it will relocate in the next few weeks. Until then, the two small rooms adjacent to the main workshop that house the company’s inspection equipment will remain crowded. In the larger of the two rooms, three DEA Global Advance co-ordinate measuring machines (CMMs) with Renishaw probes check samples of parts for everything from thermal imaging cameras to components destined for the Joint Strike Fighter. Alongside the main metrology lab’ is a smaller room housing the company’s largest CMM: a Metris LKV CMM equipped with the Renishaw REVO five-axis measuring head and probe system; part of a recent investment in inspection equipment that totalled around €300,000.

For most precision engineering businesses, the Metris and Renishaw REVO combination would be enough to cater for their metrology needs. But Escribano isn’t your typical workshop and its customers are somewhat more demanding, leading to further investments in other advanced metrology systems such as a white light interferometer microscope for measuring roughness, and a contact profile meter capable of assessing the size and texture of a part’s surface.

Sophisticated expertise and technology
The Madrid-based company is a rarity; privately owned engineering workshops with the expertise and the technology to deliver components and systems for such sophisticated applications are few and far between. No one at Escribano can or will talk about its customers or their products, but Humanes is happy to discuss what the company is equipped to do and how it does it.

“We specialise in machining complex, 5-axis parts in aircraft-grade aluminium, stainless steel, nickel alloys, copper and titanium,” he says. “The only way to be good at this kind of work is to make the necessary investments in technology and people. Our customers can choose between some of the best equipped suppliers in the world, so we have to make sure we can deliver exactly what they want, when they want it.”

A large proportion of Escribano’s production is for the US defence sector, which probably has more small, privately owned precision engineering companies than any other country on Earth so the question is; why would a US defence contractor choose to outsource some of its most complicated, quality-critical parts to a company in Spain, instead of one closer to home?

“Some people might assume that we win business because Spanish labour costs are lower than they would be at a similar, US company,’ says Humanes. “But they would be wrong. If that were the case the work would simply migrate to Asia. The truth is we are competitive because we invest in the best technology and we train people to high levels. We don’t just benchmark ourselves with competitors in Spain or Europe, we aspire to be the best in the world.”

General precision engineering may, thanks to the technology, be getting easier, but Escribano’s willingness to meet almost any standard of engineering precision means that even during the worst recession in living memory – and the Spanish economy is suffering the effects as acutely as any country – this family-owned company is still busy 20 hours a day.

Renishaw is highlighting a developing family of high performance hardware and software products for co-ordinate measuring machines that are specifically designed to aid the measurement and manufacturing of aerospace blades.

All products complement the multi-award winning REVO® 5-axis measurement system and include APEXBlade planning software for REVO sweep scanning and DMIS programming, MODUS airfoil analysis for the calculation and reporting of blade section profile and airfoil characteristics, and SurfitBlade to aid reverse engineering of the complete airfoil.

Historically blades have been measured in sections due to the limitations of measurement techniques. Now, the new family of Renishaw products enables the whole blade to be inspected quickly and accurately allowing unlimited section or full surface analysis based on high precision contact probe data.

APEXBlade is a software package designed to quickly generate collision free programs that drive the REVO measurement system to carry out complex ‘sweep scans’ that will collect point cloud data from across the complete blade surface. The CAD model is imported into the virtual REVO CMM environment prior to the automatic generation of the measurement plan. Both transverse and longitudinal scans are supported and each sweep can be split, which is useful for edges where the actual position is expected to be significantly different from the nominal CAD. Once the user is happy with the program, a DMIS file is generated that can be executed within Renishaw’s MODUS metrology software.

REVO blisk CAD fadeA key advantage of the new Renishaw approach to blade measurement is that a cloud of tip centre data points is generated over the entire airfoil and root surfaces. The MODUS point cloud sectioning (MPCS) functionality then allows ‘on surface’ sections to be constructed by intersecting any defined plane with the captured point cloud. This can be carried out at the time of measurement, or in the future if further sections at different locations are required, without the need for re-measurement of the blade.

The MODUS airfoil module then allows the user to take the nominal aerofoil sections available from the CAD model and the actual sections from the MPCS to provide blade fitting functionality for the reporting of blade section profile and aerofoil characteristics. MODUS offers comprehensive graphical reporting tools and the profile measurement results, which are fully integrated with all other feature measurement reports, can be output in pdf file format.

Integrated bladed rotor montageFor users requiring a reverse engineering capability, Renishaw’s SurfitBlade software is an offline application used to generate NURBS blade surface forms for use in downstream processes such as computational fluid dynamics and finite element analysis. It also allows average blade geometry to be established from a series of blade results.

In summary, the Renishaw airfoil inspection suite provides automatic generation of the CMM program, rapid, high accuracy REVO data collection and comprehensive tools for cross section or full surface analysis.