Few companies involved in the manufacture of aero engine components can boast a heritage that stretches back to the dawn of the jet engine age. One such concern is JJ Churchill. Founded by Walter Churchill on Christmas Day 1937, Churchill Components, as the company was originally known, began life as a supplier of machined engine parts to Armstrong-Siddeley. Two years after the start of WW 2 the company relocated to its current, although now much expanded, site in Market Bosworth. As Walter Churchill had worked closely with Sir Frank Whittle in the 1930s, the transition to gas turbine work was a natural step and compressor blades became a core product from the mid-1940s. The Aerospace sector remains JJ Churchill’s principal marketplace and the manufacture of compressor blades its main activity, although the company has diversified and manufactures for the Defense, Diesel Engines, Power Generation and Nuclear industries.
In addition to being a renowned specialist in the production of gas turbine blades from forgings and castings, JJ Churchill has developed a high level of expertise in the machining of blades from solid billet. Now, when possible, rather than machining large batches of forgings and castings to size, state-of-the-art highspeed 5-axis machining centres are used to machine blades in a single set-up from solid billet. The adoption of machining from billet procedures has led to impressive time savings; it has also slashed lead times and increased overall efficiencies. In addition, when compared to forged and cast blades, blades that are machined from solid can be held to much more demanding dimensional tolerances.
To ensure that the impressive efficiencies and shorter lead times gained by its innovative production methods are not squandered, JJ Churchill relies on a range of highspeed, Mitutoyo CNC Coordinate Measuring Machines (CMMs) to ensure rapid and precise blade inspection. The company’s most recent CMM purchase means that it now has nine, various capacity Mitutoyo Crysta Apex CM Ms, each fitted with Renishaw SP 25 analogue scanning probes and running Mitutoyo MCOSMOS CMM software. To enable the accurate evaluation of aerofoil geometry each CMM utilizes Mitutoyo’s Mafis aerofoil analysis software. So that CMM output is not compromised all programming is done offline which enables new products to be introduced with minimal CMM down time.
Bruce Tarry, JJ Churchill Quality Technical Manager explained. “JJ Churchill’s quality management system is accredited to BS EN /SO9001. As we operate in a wide variety of challenging markets and because of the nature of our customers, we retain a range of specialist NADCAP process approvals, we also have a variety of customer specific accreditations.
In addition to other checks, our compressor blades undergo 100% dimensional inspection and are measured to the highest standards of precision. Given our production volumes and the complex, variable freeform geometries involved, our blade inspection function requires a system that delivers both speed and high levels of accuracy. As we were aware of the progress made in the field of CMMs and compressor blade related software, and in accordance with our continuous improvement policy, in 2008 we investigated the available high specification CMMs that had the required levels of precision and speed to keep pace with our increasing compressor blade output.
Having considered several other machine and software packages, we decided that Mitutoyo’s Crysta-Apex CMM, with MCOSMOS and Mafis aerofoil inspection software, represented the ideal CMM and software combination. The Crysta Apex scored highly on all of our required criteria, in addition to having the high accuracy specification we needed, its scanning capability meant that the CMM could considerably speed-up the throughput of our blade inspection.
Because of the technically demanding nature of our work, as with our machine tools purchases, in addition to sourcing the most cutting-edge inspection technology available, we always ensure that any chosen supplier is able to deliver the levels of service and technical back-up we require. The assurances given by Mitutoyo UK gave us the confidence to proceed.
As our first Mitutoyo Crysta-Apex CMM proved to be a great success and given the excellent service we received from Mitutoyo UK, we soon ordered further Crysta-Apex models in a range of capacities. Our most recent purchase means that we now have nine Mitutoyo Crysta-Apex CMMs located in dedicated, environmentally sealed enclosures operating in production cells throughout our facility.
As each CMM operates in relatively close proximity to the source of blade manufacturing, we are able to provide rapid, precise feed-back of measuring results using Mitutoyo’s Measurlink SPC software and to truncate our production and inspection cycles. Not only have each of our Crysta-Apex CMMs proved extremely accurate and fast, they have been ultra reliable. In addition, we have benefitted from the excellent levels of service provided by Mitutoyo UK.”
Crysta-Apex CMM:
Mitutoyo Crysta-Apex CM Ms, as used by JJ Churchill, incorporate innovative moving-bridge type machine structures and are designed and constructed using advanced lightweight materials. These features help to provide the high motion stability that enables increased scanning speeds and high accuracy.
MCOSMOS Software:
Mitutoyo’s MCOSMOS modular suite of CMM software is available to meet the simplest to the most complex measurement and analysis needs. MCOSMOS1 contains the modules needed for handling basic measurement and part program creation while offering powerful gear analysis options. MCOSMOS2 extends the capabilities to online/offline part-program creation directly from a CAD model, and MCOSMOS3 further extends geometry handling to freeform surfaces, with an aerofoil option if required.
Measurlink provides statistical analysis of measured results in real time, as well as an offline process analyser module. The system is networked directly into JJ Churchill’s database so that an overview of all parts processed is readily available.