Few outside the tile-making and building sectors realise that roof tiles must be manufactured within a tolerance of +/-0.5mm. This requires precise measurement of prototype and mass-produced tiles to ensure accuracy. Metrology staff also check mould wear, tungsten carbide wear parts, and tooling condition. Sometimes, reverse-engineering replacement parts or creating CAD models for legacy tiles or inspecting 3D-printed items is necessary to prevent delays.
At BMI Group’s Crawley Technical Centre, Design Engineer Luke Kelly and his team have been using a portable measuring arm inspection system supplied by LK Metrology. Replacing a smaller, unsupported arm and manual tools like callipers, the new setup includes a 7-axis FREEDOM Arm Classic Scan with a 2.73m reach, touch probe, and LK’s laser line scanner, since late 2023, after acquiring Nikon Metrology’s business. The system features a rotatable 300mm FREEDOM Index Table, mounted on a metrology table, all supplied by LK. Innovmetric’s PolyWorks Inspector software from 3D Scanners (UK) offers advanced analysis, surface evaluation and report generation.
An essential inspection involves assessing die-cast aluminium moulds used for forming the underside of concrete tiles in extrusion. Pallets, which can number tens of thousands, suffer from abrasion and erosion. Replacing a large factory’s pallets can cost over £1m, making regular sampling crucial to evaluate condition, predict lifespan, and spot issues on the production line. The new LK system has improved this process, which is increasingly needed as pallets are sent for analysis more often. The group has hundreds of pallet sets for various products, including main tiles, cloak verges, ridges, and fittings.
Luke explained: “Our previous metrology methods for assessing the aluminium pallets, and indeed the tiles themselves, were time-consuming to set up and analyse. We took only 16 measurement points around the edges of each pallet, for example, so they wouldn’t show some of the wear in the centre of the objects that the laser scanner is able to. The amount and quality of the metrology data have increased enormously with laser scanning, allowing us to provide much more detailed reports to our tile factories so they can make any necessary adjustments to the production line and predict the number of passes the pallets can make before needing replacement.”
“Reverse engineering of tiles using the scanner is much faster and richer in detail than our previous method of taking individual cross sections. For some applications where we want a reference CAD model, it will save us days of work creating it from scratch, as we can use the STL output from the laser scanning software. The touch probe is mainly needed on the end of the LK arm for checking, both to the design and to EN 1024 standards, the twist and camber of clay tiles after they have been fired in a kiln. Inspecting the requisite 10 clay tiles each time would take too long to complete by laser scanning.”
Crawley’s component sizes vary greatly from 0.5mm sheet metal to large solar roof panels over 1m. The LK metrology solution handles all, offering more comprehensive reports. Luke said scan times are quick, and reporting tools are user-friendly, producing clear images for specialists. The index table speeds up measuring smaller parts needing all-around access. The end-of-arm probe, touched into fiducial dimples around the table, makes updating the coordinate system via the FREEDOM Index Table macro simple, allowing continued surface data capture.
The BMI Technical Centre is now considering acquiring an LK metrology-grade tripod so that the portable measuring arm can be taken into the group’s factories to perform QC on-site. This would reduce the time delay and costs associated with delivering sample pallets, tiles, and other items such as legacy machinery components to Crawley for inspection.
BMI UK & Ireland is part of BMI Group, the largest roofing and waterproofing company in Europe with a significant presence in Asia and Africa. It brings together some of the most trusted brand names in the industry, including Redland, Icopal, Sealoflex and Rosemary. The global group has a considerable presence in the UK, with four concrete roof tile factories, a clay tile manufacturing plant and another for producing tiles from recycled slate. BMI is the only manufacturer in the UK and Ireland of both pitched and flat roofing solutions, making it uniquely placed to support any new build or renovation roofing project.
