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Automotive trends drive widespread use of casting impregnation

As automotive OEMs increasingly look towards mega-platforms for vehicles as a way to reduce costs, implement greater production efficiencies, achieve more efficient product launches, and maximise greater economies of scale, suppliers in turn are changing their approach to post-casting processes. Stephen Hynes, marketing director at Ultraseal International looks at the issue for Foundry Trade Journal.

The rise in mega-platforms for cars - common parts, designs and architecture developed by OEMs for use across multiple vehicle models and even different marques - started several years ago and shows no sign of abating.
VW is expecting its MQB common platform, already used in six different models including the Passat, to be deployed in six million vehicles by 2020; General Motors, which had 24 platforms in 2014, is expecting to reduce them to just four by 2025. Renault-Nissan, Toyota, Volvo and Peugeot-Citroen have all developed common platforms. 
This trend has implications for suppliers of cast metal parts. If they fail to get their parts specified in a platform, it could see suppliers missing out for a long time on a large contract, with fewer alternative contracts available on which to bid. To win, they need to be able to reassure OEMs and tier one suppliers that their parts are top-quality - the risk for OEMs of using a mega-platform for larger numbers of vehicles is that if a fault develops, a recall would be very bad news indeed.
Add in to that the move towards the greater occurrence of cast-in features, rather than bolt-on components and therefore less reliance on assemblies; the increasing complexity and added value of automotive parts; and it is clear that a focus on quality is becoming paramount.
As a consequence, to combine quality with higher volume production, producers of automotive castings are moving towards fuller automation of post-casting processes such as casting impregnation with porosity sealants.
Porosity is a commonplace problem and can seriously affect the quality of cast metal components by causing them to leak. That’s why many OEMs and suppliers routinely impregnate them with porosity sealants as a quality enhancement.

Full Automation
Now, with the rise of large-scale production runs of single parts for mega-platforms, an increasing number of companies want to carry out casting impregnation as a more fully-automated process integrated into a just-in-time production line.
Whether they have traditional top-loading casting impregnation equipment, or the latest, two-stage, small footprint, front-loading machine such as the R-FL-Duplex Plus, they want greater automation, fast process times and a reliable system.
People often associate casting impregnation with automotive parts such as engine blocks and compressors, but the process is widely used for a whole range of powertrain components.
These include cylinder heads, cam carriers, cam covers, fuel pumps, fuel rails, heads, inlet and fuel system components, oil pans, oil sumps, thermostat housing, timing chain covers, torque converter case/bell housings, transmission cases, pump castings and valve body castings, turbo chargers and water pumps.
Porosity is a natural phenomenon that occurs during the casting process itself. Microscopic holes form in cast metal parts for a variety of reasons, including the natural shrinkage of the hot metal cooling down within the die mould. It can also happen if water vapour, or traces of die lubricant are trapped in the molten metal. As a consequence - although it can be controlled by careful casting - it is extremely difficult to eliminate altogether, especially during volume production runs.

Aluminium More Prone Than Steel
Another trend that is increasing the demand for fully-automated casting impregnation is the increasing use of aluminium in automotive production, fuelled by a desire to improve fuel economy and meet ever-tougher air quality standards. 
Ford has famously launched its first all-aluminium pick-up truck, the F150, and the ‘aluminium-intensive’ Jaguar XE is the most fuel efficient Jaguar ever at 75mpg (mixed cycle). Manufacturers of diesel cars in particular are looking at ways of off-setting the weight of extra equipment being fitted to meet the exhaust emissions standards of Euro 6, introduced in the UK for cars in September 2015.
Aluminium is more prone to porosity than steel, and the number of automotive components being made in aluminium is increasing - a trend that is expected to continue.
Fortunately, casting impregnation is also moving with the times and new techniques such as the two-stage impregnation process are making it easier than ever to successfully combat porosity in cast metal parts.
The R-FL-Duplex Plus casting impregnation machine has reduced the impregnation process to two stages - eliminating the drain and cold wash modules. Parts go straight from an autoclave to a hot cure tank. It uses Ultraseal’s global benchmark recycling sealant Rexeal 100™ and both the water and sealant are recycled from the hot cure tank to ensure that a fully closed loop system is achieved. The process is fully automated and can run round the clock with minimal downtime. 

Contact: Stephen Hynes, Ultraseal International, tel: +44 (024) 7625 8444, email: sales@ultraseal.co.uk web: www.ultraseal.co.uk