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New Cell Helps Widen the Applications of High Pressure Diecasting

The benefits of aluminium high pressure diecasting for high volume production, particularly for the automotive industry, are widely appreciated. However, there are very few foundries which focus on bringing the precision and versatility of this technology to industries where annual volumes are relatively small. UK-based MRT Castings specialise in exactly this area, and are proving that, with the right equipment and an innovative approach, the benefits of the process, such as excellent cosmetic finish and dimensional accuracy, can be enjoyed by customers with smaller volume demands in markets such as the medical, defence, marine and electronics industries. 

The company’s unique approach for these smaller volume customers means they need to be much more than a traditional foundry. As these customers often have no experience of designing diecastings, and have none of the other necessary support processes within their supply chain, MRT has to offer the complete solution and so works in close partnership with customers’ engineers to optimise component designs for efficient casting manufacture. They then manage the tooling process, prior to starting casting production at the company’s foundry in Andover, where they operate pressure diecasting cells from 220t to 530t locking forces. The facility in Andover also includes a busy gravity diecasting foundry, further widening the range of components produced. 

As many of MRT’s components are extremely complex, they often have high machining content, so the in-house CNC machine shop is one of the most advanced in the industry, equipped with 14 modern machining centres. The company also offers a full range of surface finishing processes. There is also a dedicated 4,000ft2 assembly facility for electro-mechanical assembly, and specialist packing services, enabling MRT to provide the complete finished product manufacturing process under one roof. 

Using high pressure diecasting machines for small volume production means that the equipment needs to be extremely versatile to support the manufacture of a wide range of different components. So when MRT needed to invest in a new diecasting cell to support their continuing growth, the range of features required to support the diversity of castings created a challenging list for potential machine suppliers. The company who best rose to this challenge was the Italian manufacturer Colosio. Based in Botticino Sera, near Brescia, Colosio has been producing diecasting machines for over 40 years, and is able to offer the complete solution in their field. In partnership with sister company, Relbo, they manufacture diecasting machines, automatic ladles, die sprayers, and extractors.

Consistency of casting 
In June, MRT installed the new Colosio PFO250 cold chamber diecasting cell. The machine delivers a locking force of 250t, making it suitable for aluminium components up to approximately 3.5kg. The PFO250 features real-time shot control, whereby process parameters, pressures, speeds and strokes are programmed, then monitored and adjusted automatically ensuring absolute consistency of casting quality. 

MRT’s typical production batch sizes for high pressure diecastings range from as little as 50 shots to around 5000, so optimising set-ups is critical to making the process economically viable for small batch projects. Given that the company’s team is performing die changes virtually every shift, they get plenty of practice! In addition to good teamwork, and efficient procedures, there are a number of other tools used to optimise this exercise. Die designs have been standardised and common components are used wherever possible. Dies are prepared in the in-house toolroom prior to any change, so that the minimum of work needs to be done during the machine down-time. World-class lean manufacturing techniques are employed throughout the company, so working areas and tools are well laid out and organised to improve efficiency. MRT employees have even visited Japan to study set-up reduction techniques in action in Japan’s leanest manufacturing sites. 

Quick die change – not a problem 
The new Colosio diecasting machine has also been optimised with several features to help MRT with the quick die changes required. Many of these features would normally only be included on much larger machines, but because of Colosio’s design flexibility and in-house manufacture, the features were able to be incorporated on to the PFO250 specifically to meet MRT’s unique demands. These features include automated tie-bar extraction to ensure ease of access for tool removal, motorised die-height adjustment and motorised shot height adjustment with automatic clamping. All die-specific injection and clamping parameters are stored within the Colosio machine’s digital ‘Fullcontrol’ control system, and can be quickly recalled the next time the tool is set up. 

One of the greatest advantages with this cell is that all the peripheral devices were manufactured for MRT by Colosio and the cell has been completely integrated into the one control system, so recalling a programme on the machine when a die is set up for a production run will not only recall all of the die and injection parameters, but also all of the ladler, die spray, and extraction programmes, which makes significant time savings on every set-up. This single interface has also greatly simplified operator training, and dramatically reduced the initial installation time for the new machine, which was fully operational within 10 days of arriving in the UK. 
The peripheral devices installed include Colosio’s Rotofast AL automatic ladler, and Relbo’s Plus 2-axis die sprayer and Arcofast 3 extractor. These devices greatly improve productivity of the cell, but also the consistency, controlling every variable automatically to optimise quality and repeatability. The Relbo Plus sprayer is a fully integrated two-axis automatic die sprayer, enabling very fast, effective and consistent lubrication of even the most complex die forms. The Relbo Arcofast extractor and integrated cooling conveyor further increases productivity and improves repeatability. 

Joined up thinking 
As Colosio’s UK agents are Ramsell-Naber, MRT’s principal supplier of furnaces for many years, MRT was able to purchase a new Ramsell gas-fired bale out furnace, with recuperative burner, as part of the turn-key package. The recuperative burner helps to reduce energy consumption and emissions, supporting MRT’s ISO 14001 accredited environmental programme. 

With such a busy and diverse workload going through the machine, maximising machine utilisation is critical, so any problems need to be dealt with extremely quickly. MRT’s PF250 is equipped with Colosio’s Teleservice module, so that the manufacturer’s applications engineers in Botticino Sera can remotely access MRT’s machine control system over the internet to overcome any technical queries or apply any software enhancements.

The new diecasting cell is part of an on-going investment programme at MRT, which is gearing up to double its production capacity over the next three years. Growing export sales, and increasing demand from the company’s niche market sectors, are clearly testament to MRT’s philosophy that high pressure diecasting has benefits to a very diverse market, regardless of volume. 

Contact: MRT Castings Ltd, South Way, Walworth Business Park, Andover, Hampshire SP10 5JT UK.
Tel: +44 (0) 1264 324021
Email: general@mrt-castings.co.uk
Web: www.mrt-castings.co.uk 
Web: www.colosiopresse.it