Published on 25 January 2013
A Leeds-based plastics component manufacturer is reaping the benefits of carving a niche in the international plastics market, and of investing in technology that has given it significant competitive advantage over other plastics fabricators in the UK - an achievement made possible with the assistance of joining experts TWI Ltd.
Barkston Plastics Engineering Ltd started in the late 1960s as a distributor of plastics and rubber materials, but soon moved into plastics fabrication, steadily developing its business since then.
For many years it has been using conventional methods for welding its parts - hot gas welding, extrusion welding and chemical bonding - with great success. However, the emergence of cheaper products from manufacturers in the Far East has meant that manufacturers like Barkston have had to reassess their business model.
Early on, Barkston recognised that there was no way that it could compete with these imports on price, while it continued to use the traditional joining processes, all of which were labour-intensive, and dependent on the availability of skilled operators. The decision was made to investigate methods to reduce the cost of production, and this was when Barkston called on TWI's assistance.
With TWI's knowledge and experience of all plastics joining processes, it was in an ideal position to examine Barkston's existing production methods, and the components made. It was decided that this review would focus on a single range of products, that being polypropylene tanks used to contain heated corrosive chemicals used in anodising aluminium plates for lithographic printing.
The review concluded that laser welding would be a suitable alternative to the conventional welding processes. Welding trials at TWI proved that the laser welding matched the performance of the original welding process (in this case, hot gas welding), with increased reliability and improved appearance of the component. Indeed, laser welding represented a reduction in welding time of about 75% due to increased automation.
Having demonstrated the capabilities of laser welding, TWI went on to produce samples of the tanks, so that Barkston could show them to its customers, and gain acceptance of the tanks made using the new technique. This was achieved with relative ease, and Barkston made the decision to invest in laser welding facilities.
Again, TWI was able to provide assistance. TWI's experts wrote a specification for the equipment required, and then established the contacts between Barkston and the equipment suppliers. Since installing its laser facilities in the middle of 2005, Barkston Plastics has fabricated all its tanks using laser welding.
While assessing the conventional laser welding process, Barkston also looked into the possibility of using the Clearweld Process. The Clearweld concept has been developed and is made available for real-world applications exclusively by Gentex Corporation. It is now offered as a single, flexible solution for joining transparent or opaque thermoplastics, via weldable resins or coatings.
Clearweld incorporates infrared absorbers, developed by Gentex in unique material systems, including coatings and polymer resin compounds, designed for use in a variety of production processes. Simply applying a thin layer of the coating at the interface of two pieces of plastic concentrates laser energy. A localised melt of the substrates results in an instant weld, requiring no cure time and with no particulates or visible colour. Welding of resin compounds works in much the same way while eliminating the coating application step.
As Tony Blackmore, Technical Director of Barkston Plastics, observes, 'Clearweld is particularly suitable for joining parts which need to be clear or have a predetermined colour.' Whilst this was not a requirement for the initial laser welding application, there were several ranges of product in the Barkston Plastics portfolio for which Clearweld would prove to be ideal. These include protective enclosures for handling objects that need to be kept in an isolated environment, high integrity healthcare products, and other transparent products for use in sterile atmospheres and environments.
Once again, trials of the new technology proved successful, and Barkston has now integrated Clearweld into the manufacturing process of a number of its product ranges. Not only this, but it has entered into a partnership with Gentex Corporation to develop new applications for Clearweld within the UK and further afield into Europe. Tony Blackmore continues: 'Introducing the Gentex absorber has provided us with an ideal opportunity to develop our business significantly'.
Gareth McGrath, Gentex Corporation's Commercial Manager, adds, 'The exceptional engineering skills at Barkston Plastics provide companies with a unique opportunity to benefit from the advantages of Clearweld'.
TWI's assistance to Barkston Plastics was provided under TWI's Technology Transfer programmes, Joining Forces Yorkshire and Humber and Laser Advanced Manufacturing (LaserAM), funded by Yorkshire Forward and Objective 1. These programmes were aimed to boost growth, competitiveness and innovation in the region's engineering manufacturing companies, and to generate and preserve employment in the Yorkshire region.
For information about TWI's capabilities please contact us.