FEATURE FASTENINGS & ADHESIVES See the light with UV bonding
Eurobond Adhesives explains all you need to know about UV light curing adhesives
U
V light curing adhesives cure on demand, remaining completely
inert and in a liquid state when they are applied to a substrate. These are then subjected to controlled and concentrated UV light. Despite often being thought of as
complicated to use and high tech, however, UV light curing adhesives are easy to use, versatile and can offer many benefits. As a result, they are used in applications ranging from the manufacture of disposable medical devices – such as chest drains, syringe needle bonding, catheter tube/bag sets and blood filter housings – to electronics, optical lens bonding and fibre optic filament splicing, and in the manufacture of glass and acrylic furniture.
damage temperature sensitive substrates. Gas discharge lamps
UV light curing adhesives are suitable for applications in a variety of industries
ACRYLATE- OR EPOXY-BASED? Typically there are two types of chemistry to choose from. Acrylate-based adhesives are widely used for bonding clear substrates such as PMMA, PVC, SAN, PC and glass, either to themselves, in combination, or to some metals. These offer a fast curing time, excellent adhesion properties, are available in a range of viscosities from ultra-low to thick gel, and they can be used in a variety of applications. Epoxy-based UV adhesives tend to be used as
coatings. These have superior environmental resistance, a wider operating temperature range, a low ionic and alkali content, low shrinkage, and cure to a tack-free dry finish.
LIGHT CURING Selecting the correct UV light curing equipment for the application is also critical. In the main, there are two types of UV light curing systems: high pressure gas discharge lamps or LED lamps. Acrylic- and epoxy- based adhesives can be cured with either. Some special acrylic adhesives can be cured using
high intensity visible light 405-420nm – for example, when bonding UV impermeable PC or laminated glass. Others, particularly in electronic PCB applications, may require a combination of UV light and heat to cure the areas in shadow underneath SMD’s. The vast majority, however, can be cured using high intensity 365nm UV light. Unlike gas discharge lamps which have a broad
light spectrum from 340nm to 420nm, LED light sources have a monochromatic light spectrum with specific light wavelengths matched to the curing requirements of the adhesive used, with the most common being 365nm and 405nm. LED curing lamps have no warm up or cool down period, and can be switched on and off repeatedly, providing instant full intensity UV light. These also do not produce any infrared heat which could distort or
16 SEPTEMBER 2019 | DESIGN SOLUTIONS
have to warm up for a few minutes before they reach optimum intensity. They cannot be turned on and off repeatedly, and the lamp has to cool down which could take up to 10 minutes before it is ready to use again. The useful bulb life of a gas discharge lamp is around 500-750 operating hours whereas an LED lamp can last between 10,000 and 20,000 depending on the system used. Careful consideration
should be given to the most suitable type of UV light system, of which there are five main types: • Handheld or jig mounted ‘flood lamps’, which emit UV over a given area and can be combined with a conveyor system to deliver the product to the light source.
• Fibre optic light guides which deliver UV light along single or multiple fibre optic or liquid filled light guides, which give a very narrow beam of intense UV light.
• UV light cabinets such as Honle’s UVA cube are self-contained enclosures in which multiple bonded parts can be placed and cured at the same time.
• UV Laser pens are simple hand held precision LED UV light sources and are ideal for production or laboratory work.
• LED UV Torches, which are battery powered and emit a high intensity narrow beam of 365nm UV light. These are ideal for small bond lines, prototyping, small scale production, and creating decorative artwork.
Eurobond Adhesives
www.eurobond-adhesives.co.uk
A FASTENER SOLUTION FOR THE LUXURY ROCKY MOUNTAINEER
Operating over four routes across the Canadian Rockies and with each train capable of carrying up to 900 passengers, the Rocky Mountaineer tourist train offers customers a high level of luxury. The carriage design teams needed to consider seating systems that were of the highest quality, but which would allow for worn or damaged seats to be replaced quickly, quietly and cleanly, either while en-route or on turnarounds between journeys. The manufacturers were also keen that replacement parts, such as seat bases, could be fitted without the need for either special tools or specialist knowledge. So, the Rocky Mountaineer team engaged with Germany-based Probatec which, having investigated a variety of options, turned to Bollhoff’s SNAP-LOC fastener as its preferred method of attaching the seat bases to subframes in all of the carriages. Based on Bollhoff’s ball and receptor socket design, SNAP-LOC offers significant strength, is light, clean and, when installed, invisible to users. When required, a seat base can be changed in seconds, with a secure and guaranteed fit every time. A damaged unit is simply pulled off and the replacement base positioned accordingly, before being ‘clicked’ into place. SNAP-LOC also acts as an isolator between the carriage chassis and the seat base, further reducing vibration.
Bollhoff T: 01482 325425 AM FASTENERS FOR AIRCRAFT ASSEMBLY
Frazer-Nash is using a Renishaw AM 400 additive manufacturing (AM) system to produce a novel fastener for its customer, Kwikbolt, for use during aircraft assembly. Kwikbolt is one of only a few businesses in the world to produce a specific temporary
fastening device, which is used to align aircraft panels and fuselage during assembly. The component simplifies the manufacturing process and ensures that aerospace companies no longer require a bespoke tool for every panel, helping to reduce costs, improve precision and speed up assembly. By using AM, Frazer-Nash is able to produce components cost-effectively in small batch sizes, explains Renishaw. With no custom tooling required, there have been improvements in speed and a reduction in manufacturing costs.
Renishaw
www.renishaw.com/additive
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
