Page 61 - Australian Paint & Panel March-April 2020
P. 61

 of course have a significant influence on where, or if you can, partially replace or section a panel. It’s not safe to guess.
ADHESIVE EVOLUTION
Adhesive bonding will evolve too. It’s un- likely we shall see many bonded-only cars; curing the adhesive is too slow in production to enable many cars to be built profitably. We may see bonding as the so- lution for some specific models, but prob- ably these will be the more expensive prestigious cars, and likely employing carbon fibre.
Increasing requirements for absorbing crash impact forces, particularly to protect occupants but also battery packs for electric or hybrid vehicles, is leading to develop- ments in adhesives. For crash structures a very strong adhesive is of course required, but newer vehicles may not want it to be rigid as this could cause adhesive failure in a crash. Hybrid adhesives are being devel- oped, to be strong, but with a degree of flex- ibility in them. These will need very spe- cific applications.
New rivet technologies that enable dif- ferent pressures on each side of the stack for joining are a good solution for mixed materials; steel and aluminium. The stronger material can then take more of the joining forces. So, a specific rivet or fastener will need to be applied, from a specified direction, to ensure a safe joint. Some, where joining a fibre-reinforced plastic, will have a greater flange to spread the pressure and avoid propagat- ing the hole it’s applied through.
We have already seen, from BMW, a need for a thicker adhesive bond, together with a specific rivet, to enable one material to ‘float’ over another due to the different thermal ex- pansion rates of two different materials, in this case carbon fibre and steel.
For the future caution is advised where we can partially replace a panel, but also for very specific joining requirements and parameters for many panel combinations and vehicles. More than ever we need to re- fer to vehicle-specific repair information, and the range of joining skills of our work- shop teams will need to continue to develop.
WWW.PAINTANDPANEL.COM.AU
SIKAPOWER
SIKAPOWER 4720 IS A
two component, high- strength epoxy adhe- sive that has excellent adhesion properties on a wide variety of sub- strates. It's specifically designed for metal and composite panel bond- ing with exposure to high dynamic stress areas such as door skins, rear body pan- els, roof skins or quar- ter panels. Conforms to OEM standards.
Available from SAPE: 02 9772 9000.
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