Adam Ward explains how light-weighting techniques allow vehicle manufacturers to respond to industry demands
With strict emission regulations designed to reduce pollution, and consumers demanding vehicles that feature all the latest modern technologies and better mileage, car manufacturers are faced with a challenge to meet these requirements and remain profitable. In a bid to achieve this, manufacturers have begun to turn to light-weighting techniques, but as mixed materials continue to be used more in vehicles, one of the biggest issues engineers are confronted with is how best to bond materials together.
Making Light Work Of Manufacturing
Light weighting focuses on reducing the weight of components inside and outside
of a vehicle. Traditionally focused on low-volume sports cars or high-end vehicles, efforts are now being applied to mass-produced products and weight reduction has become an integral part of the design process.
When it comes to bonding materials together on vehicles, mechanical fasteners are a popular choice and have played a central role in car manufacturing for years. However, to address many of the challenges faced today, removing mechanical fixings from a vehicle, and replacing them with a lighter alternative, such as tape, offers a range of benefits.
Bonding Together To Find A Solution
One of the main benefits of applying adhesive technology is that the substrate does not need to be thick to accommodate stress points. This means that thinner and more lightweight materials can be used in the process without compromising on design or performance.
Adhesive bonding also acts as a sealant and can eradicate many of the issues associated with drilling holes to add fasteners and rivets, such as weakening of the substrate and moisture ingress and corrosion problems.
As well as reducing noise, vibration, and harshness (NVH), which is not only annoying to the consumer but represents wasted energy, adhesive tape can also help dissipate energy rather than transmit it.
The Heat Is On
It could be argued that traditional thermal bonding techniques such as welding and soldering are still the industry preference due to their perceived value for money and quick turnaround time.
However, when you take preparation and other pre-assembly costs into account, this might not necessarily be the case. When applying adhesive technology, production costs and finishing times are often faster. Besides, reworking the bond is easier when it comes to disassembling, reworking, or repair.
Another important aspect to bear in mind here is the issues surrounding health and safety. As most adhesives can be applied at room temperature, without the need for intense heat, worker comfort and safety are also improved.
However, as with most things in life, it is never as easy as it sounds. Understanding the actual stresses and loads of different adhesives to select the right material for each specific application can be challenging. For this reason, it is important to choose the strength and durability of the adhesive to suit the individual requirements of the substrate and application.
Just as there are different metals, alloys, and composites that work best in different parts of the vehicle, there is also a wide variety of adhesive tapes. For example, double-sided, heat-curable, and acrylic foam tape can be used for cladding, whereas wheel arch and trim attachment adhesive tape offers a durable and reliable bond that can be used with a variety of different substrates.
For applications without the use of primers or adhesion promoters, such as nameplate attachment and sensor attachment, primer-less bonding tapes are an option and can be applied quickly and easily.
To address the issues previously discussed with drilling holes, attachment tapes, such as those formulated to EPDM/TPE, neoprene and PVC offer a particularly durable sealant solution for doors and headlamps.
And, when it comes to permanently attaching emblems or nameplates, there is also a wide range of adhesive tapes that offer a peel-and-stick application to a wide range of surfaces without punching unsightly holes.
In terms of fastening solutions, adhesive tapes also offer an alternative application for headliners and sunroofs, to name but a few. Many fastening issues also address bonding and NVH challenges in many areas inside the vehicle.
Another issue to bear in mind when choosing a bonding technique is thermal expansion capability. It is a well-known fact that materials can expand or contract according to the ambient temperature. This could potentially lead to a variety of problems, such as unwanted moving between parts and letting in moisture or air, which could, in turn, result in product failure. To combat this problem many manufacturers now offer tape that can bond a range of surfaces with different coefficients of expansion and contraction, without compromising on design or performance.
The Future Looks Lighter
As car owners demand better mileage, and governments push for fuel efficiency and better air quality from lower emissions, design and process engineers in the transportation industry are faced with a big challenge that will include addressing weight components inside and outside the vehicle.
As the type of material used can make a huge difference in the weight of each component and the overall weight of the car, the practice of light weighting can only continue to grow as engineers try to remove as much unnecessary weight as possible. Subsequently, the importance of choosing the best possible bonding technique will increasingly play a central role.
Adam Ward is with Brammer, Buck & Hickman