Adhesive Solutions for Fire Trucks and Other Specialty Vehicles

The current challenges for Fire Truck and other specialty vehicle manufacturers are complex and ever-changing. Challenges include supply chain volatility, rapid design changes to accommodate electrification, and new ways of differentiating between manufacturers.

Supply Chain Simplification:

Using adhesives, such as Plexus®, can help simplify supply chain troubles because a suitable structural adhesive can replace multiple SKUs of different fasteners. As a result, Plexus adhesives dramatically reduces the risk of line-down situations due to specialty fastener stock-outs. In addition, SKU reduction by replacing with one structural adhesive can lead to significant inventory cost savings.

Even if you’re not ready to eschew fasteners altogether, applying Plexus adhesives along with mechanical fasteners at the ends can still help simplify the supply chain. This style of manufacturing leads to very fast throughput and “one-piece flow.”

Figure 1: Reducing number of different fasteners to 1 Plexus Adhesive

Light-Weighting and Design Freedom

Metal price volatility and electrification of fire trucks are two significant reasons manufacturers look to reduce vehicle mass. Plexus adhesives can help enable major light-weighting through a few means:

1. Enable the joining of lightweight materials - Plexus has primerless adhesion materials, lightweight composites, and plastics. Mixing lightweight materials with conventional metals is one of the easiest ways to reduce vehicle mass. Mixed metal designs are also possible since Plexus can bond dissimilar metals.
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2. Downgauge metal - Welding aluminum has its challenges. It takes skilled labor and has high variability of strength depending on the skill level of the welder. Replacing aluminum welding with Plexus adhesives has some excellent benefits. Plexus bonds thin gauge metal to thick gauge without warping from heat exposure. Plexus adhesives do not cause heat-affected zones (HAZ), and therefore, the strength of the aluminum does not degrade. Despite downgauging, because Plexus joins a larger surface area than welding, bonded assemblies often lead to more durable structures.

Figure 2: Percent reduction in aluminum alloy strengths due to heat affected zones from welding operations

Speeding Up Assemblies

The engineers at Plexus adhesives and Austin Hardware love the challenge of finding ways to speed up assemblies and produce more vehicles per day. A couple of ways using Plexus adhesives can help speed up assemblies:

1. Replacing welding for speed

Dispensing Plexus adhesives is around 10 times faster than welding. Therefore, when long or multiple stitch welds are required, evaluate Plexus adhesives for a production speed increase. One application, bonding metal subfloors to cross-members, is easy to convert and leads to considerable time savings.

Panel bonding

Plexus has introduced a new panel bonding adhesive called H4110. This material is a two-component hybrid adhesive with good flexibility - perfect for bonding thin panels. In addition, H4110 saves time by simplifying surface preparation (simple solvent wipe/clean) and having fast strength development, which is up to 6 times faster than 1K PU adhesives.

Figure 3: Relative time to assemble a reinforcing hat section to a flat panel with various assembly methods.

Common Fire Truck Applications

Common applications for fire trucks include bonding panels to frame, replacing welding for the vehicle structure, and bonding reinforcements and skins onto doors.

For more information on ITW/Plexus Structural Adhesives, click here.