When working with adhesive dispensing systems it is key to keep in mind the end goal to deliver quality fortified joints for structural applications, such as in automotive assembly. It is important to utilize automated systems to accomplish a required consistent quality of the joints being held by adhesive. This article gives an overview on how and why adhesive dispensing robots are used in automotive assembly at present. This article also looks at how the search for more lightweight manufacturing materials is expected to increase their utilization in the future and how to determine an optimal system.
The Evolution and Future of Adhesive Dispensing Systems in Automotive Manufacturing
Initially in the automotive industry, traditional bonding methods were used by assembly line workers such as, using bolts, welding, etc. High demands on quality, quantity, repeatability and reliable products led to automated assembly lines. Furthermore, with the establishment of new material combinations and the implementation of more demanding designs, in recent years and decades adhesive bonding has become a key manufacturing process in a number of industries. This ultimately led to these manufacturing industries shifting towards using automated robotic adhesive dispensing systems.
Why Adhesive Dispensing Systems Are Used?
Compared to traditional bonding methods, adhesives offer greater flexibility to the production process of automobile and automotive sub-components. Automatic adhesive dispensing equipment easily adapted to changes in the sub-component design, as vehicle manufacturers continue to accelerate the pace of change in automotive design (See Frost & Sullivan market insight).
Adhesives can be applied at relatively high speed on the production line. This in turn, helps the auto manufacturers in saving money and time. Parts that are bonded together don’t need holes to be drilled or punched, and assemblers don’t need to measure torque or double-check fastening operations. Eliminating fasteners also lowers vehicle weight, which is no small thing for automakers trying to maximize fuel economy. These potential cost savings are extremely important to the automotive manufacturing industries and their continuous effort to minimize costs.
There are different reasons why manufacturers keep on expanding the utilization of adhesives in automotive, for example, improved NVH (noise, vibration and harshness) characteristics and the increasing use of plastic and aluminum in automotive manufacturing.
Types of Adhesives Used in Automotive Assembly Systems
Adhesives bond a wide array of automotive assemblies, including windshields, brakes, wire harnesses and exterior trim. Beyond these traditional applications, adhesives are now being used in applications that were once the exclusive domain of thermal and mechanical joining methods, including the frame, body, dashboard, engine and weather stripping.
Structural Adhesives: Methacrylates are among the most widely used adhesives in the automotive industry. Methacrylates are good for assembling interior components because they are flexible enough to absorb impacts, but rigid enough to withstand high temperatures. These adhesives do not emit vapors that could adversely affect air quality inside a vehicle. Another benefit about using methacrylates for bonding plastics is that they don’t affect recyclability of the product.
Cyanoacrylates can also be found in automotive assemblies. Cyanoacrylates are solvent-free, one-component, room-temperature curing adhesives. When pressed into a thin film between two surfaces, cyanoacrylates cure rapidly to form rigid thermoplastics with excellent adhesion to most materials.
Acrylics are another structural adhesive that is widely used in automobiles. Available in both one and two part formulations, acrylics bond well to many substrates, including plastics, glass, ceramics and stainless steel.
Epoxies have also found their way into automobile via electrical and electronic assemblies. Epoxies come in a wide variety of types and formulations for different applications. They can be rigid or flexible, one or two part, heat curing or UV curing. Epoxies absorb vibration and shock, and they dissipate heat.
Tapes and Films: A variety of adhesive tapes and films are also used in vehicles. For example, a polyamid structural adhesive film from is used to bond rearview mirrors to windshields. An unsupported, thermosetting, clear film, the adhesive provides high peel, shear and cleavage strength when bonding metal parts to metal, glass or ceramic.
Tapes are also used in automobiles. A structural bonding tape with an epoxy-modified acrylic adhesive is used to attach plastic or metal clips to painted or primed body panels. The adhesive is pre-applied to the clips, which are then pressed into place on the panels. Once attached, the adhesive is cured with heat to provide structural strength. Bonded clips eliminate the need to stamp holes or form upturned flanges in the sheet metal.
Threadlockers and Retainers: Threadlockers are liquid, one-component anaerobic adhesives that cure when exposed to metal ions in the absence of air. They can be applied as a liquid at the time of assembly, or they can be preapplied to fasteners in the form of encapsulated beads in a dry film. When the fastener is installed, the beads break, releasing the adhesive. Threadlockers provide 100 percent contact between the two parts. As the material cures, it completely fills the tiny gaps between the interfacing threads, locking the fasteners in place. Because they seal threads as well as lock them, threadlockers are also desirable for applications involving fuel, oil, coolant and other fluids.
Liquid Gaskets: Liquid gaskets are adhesives that take the place of die-cut or molded solid gaskets made of cork, rubber and other materials. They have many automotive applications, including oil pans, oil seals, transmission pans, crankcases, axle covers, oil and air filters, fuel tanks and constant velocity joints. Although liquid gaskets are not considered structural adhesives, they do provide mild adhesion between the mating surfaces. This unitizes the assembly and limits relative motion between the parts.
What to Look for in an Adhesive Dispensing Robot
Dispensing adhesives can be challenging application. Choosing the right dispensing adhesives system is essential for success. Automated dispensing systems need to be precise – programmed down to the millimeter – to evenly and accurately dispense adhesives. Without this accuracy, profits are diminished through cleaning and rework. Along the same lines, a robotic adhesive system must be consistent and repeatable.
On the other hand, adhesive dispensing systems must balance this need for accuracy and consistency with the need for flexibility. Most adhesive dispensing systems will need to be able to dispense beads, arcs, circles and dotted lines. Robotic adhesive dispensing systems require superior levels of accuracy, consistency, and flexibility to be productive. Choosing the right equipment can help you achieve all three qualities in a robotic adhesive dispensing system.
Innovative Automation Inc. Automated Adhesive Dispensing System Case Study
Adhesive dispensing system can be used in a wide range of industrial applications. Innovative Automation have successfully designed and integrated robotic
dispensing cells like, silicone foam application, primer application, taping foam application, etc.
Innovative Automation can help design and integrate an optimal robot, dispenser and vision system depending upon the application requirements such as, reachability, load capacity, number of axis, speed, error proof etc.
Innovative Automation builds, customizes and configures for reliability, efficiency and cost effective dispensers. If you are ready to get started on your next assembly project and would like to learn more about how robotics assembly can help streamline the process, contact us today.