Robotic dispensing applications

Dispensing of adhesives and sealants is accomplished robotically in many industries. The following robotic dispensing applications of adhesive and sealant, are taken from the automotive industry where the majority of robotic dispensing applications are used. 

Robots are used to dispense adhesives and sealants throughout the automotive industry today. Automation requirements will be examined for windshield bonding to the vehicle, door manufacturing, passenger compartment interior seam sealing, and the application of sealants during the buildup of the vehicle body. These account for the vast majority of robotic sealant and adhesive dispensing applications in the automotive industry. 

Another system control feature often required for robotic systems is an automation interface card that allows signals to be sent back and forth between the robot, the cell controller, and the system controller. Signals such as SYSTEM READY indicate that there are no major malfunctions and that the system has reached application temperature. Another valuable system control feature in a robotic dispense system is simplified gun purge capability. In the event that skilled personnel that know how to facilitate a purge signal from the robot cannot be located, an easily located button on the system controller for this purpose is important. All of these features are needed to minimize downtime, which is often the yardstick by which robotic systems are measured. 

The material traditionally used in windshield bonding has been a single-component moisture-cure urethane. These urethanes are often high in viscosity resulting in high application pressures to meet the robotic dispense rate. 

Header systems with manual or automatic dispensing valves have been designed to carry adhesives and sealants over long distances within the plant. Distances of as much as 300 ft are not uncommon with drops at points of application. Figure 17.7 shows a modular header system. Adhesives and sealants are nearly ideal materials for application by robots. Robotic application is commonly used in the automobile industry to increase quality and to reduce labor and material cost.7,8... 

Robots are fast gaining prominence in the field of material dispensing, especially in the application of adhesives and sealants. The use of robots provides the end user with the following benefits ... 

For routine syntheses of labelled compounds, automated procedures have been developed which enable fast, safe, reproducible and reliable production. Automation has found broad application for the synthesis of radiopharmaceuticals. All steps must be as efficient as possible. For that purpose, target positioning and cooling, irradiation, removal of the target after irradiation, addition of chemicals, temperature and reaction time, purification of the product and dispensing are remotely controlled. Automation may be aided by computers and robotics may be apphed. 

Solid-phase extraction has been automated. The first application systems utilized robotic systems, and then automated xyz liquid-handling systems. The automated liquid-handling systems are designed to handle pipet tips to dispense liquids. So... 

A new technological development for hot melts is their application by robotics (87). Robotics have been used to apply hot melts to structural components, e. g. , fiberglas-reinforced components. In one case, structural adhesives are applied at 480 F (249 C) with a specially designed hot-melt dispenser and gun marketed by Monsanto Co. Robotics have also been used to apply hot-melts to make PSA s. Robotics are useful in applying hot-melts to gaskets and seals. In general, robotics provide higher productivity, improved quality, and reduced cost. 

In the Automotive industry there is a trend towards complete automation of production lines. In the application of adhesives/sealants for gasketing, the principles of dispensing have normally been to use a pressure-time system, or alternatively a cartridge system with a robotic head. However, a faster system is to screen print an anaerobic on to the surface of a component. 

In addition to the preforms and pellets mentioned in Section II.A.l.c., there are other forms of solid adhesives that have much versatility of use. Films and tapes have long been used in the manufacture of bonded flat structures. In particular, the aerospace industry has used a wide variety of film adhesives. In general, these products are handled manually. Occasionally such equipment as tape dispensers are used as assists to manual applications. Work is presently in progress to develop an automatic device to apply strips of film adhesive to automobile hoods. This device will be a curve-following robot that will place the adhesive in the hemming flange around the outer edge of the hood. 

The robots may apply dots, lines, at high speeds and very accurately. There are also rotary dispensing systems, with rotary tables which are convenient for dispensing circular patterns. They are adjustable in rotation speed, circles, diameters and dispensing time. They dispense from barrels, cartridges or valves mounted on the Z axis gantry. Figures 88 to 90 show several applications in electronics, Hifi and other industries. 

Figure 9.12 Structural bonding application for a reinforced plastic bumper assembly for a truck. The equipment dispenses a two-component structural adhesive onto the bumper assembly before it is integrated into the truck. In production, this is typically done robotically with a manual backup system (shown). The system being used is a See-Ro 488 meter/mix system the dispense gun in the picture is model 2200-250-000 dual-spool Snuf-Bak dispense valve that utilizes a No-Rush disposable static mixer nozzle. (Photo provided by Sealant Equipment and Engineering, Inc.)...

Selection of the robot and the dispensing equipment are of primary importance when automating sealant and adhesive application processes. Those installations that have taken into account all aspects of the application requirements have been successful. 

Independent of final adhesive viscosity, hand application, by spatula, palette knife or trowel, is often the favoured method. However, once mixed, low viscosity adhesives are frequently pumped to an applicator gun, which is often robotically controlled. Higher viscosity paste adhesives can make use of hand-held cartridge dispensers which not only mix the adhesive, as indicated above, but also can apply a bead or stripe of adhesive to the substrate, dependant on the design of the applicator head. 

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