Industrial gluing systems manufacturer Baumer hhs, based in Krefeld, Germany, is attracting considerable attention in the market with its Plug & Glue concept, developed for its Xmelt family of hot melt systems for the purpose of system optimisation and preventive maintenance. For example, the corresponding patents on this technology – which offers customers decisive advantages in terms of ease of use, maximum operational reliability and optimum results in glue application – have been cited unusually frequently in other published patent applications.
The Plug & Glue systems are based on hardware/software interaction, where the hardware provides identification codes and operating parameters with the help of data chips. In other words, all hot melt application heads and hoses on the Xmelt systems from Baumer hhs are equipped with individual data carriers. The system uses the data they store to keep operation within optimum range. This applies to optimizing temperature control, for instance, key influencing parameters of which include the heat-up time of the hot melt system, the control deviation values, and specific component characteristics, such as the length, heater resistance and position of the temperature sensors.
Depending on the application and its requirements, a variety of different hot melt hoses and application heads with variable heat output levels and control modes can be connected to the Xmelt family of hot melt units. In practice, a hot melt system’s original configuration is frequently modified later on, for example when the demands imposed on production change, or component failure makes it necessary to connect replacements with different characteristics.
Eliminates a source of error
In most conventional hot melt systems, the control parameters for each connection channel must be entered manually on the system’s control unit. “This step is a source of error that we have now eliminated with our Plug & Glue system,” explains Thomas Walther, Head of Engineering and Technology at Baumer hhs. In order to minimize the number of parameters that have to be entered, some manufacturers of conventional hot melt systems try to operate the hoses and application heads with ordinary control settings or self-optimisation algorithms. But clearly a five meter-long hose, for instance, must be supplied with a different level of energy than a three-meter one, if the operator wants to avoid burning the hot melt adhesive or overshooting the temperature.
Self-optimisation algorithms on the other hand automatically capture the parameters via test procedures. They cannot, however, be used to determine the limit values for heat output or the operating temperature. This method also poses technical safety risks, because in the case of gradual or spontaneous changes in the parameters, self-optimisation may prompt the system to adapt temperature control to new, erroneous parameters. Potential consequences include overheated adhesive, destroyed components and, in the worst case, even fire.
Optimum operation made possible
“In contrast, if the control parameters are always known, the individual system components can be operated within optimum range,” says Walther, emphasizing the difference. “The parameters are stored in the components themselves, which results in tremendous advantages.” For instance, when the system is reconfigured, the parameters automatically move with the components, meaning they must not be transferred manually from one channel to another. In addition, more parameters can be stored than in conventional systems, which supports even more accurate adaptation of the control algorithm.
In the event of errors in the control system, the values stored on the data carriers are used and not the current values. This prevents temperature control from getting off track and causing safety-related problems due to incorrect input parameters. It also reduces the risk of falling below the set-point temperature and the adhesive viscosity from rising as a result, which otherwise often leads to application problems. Finally, this innovative concept from Baumer hhs also keeps the temperature control system from overshooting the target and thus prevents thermal degradation of the adhesive. Because the set-point value is known, and can be compared with the current value, any deviations can be identified sooner. By contrast, in conventional systems, it is difficult to detect any gradual drifting of the values out of range.
Because the maximum permissible operating temperatures are stored on the data carriers in the hot melt hoses and applications heads on the Xmelt units from Baumer hhs, the components can automatically shut down the heat channels assigned to them if the maximum limit is exceeded. This technical safety feature prevents the components from exceeding a permissible, upper limit in temperature in the event of operating errors. “The Plug & Glue concept from Baumer hhs offers all of these critical process and technical safety advantages,” says Walther.
Effective preventive maintenance
The data carriers also help to optimize preventive maintenance of the hot melt hoses and application heads in the Xmelt units and therefore to achieve even higher system availability. For instance, the chips store the number of operating hours of the individual components. Other parameters that limit service life, such as operation cycles, can also be optionally stored. Based on trials and practical experience, Baumer hhs decided in favour of operating hours, because most components fail as a result of burned adhesive. This risk is especially high when application heads are heated, but idle for an extended period without applying adhesive, a condition that would not be detected if the operation cycles were stored. In turn, for the hot melt hoses, storing the operation cycles of the application heads is entirely meaningless. For them, the number of operating hours is likewise the decisive parameter.
By storing operating data in the individual components, the data moves with them when they are used elsewhere, even when they are operated on other hot melt systems. This would be impossible if the data were stored in the control units.
Storing the operating data in the individual components supports scheduled, component-specific, preventive maintenance, which is an economic advantage. In practice, preventive maintenance frequently is performed on all components at the same time across the board, regardless of their operating hours. In contrast, component-specific maintenance based on individual recorded data is more targeted and eliminates the unnecessary costs of premature maintenance.