Contactless infrared welding of plastics is suitable for both small and large components right through to truck instrument panels. Frimo JoinLine infrared welding systems cover the entire range of applications. During the VDI congress and exhibition in Mannheim, the Lotte, Germany-based company, will show the advantages infrared welding can offer compared with hot gas welding and established processes such as hot plate welding and vibration welding.
Frimo offers the Highspeed infrared welding system specifically for small to medium-sized components, for instance, from small air valves to various pipes, containers or engine compartment applications to interior components such as glove boxes. A special drive system allows for movement speed, which has not been possible in infrared welding technology until now. In terms of critical changeover times, these comparably high speeds are becoming ever more necessary for energy-efficient and strong welding of high-performance plastics. For this reason, Frimo equips its Highspeed infrared welding systems with linear motors. According to the company, these motors are characterised by low maintenance, a high degree of repeat accuracy, of availability and low-noise operation. Precision is said to be guaranteed through the retrieval of actual values from the route, allowing any slips of the drive train, for example, the gear rack, to be eliminated.
As the infrared emitters are only switched on during the plastic’s brief heating time, the process allows for lower consumption of resources and energy. The parameter and control options have been optimised to such an extent that it is now possible to set the optimum movement and temperature values for the thermoplastic to be welded. This is said to provide strength of the welded joint, with a high degree of repeat accuracy.
Thanks to contactless heating of the plastic, infrared welding is also intended to meet increasing requirements for there to be no particles after the joining process, for instance, for air and oil-ducting components. Many manufacturers of such components are imposing increasingly strict standards and regulations in this area. Infrared welding is also to be recommended for the welding of reinforced high-performance plastics, such as fibreglass reinforced polyamides, which are being used more and more as structural components in lightweight construction. The process is claimed to offer high degrees of strength, which is of particular interest in safety-related areas, and also allows for 100% gas-tightness. Flexibility is catered for both in the use of the materials to be welded and in the design, for example, it is also possible to weld complex 3D geometries.
Flexible tool and system technology
The Frimo system portfolio for infrared welding currently includes six standard machines, from mini to maxi, for virtually any application. The system is said to allow for rapid and flexible tool changes, for example, from the front or the back of the machine. The cartridge construction of the tools allows for flexible handling and, at the same time, ensures good protection of emitter blocks. Different sources of radiation are used in terms of tool technology. For the majority of applications, short-wave glass bulb emitters have proven to be suitable. These can be used either (most commonly) as twin-tube emitters in the standard design or as an individually adapted contouring emitter. Protective shadow plates are used to protect critical areas that are not allowed to heat up, and can also be cooled. Depending on the requirements of the project, Frimo now also uses medium-wave infrared emitters, either as a glass emitter or as a metal foil emitter. Metal foil emitters have a special nickel coating and are laid in a milled groove. A range of automated solutions is also available.
An important aspect, and not simply for quality assurance of safety-related components, is monitoring of the temperatures occurring on the surface of the joining partners. Frimo uses thermal imaging for this. Very small cameras, which are integrated into the machines, are used to guarantee complete process monitoring and documentation at all times. Data is transmitted to superordinate systems so that it can effectively also be used for remote maintenance. The systems’ control technology has been set up so that compensation of part tolerances within the infrared welding process is possible. This is particularly advantageous in the case of infrared welding of gas and liquid-ducting systems.