When drying using the convection process, the process atmosphere is heated up using a hot-air fan and then flows onto the components. The heating elements are attached above and below the transport system. The flow speeds of the upper and lower heating zones are individually adjustable so that the assembly is heated through evenly. This prevents tension in the material.
In the combination heating process, the heat transfer is carried out with infrared radiation, which is supported by central convection heating. All heating chambers are equipped with high-performance IR radiators. The IR radiation penetrates the circuit board and drives out the solvents from the interior. This enables a faster and more efficient drying process. For the additional convection, the volume flow can be pre-set. The heating base of all IR radiators can also be equipped with glass covers to protect against contamination and for easier cleaning.
The RDS drying systems can be designed with single lane or dual lane transport, with a pin chain conveyor and variable width adjustment or as heavy load transport for goods carriers based on the customer’s requirements. The optional underfloor return transport that can be integrated offers a space-saving solution for circuit board/goods carrier return.
The following transport versions are available:
- Single lane transport: 80 – 460mm
- Dual lane transport: 2 x 90 – 250mm
- Heavy load transport: in accordance with customer requirements
The exhaust system ensures safe removal of solvents among other things. Appropriate mechanisms are attached to the input and output of the process chamber, as well as between the heating zones. The process exhaust air is supplied directly to the extraction through the fan. The substances to be hardened and the exhaust products released determine the extraction volume. The extraction function is monitored by a pressure sensor. If there is a problem, the heating switches off automatically and the inflow of new components is stopped. This prevents any flammable gas mixtures from forming in the system.
In the air-cooled cooling zune, the hot process exhaust air is extracted via the attached exhaust hoses. As well as this, cold ambient air is aspirated and blown in via the panel of nozzles to cool the components. With the water-cooled cooling option, the cooling process is carried out via heat exchangers. There is the option of controlling the cooling process precisely with separately adjustable fans in the individual zones and influencing the cooling gradient accordingly.
The control elements of the RDS drying system are easily accessible for minimal maintenance costs. The heating base of the IR radiator can also be equipped with glass covers to protect against contamination and for easier cleaning. This considerably reduces the maintenance required and increases the service life of the radiators. Here, Rehm relies on tried-and-tested components from the reflow soldering systems.