RDS_Lacktrockner_en.pdf - 第6页

6 Optimum heat management with IR radiation and convection Thanks to our many years of experience, we know precisely which actuators are needed to set up a system that can be adapted simply and individually to the variou…

Lacquer and casting hardening

To achieve the best drying results, it is important to precisely

coordinate the process and material. We differentiate between

physically hardening lacquers, which harden very quickly pure-

ly with the release of solvents, oxidative-hardening lacquers,

which dry with atmospheric oxygen, chemically hardening

lacquers, often 2K materials and radiation-hardening

lacquers which harden with UV radiation, for example. A

separate UV dryer is required for the latter. The RDS systems

are perfect for hardening polyurethane resin, acrylic resin,

epoxy resins, acrylate resins and silicone-based casting

compounds.

A slow heating of the assembly is essential, particularly

when it comes to protective coatings that contain volatile

solvents, because an excessively high temperature gradient

during the heating phase can cause the top layer of the

coating to harden too quickly and the underlying solvent

will no longer be able to escape. For this reason, the drying

systems from Rehm Thermal Systems feature two short

zones at the inlet area which are regulated separately in

order to provide the optimum temperature gradient for the

corresponding paint.

Innovative procedures

adjusted to material and product

Optimum heat management

with IR radiation and convection

Thanks to our many years of experience, we

know precisely which actuators are needed to

set up a system that can be adapted simply and

individually to the various process requirements

and product landscapes of our customers.

The RDS systems are modularly structured.

The efcient upper and lower heaters work with

infrared radiation (IR) and/or convection to dry the

various materials reliably. By implementing these

two heat transfer processes, the systems are

optimally designed for the processing of lacquers

and castings containing solvents. The RDS drying

oven thus consists of several separately adjusta-

ble heating zones. In the warming-up phase, the

component and the protective lacquer are heated

up. Both the upper and lower IR radiators can be

controlled with different set-point temperatures.

Thus in the inlet area of the dryer, an increased

amount of IR radiation and a reduced convective

heat transfer is applied to the component. This

means that lacquers in particular are heated up

evenly and, thanks to the low convection, are not

dispersed onto the component.

In the drying phase, the temperature is main-

tained until the material has hardened completely.

A stronger convection is needed for this, as the

evaporating solvents need to be discharged. In the

subsequent cooling phase, the components are

cooled down gently.

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 adjus-

table so that the component is heated through evenly. This

prevents tension in the material.

Convective drying

In the combination heating process, the heat transfer is car-

ried 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 efcient 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.

Combination heating process with IR

First-class heating performance and top heat management

Upper and underside heating using convection and/or IR heating elements

Variable heating chamber length and optimum process adjustment

Flexible transport systems based on customer request

The RDS drying systems can be designed as 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 variants are available:

› Single lane transport: 80 – 460 mm

› Dual lane transport: 2 x 90 – 250 mm

› Heavy load transport: based on customer requirements

Transport system

Transport