| Before
a Paint finish can be successfully applied, the surface of the item to be painted
should be clean and meticulously free from any type of oil or grease contamination.
| |
| | To
remove this contamination from the product it is usual for metal products to be
'Pre-Treated' prior to either a Paint or a Powder coating being applied. |
| 'Pre-treatment'
has additional importance when Powder Coatings are to be applied to a product.
| |
| | Because
Powder coatings exhibit higher cohesion properties and lower adhesion properties
than Wet paints, the coating tends to be tougher than with Wet Paint systems but
its adhesion to the product tends to be lower. |
| Ideally
therefore the metal surface should be prepared chemically so that it presents
an ideal 'key' for the powder to successfully adhere. | |
| | The
RDM Aqueous Combined Degrease/Phosphate Plants are ideally suited to 'Pre Treating'
metal products, with the degrease chemicals removing any oils and the phosphate
chemical providing the chemical reaction to provide an ideal surface key. |
The vast majority of contemporary RDM Pre-treatment systems utilise the designs
shown. The product is hung from a motorised conveyer which conveys it through
typically a large robust Tunnel arrangement. The Tunnel comprises of a series
of zones or Stages each with a different function.
Complete
Plant Schematic Layout
Click
on the above image to download the
Pretreatment Plant Brochure
The
Inlet and Outlet Vestibule Zones ensure that as Products enter or leave the Plant,
the Sprayed Aqueous solution does not escape. The Heated Zones comprise of a holding
tank beneath the Plant. This tank is Heated by means of a fuel burner or steam.
The Hot Solution or Water is drawn from the tank by a pump and fed to a precisely
spaced set of spray nozzles around the product. As the product passes through
the Fine Spray it is cleaned, phosphated or rinsed. The liquid runs back into
the tank for recirculation and filtration. Drain zones between the Stages reduce
the risk of cross contamination. Following Aqueous Pre treatment, products usually
pass through a forced hot air recirculation dry off Oven. This system requires
a minimum amount of operator input and so it is ideally suited to conveyorisation
and automation.
