Wirework or wire product has been used in countless industries over the years. Many of these industries have required a hardwearing protective coating over the part that also provide a high level of corrosion protection. Over 50 years ago this fluidised bed coating process was invented to satisfy this requirement. The process involves the following steps:-
- The parts are hung unto jigs using high temperature fibres or very fine wire.
- The jig with the components hanging beneath it are then transferred into an oven an heated to approx. 350°C. The jig is then removed from the oven and lowered so that the parts beneath it are submerged into a tank of coating material that is fluidised by forcing air through it. This fluidising allows the parts to enter the material with little resistance.
- The parts are kept submerged for a pre-set time (the longer the time the more material is deposited onto the part, until the part has cooled to a point where it is below the melting point of the coating material).
- The parts are removed from the tank by lifting the jig.
- If required the jig and parts are pushed back into an oven to cause the coating material to melt further.
- The parts are then air cooled or quenched by using a water bath – typically with additives to stop the formation of air bubbles.
- The parts are then removed from the jigs and the sacrificial hanging wires cut off.
Using this technique a wide variety of coating materials can be applied and the process has the inherent advantage that the parts are submerged in the powder thus ensuring that the components are completely covered. The process is therefore more reliable than spray application. More details on materials available and their characteristics can be found on the Hebble Plastic Coatings Page of our website.