Powder Curing

Powder can be cured by either convection ovens or radiant ovens, or a combination of both.  Care must be taken to ensure that the coating is not damaged whilst in its powder state.  At this time it is extremely vulnerable to damage through draughts or sudden knocks. Air curtains that are a standard feature of convection ovens must be designed so that the air velocity doesn’t blow off the powder.

A proven method is to elevate the oven and have the coated product enter through openings in the bottom face.  Such openings do not require air curtains as the thermal head will retain heat inside the oven.  The example shown here has the powder curing oven located above the drying oven, saving floor space and material

Powder curing is similar to wet paint, in that the temperature of the product must be raised to the curing temperature, and then held at curing temperature until the cure is completed.  As the product reaches temperature the powder will begin to gel, from this point onwards air movement will not damage the coating.  An alternative solution for an in-line oven (especially where there are height constraints in the building) is to have a radiant section at the entry end to heat up the product until the powder gels.  The remainder of the oven may then be a standard convection design with air curtains to prevent heat spillage.   

Pengrave Engineering Ltd, off Delta Way, Bridgtown, Cannock, Staffordshire WS11 0DJ
Tel: 01543 577142 Fax: 01543 577930 Email: sales@pengrave-engineering.co.uk