How is Knotwood™ made?
Extruding Knotwood™ Profiles
The process begins by heating the stock billet material. It is then loaded into the container in the press. A dummy block is placed behind it where the ram then presses on the material to push it out of the die. Afterward the extrusion is stretched in order to straighten it.
Pre Treatment of Aluminium
In this process, the mill finish aluminum profiles are treated with a strong acidic cleaner to ensure the removal of the specified oxide layer thickness equating to more than 1 g/m². After the acid wash the aluminium is immersed in a controlled chromic acid bath with special additives, a chemical conversion reaction occurs at the metal’s surface. This reaction produces a thin oxide film with entrapped chromates and dichromates. This process ensures the aluminium is resilient to corrosion.
The next stage in Knotwood’s™ process involves powder coating. Electrostatic guns will be used to make 80-120µ (microns) powder paint layer. Polymerization will be performed afterwards by heating the profiles to 220 degree Celsius for 30 minutes. The base coat that is applied is very durable and scratch resistant. This coat also serves as protection of the aluminum from external factors such as abrasion, corrosion, weather, humidity and UV damage.
The final stage is all about decorating the powder coated aluminum. The Knotwood™ wood grain film needs to cover the entire aluminium profile, the profile is then set on the conveyor system. We then usa a vacuum suction system to remove the air from the film bags. The conveyor will insert the aluminum profile into an oven to make changes to the ink pigments, which will be converted from solid to gas then back to solid again resulting in a perfect thermo print. Knotwood ships with the film intact for better transport.