As the paint track moves, the hung parts pass through various specific stages which ensure the final quality of the paint finish:
Stage one – Pre-treatment
A highly Alkaline cleaner is applied to the parts which removes any manufacturing residue and other dirt, the parts are then rinsed firstly with mains water and then with demineralised water. A saline based liquid pre-treatment called Oxsilan 9810 is then applied which relies on chemical bonding to protect against corrosion. Finally, the parts are rinsed with demineralised water once more.
Stage two – drying
The pre-treated parts are then passed through an oven at around 180 degrees to dry them ready for the epoxy paint powder.
Stage three – powder application
The track now carries the grounded parts through an automated spray booth where electrostatic spray guns begin to apply the charged powder to the parts. The parts then pass through another area where manual electrostatic spray gun operators cover any difficult to reach areas.
Stage four – stoving
Finally, the coated parts will pass through a gas-fired tunnel oven to cure the powder. The required temperature of the oven will depend on the type of powder applied and at the critical temperature, the powder will begin to flow and then bond. This bonding creates the final smooth finish of the paint.
Example of Alpha Manufacturing’s powder coating plant: