To start with the items are booked into an allocated slot. This system is used so customers know when their items will be ready.
Once the specified slot is available the items are loaded at ground level by an experienced workforce with steel hooks that reflect the weight of the item.
The items are then carried by the line up to the phosphate tank where they are washed with a specialised iron phosphate, then rinsed in de-ironized water, dried in the dry off oven and conveyed to the application stage.
This is an electro-static application of powder. The powder is negatively charged by an electrode inside the powder guns which creates an iron cloud.
The items to be sprayed are earthed to the conveyer via the steel hooks and this causes an electro-static attraction of the powder particle to the item.
The item is then placed into a high temperature curing oven to allow the paint to bond to the surface.
Advantages of Powder Coating
There are several advantages of powder coating over conventional liquid coatings:
- Powder coatings emit zero or near zero volatile organic compounds (VOC).
- Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging.
- Powder coating production lines produce less hazardous waste than conventional liquid coatings.
- Powder coated items generally have fewer appearance differences between horizontally coated surfaces and vertically coated surfaces than liquid coated items.
- A wide range of special effects is easily accomplished which would be impossible to achieve with other coating processes.
- Powder coating is allot more durable than most conventional wet sprayed coatings.
- Powder coating can be allot faster than wet spraying in terms or curing / drying times.
While powder coatings have many advantages over other coating processes, there are limitations to the technology.
For optimum material handling and ease of application, most powder coatings have a particle size in the range of 30 to 50 µm and a TG > 40°C.