Arkema has originally developed a process under the name “Minicoat” for the coating of small articles. Based on this process, Rilsan® MC grades and Rilsan® Techline grades are specially designed for the coating of small items, like adjustors in the lingerie industry. MC grades have an average particle size of around 50 microns that allow for very high productivity and controlled thickness.
Minicoat / Maxicoat Process
When to select the minicoat process?
Minicoat process is particularly well adapted for small parts ; nice coating with regular thickness can be achieved even for < 0,5 mm part thickness.
Flexible part design
Minicoat process can be used for different shapes of part ; flat profiles are the most suitable but 3D parts can be also coated with this process.
Productivity up to 10,000 parts/h can be reached due to the fact that parts are only set out on a conveyor (for both preheating and post fusing steps)
Dye operation can be easily conducted on parts coated with white grades
Minicoat process allows to get homogeneous coating thickness and nice aspect with adapted preheating conditions and good bowl design.
No Hanging Mark
One of the advantages of the Minicoat process is that the parts are not hung but put directly on the conveyor belt so there is no mark on the coating.
A surface preparation is necessary, requiring cleaning, surface treatment and primer application. For further information, please refer to the leaflet Surface pre-treatments and primers.
Part preheating between 300C and 450C. Temperature and time might be adjusted depending on part dimensions.
Position of the parts on the conveyor belt is very important:
- It will affect the rate of rejected parts for marriage (stuck parts)
- Recommended distribution is staggered position (quincunx)
- Parts feeding on the belt conveyor can be done automatically with adapted system (distribution in different corridors
Preheating conditions have to be adapted to the piece geometry : High temperature and low heating time for thin parts, and Lower temperature and longer heating time for more massive parts.
At end of preheating the parts must have the same temperature.
Falling height between exit of preheating and dropping zone has to be as short as possible so that the loss of heat is minimal. Coating thickness only depends on the metal temperature at the dropping moment. Standard range value of coating thickness is from 120 to 250 µm.
Powder in the dropping zone must be well fluidized in order there is no impact mark on the coated parts.
Post fusing step is conducted to get a smooth aspect of the coated parts. Post fusing is successively conducted for upper
Face then lower face or the parts, generally by automatic process including the flip of parts.
The operation is done on a separate line at high speed ; post fusing step can be delayed if time between coating and post fusing > 4h, parts must be stored at 60C to avoid moisture absorption.
Other Specialized Coating Techniques
Rilsan® Fine Powders are well suited to most other standard processes usedfor powder coating: hot (flock) spraying, rotomolding, pipe lining, and flame spraying, to name a few.
These processes are particularly adapted to the coating of large or bulky parts (valves, pumps, cylinders), articles with intricate designs (heaters), or large diameter pipes that are too large to be dip-coated.
Depending on the final coating properties required, both the processing conditions and the grades compatible with these technologies should be studied and chosen specifically. Our technical support team will be pleased to assist you further in this regard.