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Wire & Cable ASIA – November/December 2013
CANDOR Sweden AB
Tel: +46 11 21 75 00 Fax: +46 11 12 63 12
Email:
Single wire plating plant
• Electrolytic plating
• Candojet hot water cleaning
• Electrolytic & Ultrasonic degreasing
• Welding wire cleaning and copper coating
• Pickling & phosphating
Ultrasonic
& Electrolytic
Multi wire cleaning plant
Rapid Coat powder coatings are
manufactured by Rapid Engineering Co
Pvt Ltd (RECPL).
Located at a two-acre site in New Delhi,
India, Rapid Coat manufactures both
thermoplastic and thermosetting
powder coatings, which are sold
globally.
HAPA stands for high adhesion polymer
alloy. As the name suggests, it is a
thermoplastic polyethylene alloy. These
plastic coating powders have been
specifically designed to provide a long
lasting, chemically and mechanically
tough coating for both exterior and
interior applications.
The HAPA coating has excellent
adhesion to the base metal and is
almost impossible to peel off.
HAPA powders are available in a variety
of grades:
HAPA SC (spray coating): The powder
item size is very fine and designed to be
sprayed onto the item using
electrostatic spray guns. The air
velocity and powder flow should be
suitably adjusted so as to prevent
overspray or bouncing back of the
powder spray.
HAPA DC (dip coating): This grade of
powder is designed for coating by the
dip/fluidised bed coating method. In
this method, the heated item is dipped
into a fluidised bath containing the
powder for 2-5 seconds.
HAPA granules: These granules
possess the same properties as the
other grades but are designed for
coating using the extrusion coating
method.
HAPA powders find many applications
given the tough and durable coating
properties along with the flexibility
available in methods of coating. Some
of the most common applications of
HAPA are: playground equipment,
garden furniture, outdoor benches,
welded wire mesh, wire mesh rolls,
chain link fences, security fences, fence
posts, pipelines, automotive clamps,
automotive fuel tank filler pipes, fire
extinguishers, battery boxes,
submersibles, fan guards and lamp
posts.
The coating methods include:
1. Fabrication: The metal plate is
de-greased, de-rusted, de-scaled,
passivated and cleaned. Thin ‘wire
loops’ or hooks should be attached at
suitable locations, for ease of handling
the item, so as not to mark the product
appearance. These are later cut off or
removed.
2. Preheating: The bare item is heated
in the oven at 250-300°C (480-570°F)
for 5-10 minutes. The heating time and
temperature depends on the mass of
the item and the loading of the oven.
This has to be practically ascertained to
provide the desired production rates
and coating thickness.
3. Coating: The heated item can be
coated in two ways: Spray coating, the
powder can be sprayed onto the item
using electrostatic spray guns. The air
velocity and amount of powder should
be suitably adjusted so as to prevent
overspray or bouncing back of the
powder spray, or
Dip/fluidised bed coating: The heated
item is dipped in a tray containing the
powder and the powder is splashed on
it, or the item is dipped in a fluidised
bed of the powder for 2-5 seconds. The
powder will stick to the hot item.
Once the item is coated, care should be
taken to ensure it does not rub or come
into contact with any surface to prevent
damage. A rough, powdery, but uniform
coating on the item is obtained. The
excess un-melted powder is shaken off
with a slight jerky motion or light
tapping. The coating thickness
increases with the pre-heating
temperature and dipping time.
To smoothen out the powder and
provide a glossy surface, the item is
re-heated in the oven for 2-3 minutes.
The suggested temperature varies
between 120-140°C. This causes the
powder to melt, sinter and flow out.
Excessive heating may cause the
coating to discolour or sag. The item
should be carefully taken out of the
oven, without the coating coming into
contact with any other surface, and
allowed to cool in a clean, dust-free
atmosphere. Sometimes water
quenching is also resorted to for wire
products.
The thin ‘wire loops’ attached earlier for
handling the item are carefully snipped
off at the base so as not to mar the
appearance. The item is inspected for
pinholes or blemishes. These can be
filled or repaired with a little powder with
a small soldering iron or hot air gun.
Rapid Engineering Co Pvt Ltd – India
Website:
Long-lasting Rapid Coat