500mm Aluminium Coil Coating Equipment Coil Paint Line

Valued aluminum coil coating line

with foil rolls, recuring furnace, etc.

Color coated plate normally refers to the product of cold rolled or galvanized plate, whose surface is pretreated (degreased,phosphated or passivated), then coated (or roller coated) a layer of coating tobe dried up.

Because of the high intensity, high corrosion resistance, easy machiningperformance and rich color options etc., color coated plate is widelyapplicable to the civil construction, communication, light industries, homeappliance and automobile industries and so on, particularly the civilconstruction industry, plants, re-locatable houses, doors and windows haveconsiderable demands of the plate.Printingand laminating line derived from color coating line can produce all kinds ofcolors and decorative pattern of color steel plates with wood grain, leathergrain, marble etc., which has wider application and higher added value. Theseplates have been widely used in both inside and outside decoration of thehousehold appliances and construction industry, especially in places of high fireprevention requirements like hotels, restaurants, cinemas and theatres, largevenues and ships etc, and printed coated steel plate has become the firstchoice.

Cooling and Quenching
Cooling of aluminium strip prior to quenching with water is a critical part of the line design. In aluminium coating lines this is typically done with ambient air being applied to the strip at either the exit zone of the oven or in a separate air cooler located after the oven and prior to the quench. This is necessary to avoid thermal shock; created by too rapid cooling of the strip resulting in a metallurgical change that induces strip shape. Air cooling is used to reduce the strips PMT (Peak Metal Temperature) to around 150-170 deg C. The added benefit of this is seen when incorporating hot film laminating, typically requiring a strip temperature around 180 deg C.

Water quenching ensures that the colour coated strip is not recoiled at too hich a temperature. This can lead to coil collaspe, blocking and marring, common defects associated with poor temperature control. Water quenches are similar for both steel and aluminium, however aluminium will cool quicker and it is imperative to have even cooling by water, as hot spots can create defect patches on some coatings, especially PVDF’s which are commonly used in aluminium colour coating.

Line Tensions
Tension control in the strip is a critical aspect of any process line, however aluminium requires a high degree of control, especially for lighter gauges. Aluminium colour coated coil can be as light as 0.18mm (equivalent to 0.06mm steel). Strip tear offs / breaks will occur unless excellent tension control is applied. This is done by the lines bridles using rubber covered rolls. However, in some applications the use of tungsten coated rolls may provide increased coefficient of friction, improving performance, reducing slip and improved strip tension control.

It is important when considering any process line design to be realistic about the gauge range to be processed, however, this becomes more critical for aluminium, as roll sizes and motors power need to be optimised to provide satisfactory performance throughout the gauge range.