Powder Coating
Our powder coating holds the approval of the now BS EN ISO 9002 (2000). Included within these standards is the control of:
Measuring instruments
Incoming and outgoing goods
Inspection
Non – conforming Items
The company works to BS 6497: 1984
The Powder Coating Method – an Outline
Powder coating provides a decretive finish to hot dip galvanising and black steel. On application to a galvanised component it gives a long lasting low maintenance finish available in a vast range of colours.
The Plant
The Powder coating plant consists of:
I. A alkali cleaning tank electrically heated to circa 70ºC - 1 @ 3500 x 2900 x 900
II. A acid cleaning tank electrically heated to circa 55ºC – 1 @ 3500 x 2900 x 900
III. A zinc phosphate pre–treatment tank electrically heated to circa 70ºC – 1 @ 3500 x 2900 x 900
IV. A deionised water tank – ambient temperature – 1 @ 3500 x 2900 x 900
V. Travelling overhead crane hoists
VI. A degassing oven – gas heated – 1 @ 3500 x 3000 x 900
VII. A spray booth ( Main) and also portable spray booth
VIII. A curing oven – gas heated
The Process
ALKALI CLEANING TANK |
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RINSE |
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ACID CLEANING TANK |
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RINSE |
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ZINC PHOSPHATE |
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RINSE |
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DE GAS / DRY OVEN |
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SPRAY |
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CURE OVEN |
In order for the powder coating process to take place correctly it is essential that the surface of the component to be powder coated is completely free from scale, grease, paint and rust.
Black steel components need first to be immersed into an alkali cleaning tank for 5 – 15 minutes at circa 70ºC. Following this they are rinsed in a water tank.
Both black steel and galvanised components need acid treatment at a temperature of circa 55ºC. Black steel components will be immersed for up to 1 hour until clean of rust or scale. Following this the components are thoroughly rinsed.
Zinc Phosphate treatment is important to ensure a good coating. Galvanised components are immersed for 3 - 4 minutes. Black steel components are immersed for 15 minutes. The components after immersion are inspected visually, then thoroughly rinsed off and finally rinsed in the deionised water tank.
Black steel components then require time to dry. Temperature and time are not of importance.
Galvanised steel components then require surface degassing at a temperature of 40ºC above the temperature of the curing oven for a minimum period of 15 minutes.
Once cooled powder coated components pass through the curing oven at 200ºC for 8 minutes (metal core temperature).
Components are then visually inspected and packed appropriately for despatch.