“Coil Coating”

(Not to Scale)

DualUncoilers

Joiner

EntryAccumulator

Exit Accumulator

Finish Oven

Prime OvenCleaningSection

PretreatSection

Inspection &Physical TestArea

WaterQuench

Recoiler

Shear

Prime & QuickChange Coaters

WaterQuench

FinishCoater

Overall line length - Approximately 700 feet

Strip to thread the line - Approximately 2800 feet

Schematic: Typical Coil Coating LineGeneral Overview

Coil Coating: The ProcessGeneral Overview

• Receiving• Entry Section• Cleaning & Pretreatment• Coating & Curing• Exit End• Physical Testing

• Record Identity• Visual Inspection• Obvious Damage

– Dents, Torn Paper, etc.

– Wet?• Material Handling Crane

or Forklift• Store for Future Use

Capacity: 3 Mos.

Coil Coating: The ProcessReceiving

Coil Coating: The ProcessGeneral Overview

• Receiving

• Entry Section• Cleaning &

Pretreatment• Coating & Curing• Exit End• Physical Testing

• Get Steel l- FIFO & ID

• Check Metal Specifications– Grade/Gauge/

Width/Etc.– Quantity/Coil

Size• Check Condition

– Edges– Shape– Zinc Surface

Coil Coating: The ProcessEntry Section

• Coil Cars Floor or Pit

• Pay Off Arbors• Coil Size

– Width – ID or OD &

Weight • Joiner/Welder

Coil Coating: The ProcessEntry Section I

• De-burring Rolls• Pre-cleaner• Entry Bridle• Entry Tower

Hydraulic/Electric

Coil Coating: The ProcessEntry Section II

• Receiving• Entry Section

• Cleaning & Pretreatment• Coating & Curing• Physical Testing• Exit End

Coil Coating: The ProcessGeneral Overview

• Rinse• Clean & Brush• Clean & Rinse• Chemical Treatment

– Single or Multi-Stage• Final Rinse• Waste Treatment; Chrome

Coil Coating: The ProcessCleaning & Pretreatment I

The key to quality is preparing the metal to accept the paint. Pretreatments enhance the corrosion resistance of the system. The type of pretreatments used depends on the base metal.−Galvanized - Zinc Phosphate 37S−Galvalume - Chromate Oxide 1310−Final Rinse - Parcolene 62 Chromic Acid−Dried-in-Place Coatings: 1402W (some Cr. free)−Duplex Complex Oxide or Zinc Phos. & 1402W

Coil Coating: The ProcessCleaning & Pretreatment II

Coil Coating: The ProcessCleaning & Pretreatment III

A liquid used to produce a corrosion-resistant, organically bonded coating on Aluminum, Galvalume and Galvanized.

Incorporating a chromate rinse which is the major agent that allows the primer to bond to the substrate and helps prevent corrosion.

Benefits of Pretreatments: Provides superior long term corrosion. Effective on Aluminum, Galvalume and Galvanized. Coating quality is consistent.

• Receiving• Entry Section• Cleaning & Pretreatment

• Coating & Curing• Physical Testing• Exit End

Coil Coating: The ProcessGeneral Overview

• Specification– Primers, Backer, Topcoat– Cure time & Line Speed

• Coater Paints Topcoat & Backer at the Same Time

• Usually Two Complete Sets−Coater, Oven and

Quench for Primers and finish Coats

Line Direction

Coil Coating: The ProcessCoating & Curing I

Coil Coating: The ProcessCoating & Curing II

• Coating Speeds up to 650 fpm– Speed dependent on

cure requirements, gauge and solvent loads

• Ovens mostly Cantenary Type - 130 to 160 ft. long

• Cure is Determined by Peak Metal Temperature

• Cure Occurs in 14 - 22 Seconds

Coil Coating: The ProcessCoating & Curing III - PRIMER

The base layer of the paint applied by the coater to the pretreated substrate.

It is formulated to provide corrosion protection to the base metal and to enhance adhesion between the top coat (paint) and the base metal.

Standard Primers: Water Based Urethane Based

• Receiving• Entry Section• Cleaning & Pretreatment• Coating & Curing

• Physical Testing• Exit End

Coil Coating: The ProcessGeneral Overview

• Utilize a Color Difference Meter

• Assigns value corresponding to the amount of light at each wavelength

• Value is compared to and held in tolerance of Color Standard

Coil Coating: The ProcessPhysical Testing – Hunter L.A.B.

L = +0.2

a = -0.4

b = -0.3

Specimen

Light Source Diffraction Grating

Diode Array

Data ProcessorData Display

• 5/8” diameter steel ball is dropped from a prescribed height onto the panel.

• Effect leaves a deformation that is subject to cross hatch and tape test.

• Tape (Scotch #610) is aggressively adhered and pulled (not peeled) away from the sample.

Coil Coating: The ProcessPhysical Testing – Reverse Impact Adhesion

• Brake press forming of metal sample

• Tape (Scotch #610) aggressively applied and pulled away

Coil Coating: The ProcessPhysical Testing – Flexibility

• Scribe cut with calibrated blade• Visual inspection with reticle

enable microscope• Measures Primer DFT• Measures Topcoat DFT

Tooke Gauge

Coil Coating: The ProcessPhysical Testing – Film Thickness

• MEK = Methyl Ethyl Keytone

• Indicates Proper Cure

• Solvent is liberally applied and cheesecloth is stroked back and forth across panel face for prescribed # of strokes

Coil Coating: The ProcessPhysical Testing – Solvent Resistance

• Instrument measures reflected gloss

• Typically measured at 60°

• Ultra low gloss measured at 85°

Coil Coating: The ProcessPhysical Testing – Gloss Meter

• Receiving• Entry Section• Cleaning & Pretreatment• Coating & Curing• Physical Testing

• Exit End

Coil Coating: The ProcessGeneral Overview

• Recoil• Coil Tipper - Coils Eye to the

Sky• Package - Paper Wrap & Skid• Tag/Record• Store or Ship

Coil Coating: The ProcessExit End