Substrates and Paints

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					“Coil Coating”
    Schematic: Typical Coil Coating Line
    General Overview                 (Not to Scale)

                  Entry                                          Exit
                  Accumulator                                    Accumulator
                                     Finish            Water
                                     Coater            Quench
                          Pretreat                                             Recoiler
                          Section             Finish Oven
                                                                         Shear




             Joiner      Cleaning             Prime Oven
                         Section
                                                                     Inspection &
                                                        Water        Physical Test
      Dual                      Prime & Quick           Quench       Area
      Uncoilers                 Change Coaters


Overall line length - Approximately 700 feet
Strip to thread the line - Approximately 2800 feet
Coil Coating: The Process
General Overview

 • Receiving
 •   Entry Section
 •   Cleaning & Pretreatment
 •   Coating & Curing
 •   Exit End
 •   Physical Testing
Coil Coating: The Process
Receiving

 • 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 Process
General Overview

• Receiving
• Entry Section
• Cleaning &
  Pretreatment
• Coating & Curing
• Exit End
• Physical Testing
Coil Coating: The Process
Entry Section
• Get Steel l- FIFO &
  ID
• Check Metal
  Specifications
   – Grade/Gauge/Wi
     dth/Etc.
   – Quantity/Coil
     Size
• Check Condition
   – Edges
   – Shape
   – Zinc Surface
Coil Coating: The Process
Entry Section I
• Coil Cars
  Floor or Pit
• Pay Off Arbors
• Coil Size
   – Width
   – ID or OD &
     Weight
• Joiner/Welder
Coil Coating: The Process
Entry Section II

 •   De-burring Rolls
 •   Pre-cleaner
 •   Entry Bridle
 •   Entry Tower
     Hydraulic/Electric
Coil Coating: The Process
General Overview
      • Receiving
      • Entry Section
      • Cleaning & Pretreatment
      • Coating & Curing
      • Physical Testing
      • Exit End
Coil Coating: The Process
Cleaning & Pretreatment I

• Rinse
• Clean & Brush
• Clean & Rinse
• Chemical Treatment
   – Single or Multi-Stage
• Final Rinse
• Waste Treatment; Chrome
Coil Coating: The Process
Cleaning & Pretreatment II
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 Process
Cleaning & 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.
Coil Coating: The Process
General Overview

• Receiving
• Entry Section
• Cleaning & Pretreatment
• Coating & Curing
• Physical Testing
• Exit End
Coil Coating: The Process
Coating & Curing I

 • 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          Line
      finish Coats               Direction
Coil Coating: The Process
Coating & 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 Process
Coating & 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
Coil Coating: The Process
General Overview

        •   Receiving
        •   Entry Section
        •   Cleaning & Pretreatment
        •   Coating & Curing
        • Physical Testing
        • Exit End
Coil Coating: The Process
Physical Testing – Hunter L.A.B.
                                   • 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 Process
Physical Testing – Reverse Impact Adhesion
  • 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 Process
Physical Testing – Flexibility
 • Brake press forming of metal
   sample
 • Tape (Scotch #610) aggressively
   applied and pulled away
Coil Coating: The Process
Physical Testing – Film Thickness

 • Scribe cut with calibrated blade
 • Visual inspection with reticle
   enable microscope
 • Measures Primer DFT
 • Measures Topcoat DFT


                                      Tooke Gauge
Coil Coating: The Process
Physical Testing – Solvent Resistance

 • 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 Process
Physical Testing – Gloss Meter


 • Instrument measures
   reflected gloss
 • Typically measured at
   60°
 • Ultra low gloss
   measured at 85°
Coil Coating: The Process
General Overview

      •   Receiving
      •   Entry Section
      •   Cleaning & Pretreatment
      •   Coating & Curing
      •   Physical Testing
      • Exit End
Coil Coating: The Process
Exit End
 • Recoil
 • Coil Tipper - Coils Eye to the
    Sky
 • Package - Paper Wrap & Skid
 • Tag/Record
 • Store or Ship