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15. Electrolytic Plating Process: Plating requires the plastic parts to be
electrically conductive. To achieve this conductivity, the plastic parts are subjected
to an electroless plating operation. Plastic parts are first submersed in a sulfuric
chromic acid bath which slightly etches the plastic surface, creating microscopic
pockmarks. The plastic parts are then placed in a activator bath, and an accelerator
bath making the parts chemically attractive to the metals suspended in the
electroless plating bath solution. These plating metals get deposited in the
pockmarks. It is the first phase in the electrolytic plating process which provides a
dull metallic finish and makes the parts electrically conductive. Electrolytic plating
creates bright chrome surfaces.
16. Dyeing, where dye molecules penetrate below the surface.
17. Mechanical surface changes, such as polishing, grinding and embossing &
surface textures.
18. Sublimation Printing: In sublimation (diffusion) printing, color in dry dye
crystals is transferred from a release film to a plastic substrate under heat and
pressure. The dye crystals vaporize and the vapor penetrates the plastic part,
yielding a durable, wear-resistant decoration. This process is cost competitive with
other processes, such as two-stage injection molding or silk screening. It is,
however, limited to polyesters and polyester-based alloys by currently available
dyes intended for textile applications. New dyes are under development for
applications with other than polyester-based thermoplastics.

FLAMMABILITY TEST FOR PLASTICS

Underwriters Laboratories (UL) is an independent organization that provides
product safety testing and certification. Their UL94 testing procedures and rating
system for thermoplastics flammability are the generally accepted standard
throughout most of the world. Different UL94 ratings are given based on variations
of the test method and results:
• UL 94-5VA Surface Burn; Burning stops within 60 seconds, test specimens
MAY NOT have a burn-through (no hole). This is the highest (most flame
retardant) UL94 rating.
• UL 94-5VB Surface Burn; Burning stop within 60 seconds, test specimens MAY
HAVE a burn-through (A hole may be present)
• UL 94 V-0 Vertical Burn; Burning stops within 10 seconds, NO flaming drips are
allowed
• UL 94 V-1 Vertical Burn; Burning stops within 60 seconds, NO flaming drips are
allowed
• UL 94 V-2 Vertical Burn; Burning stops within 60 seconds, Flaming drips ARE
allowed.
• UL 94 H-B Horizontal Burn; Slow horizontal burn test (H-B) are considered
ôself-extinguishing". This is the lowest (least flame retardant) UL94 rating.

For further information: www.ul.com

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