I. Printing
If words or pictures are to be printed on the surface of plastic
products, the following methods shall be adopted.
1. Web plate silk printing
This is the most common and also most widely adopted method;
it is usually applicable to printing of plat surfaces or surfaces
with small curve.
2. Curved surface printing
Curved surface printing principle
For curved surface printing: Put printing ink into intaglio
plate graved with specified words or pictures at first, then
duplicate these words or pictures onto a curved surface, then
use this curved surface to print these words or pictures onto
final product surface, finally cure the printing ink by heat
treatment or ultraviolet light irradiation.
Curved surface printing technique:
A. Degreasing of formed products
B. Surface treatment of formed products (if necessary)
C. Printing
D. Curing process of printing ink
E. After treatment of excessive printing£¨ if necessary£©
Printing process
A. Put printing ink into the intaglio plate
B. Scrape off excessive printing ink
C. Extrude the curved surface to get printing ink
D. Transfer print the ink on curved surface onto the surface
of formed products
E. Clean the curved surface, printing plate £¨if necessary£©
Migration printing
At first print words or pictures from the
printing plate onto the rubber plate or rubber roller, then
transfer print words or pictures from the rubber plate or
rubber roller onto the surface of form products.
Advantage£ºSeveral colors shall be applied
during one process.
Disadvantage£ºLow production capacity, print lines with high
opacity can not be achieved. How to select appropriate rubber
plate, rubber roller and ink volume
3. Gold stamping
Using color foil and hot mould graved with motif or words,
make colored swelled motifs or words on product surface
under controlled temperature and pressure. Press the hot
mould installed on the fixed press against appropriate area
of the product partitioned with the color foil.
II. Painting
Common methods of plastic product surface treatment (color)
include£º
A. Ordinary coloring: Manual painting is usually adopted
for this method. Wear prevention property is poor and paint
is liable to peel off.
B. PU polishing paint: After primer is dried, apply a layer
of PU polishing paint on the surface to obtain good wear
prevention performance and glossiness. Common household
electrical appliances and daily use goods pass through this
kind of PU treatment.
C. UV polishing paint: After primer is dried, apply a layer
of UV polishing paint to get good glossiness, hand feeling
effect and wear prevention performance. Communication moulds
normally adopt this kind of treatment.
IV. Electroplating
Electroplating: Use electrolytic method to deposit metal
or alloy on work piece surface to form uniform, fine, cohesive
metallic layer, i.e. it is a process of combination of physical
and chemical changes.
Applications£º
a£® Anti-corrosion
b£® Protection and decoration
c£® Wear prevention
d£® Electrical property: Provide coating with conductivity
or insulating property according to requirements of work
piece.
e£® Process requirements
Use electrolysis to form uniform, fine, cohesive metal or
alloy sediment layer on product surface: This process is
complex but provide many advantages. For example many metals
and colors can be achieved, and price is relatively low
compared with similar techniques.
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