4. Laying off
• Before a lens can be edged,
• marking of cyl axis
pd
lens size,according to frame
etc. should be marked in the correct
position relative to the lens shape & specific
individual Rx
by using….
5.
6. Lens cutting & chipping
• In the past lens cutting & chipping process involved
• Glass cutter: that outlining the desired lens shape on
the glass with an appropriate marking
• The lens was cut several mm larger than required,for
some inaccuracy in chipping the lens & lens edge finish
• After lens cutting,outermost areas of glass were
removed using chipping pliers
• This is done only in manual edging process,in the
automatic edger,the full lens is edged to the required
shape
7. edging
• This step involves the finer edging of the lens
to the shape of the frame rim and creating a
bevel for the lens to be seated in the frame
groove.
• The edger has multiple wheels, provided for
gross edging, finishing and for bevel creation.
• Flat edge : rimless
• Bevel edge : rimmed frame
8. • To converting an uncut lens to the desired lens
shape
Edging
manual auto
pattern Pattern less
9. Manual:hand edging
• Types of hand edger
- ceramic wheel
- diamond wheel
• Now days more useful for:
- edge smotthing
- reducing a lens size
- reshaping the len
12. AUTO EDGING
• Pattern Edgeing: (semi auto)
Information from the pattern edger shape is
used to cut out. This pattern is then run along
a sensor, the data from which, is used by the
edger to edge the lens
• Patternless Edgers: (fully auto)
information from the frame scanner/tracer is
transferred directly to the edging machine,
which edges the lens accordingly
13. Pattern/edging former
• For converting an uncut lens to the desired
shape is by the use of former/pattern.
• Made from flat plastic material or metal plate
• It is held in position by holes to determine the
horizontal line of shape& standard oc position
• Available in according different eyesize
15. Pattern Measurements and
Terminology
• mechanical center:
of a pattern is the point on the pattern around which the
pattern rotates.
- The mechanical center is easy to find since it is found in the
middle of the large hole in the pattern
• Pattern Making :
Because of the vast number of available frame styles, it is
impossible to have a complete library of patterns
-36.5 mm standard size
- to prevent pattern distortion,the pattern made larger
19. Steps & facilities
• Electronic shape
• Required lens and frame materials as a option
• Patternless edging viewing screen
- that shows lens shape
-show the edge of the lens
• Lens drilling as an option
• Self-calibration & decentration calculation –
because tracer knows dbl & pd
27. Lens fitting
• lens is inserted into the frame.
• SPRINGING IN : insertation of the lens in
rimmed frame
• RIMLESS FITTING : insertation of the lens in
rimless frame
