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PERFORATING
STANDARDS
Sheet and plate size specifications
Mill tolerances are standard for width and length, pulls and
stretch caused by perforating unless stated otherwise.
Spacing of perforations
All perforations will be designated by either center spacing
or open area.
Margins (perforated material)
Stock size sheets and plates - long sides will have minimum
margins, short sides will have either minimum or no margins.
Resheared after perforating - special margins can be provided
to specification with the exception that a tolerance must
be allowed for the limits of the tool.
End patterns
FINISHED END PATTERN UNFINISHED END PATTERN
Should you require a finished round hole and pattern in either
a straight or staggered pattern, please specify and anticipate
high costs.
Stock Items
Stock items are available in cold rolled steel having round,
oblong, square and rectangular shapes. Types of holes ranging
from 1.00 mm to 25.00 mm, thickness of the sheet from 10gauge
onwards,width max. 48" and length as desired.
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VARIOUS
TYPES OF PERFORATIONS
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FORMULAS
FOR DETERMINING PERCENTAGE OF OPEN AREAS
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ORDERING GUIDE AND
CATALOG REQUEST
please review the following facts before ordering.
1. Metal to be perforated
2. Thickness in gauge or inches
3. Quantity in pieces or sheets
4. Perforation size - diameter of holes and center spacing
5. Shape of perforation- round, square or oblong
6. Margins - where they appear and dimensions of the same
7. Resquaring - if necessary
8. Cutting - to circles of special shapes
9. Any special service requirement
CHECKLIST OF PERFORATING
COST INFLUENCES
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Material
type
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Remember
the least expensive material may not be cost; a higher
strength alloy reducing thickness. Keep hardness below
80Rb.
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Material
thickness
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Thinner
materials perforate easier and faster.
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Hole
shape and pattern
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Round
holes are the most economical, 60 staggered round hole
pattern strongest and most versatile.
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Hole
size
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Do
not go below 1-to-1 ratio with sheet thickness. Stay
2-to-1 larger if possible.
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Bar
size
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Do
not go thinner than 1-to-1 ratio with sheet thickness
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Centre
distance
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It
controls feed rate and thereby the production rate.
If possible a pattern with longer center to centre distance.
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Open
areas
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Extreme
open areas proportions tend to increase distortion;
if possible choose under 70%.
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Margins
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Keep
side margins to a minimum to reduce distortion. Use
standard unfinished end margins if you can.
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Stick
to standards
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Specify
standard hole patterns, materials dimensions and tolerances
whenever possible before specifying a "Special " consult
us so that existing toolings can be used.
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Perforating
burrs
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Accept
normal commercial burrs unless otherwise specified.
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TOP
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