Ties Per Inch | Perforation
Perforations are classified by bursting strength and type.
The bursting strength is referred to as "ties per inch" or TPI. The
type of perforations are horizontal or vertical, which can be full or partial.
The integrated and affixed products will have different limitations determined
by the type of attached product and the type of carrier.
Ties Per Inch
The tie or tab is what is connected to the paper while the
perforation is the cut in the paper. TPI are generally determined by the function
of the perforation on the product. Some of the common ties per inch (TPI) are
3, 4, 6, 8, 10, 50 and 72. The length and number of ties will determine how
easy or difficult the perforation tears. The manufacturer will most generally
use their standard TPI for the type of product being manufactured. If something
special is required, consult your supplier about the necessary requirements.
The single card itself will not generally have
a perforation added to it because the end use of the card does not have a need
for a perforation. An affixed label would normally be die cut to allow part
of the label to detach from the rest but a perforation could be added if necessary.
The carrier, however, of the card or label could have a need for an additional
perforation added to it. The guidelines for perforations on the carrier would
be according to the type of carrier used.
Integrated cards are sometimes perfed into the
carrier to allow removal of the card. The perf eliminates the need for a patch
on the back of the carrier to hold the card onto the carrier. Determining the
TPI to use for the perforation will depend on the weight of the stock, the type
of stock, how the integrated product will be handled after the card is perfed
into the carrier, and preference as to what type of edge the card will have
when detached from the carrier.
Enlarge View of Card Edges
A 3 TPI perf would produce a card with just a few
ties on the edges when perfed out of the carrier.
Using a micro perf (50 or 72 TPI) would produce
a card with a very fine perforation, giving the card's edge a smooth
Integrated labels are generally die cut into the
carrier to allow for easy removal from the liner patch, see Die
Cutting. The carrier of the integrated card or label could have a need
for an additional perforation added to it even if the card or label does not
have a perforation. The guidelines for perforations on the carrier would be
according to the type of carrier used.
Be sure to discuss your perforation
requirements with your supplier so he can determine if they are within
the manufacturer's capabilities.
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