Pkg Solutions
Quality Glossary
ROTARY DIE CUTTING
The Rotary Die Cutting machine is designed to process boards for
subsequent making into many different forms of containers at speeds up to
15,000 per hour. They tend to not be as good at producing intricate work as
flatbed machine. (Measurement variance may be up to 1/8" or 3 mm +/-)
The die-cutting unit consists of a series of gear driven shafts, two of
which carry the die clamping rings and two the polyurethane covered
anvils. Pull roll shafts lie between the two pairs of die cutting shafts.
Appropriate shafts are adjustable for board caliper.
Trimming Knives are also fitted on the upper and lower pull roll shafts
and can be adjusted laterally to suit the width of trim required. Two
pairs of die shafts and anvils allow cutting and creasing to be done on
each side of the board. Each die shaft has radial adjustment, by
compensator, which has the effect of accurately positioning the leading
and trailing die cut in relation to the front edge of the board.
Cutting without waste ejection is recommended to be done on the first
pair of cylinders. Complete cut-out work and stripping is recommended to
be done on the second pair of cylinders. With this arrangement scrap
cuttings will not carry through on top of the board but will drop directly
onto the air conveyor waste disposal system.
As the unit is preceded by a Flexo Print Unit sections of the
polyurethane cover can be removed from the anvil shaft to prevent
off-setting from the printed areas of board.
The method of removing scrap often incorporates an air blowing system with low
pressure, high volume, fan assembly on the side of the machine. The bed of the Die Cut Unit is formed into an air duct. The top-plate is
louvered so that the low pressure air blows out in the direction of board
travel. The scrap cuttings fall naturally to the bed of the unit and are
conveyed by the air away to a suitable collecting point. Pin stripping
forms for waste removal systems are also employed in some rotary die-cutting
machines.
SUMMARY
These machines are designed to run at high speed and
while they sometimes lack the accuracy and ability to deal with small high
number out work, rotary die-cutters are often the best types of machines for
producing packs such as produce trays and large displays.