the curved surface of the skirt if the side is etched rather than the top. Variations in surface finish also come
into play during reading. A rough surface may confuse
the reading system and generate false rejects.
Side printing is also possible with a continuous ink jet
(CIJ) printer. The advantage of side printing with CIJ is
the ability to print on the glass as well as the side of the
aluminum skirt. Glass printing allows the body label to
be placed over the printed code (after verification) to
prevent confusion for end users and automated reading
systems such as track and trace systems. However, you
run into the same problems with orientation as any side
printing, plus glass printing introduces contrast concerns about visible ink on a transparent and reflective
surface. Some combinations of ink with glass or aluminum can survive sterilization processes, but testing is
required and various inks and surface materials may
need to be experimented with.
Printing with CIJ on top of the flip-off cap has several advantages. Orientation issues are eliminated and
identification of multiple vials is possible, for example,
a wide field of view camera system looking down at an
entire tray. Also, contrast is excellent and the surface is
flat, so false rejects will be less than side printing and
etching, UV ink can be used to prevent confusion over
which Datamatrix should be scanned with your track
and trace system (see Figure 2).
Again, care must be taken when selecting the flip-off cap material and surface finish, UV ink blends, the
color of the cap and even the product itself. Sometimes
product in the vial will light up like a light bulb when
passing under a UV lamp!
Another consideration to your flip-off cap is labeling.
The World Health Organization (WHO) PQS performance specification E06/IN05.2 discusses the requirements for a Vaccine Vial Monitor (VVM). A VVM is
a temperature indicating label that informs the dose
administrator whether the product has maintained temperature requirements since leaving the manufacturer
(see Figure 3).
Before Heat Exposure After Excessive
With this or any other type of labeling on the flip-off
cap, the combination of the label adhesive, flip-off cap
material and surface finish play a key role in good adhesion for immediate needs downstream and long-term
needs in the field.
Lastly, the type of handling that the cap will see
during the accumulation, inspection and packaging
processes should be considered. A flip-off cap that is
larger in diameter than the body of the vial will not
accumulate on a conveyor or in a tray without falling
over. Packaging applications that require the vial to be
handled with grippers can be tricky with flip-off caps
that are not uniformly shaped. If vacuum cups lift the
vial by the top of the flip-off cap, a smooth surface is
needed and excellent adhesion of a VVM label, if applicable, is critical to prevent accidental removal of the
VVM and dropping of the vial.
As with all packaging components, the full process
should be taken into account during the selection and
specification process of your flip-off cap. The identification, inspection, handling and packaging processes,
as well as storage environment should be defined, at
least in a general sense, prior to selecting flip-off caps.
If questions arise, usually simple testing can alleviate
concerns or bring issues to light that can be addressed
before hitting the production floor.
Figure 2: Cap with printed UV code (© 2017 Integrated
Project Services, LLC)
Figure 3: VVM label (Courtesy of Temptime Corporation)