Carnation
Corporate Offices
5045 Wilshire Boulevard
Los Angelos, CA 90036
April 13, 1987
Dear Mr.Pleacher:
We appreciate the interest you expressed in examining
the height-to-diameter relationship of containers used
in our food products. A 1:1 ratio of height versus diameter
is the most efficient use of material, if only the surface
area of material is considered. However, there are many other
factors which must be considered when designing a can for a
particular product. Listed below are some of these other factors:
1) Thermal Processing -- There is an inverse relationship between
the most efficient design for cans relative to surface area and
the amount of processing time required to sterilize the product
contained within. In other words, a tall thin can or short wide
can will require considerably less processing time and energy to
achieve commercial sterility than a can which is nearly equal in
height and diameter.
2) Strength Requirements -- During thermal processing, considerable
internal pressure develops. This pressure can cause the ends of
the can to become permanently distorted. Because of this, ends on
most cans are made of metal which is substantially thicker than
that used in the can cylinder. Therefore, there is not a simple
cost-to-surface area relationship relative to metal. As this can
becomes taller and the end becomes smaller, thinner metal can be
used in both the cylinder and the ends.
3) Can Manufacturing Line Changeover Time -- Virtually all can lines
run a variety of can sizes. The time required to change over from
one can size to another is considerably less if only can height is
changed, rather than height and diameter. In addition. since the
same ends can be used if only the height is changed, the machinery
used to manufacture ends does not have to be changed over to a
different diameter. Reduced changeover time translates into reduced
downtime and increased line efficiency.
4) Scrap Loss -- Generally, more metal scrap is generated as the
diameter is increased.
5) Warehouse and Shipping Efficiency -- Smaller diameter cans make more
efficient use of packaging and shipping space.
As you can see, cost and efficiency of a container are related to factors
other than just the amount of material used. These are just a few of the
factors which must be taken into consideration when designing a can. We
hope that you now better understand that container design is not quite as
simple as minimizing surface area.
Once again, thank you for your genuine interest.
Sincerely,
Vince Daukas
Assistant Product Manager
Friskies Buffet
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