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CALIBRE* polycarbonate resins are proven
materials that can be quickly and easily injection molded
into quality parts with excellent aesthetics and physical
properties. While molding problems do occasionally occur,
most are readily resolved or prevented with attention
to the following recommendations.
- Understand the process and Product
A thorough understanding of both the
theory and mechanics of the injection molding process
and of the machinery and other equipment employed is essential
to trouble-free operation. This also applies to the particular
being processed. Operators should be reasonably familiar
with the chemical, physical and mechanical properties
of these materials and should be able to anticipate the
probable behavior of the resin under varying heat and
pressure conditions. Anticipating potential problems and
correcting them before they occur can significantly shorten
start-up and production times.
- Change Only One Control
or Condition at a Time
This
may seem obvious, but experience suggests that this is
the one rule most often neglected. Clearly, if more than
one control is changed at a time, there is no way to monitor
which control was responsible for the change in the machine
operation.
- Allow Sufficient
Time for a Change to Take Effect
Allow sufficient time (i.e., 10 shots)
after each change for the material and the machine to
adjust and reach equilibrium. Obviously, if sufficient
time is not allowed before additional changes are made,
there will be no way to accurately monitor whether or
not a particular change was effective. ˇ°Sufficient timeˇ±
depends on the nature of the control or other factor that
was changed, the shot size (especially in relation to
the barrel capacity), and the length or complexity of
the overall cycle
- Keep an Accurate
Record or Log of Each Change
Keeping an accurate and detailed log of each
change and saving it as a permanent record of the total
job is an excellent practice. This record should include
the machine number, the material or resin lot numbers,
machine conditions and performance, mold and part identification
numbers, etc. Such a record can be very helpful the next
time the same machine, mold or material is used. This
record can also be extremely useful in preparing future
cost estimates for molded parts.
- Provide Clear, Written Instructions
Once a solution to a
problem has been found, post clear, written instructions
on or near the machine in question. Also enter these instructions
in the log or job history. |
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"*" Trademark of the Dow Chemical Company, licensed for use by LG DOW
Polycarbonate LTD.
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