Resin Puzzle Key
www.protomold.com
(763) 479-3680
Your sample resin cube has been designed to
illustrate nine of the most common thermoplastics
used in rapid injection molding.
Each of these resins has unique properties as
summarized on in this booklet. Assembly, however,
is required (and good luck with that).
For the puzzle-impaired, we have included a
very cool animated solution on our website at
www.protomold.com/fwd/puzzle-solution.
Technical information for these generic materials
is available for free from IDES — The Plastics Web®
at www.ides.com/pm.
Order rapid injection molded parts online at www.protomold.com.
It’s easy, and your detailed, interactive ProtoQuote® will amaze you.
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HDPE — High Density Polyethylene.
Pros: Impact, and wear resistant. Flexible,
can have very high elongation before breaking.
Generally good chemical resistance.
Cons: Sensitive to thick sections in your
part. It may have voids, bubbles or sink. Poor
dimensional accuracy. Low mechanical and
thermal properties. Price is low to very low.
PP — Polypropylene. Pros: Impact (some grades) and wear resistant.
Flexible, can have very high elongation before
breaking. Resistant to acids and bases.
Cons: It is sensitive to thick sections in
your part which may cause voids, bubbles or
sink. Poor dimensional accuracy. Low mechanical
and thermal properties. Poor resistance to
organic solvents. Price is low to very low.
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ABS — Acrylonitrile Butadiene Styrene.
Pros: Excellent impact resistance. It can have
good appearance for cosmetic parts. Strength is
moderate. Good resistance to acids and bases.
Cons: It is sensitive to thick sections in your part
which may cause voids, bubbles or sink. Attacked
by hydrocarbons and organic solvents. Heat
resistance is low. Price is low to moderate.
PC/ABS — Polycarbonate/Acrylonitrile
Butadiene Styrene blend. Pros: Excellent impact resistance. Excellent
dimensional stability. Good strength. Good
cosmetics. Good resistance to acids and bases.
Cons: It is sensitive to thick sections in
your part which may cause voids, bubbles
or sink. Poor resistance to organics and
hydrocarbons. Price is moderate.
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POM — Acetal (polyoxymethylene).
Pros: High strength, good lubricity and
resistance to hydrocarbons and organic
solvents. Acetal machines well.
Cons: Sensitive to thick sections and nonuniform part geometry. It may have voids,
excess shrink or warp. Poor resistance to
acids and bases. Price is average to high.
PBT — Polybutylene Terephthalate
(member of polyester family).
Pros: Good electrical properties for power
components. Moderate to high strength
depending on glass fill. Unfilled grades
tough and flexible. Good resistance
to organic solvents and fuels.
Cons: Hard to fill thin parts. Glass filled resins
very prone to warp. Poor resistance to acids,
bases and hydrocarbons. Price is moderate.
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PA66 GF33 nylon with 33%
glass fiber fill (polyamide).
Pros: High strength over wide temperature
range, up to 450°F (232°C). Chemical
resistant except strong acids or bases.
Cons: Parts are subject to warp due the
shrink difference parallel and perpendicular
to fill and a high shrink base resin. Molded
parts in your application can absorb moisture,
changing dimensions and mechanical
properties. Price is moderate to high.
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PA 66 — nylon (polyamide). Pros: High strength. Chemical resistant
except strong acids or bases. Flows
well, good for thin part geometry.
Cons: Parts are more subject to warp due to nonlinear shrink. Molded parts in your application
can absorb moisture, changing dimensions and
mechanical properties. Price is moderate to high.
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PC — Polycarbonate. Pros: Excellent impact resistance and strength
at low and high temperatures. Available in
visually clear grades. Good heat strength.
Cons: It is sensitive to thick sections in
your part which may cause voids, bubbles or
sink. Fair to poor chemical resistance which
can cause stress cracking or opaque dulling
of the surface. Price is moderate to high.
Note: These descriptions are general and relative. You will need to obtain manufacturer’s data
on resins you wish to use and make your own determination of suitability for your application.
www.protomold.com
(763) 479-3680