Basic info - Plastics

Acrylic (Cast)
Description Moderate tensile strength material with good abrasion resistance qualities. Has low impact resistance and a tendency to split or crack under sheering forces. Optimal material in applications that involve heat-warping.

Highest operating temperature 150+ F to 250+ F

Tooling Behavior Better friction tolerances than ABS or Polypropylene, but will melt fairly quickly under friction. Can be very picky about blade types and lower blade speeds will need to be used. Much be worked with in a similar manner to balsa wood due its semi-brittle nature.

Avoid Abrasive cutting tools or anything that creates excessive friction. Will fume moderately when heated so wear a filtration mask when cutting.

Commonly Available Colors Clear, Opaque (White, Grey, Black, Red, Yellow, Blue, Green), Solid Tints (White, Grey, Bronze, Red, Blue, Green, Yellow, Amber), Fluorescent/UV Tints (Amber, Red, Green, and Blue)

Acrylic (Extruded)
Description Often used to replace glass, provides outstanding optical clarity even at greater thicknesses. Has a smooth surface for use as windows and signs, but is less impact resistant than polycarbonate. Higher potential for fume production and more brittle than cast acrylic. Difficult to machine and has an even higher tendency to split or crack under sheering forces than cast acrylic. Most often seen in the form of bars, rods, tubes, balls, and discs.

Highest operating temperature 150+ F to 250+ F (Does melt faster than Cast Acrylic due to its higher molecular density)

Tooling Behaviour Better friction tolerances than ABS or Polypropylene, but will melt fairly quickly under friction. Can be very picky about blade types and lower blade speeds will need to be used. Much be worked with in a similar manner to balsa wood due its brittle nature. Extruded Acrylic is slightly more fragile than Cast Acrylic and is therefore harder to work with.

Avoid Abrasive cutting tools or anything that creates excessive friction. Will fume moderately to excessively(depends on the brand) when heated so wear a filtration mask when cutting.

Commonly Available Colors Clear, Opaque (White, Grey, Black, Red, Yellow, Blue, Green), Solid Tints (White, Grey, Bronze, Red, Blue, Green, Yellow, Amber), Fluorescent/UV Tints (Amber, Red, Green, and Blue)

Acetal (Delrin)
Description An exemplary high density plastic that is and almost perfect aluminum substitute. Dimensionally stable, high tensile strength, wear resistant, and fairly impact resistant. Comonly used to make bearings, pulleys, and wheels. Only downside is comparatively high cost (mainly due to high density).

Tooling Behaviour Shreds into fine pieces when the correct blades are used and it very receptive to tooling. Has a very low tendency to melt under friction, unless the wrong blade type is used when cutting it. Flexes easily and accepts high pressure amounts. Very easy to tap and drill. Machining experience comparable to aluminum in most circumstances.

Commonly Available colors Opaque Black and White

ABS (Pure, not ABS/PVC blend)
Desciption Tough and impact-resistant, this material works well for protective applications such as small appliance housings. Commonly used to make hard-sided luggage and is the standard material choice for plastic injection moulding (and therefore) it's what most of the plastic parts in your computer are made out of.

Highest operating temperature 100+ F to 200+ F

Tooling behaviour Heats and melts very quickly above 125F. Use Slowest speeds possible with medium tooth count. Easy to carve with standard hand tools.

Avoid Abrasive cutting tools or anything that creates excessive friction. Will fume excessively if heated so wear a filtration mask when cutting.

Commonly Available Colors Black, Brown, Beige

PVC & CPVC
Description Low cost and ease of availability. Extremely high chemical and moisture resistance and very good impact resistance. However it mars fairly easily under abrasion and has comparatively poor tensile strength.

Highest operating temperature 100+ F to 200+ F (300F for CPVC)

Tooling behaviour Provided the right blades are used, PVC can be as easy to work with as medium density natural woods. Behaves similarly to polycarbonate, but can be much more aromatic (smelly) due to its lower maximum operating temperatures.

Commonly Available Colors Grey, White, Clear (expensive)

Polyethylene
Description Coming in a very wide variety of material densities this plastic is the most commonly used plastic in product manufacturing due its low cost and ease of injection moulding as well as recycling properties. Resists abrasion very well but has sub-par ability when it comes to structural rigidity and won't withstand much flexing.

Highest operating temperature 100+ F to 200+ F (300F for CPVC)

Tooling behaviour Usually not desirable because it can become dimensionally unstable at lower temperatures, and melts excessively when being cut.

Polycarbonate
Description Offers impact strength over a wide temperature range. Use indoors and outdoors. Offers a superior ability to resist being torn apart. They generally can withstand a pulling force greater than 10,000 psi. Has a greater ability to withstand a forceful sudden impact, similar to being struck by a hammer. Products listed with high impact strength generally can withstand 5 foot-pounds of energy per inch of thickness under normal conditions.

Highest operating temperature 200+ F to 300+ F

Tooling Behaviour Shreds into fine pieces when the correct blades are used and it very receptive to tooling. Has a very low tendency to melt under friction, unless the wrong blade type is used when cutting it. Flexes easily and accepts high pressure amounts. Very easy to tap and drill. Machining experience comparable to aluminum in most circumstances.

Commonly Available colors Clear, Opaque Black, White Tint, Grey Tint, Bronze Tint, Black Tint, UV resistant Black Tint (used for public transportation applications)

Polyester (PETG)
Description Extremely low cost Polycarbonate substitute material, but is considerably softer and therefore has lower abrasion resistance. Optical clarity is also lower.

Highest operating temperature 100+F to 150+F

Tooling Behavior Can be temperamental in that it can cut a little bit too easily at times. Feels vaguely similar to wax and caution is needed to avoid overheating the sheets as they will become quite sticky against blades inducing friction. Generally best to avoid this material if you need to cut out any complex or intricate shapes due to that property.

Polypropylene
Description Most commonly used plastic across a wide variety of applications due to its low cost. It has a hard, smooth chemically resistant surface. Is non-toxic. Commonly used for pipes, valves, and fittings.

Highest operating temperature 100+ F to 200+ F

Tooling Behaviour Heats and melts very quickly above 125F. Use Slowest speeds possible with medium tooth count. Easy to carve with standard hand tools but can discolor under pressure.

Avoid Abrasive cutting tools or anything that creates excessive friction.

Commonly Available Colors Black, Brown, White, Translucent White

Guide Courtesy of Captin Slug

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