Engineering Plastics, Compared: ABS, PC, PEEK, PA12, and Their Right Use Cases

There is no single 'best' engineering plastic. The right choice depends on temperature, chemical environment, cost, and how the part is made. This article walks through the four polymers we quote most often and the framework we use when a customer asks 'what plastic should I use?'.

Headline properties

ABS: the everyday workhorse

ABS is the cheap, machinable, easy-to-paint plastic for housings, dashboards, consumer electronics enclosures, and prototype rapid iteration. It accepts adhesive bonding well and machines without melting if you use sharp tools and steady feeds.

• Indoor consumer products and electronics housings.
• Functional prototypes that need to look real.
• Parts that need acetone vapor smoothing for cosmetic FDM.
• Avoid: outdoor exposure, hot environments, strong solvents.

PC: when impact matters

Polycarbonate has roughly 200x the impact resistance of ABS. Bullet-resistant glazing, lab safety enclosures, and machine guards all rely on PC. It also has surprisingly good optical transparency when properly molded or polished.

PEEK: the high-performance polymer

PEEK is metal-like in performance: it survives 260 °C continuous service, resists nearly all chemicals, and machines like aluminum if your tools are sharp. The catch is cost — raw stock runs 10-15x more expensive than ABS.

• Aerospace brackets and fluid components.
• Medical implants (Implantable PEEK is a separate grade).
• Oil and gas valve seats.
• Semiconductor handling parts that see plasma.

PA12 (Nylon 12): the additive workhorse

PA12 is the powder-bed fusion default. Properties are isotropic enough to use it for end-use parts, and the chemical resistance is good for most non-aggressive environments. Pair it with carbon fiber reinforcement when stiffness matters.

Decision matrix

Specifying plastics on Uretyco

Each platform quote shows compatible material grades for the chosen process. CNC quotes default to standard rod and sheet stock; injection molding quotes default to common pellet grades. Always check the data sheet for the supplier-specific grade — different suppliers' '6 GF Nylon' is not the same product.