Material Selection Guide for Precision Machined Components

Category: Technical Guides | 7 min read

Choosing the right material affects machinability, cost, lead time, and performance. This guide covers common engineering materials and their applications for CNC machining projects.

Aluminium Alloys

6061-T6 — The most common general-purpose aluminium alloy. Excellent machinability, good corrosion resistance, and widely available. Ideal for brackets, housings, and structural components.

7075-T651 — High-strength aerospace-grade aluminium with excellent fatigue resistance. Used for aircraft structural components, high-stress brackets, and performance applications. More expensive than 6061 with longer lead times.

Stainless Steels

304 — General-purpose austenitic stainless with good corrosion resistance and formability. Used for food, medical, and architectural applications.

316 — Superior corrosion resistance for marine, chemical, and medical applications. Higher cost than 304 but essential for salt water and aggressive chemical environments.

17-4 PH — Precipitation-hardened martensitic stainless combining high strength with corrosion resistance. Used for aerospace, defense, and high-performance applications.

Carbon and Alloy Steels

1018/1020 — Low carbon steels with excellent weldability and machinability. Cost-effective for brackets, pins, and general structural components.

4140/4340 — High-strength alloy steels for demanding applications. Heat treatable for hardness up to 50 HRC. Used for shafts, gears, and high-stress components.

Engineering Plastics

Delrin (Acetal) — Excellent dimensional stability and low friction. Ideal for gears, bearings, and precision mechanical components.

PEEK — High-performance thermoplastic for aerospace, medical, and chemical applications. Expensive but offers exceptional strength-to-weight ratio and chemical resistance.