What materials are commonly available for custom CNC machining parts production?

Question

Accepted Answer

Quick Answer

CNC machining works with virtually all engineering materials. The most common are aluminum 6061 and 7075, stainless steel 304 and 316, carbon steel, titanium grade 5, brass C360, copper C110, and engineering plastics including PEEK, Delrin (POM), Nylon 6/6, and ABS. Each material offers distinct properties in strength, corrosion resistance, machinability, and cost.

Aluminum Alloys

Aluminum 6061 is the most popular CNC material -- excellent machinability, good strength, corrosion-resistant, and economical. Aluminum 7075 offers higher strength (comparable to steel) for aerospace applications. Both are ideal for structural parts, enclosures, brackets, and prototypes. Cost: $.

Stainless Steel

Stainless steel 304 is the standard for corrosion-resistant applications -- food equipment, medical devices, and architectural components. Stainless 316 offers superior chemical resistance for marine and pharmaceutical environments. Both require slower machining speeds but produce durable, long-lasting parts. Cost: $$.

Engineering Plastics

PEEK: High-performance thermoplastic with excellent mechanical strength, chemical resistance, and high temperature tolerance (up to 260°C). Used for medical implants, aerospace components, and semiconductor equipment. Delrin (POM): Low friction, high stiffness, excellent dimensional stability -- ideal for gears, bushings, and precision mechanical parts. Nylon 6/6: Tough, wear-resistant, good impact strength. ABS: Economical general-purpose plastic for prototypes and housings.

Specialty Materials

Titanium Grade 5 (Ti-6Al-4V): Exceptional strength-to-weight ratio and biocompatibility. Used in aerospace and medical implants. Challenging to machine but produces superior parts. Brass C360: Excellent machinability, decorative appearance, corrosion-resistant. Ideal for fittings, valves, and decorative components. Copper C110: Outstanding electrical and thermal conductivity for heat sinks and electrical components.

Why Choose SOMI Custom Parts

At SOMI Custom Parts, we have extensive experience machining over 50 different materials across metals, plastics, and specialty alloys. Our engineers provide material selection guidance based on your specific application requirements -- whether you need the light weight of aluminum for an aerospace bracket, the chemical resistance of stainless 316 for food processing, or the high-temperature performance of PEEK for semiconductor equipment. We maintain material certifications for full traceability.

Case Study

A semiconductor equipment manufacturer needed ionizer components machined from static-dissipative PEEK with tight dimensional tolerances. SOMI developed a specialized machining protocol with reduced feed rates and custom tooling to prevent material melting. The 500-piece order was delivered with tolerances held to ±0.001" and passed all conductivity testing requirements.

Industry Data

According to a 2025 materials survey by SME, aluminum accounts for 45% of all CNC machined parts by volume, followed by steel (25%), stainless steel (12%), engineering plastics (10%), and specialty alloys (8%). The trend toward lightweight design is driving 15% annual growth in machined aluminum and titanium parts.