CNC machining is an integral part of industrial manufacturing for hydraulic systems, medical equipment, automotive parts, spacecraft components, and much more. To create these parts quickly, reliably, and at a high level of quality requires CNC milling and turning precision. Equally important, however, is the choice of materials used for the fabrication of these various components.

Plethora’s CNC machines use many materials ranging from hardened steel to softer plastics. Each of these materials has unique properties that will yield different benefits depending on its used project.

Choosing the Right Materials for a Successful Project

Designers must consider many variables when choosing which materials to use for a project. These can include the material’s strength, weight, flexibility, appearance, and cost. In some cases, the ease of using one material over another is the determining factor. Othertimes the durability of the part is the overriding concern. The part’s purpose and whether a company plans on using it as a prototype or in regular production also influence material choice.




Companies use prototypes to evaluate a part before production. However, different needs in prototyping influence the chosen materials:

  • Prototype parts require quick turnover to evaluate form, fit, and function.
  • Companies can assess different materials for final production in the prototype builds.
  • Prototypes that don’t require full function often use less expensive materials.
  • Designers might not require a complete surface finish or omit it to save time and expense.


One should choose the materials used for the final production part according to the following:

  • The hardness of the material and its ability to withstand pinpoint surface loads.
  • The material’s tensile strength to resist breaking under tension.
  • The endurance strength of the material to absorb stress.
  • The wear resistance of the material to withstand friction.
  • The material’s fabrication limitations can add time and expense to manufacturing.
  • The overall cost of the material.

The choice of materials used for a CNC machined part also depends on the industry requirements. Here are some industry examples to consider:

  • Aerospace: These parts often have complex geometries and must withstand an incredible amount of stress in their operation. The appropriate durable and light-weight materials allow for the manufacturing of unique shapes, contours, and holding precise tolerances.
  • Medical: Custom prostheses, implants, and robotic equipment for surgery and other therapies require materials certified for human contact. They must also withstand chemical disinfectants and cleaners and have the necessary strength and wear resistance.
  • Automotive: Automotive parts endure continual amounts of stress due to their operation. Materials should provide the necessary strength while holding the tight tolerances required of the engine, transmission, or other vehicle systems.

The CNC Materials Available for Your Project at Plethora

At Plethora, we have a wide range of materials to choose from for manufacturing your prototype or production parts.



As a cost-effective option, many different industries use aluminum, including aerospace, medical, and automotive. Its strength and resistance to corrosion make it a lightweight alternative to steel. Learn more about aluminum here. Additional alloys are available by request.

Attributes: Plethora offers:
Corrosion resistant ALUMINUM 6061
High strength-to-weight ratio ALUMINUM 7075
Strength increases at subzero temperatures ALUMINUM 2011
Absorbs shock well ALUMINUM 2024
Holds paint well MIC-6 ALUMINUM


With its high strength, long service life, and machinability, steel is one of the most popular materials used for manufacturing parts. It is used in the automotive, defense, transportation, aerospace, and electronics industries. Learn more about steel here. Additional alloys are available by request.

Attributes: Plethora offers:
High strength 1018 STEEL 1144 STEEL
Tough and durable 1020 STEEL  12L14 STEEL
Machinable and workable 1040 STEEL  4130 STEEL
Good thermal conductivity 1045 STEEL   4140 STEEL
Long service life 1117 STEEL

Stainless Steel

Protected by the chromium within it, stainless steel has natural protection from corrosion. Along with its durability, this makes stainless steel an excellent choice for parts exposed to harsh environments in the marine, food processing, medical, and petrochemical industries. Learn more about stainless steel here. Additional alloys are available by request.

Attributes: Plethora offers:
Corrosion-resistant 303
Excellent durability and strength 304
Self-repairing surface 316
Heat-resistant 416
Long service life 17-4PH


Copper is easy to work with, resistant to corrosion, and highly conductive, making it an excellent choice for several industries. The plumbing industry uses copper for pipes and fittings. The thousands of delicate metal traces on a computer’s motherboard also use copper. Learn more about copper here.

Attributes: Plethora offers:
Electrical and thermal conductivity 101 COPPER
Weather and chemical corrosion resistant 110 COPPER
Ductility properties and easily machinable Both


A gold-like color and surface finish make brass a preferred choice for electronic components and electrical and hydraulic systems. Brass is also easily machinable and versatile making it useful for industries ranging from aerospace to household fixtures. Learn more about brass here.

Attributes: Plethora offers:
Electrical and thermal conductivity 260 BRASS
Corrosion resistant 360 BRASS
Easily machinable and malleable 464 BRASS


Bronze alloys obtain physical properties, such as durability, conductivity, and corrosion resistance, from the specific mix of their component metals. Along with its high coefficient of friction, this makes bronze an excellent choice for bushings, bearings, threaded nuts and bolts, and electrical terminals. Learn more about bronze here.

Attributes: Plethora offers:
  • Superior hardness compared to iron
  • Electrical and thermal conductivity
  • Corrosion-resistant


Plastics’ softness, range of colors and finishes, and low weight make it ideal for many applications. Its softness may not hold the same tolerances, but the low cost can reduce time and expense for quick evaluation prototypes. Learn more about plastics here.

Attributes: Plethora offers:
Durable ABS | PEEK
Produce less friction HDPE | PEI (ULTEM)
Resistant to chemical contaminants LDPE | PTFE
Wide range of colors and finishes NYLON 66 | UHMW