Prototype Material Selection Guide: ABS, PC, Aluminum & More

Material selection is one of the most critical decisions in prototyping. It directly impacts the appearance, structural strength, cost, and lead time of your prototype. Choosing the right material can mean the difference between a prototype that accurately represents your final product and one that falls short. This guide provides a comprehensive comparison of the most commonly used plastics and metals in prototyping, along with practical advice to help you make the best choice.

Common Plastic Materials for Prototyping

Plastics are the most widely used materials in rapid prototyping due to their versatility, cost-effectiveness, and ease of processing. Below is a detailed comparison of 8 commonly used plastics.

Plastic Material Selection Tips

ABS is the go-to choice for most general-purpose prototypes. It offers an excellent balance of mechanical properties, machinability, and cost. If your prototype needs to simulate an injection-molded part that will be produced in ABS, this is your best match.

PC should be your choice when transparency and impact resistance are required. It withstands higher temperatures than acrylic and is significantly tougher, making it ideal for functional prototypes that need to survive testing.

PMMA (Acrylic) offers the best optical clarity among all plastics, but it is more brittle than PC. Use acrylic for display prototypes and optical components where transparency is the priority, not mechanical stress.

Nylon (PA) excels in wear-intensive applications. Its self-lubricating properties make it ideal for gears, bearings, and sliding parts. Both CNC machining and SLS 3D printing are viable processing options.

POM (Delrin) provides exceptional dimensional stability and low friction. It is the material of choice for precision mechanical components like gears and bushings where tight tolerances are critical.

PP is lightweight and chemically resistant, making it suitable for containers and components with living hinges. Its flexibility makes it a good choice for snap-fit designs.

PBT is commonly used in electrical and electronic applications due to its excellent insulating properties and heat resistance. If your prototype involves connectors or electrical housings, PBT is worth considering.

Photosensitive Resin is ideal when you need high-detail appearance models quickly. SLA 3D printing with resin produces parts with excellent surface finish and fine feature resolution, though the parts are more brittle than CNC-machined plastics.

Common Metal Materials for Prototyping

When your prototype requires structural strength, thermal conductivity, or a premium feel, metals are the way to go. Here is a comparison of 6 commonly used metals.

Metal Material Selection Tips

Aluminum is by far the most popular metal for prototyping. 6061 offers excellent machinability and corrosion resistance at a reasonable cost, while 7075 provides higher strength for demanding applications. Both can be anodized for color and surface protection.

Stainless Steel is the choice for applications requiring corrosion resistance, hygiene, or a premium aesthetic. 304 is the standard grade for most applications, while 316 offers enhanced corrosion resistance for marine or medical environments.

Magnesium Alloy is the lightest structural metal available, with excellent strength-to-weight ratio and heat dissipation properties. It is increasingly used in portable electronics and automotive lightweighting applications.

Brass offers excellent machinability, electrical conductivity, and an attractive golden appearance. It is commonly used for valves, fittings, and decorative components.

Carbon Steel is cost-effective and strong, making it suitable for structural and mechanical parts where corrosion resistance is not a primary concern.

Titanium Alloy offers the best strength-to-weight ratio among all metals and is biocompatible, making it the premium choice for medical implants and high-performance aerospace components. It is, however, the most expensive option and more challenging to machine.

Three Key Questions to Guide Your Material Selection

Before finalizing your material choice, ask yourself these three critical questions:

1. What Is the Primary Purpose of the Prototype?

• Appearance verification — If you need to evaluate the look and feel of your design, choose a material that closely matches the final product aesthetics. ABS or photosensitive resin are excellent for plastic parts, while aluminum is ideal for metal appearances.
• Structural testing — If mechanical properties matter, select a material as close as possible to your production material. This ensures your test results are meaningful.
• Functional testing — If the prototype needs to actually function, use the real production material whenever possible. This is especially important for parts that will experience stress, heat, or chemical exposure.

2. What Material Will You Use for Mass Production?

Whenever feasible, prototype with the same material you plan to use in production. This gives you the most accurate feedback on how the part will perform and how it can be manufactured at scale. It also helps identify potential manufacturing issues early in the development process.

3. What Is Your Budget and Timeline?

• Tight budget or quick turnaround — 3D printing with standard resins or plastics is often the fastest and most economical option.
• Larger budget, higher precision requirements — CNC machining delivers superior accuracy, surface finish, and material properties. The additional cost is justified when precision is critical.