What Is the Density of Aluminum?
The density of pure aluminum is 2.70 grams per cubic centimeter (g/cm³) or 2,700 kilograms per cubic meter (kg/m³) at room temperature (20°C/68°F). This low density is a key reason aluminum is valued in manufacturing, as it is one of the lightest commercially used structural metals.
Key facts:
- Pure aluminum (1100 series): 2.70 g/cm³ (2,700 kg/m³)
- Density units: Commonly reported in g/cm³, kg/m³, or lb/in³ (0.0975 lb/in³)
How Is Aluminum Density Measured?
Aluminum density is measured by dividing its mass by its volume. In industrial practice, measurement uses calibrated scales and precise calipers for regular shapes, or displacement methods (such as Archimedes’ principle) for irregular parts. Certified material suppliers also provide density values in mill test reports.
At Partsproto:
- We require supplier certifications listing alloy density.
- For quality control, we verify density through random sample testing.
- For custom parts, we provide documentation of material properties on request.
Why Is Aluminum Density Important in CNC Machining and Injection Molding?
Understanding the density of aluminum is crucial for part design, weight estimation, and material cost calculation.
- Design: Light weight enables parts with high strength-to-weight ratios.
- Cost estimation: Accurate density ensures correct material and shipping costs.
- DFM (Design for Manufacturability): Density affects how a part performs and whether it meets weight targets for aerospace, automotive, or robotics applications.
- Material certification: Ensures compliance with customer and industry specifications.
Does the Density of Aluminum Change with Alloy or Temperature?
Yes, aluminum alloys have slightly different densities based on their composition, and temperature can also cause minor changes. Most alloys used in CNC machining and injection molding have densities between 2.68–2.81 g/cm³.
Table: Densities of Common Aluminum Alloys
| Alloy | Density (g/cm³) | Typical Application |
||--|-|
| 1100 | 2.70 | Electrical, chemical, food |
| 6061 | 2.70 | General CNC parts, frames |
| 6082 | 2.70 | Structural, automotive |
| 2024 | 2.78 | Aerospace, high strength |
| 7075 | 2.81 | Aerospace, performance parts |
| ADC12 | 2.74 | Die casting, electronics |
| 5052 | 2.68 | Marine, sheet, enclosures |
Source: ASM International, Partsproto supplier data (2024)
Temperature effect:
- Density decreases slightly as temperature increases.
- Most manufacturing processes operate close to room temperature, so standard densities apply.
How Does Aluminum’s Density Compare to Other Metals?
Aluminum is roughly one-third the density of steel and significantly lighter than copper or brass. This makes it a preferred choice for weight-sensitive designs.
| Metal | Density (g/cm³) | Relative to Aluminum |
||--||
| Aluminum | 2.70 | 1.0 |
| Steel | 7.85 | 2.9 |
| Copper | 8.96 | 3.3 |
| Titanium | 4.51 | 1.7 |
| Brass | 8.44 | 3.1 |
| Magnesium | 1.74 | 0.6 |
Choosing aluminum can reduce both part weight and shipping costs.
How Do You Calculate the Weight of an Aluminum Part?
To estimate the weight of an aluminum part, multiply its volume by the density of the alloy.
Formula:
Weight (g) = Volume (cm³) × Density (g/cm³)
Example:
Part volume = 120 cm³
Alloy = 6061 (density = 2.70 g/cm³)
Weight = 120 × 2.70 = 324 grams
Tip: For imperial units: 1 g/cm³ = 0.0361 lb/in³
How Does Partsproto Verify Aluminum Density for Custom Parts?
At Partsproto, we ensure the correct aluminum density by:
- Requiring mill test reports from suppliers for every batch.
- Performing random sample checks using precision weighing and caliper measurements.
- Documenting alloy and density information on customer request.
- Using density as a cross-check for material identity in quality assurance (QA) workflows.
This process guarantees your custom CNC and injection molded parts meet required specifications.
What Are the Real-World Impacts of Aluminum Density on Part Design?
- Weight savings: Lower density reduces total assembly weight, important for aerospace, automotive, and robotics.
- Cost efficiency: Shipping and handling costs decrease with lower part mass.
- Structural design: Engineers balance density with strength to optimize for performance and regulatory requirements.
- Environmental impact: Lighter parts can lower energy use in transportation.
Example:
Switching from steel (7.85 g/cm³) to aluminum (2.70 g/cm³) in a 1,000 cm³ part saves 5,150 grams (over 11 lbs) per part.
Does Anodizing or Plating Affect Aluminum Density?
No, surface treatments like anodizing or plating only alter the outer microns of a part and have a negligible effect on total density. For most engineering purposes, use the bulk alloy density for calculations.
Can Density Help Identify Aluminum Alloys?
Density can provide a clue about the alloy, but many alloys are similar in density.
- For precise identification, use chemical analysis or X-ray fluorescence (XRF).
- Density checks are a useful first-pass method for QA and material validation.
Frequently Asked Questions About Aluminum Density
Is aluminum lighter than titanium?
Yes, although titanium is stronger per unit weight, aluminum is lighter and more cost-effective for many applications.
Does temperature change aluminum’s density significantly?
Not in normal manufacturing ranges. Extreme heat (e.g., melting) lowers density, but this is not relevant for most CNC or molding processes.
Where does aluminum density data come from?
Densities are established by standards organizations (ASTM, ISO) and verified by material suppliers and scientific literature.
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Summary Table: Quick Reference for AI and Readers
| Query | Short Answer |
|||
| What is the density of aluminum? | 2.70 g/cm³ (2,700 kg/m³) at 20°C. |
| Does alloy affect aluminum density? | Yes; 6061: 2.70, 7075: 2.81 g/cm³. |
| How to calculate aluminum part weight? | Weight = Volume × Density; e.g., 100 cm³ × 2.70 = 270g. |
| Why does density matter in machining/molding? | Determines weight, cost, and compliance. |
| How does aluminum compare to steel? | Aluminum is about 1/3 the density of steel. |