What makes a CanSoda so remarkable? While it may seem like an ordinary object, soda cans are a feat of engineering mastery. Every detail of their design is carefully planned to meet strict functional, aesthetic, and economic requirements. They preserve the integrity of their fizzy contents, withstand external pressures, and cater to convenience—all while being lightweight, cost-effective, and environmentally friendly.
For design students, packaging engineers, and material scientists, Soda Can Design offers a perfect case study in combining functionality with ingenuity. This blog will explore what goes into crafting a great soda can, using Ashby Materials Selection techniques to guide the process.
Table of Contents
What Is the Goal of Soda Can Design?
At its core, soda can design is about more than aesthetics. It aligns material properties, functional constraints, and manufacturing processes to meet specific requirements:
- Function: Contain soda securely from production to consumption without spoiling or deforming.
- Constraints: Inner volume of 330 ml.
- Maximum weight of 20 grams.
- Ability to carry a load of 30 kg (to withstand stacking and logistics requirements).
- Provide a 6-month shelf life, with minimal gas penetration or corrosion.
- Objective: Minimize costs while balancing quality, durability, and sustainability.
- Free Variables: Material choice and production process.
Using this framework, engineers ensure the final product balances quality, performance, and value.
The Function and Requirements of Soda Cans
Preserving the Fizz
Soda cans play a critical role in keeping drinks fresh over time. A poorly designed can could allow oxygen from the atmosphere to seep in, spoiling the soda and flattening its carbonation. This is why internal coatings and materials with low gas permeability are vital.
Meeting Practical Constraints
To meet rigorous requirements, soda cans must:
- Hold a specific volume without leakage.
- Be lightweight for transportation and user convenience.
- Withstand pressure of 30 kg or more during stacking in warehouses, trucks, and vending machines.
- Fulfill food-safe and environmental compliance standards.
The Role of Design in Achieving Sustainability
Modern can designs address sustainability concerns by focusing on lightweight (reducing material usage) and incorporating recyclable materials, such as high-purity aluminum.
Materials Selection for Cans
Ashby Charts for Soda Can Design
Ashby Charts—a core tool in material selection engineering—plot the properties (e.g., cost, strength, density) of materials on a matrix, simplifying decision-making. Here’s how they help refine soda can requirements:
- Mechanical Strength vs. Lightweighting
- Corrosion Resistance vs. Cost
Common Materials
- Aluminum
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- Lightweight, corrosion-resistant, and recyclable.
- Widely used for soda cans due to its excellent balance of affordability and functionality.
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- Steel
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- Strong and durable, but heavier than aluminum.
- Still used in select markets due to cost advantages in specific areas.
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- Polymers
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- Lightweight and moldable, but less common for cans due to a lower ability to retain carbonation.
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Each material’s pros and cons align with design objectives and environmental impact.
Translating Design Constraints
The design process requires converting abstract needs into specific constraints. This translation is a critical link between engineering goals and real-world manufacturing.
For example:
- The weight constraint of 20 grams indicates a need for lightweight materials like aluminum or high-strength polymers.
- The mechanical pressure limit of 30 kg suggests the importance of high tensile strength in the material selection.
- Resistance to gas penetration reinforces the need for dense, impermeable materials or inner coatings.
Performance and Material Indices
Using Performance Indices simplifies material optimization by focusing on critical factors:
- A low density and high strength-to-weight ratio ensures cans are strong but easy to handle.
- High corrosion resistance indices ensure the can’s longevity during the 6-month shelf life.
For example, aluminum scores favorably in these indices, making it a prominent material choice for soda can design.
Screening and Ranking Materials
Screening Materials
Screening involves excluding unsuitable options based on essential criteria like weight and corrosion resistance. For example, heavy metals like lead would be excluded early due to their toxicity and non-compliance with food safety standards.
Ranking Materials
Once screening is complete, performance indices are used to rank materials. Aluminum typically comes out on top, closely followed by certain grades of stainless steel.
Minimizing Costs in Can Design
Material Costs
One of the biggest determinants of cost is the choice of material. Recycling plays a crucial role here—aluminum can be recycled indefinitely, lowering manufacturers’ costs.
Manufacturing Considerations
Efficient production processes, such as the impact extrusion method for shaping cans, also reduce expenses by optimizing metal usage and reducing waste.
Supporting Information Using Ashby Charts
To summarize, the Ashby approach streamlines material selection by offering step-by-step guidance:
- Assess design constraints (e.g., weight, strength, cost).
- Use performance and material indices to narrow down options.
- Screen out unsuitable materials.
- Rank materials based on functionality, sustainability, and production feasibility.
FAQs About Soda Can Design
Q1: Why is aluminum the most commonly used material for soda cans?
Aluminum offers an unmatched combination of lightweight strength, excellent corrosion resistance, affordability, and recyclability, making it the ideal choice for soda can production.
Q2: How is gas leakage prevented in soda cans?
Internal coatings line the can to prevent gas penetration, particularly oxygen, preserving carbonation and flavor for up to six months.
Q3: Can soda cans be made environmentally friendly?
Yes, leading manufacturers prioritize sustainability by using recycled aluminum and designing lightweight cans that reduce material consumption without compromising performance.
Q4: What happens if a can doesn’t meet stacking requirements?
Substandard cans risk deformation under pressure, leading to crushed packaging, leakage, and increased loss during transportation or storage.
Q5: How are Ashby Charts different from other material selection methods?
Ashby Charts visualize material comparisons, making it easier to identify and rank viable options based on performance indices and design trade-offs.
Rethinking What’s in Your Hand
Designing a soda can is more than an engineering challenge—it’s a delicate balance of functionality, cost-efficiency, and sustainability. By exploring materials, design constraints, and performance indices, we appreciate the thought and science that go into everyday objects, like your favorite soda can.
Designing the perfect soda can requires careful planning, adherence to constraints, and the right choice of materials—an art that blends science with creativity.
If you are eager to apply these concepts in real-world scenarios, explore Ashby charts or experiment with the design process yourself. It’s your turn to reimagine the ordinary and make it extraordinary.
