When specifying panel materials for signage, architectural cladding, displays or interior-design elements, choosing the right composite panel can make a big difference in performance and cost. Two prominent options in today’s market are aluminum-skinned composites such as aluminum composite material (ACM) and steel-skinned composites such as steel composite material (SCM).
Between ACM and SCM, which material should you select for your project? This article walks through their construction, properties, fabrication considerations, typical applications, and how to decide which is right for your job, particularly when sourcing through Piedmont Plastics.
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What is Aluminum Composite Material?
Aluminum composite material is a strong, lightweight, and durable panel composed of two thin layers of pre-finished aluminum bonded to a solid polyethylene (PE) core. This three-layer construction provides exceptional rigidity and makes ACM panels ideal for both indoor and outdoor applications. Known for their dimensional stability, weather resistance, and easy maintenance, ACM panels are available in a wide range of colors, finishes, and thicknesses.
AluPOLY® ACM: A Proven Industry Standard
One of the most widely used ACM products available from Piedmont Plastics is AluPOLY®, a premier aluminum composite sheet designed for durability and dimensional stability. At its core, AluPOLY is made of two thin layers of aluminum bonded to either side of a polyethylene core, an engineered structure that gives it impressive strength, rigidity, and lightweight performance.
These attributes make AluPOLY ideal for a wide range of applications, from interior and exterior signage to construction and architectural cladding. It’s also often used as a cost-effective substitute for solid steel or aluminum sheets in non-structural applications. Additionally, AluPOLY meets UL 879 compliance standards for electric signage, underscoring its quality and safety for use in illuminated and non-illuminated sign systems.
Key Performance Attributes
ACM is recognized for its:
Light Weight: ACM is approximately half as heavy as traditional aluminum, making it a more cost-effective and practical option for a variety of applications.
Aesthetic Appeal and Printability: ACM combines attractive design, easy fabrication, and lasting durability with excellent printability, accepting traditional inks, paints, digital prints, and PSA media for high-quality graphics.
Corrosion Resistance: Aluminum skins naturally resist rust, corrosion, and moisture absorption, outperforming some steels in many environments and making them ideal for weather-resistant outdoor applications.
Fabrication Flexibility: ACM can be easily cut, routed, fabricated, mounted, and installed with standard tools, making it a versatile choice for applications like signage, retail displays, and machine covers.
Common Applications
Everyday uses for ACM include:
Signage and Graphics: ACM is widely used for outdoor signs, POP displays, and kiosks due to its durability, lightweight nature, and outstanding dimensional stability.
Architectural Cladding and Wall Coverings: Known for its excellent dimensional stability, ACM is suitable for building and construction applications such as architectural cladding, insulation, and wall linings.
Retail Displays and Exhibits: ACM is a popular choice for POP displays and trade shows thanks to its lightweight durability and easy fabrication.
What is Steel Composite Material?
Steel composite material is a durable structural material made by thermally bonding two steel skins to a solid polyethylene core. This construction provides exceptional strength, rigidity, and visual appeal, making it ideal for demanding applications such as signage, displays, and interior design. Magnetic receptive with a smooth, printable surface, steel composite works well with dry-erase markers, direct printing, and various mounting methods.
Key Performance Attributes
SCM is known for its:
Strength and Stiffness: With its galvanized steel skins, SCM delivers exceptional strength and impact resistance, bringing a higher modulus or stiffness compared to many aluminum-skinned composites of similar thickness.
Magnetic Receptivity: The steel skins allow SCM panels to hold magnets, making them perfect for applications such as whiteboards, menu boards, and magnetic signage systems.
Printability and Versatility: SCM features a smooth coated surface with one side optimized for printing, providing a terrific base for high-quality graphics and display designs.
Durability and Weatherability: SCM’s galvanized steel skins deliver exceptional strength, impact resistance, and flame retardance, ensuring long-lasting performance in both indoor and outdoor applications.
Common Applications
SCM's uses include:
Magnetic Boards and Dry-Erase Surfaces: SCM is magnetic receptive and features a non-ghosting dry-erase surface on one side, making it ideal for magnetic boards and writable applications.
Indoor and Outdoor Signage: Durable and weather-resistant, SCM is suitable for a wide range of applications, including interior and exterior signs.
Interior Wall Panels and Architectural Features: SCM enhances interior spaces with a modern, functional look for wall panels and decorative elements while also providing a durable, attractive option for POP displays.
Side-by-Side Comparison: ACM vs. SCM
Here’s a structured comparison of key attributes to help with specification decisions:
| Attribute | ACM | SCM |
|---|---|---|
| Skin material | Aluminum sheets bonded to core | Steel sheets (galvanized or stainless) bonded to core |
| Weight | Lightweight, often about half the weight of a solid aluminum sheet in specific grades | Heavier than equivalent ACM due to higher density of steel skins; however, composite structure is still lighter than solid plate of equal strength |
| Strength and stiffness | Good stiffness for many applications, but less rigidity compared to steel skin options for same thickness | Higher rigidity and strength per panel thickness; steel skins contribute to increased stiffness and durability |
| Corrosion resistance | Aluminum skins resist rusting; core of some panels may have limitations in fire settings | Steel skins need galvanizing/coating; joinery and dissimilar metals may introduce corrosion risk |
| Magnetic receptivity | Generally non-magnetic (aluminum skin) | Magnetic receptive surface (steel skins) enabling use of magnets |
| Fabrication ease and routing | Very good; ACM is widely routed, cut, and bent for signage/architecture | Good, but may require more robust tooling for steel skin; cutting, folding, groove routing may require special tools |
| Fire/code performance | Core type matters; PE core may limit exterior high-rise use due to fire code | Some steel composite panels are offered with fire-retardant cores and can achieve non-combustible classification |
| Typical applications | Lightweight signage, displays, architectural cladding (non-structural), machine covers, and interior walls | Magnet boards, POS/POP displays, menu boards, interior/exterior signage, and wall/ceiling panels where durability and magnetic function matter |
| Cost considerations | Generally competitive, especially where weight is a concern | Slightly higher cost may be justified where steel skins and additional performance attributes are needed |
How to Decide Between ACM and SCM
When determining whether to specify ACM or SCM for your application, consider the following factors:
Weight and Structural Support
If the project demands minimal weight (for example, large wall panels, suspended signage, installations where sub-structure capacity is limited), ACM has an advantage due to its light weight. On the other hand, if the panel must hold magnets or require extra stiffness, SCM might be more appropriate, despite its heavier weight.
Desired Surface Performance and Features
If magnetic receptivity is required (for example changeable menu boards, magnetic signage, and interactive displays), SCM is a clear choice because of its steel skins. However, if the finish is purely visual (printing, graphics, and architectural foldings) and no magnet function is necessary, ACM is more than adequate.
Environmental Exposure and Durability
For harsh environments (moisture, salt spray, exterior high-rise facades), check corrosion performance, joinery detailing, and fire-rated core options. Although ACM resists corrosion, fire-performance may require specific core materials. Conversely, SCM may offer fire rating advantages and improved rigidity, but you’ll want to check corrosion protection of steel skins.
Cost and Value for Function
ACM is often a cost-efficient solution for weight-sensitive, visual-focus applications. SCM can be pricier, but it delivers added value if stiffness, magnet-function, durability and surface finish matter. Evaluate total installed cost (panel + sub-structure + support + fabrication) and lifecycle benefits to decide which material is best for your application.
Code and Fire Performance
If the application is exterior cladding on a high-rise building or in a fire-sensitive area, ensure the composite panel is fire-rated, core material meets local building code (e.g., NFPA 285 in the U.S.), and the skin/core system has appropriate test certifications. Many standard ACM with PE cores may not meet high-rise exterior fire codes; specialized cores or SCM with fire-rated core may perform better.
Which Material is Right for Your Project?
Choosing between ACM and SCM ultimately comes down to matching the material’s performance envelope to your specific project requirements. If you need lightweight, visually appealing panels with excellent printability and ease of fabrication, ACM is a strong, cost-effective solution. However, if you need heightened rigidity, magnetic functionality, steel-skin aesthetics or enhanced durability (including potential fire-rated core options), SCM is likely the better choice.
At Piedmont Plastics, customers benefit from access to high-quality ACM and SCM materials, national distribution, and expert support. With the right specification from the start (skin material, core type, thickness, finish, and fabrication allowances), you’ll optimize performance, budget, and installation success.
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