CNC Machining Materials: Make The Right Choice

28 November 2023
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CNC machining is inarguably the lifeblood of the manufacturing industry with applications such as aerospace, medical devices, and electronics. In recent years, there have been incredible advancements in the field of CNC machining materials. Their wide portfolio now offers great combinations of material properties, cost, and aesthetics.

In this article, we will delve into the diverse world of CNC materials, and provide you with a comprehensive guide to selecting the right materials for CNC machining.

What Factors Should You Take into Account?

The availability of a wide range of materials for CNC machining gives engineers the freedom to choose the best option for their specific needs. Selecting the right material depends on several factors, such as the required strength, durability, surface finish, and cost-effectiveness.

Therefore, it is essential to understand the various factors to consider before choosing CNC materials for your projects. This will help you make informed decisions and ensure that your projects are successful.

Machining Environment

A crucial factor in choosing CNC materials is the machining environment, where different materials respond uniquely to factors like cutting speed, tool choice, and coolant. This environment encompasses variables such as temperature, humidity, and contaminants.

High machining temperatures can cause some materials to chip or crack, while excessive cutting speeds may result in severe tool wear for others. Selecting compatible coolants or lubricants is crucial to reduce heat and friction during machining. However, improper matches can lead to corrosion or damage.

By factoring in the machining environment, productivity improves, costs decrease, and the final product’s quality is assured.

Part Weight

Considering part weight is essential for cost-effectiveness, performance, and ease of manufacture. Heavier parts drive up material costs and often require larger, more expensive CNC machines, prolonging production times. Opting for lighter materials like aluminum or magnesium can trim part weight and reduce production expenses.

Moreover, part weight significantly influences product performance. For instance, in aerospace or automotive applications, lighter components enhance fuel efficiency and overall functionality. In automobiles, reduced weight enhances acceleration and handling, amplifying fuel economy.

CNC machining materials
Image: Chris Rhoads

Heat Resistance

Effective heat resistance is crucial for materials to endure high temperatures without deformation or damage. In CNC machining, the material undergoes heating and cooling cycles during cutting, drilling, or milling, leading to thermal expansion, warping, or cracking if the material lacks heat resistance.

Opting for CNC materials with excellent heat resistance not only enhances the machining process but also lowers production costs. High-temperature resilience enables faster cutting speeds and deeper cuts, resulting in shorter machining times and less tool wear.

Various materials offer different levels of heat resistance, and the choice depends on the intended use of the final product. Materials like aluminum and copper, known for good thermal conductivity, are suitable for heat sinks and thermal management. On the other hand, stainless steel and titanium, with high melting points and corrosion resistance, are ideal for aerospace and medical applications.

CNC machining materials
Image: Josh Beech

Machinability 

Machinability signifies how easily a CNC machine tool can cut, drill, or shape a material. If a CNC material is overly hard, cutting or shaping becomes challenging, leading to excessive tool wear, breakage, or subpar surface finish. Conversely, overly soft materials might deform or deflect when exposed to a cutting force, resulting in inaccuracies or poor surface quality.

Hence, selecting a CNC machining material with suitable hardness is pivotal for precision and top-notch quality components. Material hardness also influences machining efficiency and speed, where harder materials might demand slower cutting speeds or more robust cutting tools.

Therefore, choosing a material for CNC machining with appropriate hardness is critical for achieving high-quality, precision machined components. Additionally, the hardness of the material can also impact the speed and efficiency of the machining process. Because harder materials may require slower cutting speeds or more powerful cutting tools.

Surface Finish

The surface finish significantly impacts both the performance and appearance of the final machined product. A rough surface finish can increase friction, leading to premature wear and potential failure. Conversely, a smooth surface finish reduces friction, enhancing performance and durability. Additionally, aesthetics are influenced by the surface finish; a polished appearance appeals more to customers.

When selecting materials for CNC machining, considering the surface finish needs for the end product is crucial. Some materials are more conducive to achieving a smooth surface finish than others. Metals like aluminum and brass are easier to machine to a polished finish. However, materials such as carbon fiber or fiberglass can pose challenges, often requiring specialized tools and techniques to achieve the desired smoothness.

CNC machining materials
Image: Christopher Burns

Electrical Conductivity and Magnetic Requirements

Choosing materials with high electrical conductivity is vital in CNC machining as it aids in efficient heat dissipation. The heat generated during metal machining can lead to warping or deformation. High-conductivity materials like copper and aluminum effectively dissipate heat, preventing these issues.

Consideration of magnetic properties is crucial in material selection for CNC machining, especially with ferromagnetic metals like iron, nickel, and cobalt. Their strong magnetic fields can impact the cutting process. Non-magnetic materials such as titanium and stainless steel are preferred due to their immunity to magnetic fields, resulting in cleaner cuts.

Aesthetics

With CNC machining projects destined for upscale retail environments, aesthetics play a pivotal role. The chosen material must boast visual allure, encompassing appealing textures, colors, and surface finishes. Moreover, it should lend itself well to polishing, painting, or finishing processes to achieve the desired appearance.

Industries like automotive and aerospace heavily value aesthetics as a marker of product quality and meticulous craftsmanship. This significance amplifies in luxury vehicles, where consumers prioritize premium materials and impeccable finishes.

Application

The ultimate determinant in choosing a CNC material is its intended application, where various considerations play a pivotal role. Beyond the mentioned factors, practical concerns like machinability, chemical reactivity, adhesion, availability, and fatigue life shape the decision-making process.

Selecting the right materials for CNC machining heavily hinges on the intended application of the end product. Diverse materials possess distinct properties like hardness, tensile strength, and ductility, impacting their performance under specific conditions and suitability for varied applications.

For instance, in high-temperature settings, materials like aluminum or copper excel due to their high thermal conductivity and heat-resistant properties.

CNC machining materials
Image: Carlos Muza

Budget

Budget is important for various reasons in material selection. Firstly, material costs can vary widely based on type and quantity, with high-grade metals being pricier while plastics or composites offer more affordability. Setting a budget streamlines options within your financial reach.

Secondly, CNC machining expenses are considerable, reliant on material type, part complexity, and equipment needed. Opting for materials easier and cheaper to machine helps control overall production costs.

Lastly, aligning material choices with your budget impacts the final product’s quality. Cheaper materials may exhibit more defects or lower durability than higher-quality alternatives. Hence, setting a budget and choosing superior-quality materials within that range ensures durability and maintains high standards for the end product.

AMFG DARK

 

About AMFG

AMFG is a leading provider of MES software for manufacturing. Our software solutions empower manufacturers, allowing them to manage their workflows and achieve streamlined, automated processes.

With over 500 successful implementations in 35 countries and across a range of industries, we specialize in enabling companies to successfully supercharge and streamline their CNC and Additive manufacturing processes

 

 

 

 

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