Comparing Additive Manufacturing Vs Subtractive Manufacturing: What Are the Differences

Illustration comparing additive and subtractive manufacturing processes

In the development of modern industry, advances in making tech have led to many new ideas and breakthroughs. It has changed from traditional subtractive manufacturing, such as milling and turning, to the rapidly emerging additive manufacturing, also known as 3D printing. Each method has its unique benefits and uses. Companies must understand the difference. It is between additive and subtractive manufacturing. This is crucial for them to choose the best technology. In this article, we will discuss the features, pros and cons, and uses of these two methods. This will help you know how to choose the best technology for different products and conditions in modern manufacturing.

Table of Contents

What is Additive Manufacturing?

Additive manufacturing is a high-tech production method. It builds 3D objects by adding material one layer at a time. Unlike traditional subtractive manufacturing, additive manufacturing does not need cutting tools to remove material. It instead “prints” solid parts from digital design files. This approach greatly improves design flexibility. It makes it possible to produce complex-shaped parts. It also reduces material waste and shortens production cycles.

Common technologies for additive manufacturing include SLA, SLM, FDM, and PBF. Each technology has its specific application areas and advantages. For example, SLA technology can make very fine parts. It is suitable for precision engineering and medical fields. FDM technology is one of the most widely used additive manufacturing technologies. This is due to its low cost and ease of use.

In terms of materials, 3D printing can handle many types. These include plastics, metals, ceramics, and composites. As technology advances, additive manufacturing has made high-performance parts that meet the needs of industrial applications. These parts are widely used in aerospace, car making, medical devices, and electronics.

3D Printer Makes Prosthetics, Additive Manufacturing in Medical Applications

What is Subtractive Manufacturing?

Subtractive manufacturing is a traditional production process. In it, a portion of raw material is removed to get a desired part or product. The process typically involves many types of cutting. These include milling, turning, drilling, and grinding. They are designed to accurately remove material from a solid block to make a specific shape and size.

Core processes include Computer Numerically Controlled (CNC) machining. It is a highly automated subtractive manufacturing technique. In it, machine tools are programmed and controlled by computers to achieve high precision and complex shapes. CNC machining boosts productivity and repeatability. It can handle many materials, including metals (such as aluminum, steel, and copper), plastics, and wood.

In addition, electric discharge machining (EDM) and waterjet cutting are common techniques used in subtractive manufacturing. EDM removes material using an electric discharge. It is good for machining hard materials and complex internal shapes. Waterjet cutting uses a high-pressure stream of water to cut materials. It can accurately cut a wide range of materials, including metal, stone, and glass. It does this without creating a heat-affected zone, so it preserves the original material.

Subtractive manufacturing’s key is its ability to give very high machining accuracy and finish. It is great for making parts that need high precision and smooth surfaces. This method can create lots of scraps. However, subtractive manufacturing remains vital in many tough applications. These include aerospace, car making, and precision engineering.

CNC machine carving out a detailed metal part, precision of subtractive manufacturing.

Differences in Processes and Applications

Making things by adding material is different from subtractive manufacturing. The difference is in their methods and applications. Additive manufacturing (3D printing) is a bottom-up process. It builds objects by stacking materials layer by layer. This allows for complex shapes and internal structures to be made. It does this without assembly or extra tools. This method is best for prototyping and making complex components. It also works for customized products and short-batch production. It allows for much personalization and complexity without adding much cost.

In contrast, subtractive manufacturing is a traditional method. It involves removing material from a block to form the final product. This method relies on cutting and engraving tools. These include milling machines, lathes, and drill presses. They physically remove material to make the desired shape and size. Subtractive manufacturing is great for mass production. It is good when high precision and smooth surfaces are needed. This is the case in making mechanical parts and tools.

In applications, additive manufacturing technologies have been used in many industries. These include aerospace, medical, automotive, and fashion. For example, in medicine, 3D printing can make custom prostheses and devices. In aerospace, it is used to print light but strong parts. This reduces aircraft weight and improves fuel use.

Subtractive manufacturing dominates traditional manufacturing. It is common in industries that require mass production of standardized parts, such as car and machine making. This method is accurate and reliable. It is ideal for making high-volume, high-precision parts.

While both technologies have their advantages, they are not mutually exclusive. In many cases, manufacturers use a mix of additive and subtractive manufacturing. They do this to get the benefits of both. This mix is called hybrid manufacturing. This way, we can achieve more flexibility and innovation in design and manufacturing. This will result in more complex and high-performance products.

Advantages and Disadvantages

Additive and subtractive manufacturing each have unique benefits and limitations. These can help manufacturers choose the best technique based on project needs, costs, and goals.

Advantages and Disadvantages of Additive Manufacturing

Pros

Design Flexibility: 3D printing can make complex shapes. They would be hard to make with traditional methods. This gives designers an unprecedented level of freedom.

Reduced material waste: Additive manufacturing reduces waste. It does this by using only the materials needed to build the part.

Rapid prototyping: Short transitions from design to finished product enable rapid design validation and iteration. They speed up product development.

Customization and short-run production: It is good for making custom products. It is also good for short runs. And, it does not need expensive tooling or set-up costs.

Disadvantages

Cost issues: For high-volume production, additive manufacturing’s unit cost can be higher than traditional subtractive manufacturing.

Material and strength limitations: The range of materials for 3D printing is growing. But, some 3D printed materials may have lower strength and durability than traditional ones.

Post-processing requirements: Many 3D-printed parts need post-processing, like sanding and coating. This is needed before use and adds time and cost.

Advantages and disadvantages of subtractive manufacturing

Pros

High accuracy and quality: Subtractive manufacturing can make highly accurate and smooth parts. It is for applications with tight size and tolerance needs.

Wide material suitability: It can handle many materials like metal, plastic, and wood. It is not limited by the properties of the printing material.

Suitable for mass production: Subtractive manufacturing is great for high-volume production. It has lower unit costs and faster speeds.

Disadvantages

Material waste: Cutting and removing material from a block of feedstock can create more waste. This is especially true when making complex parts.

Design constraints: The process for subtractive manufacturing has physical constraints. These include the size and shape of cutting tools. They may limit how complex a part can be.

Setup time and cost: For the production of a specific part, it takes time to set up machines and tools, especially when producing different parts, which can lead to higher initial costs and production lead times.

Cost, Accuracy, and Production Volume Considerations

Cost, accuracy, and production volume are three key factors. They matter when considering additive or subtractive manufacturing. These factors directly impact the product’s quality, production efficiency, and the project’s economics.

Cost Considerations

Machine cost: Additive manufacturing equipment, especially high-end metal 3D printers, has a high initial investment. However, by removing the need for special molds or cutting tools, additive manufacturing may be cheaper. It is good for making small batches or complex parts. Subtractive manufacturing equipment may cost less at first. But, for diverse product lines, you may need to invest in many types of cutting tools and fixtures. These can add costs.

Post-processing costs: Parts made by additive manufacturing often need post-processing. This includes removing support structures, grinding surfaces, and heat treatment. These steps add time and cost. Subtractive manufacturing produces parts with a better surface finish. They may not need much post-processing. But, some applications, still need more surface prep to meet specs.

Infographic depicting cost comparison between additive and subtractive manufacturing with icons and graphs

Accuracy

Additive manufacturing can make complex shapes and details. But, its accuracy is limited by the printing technology, materials, and machine performance. For applications requiring extremely high precision, subsequent machining may be required. Subtractive manufacturing, especially high-precision CNC machining, can directly achieve high accuracy. It can also achieve a good surface finish for parts with very high accuracy requirements.

Production volume

Additive manufacturing is great for small production runs and prototyping. It allows for rapid iteration of designs without adding much cost. But, for mass production, additive manufacturing may not be as fast or cheap as subtractive manufacturing. Subtractive manufacturing is suitable for high-volume production because once setup is complete, production is fast and less expensive.

So, the best technique depends on the needs, budgets, and goals of the project. For highly customized projects with small batch sizes, additive manufacturing may be best. Subtractive manufacturing may be better for high precision and mass production. Properly evaluating these factors is critical to ensuring project success and economic efficiency.

Conclusion

In this article, we look at the differences between Additive and Subtractive Manufacturing. We analyze the strengths and limits of each and discuss their uses in different areas. Technology continues to develop. Both Additive Manufacturing and Subtractive Manufacturing are evolving. They bring new opportunities and challenges to the industry. Yonglihao Machinery is a professional CNC machining service provider. It can handle all kinds of changes and give our customers professional CNC machining services. It has deep technical skills and rich experience in subtractive manufacturing.

FAQ

3D printing is a bottom-up manufacturing process. It builds 3D objects by adding material layer by layer. Allowing complex shapes to be produced and minimizing material waste. In contrast, subtractive manufacturing is the traditional method of removing material from a block of raw material to form a final product. It is good for making parts with high precision and smooth surfaces but can lead to more material waste.

Cost-effectiveness depends on the type of production, batch size, and complexity of the part. For small batches and custom parts, additive manufacturing is usually cheaper. It does not need expensive tools or complex setups. For making many of the same parts, subtractive manufacturing may be cheaper. It has faster production and lower unit costs.

Yes, the techniques can be used together. This forms a hybrid manufacturing approach. This approach combines the design flexibility of Additive Manufacturing with the accuracy benefits of Subtractive Manufacturing. It’s for making parts that need complex shapes, but also need high precision and finish. By mixing the two technologies, manufacturers can get more flexibility and efficiency. This helps in the design and manufacturing process, making more complex and high-performance products.

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