In the development of modern industry, advances in Machining technology 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.
Or maybe you want to continue to dive deeper into what’s the difference between CNC and 3D printing. I suggest you check out the difference between CNC machining and SLS 3D printing for more specialized insight.
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.
Main Technologies
Binder jetting: Binder jetting is a 3D printing technology. It creates objects layer by layer by spraying liquid glue onto powdered material. This method can be used for metals, sand, plastics, and ceramics. This method is fast and inexpensive, making it popular for making models and molds.
Directed Energy Deposition (DED): Directed Energy Deposition creates objects by melting metal powder or wire. It is mainly used to repair or improve existing metal parts. You can find this technique in industries such as aerospace, automotive, and energy.
Material Extrusion: This method is also known as fused deposition modeling (FDM). It creates objects layer by layer by heating and extruding long filaments of plastic. This is one of the most common 3D printing techniques for plastics such as PLA, ABS, and PETG.
Material Jetting: Material jetting creates fine objects by spraying and hardening liquid materials like resin layer by layer. It is ideal for producing parts in different materials and colors. For example, jewelry design, medical models, and product prototypes.
Powder Bed Fusion (PBF): Powder bed fusion techniques include technologies such as selective laser melting (SLM) and electron beam melting (EBM). These methods use a high-energy beam of light to melt material layer by layer on a powder bed to create strong metal or plastic parts. PBF is therefore ideally suited to the manufacture of high-precision, high-strength components.
Sheet Lamination: Sheet lamination creates objects by cutting and bonding thin layers of materials such as paper, plastic, or metal. It is a cost-effective way to manufacture large models, molds, and tools.
Photopolymerization tanks (VAT photopolymerization): This method includes stereolithography (SLA) and digital light processing (DLP). They use light to harden liquid resin layer by layer. This method can produce very fine parts. Examples include dental equipment, medical models, and prototypes of complex consumer products.
Benefits of Additive Manufacturing
- Design Flexibility: Additive Manufacturing can create complex shapes and internal structures without requiring additional steps.
- High Material Utilization: Unlike traditional manufacturing, additive manufacturing produces almost no material waste. This is because it only uses the material required.
- Rapid Prototyping: The ability to move quickly from design to finished product greatly accelerates development.
- Custom Manufacturing: Additive Manufacturing is ideal for creating personalized and customized products to meet specific customer needs.
Limitations of Additive Manufacturing
- Slow Production Speeds: Additive manufacturing is layer-by-layer construction. Therefore, it is slower than traditional mass production.
- Limited Material Selection: Not all materials are suitable for Additive Manufacturing. Especially certain high-performance alloys and composites.
- Surface Quality and Accuracy: Some parts produced using additive manufacturing techniques may require subsequent processing. This is how they achieve the required surface quality and dimensional accuracy.
- Higher Costs: Especially in Additive Manufacturing of metals, equipment and material costs are high, making it suitable for small production runs.
When to use Additive Manufacturing?
- Prototyping: In the early stages of product development for rapid iterative design and testing.
- Complex Parts: For complex geometries that cannot be produced by traditional processes or are very expensive to produce.
- Low Volume Production: For the production of customized or limited edition products such as medical implants and aerospace parts.
- Lightweight Design: Additive Manufacturing is used to create lightweight structures where weight reduction and optimized performance are required.
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.
Main Technologies
Abrasion (Abrasive Machining): Abrasion technology utilizes grinding wheels or other abrasives to cut the surface of a workpiece to achieve precise dimensions and surface finish. Common abrasive methods include surface grinding, cylindrical grinding, and centerless grinding. The technology is suitable for hard materials such as metals, ceramics, and glass. Therefore, it is widely used to manufacture high-precision parts and tools.
CNC Machining Centers: CNC (Computer Numerical Control) machining centers perform multi-axis machining with computer-controlled cutting tools (e.g., cutters, drills.) CNC technology can perform a variety of processes such as turning, milling, drilling, tapping, etc., and is suitable for almost all metal and plastic materials. The advantages of CNC technology are high machining accuracy, a high degree of automation, and suitability for mass production of complex parts.
Electrical Discharge Machining (EDM): Electrical Discharge Machining (EDM) is used to melt and evaporate the material locally through the high temperature and high pressure generated by the discharge, forming complex shapes and fine surfaces. EDM is particularly suitable for machining hard materials that are difficult to cut. Examples include hard alloys and hardened steels. It is therefore often used in mold manufacturing and precision parts machining.
Laser Cutting: Laser cutting utilizes a high-power laser beam to melt or vaporize material for precise cutting. The technology is suitable for a wide range of materials, including metal, plastic, wood, and textiles. Because it can cut complex shapes with high precision. Laser cutting is widely used in sheet metal processing, advertising sign-making, and medical equipment manufacturing.
Water Jet Cutting: Water jet cutting uses a high-pressure water jet (sometimes with abrasives added) to cut materials. As a result, it does not generate heat and can avoid material deformation. It is suitable for cutting materials such as metal, glass, ceramics, and composite materials. In addition, it is especially suitable for processing heat-sensitive materials and shaped processing materials. Water jet cutting is commonly used in aerospace, automotive manufacturing, and construction.
Advantages of Subtractive Manufacturing
- High Precision and Surface Quality: Through fine machining, subtractive manufacturing can achieve extremely high dimensional accuracy and surface finish.
- Wide Range of Materials: Almost any solid material can be processed by subtractive manufacturing, including metals, plastics, wood and composites.
- Mature Processing Technology: Reduced material manufacturing technology is well established for large-scale industrial production and is supported by a wide range of tools and equipment.
- Efficient Material Utilization: material waste can be effectively reduced by optimizing cutting paths and machining parameters.
Limitations of Reduced Material Manufacturing
- Material Waste: Due to machining by removing material, material waste is large, especially when machining complex shapes.
- Longer Processing Time: For complex parts, the processing time of subtractive manufacturing is longer, especially in the case of high-precision requirements.
- High Equipment Cost: high-end CNC equipment, EDM machine tools and laser cutting equipment are expensive, and the initial investment is large.
- Processing Design Limitations: In subtractive manufacturing, certain complex internal structures are difficult to process directly, requiring multiple processes or special tooling fixtures.
When to Use Subtractive Manufacturing?
- High-precision Parts: Processing of parts that require extremely high dimensional accuracy and surface finish, such as mold making and precision mechanical parts.
- Traditional Manufacturing Processes: Subtractive manufacturing remains the dominant process in mass production, especially for machining metals and hard materials.
- Complex Geometries: Despite the advantages of additive manufacturing for complex shapes, subtractive manufacturing is still a reliable method for machining parts with complex geometries, especially when combined with multi-axis CNC technology.
- Mass Production: When product designs are fixed and demand is high, subtractive manufacturing can provide an efficient and cost-effective solution for mass production.
Related reading: CNC machining vs. SLS 3D printing
Additive Manufacturing vs. Subtractive Manufacturing Comparison Table
| Comparison Aspect | Additive Manufacturing | Subtractive Manufacturing |
|---|---|---|
| Setup | Relatively simple initial setup, especially for small-scale production and prototyping. | Complex initial setup, especially for advanced CNC and EDM equipment, requiring detailed process parameter configuration. |
| Supported Materials | Supports a variety of materials, including plastics, metals, ceramics, and composites, with some limitations for high-performance materials. | Wide range of materials supported, including metals, plastics, wood, and composites; most common materials can be processed. |
| Manufacturing Complex Shapes | Easily produces complex geometries and internal structures without additional processes. | Limited by machining paths and tools; some internal structures may be difficult to machine directly and require multiple processes or special equipment. |
| Accuracy | Dependent on the technology type; high-end additive manufacturing (e.g., Vat Photopolymerization, PBF) can achieve high precision. | Typically offers higher dimensional accuracy and surface finish, especially with CNC technology. |
| Manufacturing Speed | Slower, especially when creating large or high-resolution parts due to layer-by-layer construction. | Speed depends on equipment and process; generally faster than additive manufacturing, particularly in efficient production lines. |
| Production Volume | More suitable for small-batch production, prototyping, and custom products. | Suitable for large-scale industrial production, especially when product design is fixed, enabling efficient mass production. |
| Material Waste | Minimal material waste, limited to support structures or necessary trimming. | Significant material waste, especially when removing excess material in processes like turning and milling. |
| Surface Finish | May require post-processing to improve accuracy and surface smoothness. | Generally provides high surface finish quality directly, but post-processing such as polishing or coating may still be required for specific applications. |
| Customization | Highly suitable for personalized customization and rapid prototyping, allowing quick response to design changes. | Limited customization capabilities; typically requires reprogramming and setup, especially for customized production of complex parts. |
| Operator Skill | Requires knowledge of specific additive manufacturing equipment and materials, with relatively low operation threshold. | Requires extensive machining skills and CNC programming knowledge; higher operational demands, especially in complex machining processes. |
| Safety | Generally uses safe materials and processes, but some techniques (e.g., laser sintering) may generate harmful dust or fumes, requiring protective measures. | Involves hazards such as chips, noise, and high temperatures; operators must strictly follow safety protocols. |
| Properties of Produced Parts | Suitable for manufacturing lightweight, complex-shaped parts, but mechanical properties may be inferior to traditionally manufactured parts. | Produced parts typically have excellent mechanical properties and surface quality, suitable for high-demand engineering applications such as aerospace, automotive, and mold making. |
Applications of Additive Manufacturing and Subtractive Manufacturing
Both additive and subtractive manufacturing have important application areas in modern manufacturing.
Additive manufacturing has significant advantages in customization, small batch, and complex part manufacturing. In contrast, subtractive manufacturing dominates in high-precision, high-volume, and traditional manufacturing.
Depending on the specific production requirements, the two manufacturing methods can be used in combination. This maximizes productivity and cost-effectiveness.
Applications of Additive Manufacturing
Prototyping: Additive manufacturing processes allow designers and engineers to quickly iterate and validate product designs by generating actual prototypes from design models in a short period of time. This is particularly important in industries such as automotive, consumer electronics, and medical devices.
Complex Part Manufacturing: Additive manufacturing has significant advantages in the manufacture of complex geometries and internal structures such as honeycomb structures and topologically optimized parts. The aerospace, medical, and high-end consumer industries often utilize this advantage to produce lightweight, high-performance parts.
Customized Products: Additive manufacturing is particularly well suited for producing customized products such as personalized medical implants, customized jewelry, and specialty consumer products. In these applications, each part is unique, and additive manufacturing can produce these customized products at a low cost and time investment.
Small Volume Production: In small volume production, additive manufacturing can eliminate the cost and time associated with tooling and is particularly suited to areas where market demand is rapidly changing, such as fashion, art design and high-end manufacturing.
Application of subtractive manufacturing
High-volume Production: CNC machining centers, lathes, milling machines, and other equipment can produce large quantities of parts with high efficiency and consistent accuracy. Reduced material manufacturing is widely used in mass production areas such as automotive manufacturing, appliance manufacturing and heavy industrial equipment production.
High-precision Parts Processing: Subtractive manufacturing processes such as CNC machining, grinding and EDM can product to manufacture molds, precision mechanical parts, electronic device housings, and high-precision medical device parts.
Traditional Manufacturing: Reduced material manufacturing occupies an important position in traditional manufacturing, especially in the field of metal processing. Through cutting, drilling, milling and grinding processes, material reduction manufacturing can efficiently process a variety of metal materials, such as steel, aluminum alloys, titanium alloys and so on.
Mold Manufacturing: Through CNC machining and EDM, subtractive manufacturing can produce high-precision, high-durability molds for injection molding, stamping and die-casting processes. These molds are widely used in mass production in the automotive, electronics, and consumer goods industries.
Subtractive vs. Additive Manufacturing Costs
Machinery and Tooling Costs
Additive manufacturing usually involves high machinery and tooling costs. In particular, high-end CNC machine tools, EDM equipment, laser cutting machines, and other equipment are required. However, the purchase and maintenance costs of these machines are high. In addition, a range of specialized tools and fixtures may be required, depending on the machining needs.
On the other hand, additive manufacturing also has higher initial equipment costs. This is particularly the case with metal 3D printers and high-end photopolymerization equipment. It then usually does not require additional molds or special tools. Therefore, this can lead to cost savings in some cases.
Labor Costs
Additive manufacturing is more labor-intensive. It requires operators with extensive machining skills and knowledge of CNC programming. This is because complex setups and operations often require experienced technicians.
In contrast, additive manufacturing is highly automated and relatively simple to operate. It is therefore less labor cost. Nonetheless, additive manufacturing still requires technicians to maintain and set up the equipment.
Material Costs
The material costs for subtractive manufacturing are usually relatively low. However, due to the nature of the process, there is a lot of material waste. This is particularly the case with subtractive manufacturing of complex parts.
On the other hand, the material costs for additive manufacturing are usually higher. However, this process has a very high material utilization rate and very little waste. Therefore, in the long run, this may offset some of the high material costs.
Post-processing costs
In subtractive manufacturing, the parts are usually ready for use or require only minor post-processing. Examples include polishing or surface treatment.
On the other hand, additive manufactured parts, especially those with high requirements in terms of precision or strength, often require additional post-processing. Examples include the removal of support structures, surface smoothing, or heat treatment. These steps usually increase the overall cost.
Overall, in the short term, the initial costs of additive manufacturing may be higher. Especially in terms of equipment and materials. However, in some cases, such as custom production and small batch manufacturing, its cost advantages will gradually become apparent.
Subtractive manufacturing has higher machinery and labor costs. However, in mass production, its mature process and lower material costs make it more competitive in terms of overall cost.
Therefore, the choice of manufacturing method depends on specific production needs, production volume, material type and cost budget.
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. We can handle all kinds of changes and give our customers professional CNC machining services.
FAQ
What is the main difference between additive manufacturing and subtractive manufacturing?
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.
Which manufacturing process is more cost-effective?
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.
Can additive and subtractive manufacturing be used together?
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.