Subtractive manufacturing is a popular choice in automotive part manufacturing. The technique involves removing material from a workpiece to create precise and complex parts. It is a traditional manufacturing process that has evolved, integrating advanced technologies.
This article discusses different subtractive manufacturing processes, focusing on their applications in the automotive industry.
What is Subtractive Manufacturing?
Subtractive manufacturing refers to removing pieces of a workpiece, usually a solid block until the intended part’s specific shape, size, dimension, and structure is formed. A typical subtractive manufacturing process begins with design generation and prototype creation. This allows the manufacturer to test the design, its performance, and suitability for its intended application.
With a suitable cutting tool, it gradually removes portions of the material block to achieve the final product. Subtractive manufacturing has improved over the years with increasing technological advancement. Many machine shops now perform this technique using newer technologies like CNC machining, laser cutting, and EDM.
Why is Subtractive Manufacturing Important to the Automotive Industry?
Subtractive manufacturing is known for its high precision and dimensional accuracy. This ability allows the production of parts with excellent surface finishes, making it ideal for creating complex parts without affecting the industry’s standards. Consequently, subtractive manufacturing processes like CNC machining and laser cutting are popular manufacturing methods in the automotive sector.
Moreover, they support low and high-volume production, making them a cost-effective solution for custom automotive parts. Their capacity to deliver consistent, high-quality results helps manufacturers and OEMs maintain the strict quality control required in this industry.
Types of Subtractive Manufacturing Operations
As mentioned earlier, subtractive manufacturing includes several different processes. This section will talk about some common subtractive processes.
CNC Machining
CNC (Computer Numerical Machining) is a popular subtractive manufacturing process that uses computer-controlled machines to shape and cut a metal block with high precision. This method is the go-to process for creating intricate and precise parts necessary for modern vehicles.
It includes several machining operations, such as CNC milling, turning, and drilling. Each operation possesses unique functionalities, depending on the shape and complexity of the part you intend to machine.
CNC Milling
CNC milling is the most used CNC machining process because of its versatility. This method uses rotating cutting tools to remove material from a fixed workpiece, creating complex shapes and surfaces. Due to its ability to handle intricate geometries and tight tolerances, CNC milling is a common method for creating engine blocks, transmission components, and various structural auto parts.
CNC Turning
Unlike CNC milling, in this process, the workpiece rotates while a stationary cutting tool shapes it. Therefore, CNC turning typically produces cylindrical and conical parts such as shafts, axles, and various engine components, ensuring high accuracy and smooth finishes.
CNC Drilling
This process involves creating precise holes in a workpiece using rotating drill bits. It suits manufacturing components requiring accurate hole placements, such as engine blocks, transmission systems, and suspension parts.
Laser Cutting
Laser cutting uses high-powered laser beams to cut materials with high precision and speed. However, unlike CNC machining, laser cutting is often restricted to thin metal sheets. Therefore, this process is used for cutting metal sheets used in car bodies, chassis components, and intricate interior and exterior trim designs. Laser cutting produces parts with clean edges and detailed patterns without additional finishing processes.
Water Jetting
Water jetting utilizes high-pressure water streams, often mixed with abrasive particles, to cut through various materials, including metals, plastics, and composites. This technique is ideal for applications where heat generated from other cutting methods could damage the material.
However, it is similar to laser cutting because it does not suit machining thicker materials. Water jetting in the automotive industry is often restricted to fabricating car components like dashboard panels, glass elements, and complex metal parts, ensuring precision without thermal distortion.
Benefits of Subtractive Manufacturing Processes for the Automotive Industry
We have already mentioned some advantages of subtractive manufacturing to the automotive industry. Below is a more detailed overview of their benefits.
Precision and Accuracy
Subtractive manufacturing produces exact and accurate parts, especially with technologies like CNC machining. These features benefit the automotive industry, ensuring every machined component fits perfectly within the assembly. For example, CNC machining can achieve tight tolerance specifications of up to ±0.001mm.
This precision level makes the process an excellent fit in the automotive sector. As a result, they are used to create precision automotive components, where minimal deviation may lead to significant performance issues or safety concerns.
Material Versatility
One of the primary benefits of subtractive manufacturing is its ability to work with a wide range of materials. The process suits working with various metals and alloys like aluminum, steel, and titanium to plastics, polymers, and composites. This versatility is particularly beneficial in the automotive industry, where different parts require different material properties.
For example, engine blocks and suspension components often use high-strength metals, while interior trim and dashboard panels may use lightweight plastics. The flexibility to switch between materials without compromising on precision or quality allows manufacturers to optimize each component using any of the subtractive manufacturing processes.
Automation
As mentioned earlier, technology has revolutionized the subtractive manufacturing industry, most methods are automated. This feature allows these machines to operate continuously with minimal human intervention, increasing production efficiency and reducing labor costs.
Speed and Efficiency
Compared to newer tech like 3D printing, subtractive manufacturing processes are typically faster and more efficient for volume production. Techniques like CNC machining can quickly remove large amounts of material, making them ideal for the mass production of automotive parts.
The speed and efficiency of subtractive processes allow manufacturers to meet tight production schedules and respond swiftly to market demands. Because they have a good surface roughness, these processes often require minimal post-processing, reducing production times.
High Reproducibility and Repeatability
Reproducibility and repeatability are two other significant benefits of subtractive manufacturing, making it ideal for producing consistent, high-quality automotive parts. Once a CNC machine is programmed with the desired specifications, it can produce identical parts with almost zero variation.
This process’s high reproducibility suits parts that must meet rigorous safety and performance standards. Subtractive manufacturing processes also offer reliability and consistency, helping automotive manufacturers maintain quality control and deliver dependable products to their customers.
Limitations of Subtractive Manufacturing to the Automotive Industry
Below are the major downsides to using subtractive manufacturing technology in the automotive industry.
High Costs
The main drawback of subtractive manufacturing in the automotive industry is the high cost of the process. The machinery, such as CNC machines and laser cutters, require substantial initial investment and ongoing maintenance expenses. In addition, the operation of these machines requires skilled labor, further increasing the overall production costs.
Material Wastage
As mentioned earlier, the process involves removing material from a larger workpiece, which results in material wastage. This is especially concerning in the automotive industry, where the cost of metals and composites is high.
Specific Applications in the Automotive Sector
While we have briefly mentioned some of subtractive manufacturing’s applications to the automotive industry, we take more comprehensive information below.
Engine Components
Subtractive manufacturing is the go-to process for creating engine components such as cylinders, pistons, and crankshafts. In particular, CNC machining ensures precise shaping and drilling of these parts, ensuring they meet the high engine performance and durability standards.
Brake and Transmission System
Subtractive manufacturing processes benefit the production of brake and transmission components. Parts like brake calipers, discs, gears, and shafts require exact dimensions and high surface quality to function effectively. The subtractive methods provide the precision necessary to ensure the smooth operation of these components, even under high stress and temperatures.
Suspension and Steering Components
These techniques are extensively used in creating suspension and steering components, including control arms, steering knuckles, and suspension brackets. While these parts must be robust, they require high precision to handle the dynamic loads and stresses experienced during car operation.
Interior and Exterior Trim
Subtractive manufacturing is also utilized to manufacture interior and exterior trim car components, such as dashboard panels, door handles, and car bodies. These parts often require intricate designs and smooth finishes through CNC milling and laser cutting. The ability to produce detailed and aesthetically pleasing components ensures that the vehicle’s interior and exterior meet functional and design requirements.
Exhaust System
The exhaust system benefits from subtractive manufacturing. It consists of components like exhaust manifolds, catalytic converters, and mufflers. Precision machining ensures exhaust parts fit together seamlessly and effectively when expelling gases from the engine.
Customized Modification
Besides its use in manufacturing general car parts, subtractive manufacturing is also suitable for customized modifications in the automotive industry. Whether for performance enhancements or aesthetic upgrades, it allows for creating bespoke auto parts tailored to specific requirements.
Custom car parts include engine components, head and rear lights, body kits, and interior accessories. The flexibility and precision of subtractive manufacturing enable automotive enthusiasts and manufacturers to innovate and personalize vehicles, meeting unique customer preferences and improving overall vehicle performance.
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Conclusion
Subtractive manufacturing operations are the most used in the automotive industry because of the vast applications they offer. Their suitability to produce high-precision components without affecting quality or manufacturing efficiency is one of their most significant attributes to the automotive industry. This manufacturing method is designed to meet the industry’s high demands by leveraging advanced technology, including automation.
FAQs
What is the difference between additive and subtractive manufacturing?
The main difference between additive and subtractive manufacturing is that the former builds parts and structures in layers by adding materials in bits until the final part is achieved. On the other hand, subtractive manufacturing removes material from a workpiece, machining it to suit the desired shape, dimension, and structure.
What are the material options in automotive subtractive manufacturing?
The material options in automotive subtractive manufacturing include plastics, polymers, resin, metals, alloys, and composites. One of the main advantages of subtractive manufacturing processes is its compatibility with vast material options.
What is the difference between injection molding and subtractive manufacturing?
Injection molding involves heating a material—mainly plastic—into molten form and passing the liquefied material to a premade mold, where it cools and takes the shape of the intended part. On the other hand, subtractive manufacturing involves forming a part by removing material from the initial solid block.
