The right manufacturing technology will propel your business in a more proper direction. CNC is not just CNC milling machines and lathe machines but also includes 3D printers and robotic arms, among others. CNC machine tools and 3D printing share a lot in common. They both interpret a set of coordinates that are provided in the form of G-code and convert them into motion for milling or printing. Through a microcontroller, the instructions provided are translated into the movement of a stepper motor. The principles of all CNC machines are identical, with variations being largely in materials and uses.
What Are CNC Machining and 3D Printing?
CNC machining, or Computer Numerical Control machining, is a common subtractive manufacturing technology. It uses a series of advanced machines such as grinders, lathes, drills, routers, plasma cutters, laser cutters, and milling machines to remove excess material from raw materials and create precision CNC-machined parts with a shaped structure. CNC machining includes services such as CNC milling, CNC turning, and CNC drilling.
3D printing technology followed CNC. It is a form of additive manufacturing process that typically adds material layer by layer and forms a 3D object from a Computer-Aided Design (CAD) model. 3D printing includes Selective Laser Sintering, Stereolithography, etc.
In spite of the reality that 3D printing is nowadays simpler to use and more versatile, CNC machining services and parts still maintain their position in today’s manufacturing and cannot be replaced by 3D printing.
Additive Manufacturing vs. Subtractive Manufacturing
3D printing is an additive manufacturing process:It forms different parts by adding different particles layer by layer with the assistance of different materials, thus building a part. It can be used for producing complex designs that cannot be produced by using conventional CNC machining. It can be used in different industries and can facilitate cost savings.
CNC is a subtractive manufacturing process: That is, it carves out the needed component from a bigger block. In this type of manufacturing, you have the advantage of precision in dimensions. It also functions with various kinds of materials such as wood, plastic, and metal.
Differences Between CNC Machining and 3D Printing
In manufacturing, 3D printing and CNC machining are two common technologies with a list of their own characteristics. Their main differences are:
Difference in Working Principles
CNC machining is a machining process that is controlled by a computer. It uses CNC machine tools to perform precise cutting, milling, drilling, and other actions on materials. CNC machining generally starts with a solid block of material, and the shape required is defined by slowly eliminating the excess material. Therefore, it is a subtractive manufacturing process.
Unlike CNC machining, 3D printing is an additive manufacturing technology. In 3D printing, objects are made in a way of stacking materials layer by layer. 3D printing utilizes the use of nozzles or lasers as tools to stack powder, liquid, or wire materials layer by layer according to the design drawings until the entire piece is completed. Therefore, 3D printing is a process of adding materials incrementally.
Difference in Material Usage
CNC machining can handle a large variety of materials, including metals, plastics, ceramics, etc. Due to its high-precision machining capabilities, CNC machining can perform particularly well when it comes to processing hard materials. For example, in aerospace, automotive, and medical device manufacturing, CNC machining is typically used to manufacture precision components.
3D printing mainly uses plastic materials. Although there are some technologies in recent years that can achieve the 3D printing of metal, ceramics, and other materials, its types of materials and performance are still relatively narrow. The common 3D printing materials are ABS, PLA, resin, etc., which can be utilized in the making of prototypes, concept verification, or parts with lightweight.
Machining Precision and Surface Quality
CNC machining has very high precision and surface quality. Since it uses the method of cutting material, CNC machining can get very complex and detailed shapes, and the surface is smooth, which can meet high-standard process requirements. For example, the components required by the aerospace, automotive, and medical industries usually need to be processed by CNC in order to reach the required precision.
On the other hand, though 3D printing has made great progress in terms of accuracy, its surface quality is usually not as good as CNC machining. The layer-by-layer building process of 3D printing will leave microscopic layer lines on the surface, especially on low-accuracy printers. This calls for additional post-processing, such as grinding and painting, on 3D printed products in some applications to improve the surface quality.
Production Efficiency and Applicable Range
In terms of production efficiency, CNC machining is mostly applied in mass production, especially in high-precision demands. Through CNC machining, the efficiency of mass production is comparatively high, and a great amount of identical or similar parts can be manufactured quickly, and the processing time is relatively fixed.
In comparison, 3D printing is suitable for small-lot production or customized production. Since 3D printing builds one part at a time instead of reproducing a large number of the identical parts through cutting or milling, it is more suited to form complex, bespoke, or small-batch products. The second advantage of 3D printing is that it can directly manufacture from a computer model without involving complex mold and tool making. So it has unmatched superiority in rapid prototype development and small-batch customization.
Cost Comparison
CNC machining is generally expensive, especially when high precision and expensive material are required. Although the initial expense of CNC machining (machine, process planning, etc.) is high, once the production line is established, the expense of large-volume production is relatively low. This gives CNC machining a competitive advantage in large-volume production.
3D printing is best suited for small batches or one-off customized products since the equipment cost and material cost are comparatively low. 3D printing does not require the mold creation that is characteristic of conventional machining, thus it can greatly save the initial cost. However, when the production quantity increases, the unit cost of 3D printing will increase progressively since each product has to be printed layer by layer.
Environmental Protection and Sustainability
The CNC machining materials are usually obtained through cutting or milling, and certain material wastes might be generated. Especially when working with high-value materials such as metals, more waste products would be generated in the manufacturing process. Therefore, the environmental sustainability of CNC machining is relatively low.
On the other hand, 3D printing has a high material utilization rate. Since it uses the method of adding materials layer upon layer, there is minimal or no material wastage in 3D printing. Especially when using materials such as plastic or metal powder, 3D printing can significantly reduce the generation of waste materials and improve the environmental sustainability of the production process.
Similarities Between CNC Machining and 3D Printing
CNC machining and 3D printing have the following similarities in manufacturing. These similarities make CNC machining and 3D printing complementary technologies that can be used together in different manufacturing contexts to achieve the best manufacturing results:
- High Precision and Automation: Both can achieve high levels of automation and precise manufacturing processes, and are suitable for manufacturing complex components and models.
- Use of a Wide Range of Materials: They can both handle a variety of materials, including plastics, metals, and composite materials, to meet different manufacturing needs.
- Design Flexibility: Both can perform precise manufacturing according to design drawings and can offer support for complex internal structures and designs, such as hollow and special-shaped structures.
What Is the Best Method for Manufacturing Complex Parts?
In deciding whether to use 3D printing or CNC machining, the part complexity is the primary consideration. Both technologies have their respective design constraints.
CNC machining also has several significant design constraints, including tool access and clearance, mounting or clamping points, and the inability to machine square corners due to tool geometry. Some geometries cannot be manufactured by basic CNC because the tool cannot access all part surfaces. This is where the need for the 5-axis system comes in.
Most geometries will require the part to be rotated by the operator in such a way that the tool will have access to different sides and angles. Repositioning will increase machining and labor time, and sometimes fixtures and clamps have to be used as well. All of these will increase the cost of the final part.
3D printing can produce parts with almost no geometric limitations. Processes such as FDM can be support structure-demanding, but a little additional post-processing will not nullify the outstanding design freedom and complexity processing ability of 3D printing. It finds widespread use in aerospace, medical implants, automotive manufacturing, and so on. It allows for the creation of parts with complex internal geometries and high precision, and is suitable for the requirements of high material use ratio, brief production cycle, and design flexibility. 3D printing is capable of shortening the product development cycle and reducing development costs through rapid prototyping and part production directly.
Choosing the best manufacturing process means considering the material, complexity, production batch, and design requirement of the part. In practical application, it is often required to combine different technologies according to specific conditions to achieve the best manufacturing result.
CNC Machining Is Superior to 3D Printing
Cost is arguably the most important factor in choosing a manufacturing technology. CNC machining tends to be cheaper and more cost-effective than 3D printing.
- Speed: As we have noted, CNC is a faster solution compared to 3D printing.
- Difficulty:It is much simpler to install and implement CNC machines compared to industrial 3D printers. CNC machining makes prototyping easier because the machine can carve the design out of the material and produce the prototype using the same material that will be used for the final product. 3D printers do not produce prototypes with structural integrity.
- Quality: CNC can yield high-quality and precision-machined parts, which 3D printers cannot match.
- Product Integrity: The end product retains the strength and other material properties after CNC machining, but due to the layering in 3D printing, the materials cannot be joined at the molecular level, thus reducing the integrity of the part.
- Volume: Based on speed and cost, CNC machining is more suitable for mass production than 3D printing. There remain some disadvantages in the mass production of 3D printers, which are yet to be resolved.
KESU’s CNC Machining and 3D Printing Services
3D printing is an additive process whereas CNC machining is a subtractive process. Although their methods of machining are very different, both of them also have their own advantages and can aid in achieving the best manufacturing solutions for parts.
Our 3D printing services at KESU enable immediate prototyping of complex designs, and our CNC machining provides high-precision metal and plastic parts. With fast turnaround times, expert support, and competitive pricing, we make sure to provide the highest quality manufacturing solutions.
Conclusion
Both 3D printing and CNC machining have their respective applicable areas and advantages. At different product R&D stages and production stages, choosing a suitable machining process according to the needs will achieve more cost-effective manufacturing.
