3D printing and CNC machining are the most recognized and popular manufacturing technologies in the modern era. Both technologies give opportunities for more complex designs, make the job smooth for manufacturers, and maximize efficiency at no or little extra cost. However, many debates exist on which of the two is the better alternative for rapid prototyping.
In this text, we cover the upsides and downsides of each technology to help you choose the one that suits your needs best. Remember that both technologies have their upsides and the right choice will depend on multiple factors.
Overview of 3D Printing and CNC Machining
3DP (3D printing), is also known as additive manufacturing (AM). The rapid prototyping service builds pieces layer by layer. Like other AM processes like FDM (Fused Deposition Modeling) and SLA (Stereolithography), 3DP doesn’t require unique fixtures or tooling. This means that the initial setup expense is less than CNC machining.
If you choose 3DP, expect materials like plastics, metals, and ceramics. One advantage that makes this option popular is that it has a relatively easy setup and it’s more affordable to create complex shapes. Additionally, you’ll not have to intervene much because it can do the whole thing independently. It is excellent for novices.
CNC (Computer Numerical Control) machining is a subtractive manufacturing technology that uses various cutters and rotating tools. The aim is to transform a robust block of raw materials – better known as blank – into almost finished parts. CNC machining suits both medium to high-volume manufacturing and small one-off tasks making it one of the most popular manufacturing processes. The process offers high accuracy and various materials, excellent repeatability, surface finishes, and post-processing options.
The crucial difference between CNC machining and 3D printing is that the former is subtractive while 3DP is an additive process. Some upsides of CNC machining are a vast range of compatible materials and great dimensional accuracy. 3DP uses an energy source like a heated extruder or laser, to solidify materials into one solid finished product. The upsides of 3DP include speed, accuracy, freedom of shape, the possibility of cutting weight, and costs in parts and applications in multiple sectors.
Key Factors in Choosing Between 3D Printing and CNC Machining
There are many factors to consider when choosing which manufacturing technology to use to get optimal results. We’ve curated a simple guideline on factors to consider when choosing between CNC machining and 3DP.
- Speed and Turnaround Time: 3DP units fabricate any part in layers allowing for better design versatility and flexibility. It’s also a faster and more recommended rapid prototyping process since it’s more cost-effective and faster for smaller batches. Manufacturers also have more freedom to select between the technique, material, finish, speed, and printing factors to get the desired results. On the other hand, a CNC machining prototype service can offer faster production speed if simpler parts with precise dimensions are needed.
- Cost Considerations: While 3DP is cheaper, costs will mostly depend on the number of parts required and how fast you need them. If you need parts in large quantities or those with higher precision, CNC machining is more appropriate. 3DP is more cost-effective for low volumes. It’s worth noting that setup costs are higher in CNC manufacturing but the costs will be low per part because of large production runs. While 3DP has reduced setup costs, the costs are higher per part.
- Material Selection: CNC machining and 3DP processes are compatible with most materials, including both metals and plastics. Custom 3d printing however focuses on plastics overall, but this is changing fast as more affordable and better techniques of 3DP metal are being developed by manufacturers like Desktop Metal, 3D Systems, Markforged, and Arcam. CNC manufacturing utilizes plastics like Acrylic, Nylon, ABS, Polycarbonate, PEEK and more.
- Precision and Accuracy: CNC machining generally provides more accuracy and precision than 3DP. The technology uses precise computer-controlled movements and cutting tools to achieve better tolerances. While 3DP can also give you accurate pieces, the accuracy is lower than CNC especially when you want products with high geometric complexity.
Best Use Cases for 3D Printing vs CNC Machining
Both 3DP and CNC machining have distinct pros and cons which makes them ideal for different uses. CNC is superior in producing high-precision prototypes like aerospace and high-volume parts with great surface finishes. 3DP provides more design freedom which makes it ideal for customized parts and low-volume production of complex geometries like intricate internal features. For instance, 3DP might be excellent for producing a prototype with a complex design while a CNC machine is better suited for mass-creating the final product with consistent quality and high precision.
Conclusion
The choice between CNC machining and 3D printing for your needs depends on several key factors. CNC manufacturing provides more accuracy, high precision, and material versatility which makes it suitable for precise and complex parts. It’s also suitable for a variety of post-processing options making it excellent for massive production volumes.
If you’re looking for unique advantages in terms of prototyping flexibility, design freedom, and quick turnaround times, 3DP is suitable. Ultimately, the option you choose between CNC service and 3D printing depends on the specific requirements of your project and priorities. It’s important to use the technology that offers the right balance between speed, cost, quality, and design considerations.
