When Should You Choose CNC Machining?

When Should You Choose CNC Machining?
CNC machining is a hugely versatile and reliable manufacturing process used for a variety of applications. Whether for prototyping or production, metals or plastics, CNC machining is an essential tool for engineers in manufacturing, automotive, aerospace, medicine, consumer products, and many other industries.
But that doesn’t make CNC an automatic choice for all projects. Several other technologies are also versatile and reliable, and it is sometimes difficult to work out whether CNC offers a more effective option than 3D printing, molding, casting, forging or another process entirely.
All manufacturing processes have their own unique advantages and disadvantages, and choosing the right process involves weighing up those advantages and disadvantages in the context of the project at hand. Sometimes the choice is clear: If you need a small number of solid metal parts with a few precise incisions on its surface, CNC machining is the obvious choice. Whereas if you need a plastic part with an internal lattice pattern, 3D printing is the obvious choice.
Sometimes, however, projects seem equally suited to several manufacturing processes, forcing engineers to come to a more nuanced decision.
So when should you choose CNC machining?
1. Precise Tolerances
As the full name implies, Computer Numerical Control machining is controlled by a computer program. Essentially, the machine uses a CAD drawing file to create an item from a solid block of material. And while machines can sometimes break down or experience errors, they’re much more accurate than even the most skilled human operator.
As long as the machine is set up properly and the design files are correct, CNC machining can produce items with very tight tolerances. Some CNC machines are capable of tolerances as close as +0.05mm or 50 microns. This precision makes it easy to create prototypes exactly as you envision them, with intricate detail, multiple components or any design features you need.
2. Mimics Finished Product
Some prototypes are designed to simply mimic the appearance of the finished product, while others are designed to mimic its form as well as its function. When you choose CNC machining for rapid prototyping, the prototype will very closely resemble the finished product, including appearance as well as functionality.
Depending on the design of your prototype, you can use CNC machining to construct a single finished piece, or multiple pieces to assemble the prototype. Other rapid prototyping processes, like 3D printing, often produce visual representations of the prototype or components. CNC machining, on the other hand, creates products very similar to those produced through injection molding, which is commonly used in mass production. Therefore, CNC machining produces durable, functional pieces that will very closely resemble the finished, sale-ready product.
3. Many Different Materials Available
While processes like 3D printing generally work with plastic polymers, CNC machining works with a wide variety of different materials. Aluminum and aluminum alloys are the most common materials used in CNC machining, however there are many other materials available. CNC machines may also use brass and stainless steel, as well as non-metallics like plastics, wood and foam. This makes it easy to construct a prototype with the hardness, tensile strength, wear resistance, and other important characteristics.
4. Easy to Change
Since CNC machining is controlled by a computer program and attached to a computer design file, it’s relatively easy to change and edit your prototype as you continue to improve and develop the design. In a full-production run using injection molding or similar processes, it’s very difficult and expensive to change the design. Choosing CNC machining for rapid prototyping allows you to continue to make improvements.
5. Fast Turnaround
CNC machining is an efficient process that can give you hundreds of units in a very short time. Once the design files are perfected and the process is set up, the machines will work quickly and precisely. While 3D printing can take hours to produce a single unit, CNC machining can produce dozens or hundreds of units in the same time frame.
6. Short Run
CNC machining can produce a few dozen or hundreds of thousands of units. If you have reached the stage in your prototype development where you are ready to test your product with your first users, CNC machining can quickly produce multiple usable, durable prototypes that closely mimic the final product.
7. Finishing Options
With your parts constructed, there are also many finishing options to make it easy to get the look and feel you want for your prototype. This may be especially important if you are comparing the effects of different appearances on sales values such as a painted finish compared to a chrome finish. Or you may wish to ensure that a particular finish performs the way you expect, such as a powder coated part adequately resisting rust. Your prototype may be left as-is, or it may be powder coated, sanded, chrome plated, bead blasted, anodized, and more.
There are many advantages of choosing CNC machined for rapid prototyping. If you have reached the point in your product development where you are ready for a short run of your design, contact us. We can provide you with a quote and help you streamline your design for the most cost-effective CNC machining.