Machining and 3D printing are based on two fundamental processes – subtractive and additive manufacturing.
Subtractive manufacturing forms the basis of CNC machining and cuts away a block of material to arrive at the final part. In contrast, additive manufacturing is the concept on which 3D printing is based. In 3D printing, layers of material are added to arrive at the final part.
The development of 3D printing has encouraged manufacturers to explore the new technology, although it is still limited by speed and accessibility. However, CNC machining has established itself as an industry standard in machining.
While both have their pros and cons, there’s a lot that goes into choosing the right one. And if you’re a company evaluating the two, finding the right one depends on multiple factors like cost, material, time.
Let’s take a look at everything that you need to know to make the most informed decision between machining or 3D printing.
Evaluating the Differences Between 3D Printing and Machining
Whether you want to create functional prototypes or end parts, both technologies can offer a variety of advantages. Also, both 3D printing and machining rely on CAD data and a variety of materials. And this is where they start diverging from each other.
Physical Feature Considerations
Both CNC machining and 3D printing are limited by their tool size. In the case of CNC machining, the tool diameter will dictate the smallest negative feature that can be created. In 3D printing, the nozzle diameter in combination with Z axis resolution will dictate the smallest positive feature that can be made.
When it comes to surface finish, CNC machining takes the lead as it is able to produce a lot smoother surfaces. 3D printers can produce fit and finish, but for exceptional smoothness, machining is the way to go.
If we talk about loading, CNC machines can create parts that can withstand much higher loads. In comparison, non-structural parts are a better fit for conventional 3D printing.
Both the manufacturing technologies can use metals and polymers to build parts. The choice then comes down to which process is more readily available for manufacturing the part you need.
Also, take into account the waste that is created in both the manufacturing technologies. Since CNC machining is a subtractive manufacturing process it often results in more waste.
3D printing creates minimal waste, as it’s an additive manufacturing process, with some technologies even allowing the reuse of the minimal waste that is created.
Budget and Time Considerations
Usually, CNC machining removes material a lot more quickly than 3D printing deposits it. But if your material removal requirement is quite high, then 3D printing might be a better option.
Programming time is an important consideration. The complexity can significantly increase the programming time in CNC machining. However, once that’s done the cost per additional unit drops rather quickly. This scales well into hundreds or thousands of units per month.
For 3D printing, the programming time is fairly less and complexity has little impact on the time. The unit cost is not much affected by volume and scale can be achieved by getting more 3D printers up and running.
Labor costs are a huge consideration as well. Properly trained operators and programmers are critical to success with CNC machining. However, in 3D printing, there is only minimal training required as programming is made simple using software and can be run unattended.
As a rule of thumb, if you’re looking at scale CNC machining will work fairly well for you. But if you’re looking for quick prototyping and tooling, essentially low volume applications, 3D printing is your best choice.
How To Know Which One Is Right for You?
There is a lot to consider when we talk about machining and 3D printing. While we’ve laid out the essential differences, let’s also look at some guidelines that you can use depending upon your requirements.
How Much Are You Producing?
Making the right choice between the two can often come down to the volumes you are aiming for. If you are chasing scale, CNC machining is your best choice but when you are manufacturing in small batches, 3D printing might be more effective. Also, if you’re creating complex parts but in small quantities, 3D printing will keep your costs under control.
What Materials Are You Working With?
Since CNC machining is the more established technology, you can work with almost any material. This includes metals, plastics and wood.
However, some materials cannot be easily machined (flexible, glass). Here, 3D printing can come to the rescue. It can also work with resins and some metals.
Finally, your choice will depend upon what you need to create. Complexity, cost, materials, volume, budget, and timeline are a few factors you need to keep in mind when making the decision.
We, at Macfab, take pride in our operator’s years of experience and programming skills. Offering both CNC machining and 3D printing, our team of professionals can guide you on the best process for your requirement while maintaining top-notch quality.
Drop us a line now!