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Pros & Cons of Additive Manufacturing vs. CNC Machining

In today’s world of advanced manufacturing technology and processes, consumers have a variety of options to choose from to bring their designs to life. And with how fast limitations and opportunities can change in these industries, it may be difficult to keep up with or even comprehend the differences.

Metal additive manufacturing and CNC machining are two perfect examples of the rapid growth of technology. In the case of metal AM, the potential applications seem to expand not just by year, but by month as well.

Let’s take a closer look at the pros and cons of additive manufacturing compared to CNC machining.

What is Additive Manufacturing?

Additive manufacturing is the process of creating a component through the distribution of powder material and an adhesive binder. Many customers are starting to prefer additive manufacturing due to its ability to handle nearly any part design thrown at it, accompanied by its relatively low cost of production.

Metal additive manufacturing is also great for both rapid prototyping and mass production, making it a great choice for any stage of production.

What is CNC Machining?

CNC machining (computer numerical control machining) is the process of using automated machining tools via the power of a computer. The operator programs a specific design into the software, which then translates it to the machine, which then begins to make the part.

CNC machining is one of the most effective machining processes that manufacturers can use, and reduces the need for highly-trained experts.

Pros & Cons of Additive Manufacturing

Now that you have a basic understanding of additive manufacturing and CNC machining, we can dive into the pros and cons of each. Let’s start with additive manufacturing.

Pros of Additive Manufacturing

The pros of additive manufacturing far outweigh the cons, and the process only continues to improve. Advances in manufacturing technology will only make the process more relevant and will help strengthen its current advantages while mitigating its disadvantages and common issues.

A few of the biggest advantages of additive manufacturing include:

    • Reduced waste
    • Makes complex parts cost-efficiently
    • Vast material choice

Reduced Waste

Unlike other manufacturing processes, additive manufacturing only uses what’s needed to produce a particular product. This means that there is very minimal waste, with the only throw-away consisting of any support structures that were made during the manufacturing process. These are added to help ensure that the part being created maintains the shape it was designed to have.

Complexity is Cheap

If you were to take a part’s extremely complex design to a CNC machining manufacturer, you would most likely cringe once they gave you a cost estimate. Take it to a metal additive manufacturing company, and you’ll notice a massive price difference.

Since the additive manufacturing process starts from ground zero (as opposed to starting with a raw block/slab and removing material), it’s much easier to create complex parts at a reasonable cost. This total cost is even lower when designing a hollow part. 

Vast Material Choice

Although we have a special focus on metal additive manufacturing, there are several other material choices that can be used for an AM component. These include:

    • Thermoplastics
    • Ceramics
    • Biochemicals

Each one of these categories has several material subtypes. Even if you need an extremely lightweight material that’s durable enough to withstand impact, additive manufacturing can handle it. 

Cons of Additive Manufacturing

While there are many benefits to additive manufacturing, there are also a few cons, including:

    • Capital-intensive
    • Slower build rate

Capital-intensive

Those looking to employ the services of an additive manufacturing company, won’t need to worry about this con. However, it’s worth noting that certain technology needed for this process can cost upward of $2,000,000. Although the process is cheap to run, the machinery needed is very capital-intensive.

This is why it’s better to seek out a metal additive manufacturing company to handle production needs.

Slower Build Rate

One of the most unfortunate additive manufacturing disadvantages is that the build rate is a bit slower than other processes. 

Most printers lay down chosen material at a speed of 1-5 cubic in. per hour. Therefore, bigger parts may take a bit longer than desired. 

The good news is that certain additive manufacturing machines can produce components much quicker, with some able to achieve speeds of 732 cubic in. per hour. However, these types of speeds are still slowly trickling into the industry. 

Pros & Cons of CNC Machining

Just like the additive manufacturing process, there are also pros and cons of CNC Machining.

Pros of CNC Machining

Some of the pros of CNC machining include:

  • Ease of operation
  • Minimal supervision necessary

Ease of Operation

CNC machines take a lot of the headache out of manufacturing, especially with how easy they are to operate. 

Once a design is programmed into the machine, it does the rest of the work by itself (mostly). Highly-trained operators don’t need to be running the machine and adding to the total cost of production labor.

Minimal Supervision

Once a CNC machine is programmed, it can run continuously until the day it needs maintenance. It can run for 24 hours a day, 7 days a week, giving it the ability to handle high-volume orders with ease. 

Cons of CNC Machining

Depending on who you ask, the cons of CNC machining can far outweigh its pros. Some of the biggest disadvantages of CNC machining include:

    • Material waste
    • High cost of operation

Material Waste

Opposite of additive manufacturing, CNC machining starts with a block of raw material and then removes it bit by bit using rotating tools until it achieves the desired shape. This is known as subtractive manufacturing.

It’s not uncommon for CNC machining to produce a 50% scrap rate -- which you ultimately have to pay for.

High Cost of Operation

Due to the amount of energy needed to run these machines, combined with the extremely long periods of time they can be run, CNC machines tend to have a much higher cost of operation. 

Which Method Should You Choose?

The manufacturing method that you should choose will depend a lot on the type of part being produced, and what its application(s) will be.

In comparison to other manufacturing methods, additive manufacturing is an inexpensive method that provides as much design freedom as possible to build prototypes.

For any questions or additional information, contact us.