3D printing & CNC machining processes

CNC machining is the leading manufacturing technology at the moment. This subtractive manufacturing method is crucial to almost all industries, including automotive, aerospace, defense, medical, gas & oil, agriculture, etc.

Another technology becoming popular these days is 3D printing, which uses the additive manufacturing approach. It creates the parts in a blank canvas by adding material layer by layer.

This article will briefly discuss CNC & 3D printing by comparing many aspects to determine which manufacturing method is best for your project.

 

CNC Machining

CNC machining

In CNC, Raw workpieces are converted into desirable parts by removing material with different machining processes. Because of the computer-controlled process, the CNC machining approach is one of the most accurate and fast compared to other manufacturing approaches.

Advantages

Let’s overview some of the essential advantages of CNC machining technology.

• Precision and Accuracy

It creates parts with high accuracy because all the instructions are provided through a computer, and it doesn’t need constant attention from a skilled operator. So, the possibility of human error is eliminated. Although not all industries may require extremely exact parts, the functionality of features for the aerospace, defense, and medical industries depends on accuracy. CNC machining is capable of creating accurate details for these industries. Tolerances as small as 0.004 mm are easy to achieve with CNC.

• High Production Speed

The CNC machine can work rapidly once the CAD file is uploaded and the instructions are configured. It does not need the set-up change. However, tools might need to be changed according to the required operations. Still, tool change is not a time-consuming process.

• Complex shapes

Any virtual geometry created in design tools like SolidWorks, AutoCAD, Fusion 360, and others can be produced using CNC machining technology. So, shapes of extreme complexity are easily achievable using a range of CNC operations such as cutting, punching, drilling, stamping, turning, and many more.

• Uniformity and Repeatability

CNC machining is a very accurate method if you need high-volume production of a single design. When you produce large numbers, all parts will be uniform after you apply the exact digital instructions via computer. Features, tolerance, surface finish, and all other characteristics of manufactured items remain the same, no matter how many of them you want.

• Wide range of material options

CNC machines are compatible with Metals, wood, composites, plastics, and foam. There are hundreds of material options to choose from for your project. You can easily find the best material that satisfies all the properties (Physical, mechanical, and chemical). However, it would be best to consider the material’s machinability, tolerance, and tool compatibility once you match the properties with your necessities.

• Mobility

One of the unique benefits is that any individual or company can order and obtain the part from their design via the Internet. For any manufacturer, computer-Aid procedures are sufficient to produce the amount.

Disadvantages

CNC machining technology also has some disadvantages. Let’s see some of the weaknesses in brief.

• Waste of materials

It follows a subtractive manufacturing approach, which involves removing material from the workpiece to create the desired shape. So, the removed material gets wasted. The overall cost of manufacturing may rise if the material is too pricey.

• Need Expert operator

Although CNC machining does not require constant attention from human labor, the operator must have the necessary skills and experience to handle tasks like changing tools, following digital instructions, etc.

 

3D Printing

3D printing process

Like CNC machining, 3D printing also involves the design of parts in computer software before the 3D printing machine takes the digital input to produce the physical shapes by adding layers of material.

Advantages

Here are some key advantages of 3D printing technology in manufacturing.

• Complex Shapes

Complex shapes are easily achievable with 3D printing. It is possible to print any virtual geometry. After the design is uploaded and the instructions are given, the conditions are made by layering and fusing each individually by the 3D printing machine.

• Waste minimization

It doesn’t waste material like subtractive manufacturing because it uses additive manufacturing. Thus, it not only conserves resources but also lowers material costs.

• Environmental friendly

As material wastage is reduced by 3D printing, it is more environmentally friendly. Also, creating parts is a much cleaner process.

• Consistency and repeatability

No matter the production volume, it maintains the same quality and dimensional consistency of the parts. The quantity of defective parts is decreased since monitoring each succeeding individual part is simple, allowing problems to be identified in real-time.

Disadvantages

Due to several restrictions, 3D printing technology cannot grow the industry as anticipated. Let’s go over some of its disadvantages.

• Limited range of materials

There aren’t many options when choosing a material for 3D printing. Only a few types of metal and plastic are compatible with it. Not all materials can be altered to change the necessary temperature for printing. In addition, 3D printing is heavily dependent on plastics for material resources.

• High Energy consumption

Unlike other processes, 3D printing machines use much more energy to run because the material needs to be melted and added layer by layer. Therefore, the cost will rise if you use this for significant quantities and shapes.

• Toxic Emissions

As heating the material to prepare it for 3D printing is an essential step, there is a chance that harmful emissions will result. Working with plastics and metals may release large amounts of carcinogenic particles and volatile chemical compound emissions. These emissions harm human health, irritate the nose, eyes, and throat, and even damage organs.

• Volume restriction

The materials used and the finishing technique affect the size of the parts. If you need large shapes and volume, you might not get the desired result.

• Part Structure

The layers may separate under some force or part orientation, leading to the part structure failing.

 

Comparison of Advantages and disadvantages

So far, we briefly analyze the advantages and disadvantages of CNC machining and 3D printing technology. Now, let’s compare them one by one to see which is the most effective approach.

Comparisons of Advantages

CNC Machining	3D printing
·         Precision and Accuracy ·         High Production Speed ·         Complex shapes ·         Uniformity and Repeatability ·         Wide range of material options ·         Mobility	·         Complex Shapes ·         Waste minimization ·         Environmental friendly ·         Consistency and repeatability

 

The comparison shows that CNC machining and 3D printing have shared advantages, such as Precision, Accuracy, the capability to create complex shapes, Uniformity, and Repeatability. While they also have their unique gifts. For example, CNC machining is compatible with a wide range of materials, has a quick lead time, and is mobile. At the same time, 3D printing is more environmentally friendly and utilizes the material more effectively.

Comparisons of Disadvantages

CNC Machining	3D printing
·         Waste of materials ·         Need an Expert operator	·         Limited range of materials ·         High Energy consumption ·         Toxic Emissions ·         Volume restriction ·         Part Structure

CNC machining has two main drawbacks: material wastage and the requirement of an expert operator. If the material is not too expensive, the wastage would not significantly affect the project’s overall cost. 3D printing has many disadvantages, from fewer material options to toxic emissions and volume restrictions.

Comparisons different aspects

After comparing advantages and disadvantages, let’s compare various aspects, such as

Cost, surface finish, accuracy, speed, material options, and more.

Aspects	CNC Machining	3D printing
Material Options	CNC works with almost every material unless it can damage the machining tools. All materials, including metals and alloys, polymers, and wood, are compatible with CNC machines.	3D printing can also work with various materials but is not as compatible with large ranges as CNC machining.
Production Speed	The material choice and part complexity impact how quickly CNC machines can produce parts. However, CNC machining has a turnaround time of just one to three days, which is very quick.	Production might go more slowly because it uses additive manufacturing rather than CNC machining. The turnaround time varies between 3 and 5 days, depending on how complicated and extensive the parts are.
Surface Finish	As the machined surface finish is satisfactory. However, post-processing is simple and cost-effective in CNC machining.	In comparison to CNC, 3D printer resolution and surface quality are inferior. Some parts might need post-processing, but most products are ready to use.
Accuracy	CNC machining is one of the precise manufacturing technologies that can easily maintain a tolerance as small as 0.01mm – 0.05mm, depending on geometry.	It is also an accurate manufacturing process that easily achieves tolerances as small as 0.01mm – 0.05mm, depending on geometry.
Cost	Consumable and material costs for CNC machining are cheaper than those for 3D printing.	It is more expensive than CNC machining and might justify the cost only if you need small prototypes quickly.
Material Wastage	Since it removes the material to create the shape, material wastage is one of the most significant drawbacks.	3D printing is an additive manufacturing approach with negligible material wastage.

So, CNC machining looks superior if the material is not too expensive, such as gold and silver, and provides many more options for material selection than 3D printing.

 

Final thoughts

Both CNC machining and 3D printing have their benefits and drawbacks. However, some similarities are visible, such as precision, shape complexity, uniformity, and repeatability. 3D printing is very effective in minimizing material wastage, but using materials like steel, aluminum, titanium, copper, and many plastics might not be significant.

Overall, CNC machining looks superior to 3D printing because of the capacity for large-volume production, lower cost, no harmful emissions, and many other advantages. If you have decided to require a CNC machining service for your project, Prolean could be your best partner. We provide all types of CNC machining services at competitive prices, whether you need prototype development or large-scale production.

 

FAQ’s

Which manufacturing approach provides more structural stability to parts: 3D printing or CNC machining?

While CNC machining preserves the structural integrity of items, 3D printing adds layers to form shapes, increasing the risk of structural failure.

When to use the 3D printing approach?

If you need small prototypes in a hurry and have flexible spending limits, the ideal method would be 3D printing.

When to use the CNC machining approach?

In nearly all scenarios, you can use CNC machining technology for various tasks, including creating prototypes and large-scale production. It is a quick, efficient, and cost-effective manufacturing method.