3D Printing vs CNC Machining – Pros and Cons of Each

3D printing vs CNC machining are two entirely different, and prevalent techniques in contemporary manufacturing. 3D printing is an additive manufacturing technique, employed in plastic fabrication sectors. These techniques are normally sorted by materials and price ranges. 

CNC machining, on the other hand, subtracts material from the workpiece in question. It involves rotating tools to take off the material from a metal and plastic block. CNC machining has fewer design restrictions but provides flexibility, and even can precisely cut down difficult to hard materials. Even though cryogenically stabilized rubber materials can be processed. However, certain geometric constraints especially while handling hollow parts are involved.

This article explains the key difference between 3D printing vs CNC machining by highlighting their pros, and cons.

3D Printing Vs CNC Machining: Key Differences

3D Printing is typically employed for the creation of a 3D object by making successive layers. It involves computerized models to lay down materials like plastics, metals, or ceramics according to a set of instructions. The process enables the build-up of conveniently complicated structures either impossible or difficult to implement using other conventional techniques.

In comparison, CNC Machining turns metal, and plastic blocks cutting material using tools that rotate with the help of programming. Particularly, it’s suitable for fabricating detailed parts from a variety of challenging, stiff materials such as metals, resins, and composites.

Comparing 3D Printing Pros Over CNC Machining 

3D printing being a relatively newer technology has several advantages over CNC machining.

1. Design Freedom

Custom geometries are another strength of 3D printing. In comparison with CNC machining, it can manufacture parts with complex internal features. More specifically, you can even design biomorphic shapes. These geometries may not be feasible to accomplish with CNC Machining techniques. Therefore making design modifications, and changes does not require extensive reworking or refitting.

2. Minimal Material Waste

General 3D printing being an additive technique does not consume unnecessary material quantities. As opposed to CNC machining where material is managed by cutting away any unnecessary material. Therefore, 3D printing produces far fewer waste materials. This results in cost savings on material required to make the product and the cost of disposal.

3. Faster Prototyping 

3D printing allows fast prototype production within only a few hours. When using digital designs, they are immediately brought to the physical parts, cutting down the time. So, it is commonly employed in industries such as the automotive and aerospace sectors where time is ca ritical concern in product development.

4. Lower Setup Costs

Another prominent benefit of 3D printing includes no need for expensive tools or fixtures. Conversely, CNC machining needs new tools every time to design a new part which is quite expensive at the beginning. Moreover, the 3D printing process uses files, which means you do not need to set up tools or equipment. 

5. Customization and On-Demand Production.

3D printing is optimal for one-off, small-batch production or short production runs. Sub-assembly components are easy to adapt in response to a client’s needs. With on-demand manufacturing, the company now only orders what it needs, when it needs it, so there’s no need to keep large quantities in stock.

6. Material Innovation

3D printing is an ever-expanding technology. So, new innovative materials are being added often. Currently, advanced thermoplastics, metals, and even ceramics can be used to print parts. Some 3D printers can use multiple materials at once, allowing different parts of the same product to have different features. 

7. Tool-Free Manufacturing

Unlike in CNC machining where tools and fixtures are used, 3D printing does not involve any physical tools. The products and parts are produced from digital files which reduces the time required to change parts between production runs. Thus, the tool-free process also reduces the skilled operator and makes the process relatively easier.

Cons of 3D Printing Compared to CNC Machining

Let’s figure out the limitations of 3D Printing

1. Limited Material Selection

Compared to CNC machining, 3D printing is compatible with fewer materials. CNC machines can work on metals and alloys, and also on metal matrix composites. These materials have favorable and distinguished mechanical features. While 3D printing uses mainly engineered thermoplastics metal may not conform to strength or endurance issues.

2. Inferior Surface Finish

When using 3D printing manufacturing parts’ surfaces are not as uniform as desired. Because the layer-by-layer build-up leaves behind process traces. Sanding is usually necessary for post-processing to improve finishing. Conversely, CNC machining directly yields smoother finishing. That’s why CNC is preferable for high-precision tasks.

3. Slower for High-Volume Applications

3D printing takes more time to produce products in bulk. It assembles parts layer by layer, taking time to complete each piece. So, CNC machining is appropriate for large-scale production. After installation of the CNC machines, they can fashion many parts at once.

4. Limited Build Volume

In 3D printing, the large components may require to be bent in small portions. These sections must then be assembled, which proves to be more troublesome. CNC machines can process larger parts at once, eliminating the need for assembly lines.

Pros of CNC Machining Over 3D Printing

Let’s discuss the pros of CNC machining over 3D printing;

1. Superior Material Selection

CNC machining can machine almost every type of material. In general, metals, alloys, plastics, and composites can be shaped with simplicity. These materials are characterized by high strength, durability, and fine accuracy. However, 3D printing is limited to plastics, and fever composites available for use.

2. High Precision and Tolerances

CNC machining has high dimensional precision along with small and controlled tolerances. It can create components with a high degree of accuracy right to their actual dimensions in complex shapes. So, industries like aerospace and automotive primarily use CNC Machining.

3. Smooth Surface Finish

CNC machined parts usually come out with a polished end product. The flank-cutting process removes material with minimal surface roughness while 3D printing leads to the creation of surfaces that are relatively rough for flank-cutting. 

4. Quicker for Large Scale Production

CNC machines can fabricate parts with considerable efficiency and precision. The process is quite efficient in the reduction of cycle time. While 3D printing can take longer in reproduction since it requires adding of layers successively.

5. Larger Part Capabilities

CNC machines can accommodate much larger workpieces to design to shape. However, 3D printing may tend to divide large parts into sections and then join them together. Moreover, CNC machining can be integrated completely in one step.

Cons of CNC Machining Compared to 3D Printing

Here are the cons of CNC machining;

1. Higher Material Waste

CNC machining normally leads to increased material wastage particularly when the desired part shape is complicated. On the other hand, 3D printing involves the use of only the required quantity of a particular material. Consequently, the 3D printing process is more material efficient.

2. Longer Setup Times

Fixed manufacturing overhead is a major concern in CNC machining. Since the equipment takes a long time to prepare for tooling and fixturing. 3D printing does not require much variation and is easily adapted to quick changes in design.

3. Limited Design Flexibility

CNC machining has design limitations somehow. External surface details and internal structures or cantilevers are challenging to design by machines. However, 3D printing is capable of producing shapes and designs that are typically difficult with CNC machining.

4. Higher Initial Costs

CNC machinery and tools are comparatively expensive. An initial setup is costly particularly when it comes to producing products in minimum quantities. Further, the consumption of tools and maintenance required in the process result in constant costs over the long term. 3D printing does not require tooling and fixtures. Thus, it requires lower costs in low-volume or unique configurations.

Technical Comparison: 3D Printing vs. CNC Machining

Final Summary

To sum up, 3D printing vs CNC machining have their strengths based on the project work. 3D printing is more beneficial for design alterations, quickly created prototypes, and materials wastage for a short production of complex design geometries. However, it does not necessarily produce the required accuracy, surface finish, or material options as CNC machining. CNC is better suited for greater levels of accuracy, and mass production and operates on a more diverse array of tough materials.

Whether to use 3D printing vs CNC machining boils down to issues to do with the level of part intricateness, the material to be used, the volume of production needed, and the cost.

If you’re still uncertain about which method best suits your needs, contact Print My Parts. Our team can help you navigate the pros and cons of each and select the most suitable manufacturing process for your project.