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The difference between CNC Machining And Injection molding

Injection molding and CNC machining are two different processes that can be used to create plastic parts. They each have their own strengths and weaknesses, so it’s important to understand which process will work best for your project.

This post provides a comparison of the two methods, along with some key considerations when choosing between them.

Both injection molding and CNC machining are widely used for manufacturing plastic parts. However, these processes have different strengths that make them suitable for specific applications.

What Is CNC Machining

CNC machining is a process that uses computer-controlled machines to create precise parts and products from a variety of materials. The process can be used to create parts with very complex shapes and geometries, and can be performed with a high degree of accuracy. CNC machining is often used in the manufacturing of automotive, aerospace, and medical components.

The Advantage Of CNC Machining

The main advantage of CNC machining is its ability to produce parts with very high precision. Computer-controlled machines can repeat tasks with a high degree of accuracy, which means that each part produced will be identical to the last.
This repeatability is essential for many applications where safety or performance are critical, such as in the aerospace industry. CNC machining is also very versatile, and can be used to create parts from a variety of materials, including metals, plastics, and composites.
CNC machining is not without its disadvantages, however. The process can be expensive, due to the cost of the machines and the software required to operate them. In addition, CNC machining often requires a high level of skill and training to operate effectively.
Aluminum parts

What Is Injection Molding

Injection molding is a manufacturing process in which parts or products are created by injecting molten material into a mold. Injection molding can be performed with a variety of materials, including most of plastics for example, ABS ABS/PC Acetal Acetal Copolymer Acetal Homopolymer and etc. The molten material is injected into the mold under high pressure, and once it has cooled and solidified, the part or product is ejected.
the cost of injection molding

The Advantage And the Disadvantage Of Injection Molding

Injection molding is a versatile manufacturing process that can be used to create parts and products of all shapes and sizes. It is especially well-suited for mass production, as it is capable of producing large quantities of identical parts or products very quickly and efficiently. In addition, injection molding is relatively simple and easy to automate, which further reduces the unit cost of each part or product.
There are some drawbacks to injection molding, however. First, the initial setup costs can be quite high, as specialized molds must be created for each part or product. Second, the material that is injected into the mold must be carefully chosen and matched to the desired application, as some materials may not be compatible with the injection molding process. Finally, injection molded parts or products can sometimes exhibit surface imperfections due to the high pressure of the injection process.
Despite these drawbacks, injection molding remains one of the most popular and widely-used manufacturing processes available today. It is an efficient and cost-effective way to produce large quantities of identical parts or products, and with advances in technology, it is only becoming more versatile and capable.
If you are considering using injection molding to create the parts or products for your business, be sure to work with an experienced and reputable provider who can help you navigate the process and choose the right material for your needs.

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CNC Machining VS Injection Molding Here is a comparison of some of their key attributes:

Material selection:

Both injection molding and CNC machining can be used to manufacture parts from a variety of plastics. However, injection molding has a wider range of material options, as it can accommodate both standard and specialty materials. CNC machining is typically used with standard engineering plastics.

Part size:

Injection molded parts are limited by the size of the mold, while CNC machined parts can be any size.

Production volume

Injection molding is typically used for high volume production, while CNC machining is more suitable for low to medium volume production.


Since cnc machining involves removing material, it is generally more precise than injection molding. This means that cnc machined parts can have tighter tolerances than injection molded parts. However, there are some situations where injection molding can be more precise than cnc machining. For example, if the material being used has a higher melt flow index, it will flow more easily and evenly into the mold during injection molding. This can result in parts with better dimensional accuracy than those produced through cnc machining
In general, though, cnc machined parts will have tighter tolerances than injection molded parts. This is due to the fact that cnc machining can more precisely control the dimensions of the part being created. Injection molding, on the other hand, relies on the material flowing evenly into the mold, which can sometimes lead to inaccuracies.
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Injection molding has a higher upfront cost than CNC machining, but it is more economical for high volume production. CNC machining is typically more cost-effective for low to medium volume production.

Lead Time:

Injection molding has a longer lead time than CNC machining, as the mold must be designed and built before production can begin.

Surface Finish

The surface finish of a plastic part can have a major impact on its aesthetics and functionality. In many cases, a higher quality surface finish is desired in order to improve the look of the part or to increase its resistance to wear and tear. There are a variety of methods that can be used to achieve a high quality surface finish on plastic parts, including CNC machining and injection molding. While both of these methods can produce parts with excellent surface finishes, there are some key differences between the two that should be considered when choosing a manufacturing process.
CNC machining is generally more precise than injection molding, which means that it can produce parts with much finer detail and smoother surfaces. In addition, CNC machined parts can be made with a variety of different materials, including metals and plastics. However, CNC machining is typically more expensive than injection molding, and it often requires more time to produce a part.
Injection molding is a faster and less expensive method of manufacturing plastic parts. It is also capable of producing parts with very smooth surfaces. However, injection molded parts are typically not as strong or durable as those made with CNC machining. In addition, injection molding can only be used with certain types of plastics.

In General CNC Machining VS Injection Molding

injection molding is the better choice for high volume production and parts with tight tolerances and complex geometries.
However, if you only need a few prototype quantities or low to medium volume production, then CNC machining is likely the better option.
By considering these factors and determining which process will work best for your project, you can ensure that your parts are manufactured using the most appropriate method.

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