Difference Between Plastic Injection Molding and CNC Machining

plastic injection molding vs cnc machining

We learn the differentiation between plastic injection molding and CNC machining manufacturing processes.
Selecting an applicable manufacturing procedure for a new product is more accessible than accepting. CNC machining and plastic injection molding are frequently used and cost-effective ways to make parts.

Both methods are similar in those regards, and they are dissimilar in fabrication methods. CNC machining manufacturing operation is used for metal cutters to detach material from a workpiece to produce the final part shape.

Plastic injection molding forces liquid plastic to comply with the shape of a mold to produce the finished part. Three considerable differences exist between the two methods. That material can use these materials, and we can attain the production volume and parts of dimensional tolerances and precision.

These differences are remarkably different costs for the two processes. In these subjects, we discussed everything there is to know about CNC machining vs. plastic injection molding, which includes the advantages and disadvantages of each, and process substitutes for both.

CNC Machining Difference and Similarities to Plastic Injection Molding

In manufacturing, CNC machining is subtractive, using machines like mills, lathes, drill presses, and saws to make highly accurate parts. Computer-Aided Design (CAD) data appeared during the product design phase. CAD data is used as the principle for programming and optimizing the machine tool order and paths.

To generate the parts, the substance is then processed using cutters, such as drill bits and end mills. Additional machining, including honing, grinding machines, and hobbling, is also needed to perfect parts to customer specifications.

When physical machining parts have existed since 1300 BC, CNC machining wasn’t developed till the mid-1940s. Earlier control mechanisms that, in time, were used on CNC machines to punch code tapes as a method of communication.

In 1949, the first experimental 3-axis milling machine was designed to make helicopter blades and stiffer skin for several aircraft. In the 1970s, CAD and CAM software began integrating CNC systems.

CNC Machining is one of the world’s classically used manufacturing methods. These are used to constrict many industries, from automotive to agriculture. CNC machining is most elect to plastic injection molding due to the ability to accommodate product design changes. It also produces tight tolerance parts and the possibility of using many different materials.

What are the Advantages of CNC Machining differentiation and Plastic Injection Molding?

There are following some advantages of CNC machining over plastic injection molding:

1. Many materials can be shaped using CNC machining since during can cut plastic and metal materials.

2. CNC machining has fast tooling conduct times than plastic injection molding since compound molds don’t have to be made.

In CNC machining, beautiful surface finishes and close tolerances are accessible; they can use small-diameter tools, and each other can optimize each process parameter.

CNC machining has fast tooling conduct times than plastic injection molding since complex molds don’t have to be made.

What Are the Disadvantages of CNC Machining differentiation to Plastic Injection Molding?

There are the following disadvantages of CNC machining vs. plastic injection molding:

1. Large manufacturing volumes and price-per-part are further expensive for CNC-machined products required to the longer per-part cycle time needed to manufacture parts.

2. Labor-intensive since workpieces completed parts, and tool holders, should be stable and removed from the machine depending on the job.

Plastic Injection Molding Definition and Comparison to CNC Machining

In this process, plastic injection molding uses an injection molding machine (IMM). Plastic pellets are fed into the barrel and melted across the turn and heater bands. Molten plastic is injected into the mold and forms into the part’s geometry. The IMM holds force on the form until the products have been properly formed and cooled. The completed parts are given out, and the cycle restarts.

Brothers Isaiah and John Hyatt developed injection molding in 1872, and it is used to mold hair combs, buttons, and other small items. The first machine in 150 years of injection molding has blossomed into a multi-billion dollar in international industry. Injection molding is the most cost-effective and well-organized way to produce plastic parts than CNC machining.

What Are the Advantages of Plastic Injection Molding differentiation with CNC Machining?

There are the following advantages of injection molding vs. CNC machining:

1. It can simply produce many parts in a fast and repeatably when multiple-cavity molds can make many parts in one injection cycle.

2. In the manufacturing process, injection molding has a small price per part because the molds have long lives, and multiple-cavity molds can exceed the volume of each machine to hold up high-volume orders.

3. Minimum post-processing is required as parts are often prepared to be shipped instantly after emission, depending on the gate mode (entry point from the runner into the cavity).

What Are the Disadvantages of Plastic Injection Molding differentiation with CNC Machining?

There are the following disadvantages of injection molding vs. CNC machining:

1. It is challenging to hold product plan design changes since rework on compound molds with some plates, cams, and complex geometries can be concerning.

2. Defects inside the mold can affect finished parts with external flaws.

3. Enormous advance investment is required for mold creation since multi-cavity molds can cost wherever from a few thousand to hundreds of thousands of dollars.

CNC Machining vs. Injection Molding: Lead Cost Comparison

In CNC machining, tooling costs are notably less than for injection molding. CNC machining costs relate to the fabrication of fixtures and jigs and the procurement of raw materials and tools. Molds for injection molding can charge a few thousand dollars for single-cavity and low-cavitation molds and up to hundreds of thousand dollars for multiple-cavity molds.

While its cost is an increase over a sufficiently high production volume, suppose you have the essential machinery to build parts, and you have only required to decide on toolings like molds, fixtures, and jigs, upfront costs on CNC machining are lower.

CNC Machining vs. Injection Molding: Speed Comparison

Injection molding and CNC machining are both significant for their capacity for fast-producing parts. CNC machining is preferred for a small-volume run. Injection molding is selected for larger runs since multiple-cavity molds can fast make parts and reduce per-piece cost. The mold-making lead time takes longer to start sequence production using injection molding than CNC machining. Since CNC machining is used for small production runs and injection molding for large production runs.

CNC Machining vs. Plastic Injection Molding: Volume Comparison

Injection molding can manufacture additional parts per base machine and other parts per dollar invested compared to CNC machining. Molds can be used in multiple cavities – from one niche to various hundred. Therefore, injection molding can rapidly produce large numbers of parts, and CNC machining parts are usually made one by one. CNC machining is quickly producing regions, and plastic injection molding is even faster.

CNC Machining vs. Injection Molding: Materials Comparison

Large volumes can use large-scale materials in CNC machining processes rather than plastic injection molding. CNC machining can make parts from express plastics and metals, like aluminum and steel. Numerous thermoplastics, thermosets, and elastomers are very soft to be CNC machined. Regardless they can easily be fabricated into parts using injection molding machines.

What Are the Mutual Recourses to CNC Machining and Plastic Injection Molding?

Mutual recourses to CNC machining and plastic injection molding are there:

1. 3D Printing: Along with 3D printing, practically geometry can make – no matter how complex.3D printing obtains all above the part geometry limitations, which can differentiate the manufacturability of products using CNC machining or plastic injection molding. In 3D printing, the same materials are used in CNC machining and injection molding.

2. Casting: Casting applications won’t make parts almost as precise as CNC machining or plastic injection molding. While it relates to plastics, casting concerns pouring a liquid substance into a non-pressurized mold and allowing it to preserve. It is more straightforward than CNC machining or injection molding but can take much longer to produce parts. Casting is not appropriate for large-scale production.

What Are the Resemblances between CNC Machining and Plastic Injection Molding?

The most prominent similarity between CNC machining and plastic injection molding is that both can make use of the same materials, including polycarbonate (PC), high solidness polyethylene plastics (HDPE), and ABS (acrylonitrile butadiene styrene). Besides that, there are no various similarities between the two processes.

What Are the Other Difference between CNC Machining Besides Plastic Injection Molding?

Another option for CNC machining is CNC laser cutting:

CNC Machining vs. CNC Laser Cutting:

In CNC laser cutting, a computer-controlled laser carries around a programmed path to cut, engrave, etch, and mark parts.

It can be used as a substitute for cutting processes when it can only use on selected plastic materials due to harmful fumes emitted from workpieces during laser cutting.

What are the other similarities between Plastic Injection Molding except CNC Machining?

Another alternative to Plastic Injection Molding is:

Injection Molding vs. Thermoforming:

In thermoforming, heated and extended plastic sheets are pressed above a one-sided mold to generate parts. When thermoforming is not making parts as quick as plastic injection molding and is restricted to non-composite parts, it is a magnificent difference that can be used to construct accurate plastic parts.


This subject introduced the differentiation between CNC machining and plastic injection molding, described what they are, and discussed each of their opposing points. To learn more about CNC machining and plastic injection molding, Contact Our Professional Machinists to Discuss your 4 Axis Machining components and design requirements.

It supplies an extensive range of manufacturing capabilities, which include CNC machining and other value-added services for all your prototyping and production needs.

Leave a Reply

Your email address will not be published. Required fields are marked *

Your Comment

Search this website