Which is Better between 3D Printing and Injection Molding?

Jack Lie CNC machining expert

Specialize in CNC Milling, CNC Turning, 3D Printing, Urethane Casting, and Sheet Metal Fabrication Services.

When designing plastic parts for manufacturing, the process you intend to streamline depends upon many factors, such as the geometry of the pieces, quantity, function, material, and position in the development cycle. 3D printing and injection molding are two leading manufacturing processes; however, which approach is better is yet to be decided. Consequently, in this article, we will discuss the benefits and utilization conditions of these two processes.

What are the Benefits of 3D Printing?

Here comes a portion of the significant benefits associated with 3D printing:

  1. Fast and Versatile

3D printing is recommended for precise & repeatable prototyping and production of low-volume end-use parts to ensure faster delivery of the components. No doubt, the technology of 3D printing originally belongs to the rapid prototyping of parts. But it has now emerged as viable manufacturing for end-use production parts supported by advanced materials and processes.

  1. Designing Intricate Geometries

For manufacturing parts that are relatively simple in geometry, injection molding or CNC machining might be a more suitable and cost-effective solution. But for organic and intricate complex geometries, parts requiring multiple iterations, and small-sized plastic parts, 3D printing may be a preferable solution. Typically, the additive manufacturing approach offers greater design freedom than the injection molding or conventional manufacturing approaches. Nevertheless, the condition is that the design process has been carried out efficiently because otherwise, the degree of freedom can be costlier and more time-consuming for manufacturers.

  1. Combining Part Assemblies

As discussed above, the most significant benefit of AM is that it offers considerable freedom for designing complex part geometries. At the same time, the ability to consolidate existing part assemblies, which are commonly made from many pieces, into a single piece is another significant benefit offered by 3D printing. Ultimately, it leads to assembly cost elimination. For instance, less labor is required, operation costs are reduced, and chances for failure at any point are lower.

  1. High Durability of Parts in Lightweight

The additive materials used in 3D printing offer excellent durability while being light in weight. That is the reason behind the use of 3D-printed parts in the aerospace and automotive sectors. Although we consider the plastic material only as an additive in this post, printed Aluminum (ALSi10Mg) is also one of the most adopted materials for producing end-use parts.

  1. Customization Option

The flexibility for the customization in 3D-printed parts is another notable benefit of additive manufacturing. Along these lines, the production of end-use parts with low-volume, including patient-centric medical devices, wearables, and low-volume highly performed aerospace parts, seems ideal using 3D printing. Moreover, the customization options available with AM are unprecedented since it allows the reconstruction of low-volume parts, previously molded or cast.

What are the Benefits of Injection Molding?

Injection molding also has some benefits attached with its use as a manufacturing process:

  1. Lower Price

Cost efficiency is a significant benefit of injection molding. E.g., the cost of tooling of aluminum mold ranges from $5000 to $80,000, depending upon the design of the part and the number of components required. Accordingly, if you are looking for the large-scale production of a specific piece, the mold’s tooling cost will be satisfied with the increase in the quantity.

  1. A Wide Range of Material Choice

The raw materials utilized in injection molding are thermoplastics resins, elastomers, and liquid silicon rubber options. In this range, thousands of materials fall in the category of materials used in the manufacturing process carried out using injection molding. In contrast, only a few materials are available that can be used in 3D printing. In addition, the availability of this much more extensive range of materials makes injection molding the most famous and adopted manufacturing process by numerous industries. In this regard, the properties, functions, applications of the parts can also be controlled with the addition of desired material as raw material.

  1. Large Volumes

Amid a lot of advantages of injection molding, the production capacity using this approach becomes too high. After the initial investment in mold tooling, the mold can be used to produce thousands of parts with a wide range of sizes and complexity.

  1. Product Scalability

If you intend to design a part that you need to scale into thousands or even millions, 3D printing will not be a worthwhile option. Though some of the technologies associated with 3D printing can be used, such as multi-jet fusion, parts production is still below 1000. Alternatively, the scalability of injection molding is too high. Once prototyped quickly with the right material choice before moving to large-scale production, the design gets optimized for moldability. Furthermore, the manufacturing of millions of parts is possible using a single mold.

  1. Fast Process

With 3D printing, the turnaround time of final production parts or prototypes might be longer than expected. Given that, it can go around several weeks or even months. But in the case of injection molding, the turnaround time can be shorter. For instance, it might be a fortnight, depending upon the part’s complexity, production run size, and the type of the project.

3D Printing to Injection Molding

Much of the time, these manufacturing techniques, when combined, play a crucial role in the existing pattern of a product. The process starts from the predominant design-moderation abilities of 3D-printed prototypes. It then moves to injection molding for expanded part quantities.

In short, the manufacturing method chosen must be well suited to your parts’ application and its functions. Also, keep in mind that injection molding and 3D printing with additive materials are not the only manufacturing processes available in your toolbox. As an alternative, various manufacturing processes can be mainstreamed, including CNC machining or sheet metal fabrication, which can be used exclusively or combined with 3D printing.