3D Printing vs Injection Molding: Choosing the Right Manufacturing Process

Table of Contents

3D Printing 2
3D Printing
Source: https://ndla.no/image/10317?

In the continuously advancing world of manufacturing, two of its best methods, 3D printing and injection molding, have transformed manufacturers’ approach to the production of various parts. These two phenomenal methods adopt unique processes in manufacturing components most vital to several industries. Due to that, companies have usually sought their services for different reasons and objectives. And manufacturers have been entrusted with the decision of what method to embrace for differing project objectives. For enlightenment and knowledge acquisition, we shall be delving deeper into both methods, exploring their processes, pros and cons, and applications throughout all industries that make use of its products.

1. Understanding 3D Printing

1.1 How 3D Printing Works 

3D printing is a sophisticated method of producing components which usually entails building parts from their foundation up layer after layer. 

3D printing holds a technological advantage over its conventional counterparts in that it requires the removal of material from a solid block. Moreover, at the center of 3D printing is an additive manufacturing process that spurs the creation of difficult designs by employing the CAD and CAM processes to build its component. 

Essentially, the process of manufacturing components deploying 3D printing begins with a template of the desired project represented as a 3D model. This model is also known as the prototype design for the component to be manufactured. 

However, the essential tools that bring this design to life are the printers. These printers are very recent technologically advanced ways of achieving high-quality mold manufacturing, and they work in distinctive ways. Some of which are Fused Deposition Modeling (FDM) which works by extruding filaments. 

There is also Stereo lithography (SLA) which works better with liquid resins, while Selective Laser Sintering (SLS) as the name describes uses a high-powered laser to synthesize powdered materials to form the desired components. 

3D printing utilizes printers to convert 3D models into finished products. For that reason, the major elements in 3D printing are the printers, material, and the model to be interpreted.

1.2 Pros and Cons of 3D Printing 

With 3D printing being a technologically profound method of production, manufacturers often anticipate its wealth of benefits when purchasing it. However, they also need to be aware of its lags in specific aspects. Let’s explore some of these advantages and limitations but benefits first. 

The superfluity of benefits 3D printing offers begins from the creative design freedom that designers enjoy. With that kind of freedom in designing components, outstanding designs can be delivered and brought to life with 3D printing. The design freedom allows designers to customize products with intricate geometries while maintaining quality and brand goals. 

Moreso, 3D printing is well-suited for prototyping. In building complex prototypes with a short time-to-market frame, 3D printing assists companies develop products that change the dynamics of their brand in the market. Due to the hours taken for a 3D printed material to reach completion, it is suitable for small batch production that promotes innovation. 

On the back of all these benefits, 3D printing also presents some limitations especially for professionals engaged in the high-quality mold manufacturing industry

First is its inability to carry out large-scale productions. 3D printing is only limited to producing small-volume components due to its layer-by-layer build. In addition, the material utilized alongside 3D printing may be restricted to specific materials. Unlike traditional methods that use numerous materials in manufacturing. Several industries rely on the efficacy of 3D printing. 

Metal 3D printed component
Metal 3D printed component
Source: https://commons.wikimedia.org/wiki/File:Metal_3D_printed_component,printed_on_AddUp_machine%2849803156356%29.jpg

2. Exploring Injection Molding

2.1 The Process of Injection Molding

While 3D printing is an additive manufacturing method, meaning it adds more material to get the final product, injection molding is the opposite. Injection molding is a subtractive manufacturing method that entails the injection of molten plastic, typically thermoplastics, into a mold cavity. 

The injection molding method has been one of the most revolutionary methods in manufacturing that allow for the production of intricate dimensions and geometries under intense pressure to form the desired component after cooling and solidification takes place. 

In essence, what makes the injection molding technique a well-sought practice is the ability to handle high-volume production runs, with repeatability, and quality is a major criterion for its adoption in manufacturing. 

Major chronological steps are involved in the injection molding process, and this commences with designing a mold that fits the shape of the required design option. Although a lot of considerations go into the designing of the mold, eventually, a mold design is formed. Once that is settled, the melting of the selected plastic is next. 

Typically, these plastic materials are usually thermoplastic pellets with properties that align with the project requirement. The molten thermoplastic is then injected into the mold cavity at high pressure while cooling and solidification complete the process. 

The tooling selected for injection molding is dependent on the volume and project design, and these tools range from desktop units to giant-sized factory machines. 

2.2 Advantages and Disadvantages of Injection Molding

Injection molding is a manufacturing method that offers an expanse of benefits to companies and manufacturers alike. The quality it offers from producing thousands, even millions of similar components is unmatched. 

In addition, the cost-effectiveness and the simplification of this manufacturing process make it a top choice for manufacturers. And it is for this reason that the method can manufacture large quantities. 

What’s more? You should behold the precision and consistency within products manufactured by injection molding, with qualities like tight tolerances, outstanding repeatability, and consistency throughout the manufacturing process. 

The aesthetical appeal, surface finish, and material properties are all hinged on the versatility of material behaviors in injection molding.

What limits injection molding is its original setup cost, especially with intricate mold designs. Even so, the cost of changes to the mold already designed could be hard to fix. Unlike 3D printing where iteration of a design could be done at the snap of a finger. 

Injection molding is widely employed when considering manufacturing high-volume products with consistency, quality, and budget-friendliness. Consumer goods, aerospace, automotive, and electronic components are major industries that have benefitted immensely from injection molding.

3. Comparing 3D Printing and Injection Molding

3.1 Cost Considerations 

When comparing two comprehensive manufacturing methods such as 3D printing and injection molding, it is essential to microscopically view the cost considerations attached to both methods. This helps manufacturers decide on what method best suits their agenda for manufacturing. At first glance, 3D printing may look like a cheaper option compared to other manufacturing techniques. 

Largely because it does not require the fabrication of expensive molds yet is capable of fashioning complex designs, but this changes when taking into account the volume to be produced. 3D printing is quite suitable for customized products and small-volume productions making it cost-effective by not having to setup heavily for the small-batch production run.

Nevertheless, injection molding on the other hand is already cost-efficient in being able to manufacture in large quantities. Although the initial setup may be costly, this cost is made up for in the long run with its capacity to manufacture higher volumes of components. 

Let’s put it this way, you can utilize both as a manufacturer by initially employing 3D printing for project development and prototyping, then switch gears to injection molding when committing to full-scale production. What do you say?

3.2 Design Flexibility 

In design flexibility, it is safe to say that 3D printing technology wins that battle hands down. This is logical because 3D printing involves layer-by-layer formation of the component. And this allows designers to flex their creative muscles when designing and building the designs by 3D printing.

3D printing permits fabricating organic shapes, and complex lattice structures. Meanwhile, injection molding is very effective in its capacity likewise. 

Manufacturing precise intricate parts and high-quality products with incredible design consistency, accurate dimensions, and aesthetically satisfying. Its only limitation in design flexibility is mold fabrication. The modification of the mold after fabrication is quite difficult and expensive.

3.3 Time and Production Volume

With all that has been said thus far already tells you what you need to know about time and production volume when comparing these methods side by side. But for clarification, 3D printing holds the lead for smaller production volumes, and less time is needed for customization and small-scale production. 

For injection molding, this method thrives with full-scale production, manufacturing thousands even millions of identical parts in a limited time frame. Both methods hold their own in their various capacities, but the project requirement is responsible for determining what time is consumed considering the production volume.

3.4 Material Options

The selection of materials is based on production specifications, environmental factors, optimal performance, and applicability of the component manufactured. 3D printing provides an increasing range of materials, from resins and metals to biocompatible materials to select from. This option makes room for flexibility in achieving some industry specifications by enabling durability, biocompatibility, and strength. 

Similarly, injection molding allows a wider scope of material options, thermoplastics in particular. Thermoplastics are easily accessible along with their various material properties, which makes injection molding open to several material choices available and vast to deploy.

3.5 Surface Finish and Quality

Surface finish is a very critical part of any production run. The beauty, appeal, and overall performance of the final product rests on the quality of the surface finish present. 

3D printing can offer a smooth surface finish, but this is based on the layer thickness of the component and the technology selected in executing the process. 

Even so, some post-processing may be required to achieve the desired surface finish. Unlike injection molding, the level of smoothness on its surfaces is extremely admirable. This is a result of the well-designed mold cavity. With injection molding little to no post-processing is needed for a good surface finish. 

4. Industries and Applications

4.1 Industries Utilizing 3D Printing.

The applications of different manufacturing techniques vary and are reliant on the specific needs of the industry that determines whether these techniques are suited for their needs and requirements. 3D printing for example has proven its worth in ensuring the project specifications of various industries are met. Some of which are

  • Aerospace: In this industry, 3D printing is transforming the components manufactured to create lightweight yet strong parts with features that enhance performance and increase fuel efficiency. It is a joy to see the versatility of this method being put to good use. It doesn’t stop there.
  • Healthcare: The healthcare sector has likewise felt the impact of the 3D printing method of part production by producing custom-made medical tools such as implants, prosthetics, and patient-centric gadgets that help improve the well-being of its patients. In addition, 3D-printed instruments also have assisted medical professionals with planning medical procedures and education in the healthcare sector.
  • Automotive: Understandably so, technological advancements are constantly associated with this industry, hence the need to embrace the power of 3D printing in developing design prototypes, functional prototyping, and eventual end-use products in the industry that can help reduce lead times, simplify processes, and enhance performance.

4.2 Industries Preferring Injection Molding

Injection molding is crucial to almost if not all industries, on that account; industries that mass produce components for end-user purposes have injection molding as their cornerstone. Just like high-quality CNC Machining, injection molding offers cost-efficiency in production along with high-quality, precision, aesthetically satisfying finish, and top-performing products. Examples of industries that utilize injection molding include 

  • Consumer products: Everywhere you look, there’s an injection molded product. From plastic bottles to containers that we regularly use for various intentions. Injection molding with its ability to produce high-volume identical products with maximum efficiency is outstanding.
  • Packaging: This is another industry where injection molding thrives. This is a result of its budget-friendliness and shorter lead times in production. It can manufacture components such as bottle caps, containers, and closures for our everyday consumption.
  • Electronics: The presence of injection molded parts in electronics is seen all around us as well. Your connectors, casings, and many more components deployed in the electronics industry are made by injection molding. 
  • Medical: The medical industry has hugely benefitted from injection molding through the manufacturing of syringes and drug delivery systems that aid the seamless delivery of medical services by medical practitioners. Injection molding is significant to this sector due to its ability to comply with strict quality control standards and the mass request for medical instruments.


A quick rundown of this insightful piece has provided us with knowledge of the working principle of the 3D printing and injection molding methods of parts production and also highlights its pros and cons. 

Furthermore, we have considered the benefits and drawbacks of both methods, while helping us understand that profiting from any selected method relies on the project requirements. 

We went a step further by comparing both methods based on cost, design flexibility, and time. We also considered production volume, material options, and surface finish, and quality while identifying their different contributions to various industries. 

So, there you have it. All you need to know about 3D printing and injection molding in choosing the right manufacturing process.


Gary Liao

Gary Liao

Gary Liao is the Engineering Manager of TDL Company and has more than 20 years of mold design experience.

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