Injection Molding vs. 3D Printing for Your Custom Plastic Products

Injection Molding vs. 3D Printing for Your Custom Plastic Products

3D printing and injection molding services are two of the most common methods we use to manufacture many of today’s common plastic products. Considering all of the recent innovations in additive manufacturing technology, what advantages do you still get from the injection molding process?

Basically, while 3D printing can be better suited for rapid prototyping (largely due to speed and flexibility in iterative design), injection molding still excels when it comes to producing high-quality, high-volume plastic parts with speed, precision, and cost-effective economies of scale. In other words, for most projects, the choice between injection molding vs. 3D printing is decided by your unique product development needs and volume requirements.

Below, we delve deeper into the advantages and applications of our plastic injection molding services.

The Advantages of Plastic Injection Molding Services vs. 3D Printing:

High-Speed and High-Volume Production

Injection molding produces large quantities of parts rapidly once we’ve set up the mold and tooling. The cycle time for each part is typically extremely short, often measured in seconds, and we can largely automate the process. That’s why injection molding is generally more suitable for high-volume production than 3D printing.

While the initial tooling costs for injection molding can be high, the per-unit cost decreases significantly with higher production volumes. That makes injection molding economically viable for large production runs, leading to lower cost per part compared to 3D printing for our customers who need high-volume runs or ongoing mass production.

An Overview of the Injection Mold Design Process

Material Selection

The chosen materials can significantly affect the performance and thus the design of the mold. That’s why it’s important to decide on materials early in the process, testing multiple material options if necessary. SRC’s design team chooses the appropriate material for each mold based on numerous factors like manufacturing material, expected production volume, and the specific parameters of the molding process to be used.

Gate Design

Selecting the right gate type and location is essential for proper material flow freely and evenly into the mold cavity. Common gate types include sprue, runner, and gate at various locations on the mold. These options are considered alongside the unique features and complexity of the product design to arrive at the most optimal gate arrangement.

Runner System

Designing an efficient runner system is likewise crucial for uniform distributing material throughout the mold cavity and minimizing cycle time. This includes the layout and dimensions of runners, as well as the use of hot or cold runners to achieve the highest efficiency possible.

Cavity and Core Design

Developing precise cavity and core geometry is essential for producing accurate and high-quality injection molded parts. The design must consider factors such as draft angles, surface finishes, and cooling channels, as well as the unique physical properties of the plastic material to be used.

Draft Angles

Incorporating proper draft angles relative to part features helps facilitate ejection from the mold, preventing damage to both the part and the mold. Typically, a draft angle of at least 1 degree is needed to ensure consistent and reliable part injection.

Ejection System

Designing an effective ejection system, including ejector pins or sleeves, is crucial for removing the molded part from the mold without causing damage.

Cooling System

Efficient cooling is essential to maintain consistent cycle times, prevent warping, and ensure the overall quality of the molded plastic. Cooling channels are strategically placed to extract heat from the mold and facilitate even cooling.


Adequate venting is necessary to allow gasses to escape during the injection process. Insufficient venting can cause air to get trapped, resulting in defects like burns, bubbles, or voids in the final molded part.

Mold Steel Hardness

Selecting the appropriate hardness for mold steel is essential to withstand the wear and tear associated with repeated molding cycles. For example, we can use aluminum or softer mold steels for prototyping projects and low-volume runs. This saves money on the tooling process and allows for easier design modification.

Injection Molding Machine Compatibility

Of course, we also must make sure the mold design is compatible with the injection molding machines we will be employing for production. These considerations include clamp force, shot size, and other machine-specific parameters.

Testing and Design Validation

Perform thorough testing and validation of the mold design through prototyping and analysis to identify and address potential issues before mass production.

Quality American Injection Molding Services Since 1972

For more than half a century, SRC Plastics has remained one of Massachusetts’ leading injection molding companies for the food and beverage sector and beyond. We provide reliable American manufacturing services for virtually any molded plastic food products with a focus on better quality and better sustainability.

High Precision and Repeatability

Injection molding offers high repeatability and precision, leading to consistent part quality. The process is highly automated, which minimizes the likelihood of human error. Tolerances in injection molding can be extremely tight, allowing for intricate and complex geometries.

A Wider Material Selection

Injection molding supports an extremely wide range of materials, including engineering-grade thermoplastics, elastomers, and even some metals. The material versatility allows us to more carefully customize the mechanical, thermal, and chemical properties of your products to meet specific application requirements. Depending on the additive manufacturing process being used, 3D printing can be much more limiting in material selection.

High-Strength Plastic Parts

Injection molded parts are generally manufactured with higher strength and durability compared to 3D printed parts. This comes down to the molecular structure of the material in injection molding which tends to be more uniform and continuous, resulting in superior mechanical properties. Comparatively, many 3D printing methods produce parts that are relatively brittle.

Superior American Injection Molding Services Since 1972

SRC Plastics has remained one of Massachusetts’ leading injection molding companies for more than 50 years. We offer reliable, highly versatile injection molding services for virtually any custom plastic products, delivering precision results as economically as possible.