injection molding vs 3d printing

Injection molding and 3D printing are both manufacturing techniques frequently utilized to craft objects from various materials, with both methods having their own set of advantages and drawbacks.


  1. Injection Molding: For conventional manufacturing with injection molding, liquid plastic or rubber material is typically poured into molds at high pressure before cooling and solidifying within. Once taken from their molds these highly accurate replica parts can then be extracted as parts for bulk orders.
  2. Additive Manufacturing or 3D Printing: By contrast, additive manufacturing or 3D printing employs layer by layer fabrication techniques that rely on detailed digital models for object creation. While less cost effective than traditional manufacturing techniques, 3D printing offers unparalleled design complexity options and flexibility.

Injection Molding

Injection molding involves melting plastic material and injecting it into predetermined mold shapes for injection molding, whereupon it cools quickly before being released from its mold to produce an exact replica of said shape.


  1. Efficiency and speed: After a mold is created – which can be expensive and time consuming – larger volumes of parts can be produced with speed and efficiency suitable for mass production.
  2. Detail and precision: When it comes to generating detailed parts that closely match an original prototype with consistency and accuracy, few techniques can rival injection molding.
  3. Strength: Due to the nature of the process, injection molded parts are typically stronger than 3D printed parts.


  1. Initial cost: The cost to produce the initial mold can be significant, making this method less suitable for small production runs or one-off products.
  2. Flexibility: Any design changes require a new mold, which can be costly and time-consuming.

A classic example that underlines how well suited injection molding is towards producing parts requiring high volume uniformity and strength is none other than Lego bricks themselves.

3D Printing

In contrast to this process , stands additive manufacturing or known colloquially as 3D printing where material is deposited in thin layers through a digital model eventually building an object layer by layer upon completion via curing or sintering.


  1. Design flexibility: One advantage that comes from employing this method lies in its design flexibility which enables intricate shapes and internal structures unachievable with standard injection mold techniques;
  2. Prototyping & Lower upfront cost: : thereby making prototyping and customization easier than ever with the added benefits of speedy design alterations and singular object production without costly tooling or molds.


  1. Speed: Despite these benefits however; there are some downsides worth considering such as slow speed when compared against larger quantities of items produced through injection molding.
  2. Finish and precision: There is also a potential trade off between detail resolution and finish if one wants high quality finished products with fine details which may not be possible via 3D printing methods.
  3. Strength: Although they have their value plastic based 3D printed parts often lack the robustness and longevity found in injection molded ones.The disparity in strength can be attributed to various factors specific to each method of production.

An example of 3D printing use is the production of custom dental aligners or prosthetics. The ability to customize each piece to the individual patient is crucial here, and something that injection molding could not feasibly offer.


  1. Both methods are capable of producing complex geometries that would be difficult or impossible with traditional subtractive manufacturing methods.
  2. Both methods can use a variety of materials, including plastics, metals, and ceramics.
  3. Both processes can produce high-precision parts, although the specific level of precision can depend on the specific method and materials used.


Volume and Cost:Injection molding tends to be cost-effective for large production runs as its upfront investment can be spread among more units produced; 3D printing might prove less costly in these instances as its mold creation costs don’t need to be upfront investment costs for individual pieces or runs (ie: millions of identical Lego bricks production would likely require injection molding while printing an individual custom chess piece may prove much more economical via 3D printing).
Design Flexibility: 3D printing offers greater design versatility than injection molding, producing complex parts with complex internal geometries that would be either impossible or very costly to create using injection molding alone. For instance, 3D printing could create intricate lattice structures inside rocket engines which would otherwise be unmanufacturable with conventional injection molding methods.
Speed: For creating many identical parts quickly and at scale, injection molding tends to be faster. 3D printing may take more time but offers greater adaptability – once an injection mold has been set up it could produce thousands of parts an hour while it might take hours for one part alone to be produced on its 3D printer.
Waste: Injection molding often produces substantial waste due to excess material from its molding process and from creating and disposing of molds themselves, while 3D printing often creates less of an environmental footprint by layering material only where required.
Materials: Although both methods can work with various kinds of plastic materials, injection molding has the advantage when it comes to handling high-strength, temperature resistant plastics that might prove more challenging for 3D printing technology to handle. That being said, advancements are being made that could allow more diverse material options in this process.
Selecting between these processes depends heavily upon the needs and specifications of a particular project: production volume, complexity of design, customization needs and desired material selection as well as acceptable lead times and costs.

Leave a Reply

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