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3D printing and injection molding are popular manufacturing methods across many industries. Both methods have their pros and cons.
3D printing is an excellent pick if you want to quickly produce a prototype without spending thousands on a mold. On the other hand, injection molding is perfect for high-volume production runs once you’re satisfied with your prototype.
In this article, we help you choose the best option for your needs between injection molding and 3D printing.
Key Takeaways on Injection Molding vs 3D Printing
- Injection molding and 3D printing are both versatile manufacturing methods. However, one may be more suitable than the other based on your needs.
- Injection molding is best for achieving a better surface finish and specific mechanical properties. It also can be more cost-effective for high-volume production.
- 3D printing offers more customization options and design freedom. It’s the ideal option for low-cost production or rapid prototyping.
What is Injection Molding?

Injection molding is a highly efficient manufacturing process that involves injecting molten material into a mold. Injection molding is generally used to manufacture plastic parts but it can also be used with metals, glass, and other materials.
The process starts with liquifying the material by applying heat. The liquified material is pushed into a precisely shaped mold cavity under high pressure. The material is then allowed to cool until it solidifies. After the material solidifies, the mold is opened and the part is ejected.
Injection molding is used across a wide range of industries, including automotive and consumer electronics because it can create highly detailed and consistent parts at scale. It’s the default manufacturing method for many of the products you use on the regular, like phone cases and car bumpers.
Injection molding is an excellent choice for parts requiring high tolerances and complex geometries thanks to its cost-efficiency at high volumes, the ability to streamline the manufacturing process, and its high precision and repeatability.
Injection Molding Use Cases
Here are examples of products produced using injection molding:
- Automotive components: Dashboard components, bumpers, grilles, interior trims, and engine covers
- Consumer electronics: Phone cases, remote controls, and chargers
- Medical devices: Syringes, IV components, and surgical instruments
- Aerospace components: Ducting systems, brackets, interior components, and small structural parts
- Optical lenses and components: Light guides and camera lenses
- Agricultural equipment: Seed trays, connectors, and irrigation nozzles
Advantages of Injection Molding
Injection molding offers numerous advantages, including:
- High precision, repeatability, and efficiency at scale: The high-pressure injection process fills molten material into every detail of the mold. This helps achieve exceptional dimensional accuracy, often within tolerances as tight as +/- 0.005 inches. You can reproduce parts with minimal variation across large production runs as long as you have an optimum mold.
- Complex geometries: Injection molding can produce parts with intricate details, undercuts, and complex surface textures. This level of accuracy is difficult, or even impossible, with other methods like machining or casting.
- Material versatility: Injection molding supports a wide range of thermoplastics, thermosetting polymers, and elastomers. You can choose high-performance polymers like polyether ether ketone (PEEK) or nylon for applications that require strength, chemical resistance, or temperature stability, or use low-cost options like polyethylene for products with lower demand.
- High strength-to-weight ratio: Since injection molding allows using engineering-grade plastics, parts often have a high strength-to-weight ratio. The ability to substitute metals with high-strength, low-weight materials makes injection molding a great choice for various applications in industries like automotive, aerospace, and consumer electronics.
- Surface finish and aesthetic control: Injection molding reduces the need for post-processing because you can engineer textures, gloss levels, and decorative patterns into the mold design.
- Multi-material molding: In some cases, you can use two-shot molding to produce parts made from more than one material. This allows you to manufacture products that require soft-touch areas, integrated seals, or even conductive components without having to run multiple manufacturing steps.
Injection Molding Limitations
Injection molding is an extremely versatile and efficient process, but it does have limitations. Fortunately, you can partner with experienced injection molding companies to make sure these limitations don’t stand in the way of producing high-quality parts.
- Upfront tooling costs: Molds can be expensive based on the complexity and size of the part. Expensive molds make injection molding less commercially viable for low-production volumes unless long-term production volumes justify the cost.
- Long lead times for tooling development: The time needed to design and fabricate a mold depends on the design’s intricacy and can take some time. If the mold requires tuning after initial tests, the lead times could extend further. The lead time can be a problem if you’re looking for rapid prototyping or a quick time-to-market.
- Design constraints: Injection molding allows for complex geometries, but there are a few design limitations to keep in mind. For example, molds need draft angles to ensure parts can be ejected without damage. Parts with different wall thicknesses or ribs are prone to issues like warping or sink marks because thicker sections cool more slowly than thin ones.
Now you know injection molding use cases, benefits, and some potential limitations. Though injection molding is great for high precision, repeatability, and parts with tight tolerances, it’s not going to be the very best for every single product. Enter: 3D printing.
What is 3D Printing?

3D printing is an additive manufacturing process that involves successively depositing material layer-by-layer based on a CAD model.
3D printing is an excellent choice for rapid prototyping given its speed and ability to produce complex geometries with zero tooling. It also offers design freedom, allowing you to create intricate lattice structures, internal channels, or parts with overhangs.
There are various 3D printing technologies to choose from based on the material and application. For example, fused deposition modeling (FDM) extrudes molten thermoplastic through a nozzle, while selective laser sintering (SLS) and direct metal laser sintering (DMLS) use lasers to fuse powdered materials.
3D Printing Use Cases
Here are some examples of products that are generally 3D-printed:
- Car parts: Custom exhaust manifolds, air ducts, cooling pipes
- Aerospace components: Fuel nozzles, turbine blades, and satellite components
- Implants: Custom implants, prosthetics, and dental crowns
- Tooling and jigs: Custom tools, jigs, and fixtures
- Consumer products: Jewelry, home decor, and fashion accessories
- Architecture and construction: Architectural models and customized building components
- Healthcare and bioprinting: Patient-specific anatomical models, bio-printed tissues, and custom surgical tools
Read more about using 3D printing for aerospace tooling.
Advantages of 3D Printing
Here’s a quick overview of the many advantages of 3D printing:
- Design freedom: 3D printing allows you to produce parts with geometric complexity that’s nearly impossible to achieve with traditional methods like injection molding or CNC machining. This design freedom is especially useful in industries like aerospace that require lightweight structures or complex internal channels (such as conformal cooling channels or turbulent flow paths).
- Toolless manufacturing: 3D printing comes with lower upfront costs because there’s no need for tooling, molds, or fixtures. This is especially beneficial for low- to medium-volume production where achieving commercial viability was difficult or impossible with traditional manufacturing processes.
- Rapid prototyping: You can move straight from a CAD model to a physical part since 3D printing doesn’t need tooling. You can quickly test design concepts, fit, and functionality during prototyping and make quick iterations without spending a ton on fabricating or modifying molds.
- Customization with no extra cost: 3D printing lets you produce custom, one-off parts at no extra cost. You can tailor each part to specific requirements without modifying the machine setup. That’s exactly why 3D printing works great for various medical applications, such as patient-specific implants, that require personalization.
- Multi-material and functional integration: You can print multiple materials in a single build and integrate different material properties in one part using advanced 3D printing technologies. It allows for parts with varying hardness, flexibility, or conductivity without additional steps.
- Lightweighting: Designing techniques like topology optimization and lattice structures allow you to optimize part geometry to reduce the weight of a part without compromising its structural integrity, performance, or functionality. Lightweighting is particularly useful in aerospace, automotive, and robotics industries, where reducing part weight without compromising strength is critical.
Limitations of 3D Printing
While 3D printing is innovative and versatile, it does have a few limitations. Here’s what you should be mindful of when using 3D printing:
- May have inferior mechanical properties: 3D-printed parts can have inferior mechanical properties compared to parts produced using traditional methods. Anisotropy is a common issue—meaning parts tend to be weaker along the Z-axis because their strength depends on the adhesion between layers, which is generally weaker than the material’s intrinsic strength.
- Harder to achieve desired surface finish and tight tolerances: 3D-printed parts often require post-processing to meet quality standards. Technologies like FDM leave layer lines, while higher-resolution methods like stereolithography (SLA) or DMLS may require additional smoothing and polishing to achieve a refined finish. Achieving tight tolerance can also be a problem, especially in applications that require precise fits or moving components.
- Slower production speed: 3D printing isn’t the most ideal method if you’re looking to produce parts quickly. Even with faster technologies like multi-jet fusion (MJF) or DMLS, cycle times are far from competitive with injection molding and other mass production methods.
Injection Molding vs 3D Printing: Factors To Consider
Injection molding and 3D printing are both widely used manufacturing methods, but one may suit better than the other for your needs. Here’s what you should consider before settling on a method between injection molding and 3D printing:
Customization Options
Winner: 3D printing
3D printing offers more customization options. It doesn’t require tooling or molds, allowing you to modify each print without spending extra. If you’re working with parts that need multiple design iterations or need to produce customer-specific parts like custom medical implants, 3D printing is the ideal choice.
Injection molding offers limited customization because once a mold is created, changing the design requires spending plenty of money on new tooling.
Surface Finish
Winner: Injection molding
If you’re looking for an excellent surface finish without any post-processing, go with injection molding. The finish quality depends on the mold itself, so as long as you’re getting good quality tooling, you’ll be able to produce parts with top-notch surface finish at scale.
On the other hand, 3D printing generally requires post-processing to achieve comparable surface finish. Even with technologies like SLA or DLP, which offer better finishes than FDM or SLS, parts may need additional sanding, polishing, or coating to meet aesthetic requirements.
Materials
Winner: Injection molding
You have a wide range of material options with injection molding, including thermoplastics, thermosets, and elastomers. If you’re looking to achieve specific mechanical, chemical, or thermal properties, injection molding could be a better choice.
The range of materials you can use for 3D printing is expanding, but it’s still limited compared to injection molding. For example, FDM 3D printing mostly works with thermoplastics like PLA and ABS, while SLA and DLP focus on photopolymers. DMLS allows metal printing, but the available alloy options are fewer than you get with injection molding.
Speed and Flexibility
Winner: Injection molding for speed, 3D printing for flexibility
3D printing offers more flexibility, especially for low-volume production or rapid prototyping. It allows you to quickly implement changes without extra tooling. You can go from a CAD model to a finished part in hours, but 3D printing is slow, especially for larger parts or complex geometries.
Injection molding is a lot faster. Initial setup takes longer than 3D printing because you need to wait until the mold fabrication is complete, but production is extremely fast and often takes only seconds per part. That’s why injection molding is generally used for high-volume manufacturing. Since design changes come with expensive and time-consuming modification or fabrication of new molds, injection molding doesn’t offer the flexibility of 3D printing.
Design Complexity
Winner: 3D printing
It’s best to use 3D printing for complex geometries. For example, if your product has features like internal channels, lattice structures, or organic shapes, 3D printing will allow you to print the products without dealing with the constraints of mold design. This gives engineers more design freedom when designing parts with internal cavities or intricate structures.
Injection molding can handle some degree of complexity, but you’ll need complex molds with inserts, sliders, or multiple cavities. More complex molds are expensive, increase the cycle time, and impact mold cooling and part ejection.
Cost
Winner: 3D printing for low-volume production or prototyping, injection molding for high-volume production
The mold used for injection molding takes time to produce and costs thousands of dollars. However, once the mold is ready, the per-part costs drop dramatically. The low per-unit cost combined with a low per-unit amortized cost of a mold makes injection molding a more cost-effective option for high-volume production.
3D printing comes with lower upfront costs since there’s no need for a mold. However, the per-part cost is higher than injection molding, regardless of the volume of production. If you’re not looking to produce at scale, 3D printing is a more economical option.
Choose Between Injection Molding and 3D Printing For Your Next Project
In most cases, injection molding is an ideal option for high-volume production, while 3D printing is best for parts that require a greater degree of customization.
To learn more about 3D printing vs injection molding, head to our full webinar here.
Or if you’re ready to start your production project, we can help. UPTIVE Advanced Manufacturing offers a wide range of rapid manufacturing services, including injection molding and 3D printing, as well as CNC machining, sheet metal fabrication, and others. UPTIVE offers the ultimate speed, customization, and production quality throughout aerospace, automotive, and medical industries, and many more.
If you’re looking for help determining which process will be most suitable for the parts you need to produce, get in touch and we’ll help you figure out the best, most efficient method for your needs.