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The Ultimate Battle between Injection Molding and 3D Printing:
Which one is better for you?


When you start your project, it can be difficult to know which manufacturing technique will be the better choice, between injection molding and 3D printing.

 Today, we are going to compare the differences between these two processes, in order for you to decide which one of these techniques might be the best to give life to your project.

Time, budget, precision, volumes, are all deciding factors, that is why we will examine the pros and cons of injection molding and additive manufacturing. Keep reading to find out the strengths and weaknesses of both manufacturing methods! 

Choosing the right manufacturing technique

3D printing and injection molding are two very effective manufacturing techniques, but they are really different and will help you achieve different projects. This totally depends on your needs. Even if injection molding historically seemed more professional, there has been significant progress being made in 3D Printing. Therefore, 3D Printing has already become a truly viable alternative to injection molding, allowing manufacturers to create expertly crafted parts.   

These two techniques can help you with both your rapid prototyping process and your production. They both have their own advantages, disadvantages and differences, and that is what we are going to look at now.

What is the difference between injection molding and 3D printing?

Injection molding

Injection molding is a traditional manufacturing technique. With this process, produced parts are created by injecting material into a mold cavity. Products are shaped by injecting molten material into the mold, the material will then cool down and take its final solid shape. 

car part - injection molding
Car part created using Injection Molding, source: Mastars on Freepik

3D printing

3D printing is an additive manufacturing process, meaning that the whole manufacturing is made by adding material layer by layer. Using this process, there is no need to create a mold to produce your part, you will only need a 3D file, like an STL file. A lot of different 3D printing technologies and materials are currently available on the market.

Drone part created using SLS and PA11 CF, source: Sculpteo

Which one should you choose?

When to use injection molding?

This technology is not easily accessible, as specific professional machines are needed to use plastic injection molding. These injection molding machines contain a material hopper, an injection ram, and a heating unit.

Making molds is expensive, and the possibilities are reduced when it comes to prototyping: If you need to make several iterations, it can be quite costly to recreate molds each time, as these molds are not easily adapted to your prototype development. Since each component is created before assembly, creating complex mechanical constructions requires more labor, skills and time, meaning that price increases proportionally to the complexity of a part. 

Furthermore, plastic injection require molds to be manufactured and factories to be ramped up to speed. As a result, it can take upwards of 15-60 days (and sometimes more) to have the first part in hand

However, if you are planning for high-volume production, it can be a good solution, since it will be cheaper. Just keep in mind that this manufacturing technique includes high costs for injection molding tooling and an important turnaround time.

cost per part 3d printing vs injection molding
Injection Molding vs 3D Printing Cost Per Part Comparison, source: Sculpteo

In summary, traditional manufacturing techniques like injection molding requires mass production to even out the overhead cost of tooling, labor for assembly, and production (an injection mold can cost thousands of dollars). On the contrary, with additive manufacturing, the cost of manufacturing of one item stays the same no matter what the quantity is, making it cheaper when the quantity is small.

When to use 3D printing?

There are several ways to use additive manufacturing. You can get yourself a 3D printer, like an FDM (Fused Deposition Modeling) printer, or invest in bigger and professional 3D printers, such as SLS (Selective Laser Sintering) 3D printers. But getting your own industrial 3D printer might be an expensive investment for you or your company, and it is maybe not worth it.

You could also use a 3D printing service such as Sculpteo, you just have to upload your 3D design, choose your technology and materials.

Using additive manufacturing is especially relevant when producing prototypes or small runs, since the cost of each part stays the same for each added unit. Additionally, thanks to the nature of Additive Manufacturing, each part is created in one process, meaning that price does not increase with complexity, contrary to Injection Molding.

This means it is possible to make an unlimited amount of changes to the product. In the case of prototyping, you could update the prototype until the desired iteration is achieved. Prototyping and iterating is a crucial step before getting the product to mass production.

This great adaptability is also useful during the rest of the manufacturing process, to create unique pieces that can be easily adapted to your precise needs at a given time, taking into account progress in conception and consumers feedback along the way.

These qualities make Additive Manufacturing an ideal production technique if you need high responsiveness, which is a great asset to have when today’s world is evolving so rapidly.

influence of complexity 3DP vs Injection Molding
The influence of complexity on a part's price, between Injection Molding and 3D Printing, source: Sculpteo

So, who wins the battle?

Benefits of injection molding

Injection molding is offering great advantages to produce large volumes, with a great precision and perfect repeatability, and a wide range of high-performance materials to choose from. 

With thousands of variations within each material, vastly different properties are made accessible through injection molding. Material weight, cost, flexibility, technical properties of these different materials all make possibilities seem endless. 

Even though retooling in between production runs might be a constraint, injection molding is excellent for the mass production of finished products, allowing you to create really detailed features, thanks to the pressure applied during the process.

It also makes it quite easy to create parts with enhanced strength, making it possible to use fillers in the injection molds. 

Benefits of 3D printing

Additive manufacturing is offering many advantages, making it a real alternative to traditional  techniques, thanks to its innovative characteristics. 

First, 3D printing is perfect to iterate during the design process, as it remains an amazing rapid prototyping technique. While the technology has matured, it is also now a reliable manufacturing method for finished products.  The flexibility of the process is allowing engineers and designers to continue making changes in the 3D modeling software up until the last moments, making it an effective technique, helping you improve your product design in the long run.

Using 3D printing is also helping to avoid material waste, since only the exact amount of material needed is used, contrary to traditional techniques like CNC machining.  

3D printing also allows the improvement of your storage and supply chain management capabilities. Indeed, you can 3D print your 3D design whenever you need it, without the need for a busy storage, making it easier to dematerialize the supply chain! 

Price Comparison, IM vs 3DP
Injection Molding vs 3D Printing Price Comparison, source: Sculpteo


Chart Summary Injection vs 3DP
source: Sculpteo

In conclusion, both Additive Manufacturing and Traditional manufacturing, such as Injection Molding, are excellent methods in order to produce high quality parts and products. The rise of industrial Additive Manufacturing does not mean that Injection Molding will be replaced, for these two processes both have their unique advantages.

In the end, the best choice depends on the variables of each project, like the number of iterations needed, the size of the production run, or the complexity of the pieces.

If you choose 3D Printing, do not hesitate to contact us, and upload your file on our platform to get your instant quote!

Which technique offers better cost-effectiveness for production runs?

Which technique offers faster turnaround times?

How does each technique address design complexity and intricacy?

What are the key factors influencing material selection in both processes?

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