3D Printing Vs Injection Molding

Every year many new technologies emerge in manufacturing companies for a different purpose. 3D Printing and Injection Molding are one of them that are widely adopted by many industries. These two technologies have taken the industrial world by storm in the large-scale production of plastic products because of many factors. For example, 3D printing is becoming popular because of the availability of cheap 3D printers as well as easy to use but powerful software for creating 3D models like SelfCAD. Whatever one can visualize, they can bring it to life with much ease and they can also prepare the designs for 3D printing using its in-built slicer without having to switch to another software.

Both 3D printing and Injection molding technologies are meant to convert designers’ vision into reality as efficiently as possible. Although 3D Printing and Injection Molding are suitable for various manufacturing processes, they are different in several ways: material, method, cost, optimal applications, etc. 

3D Printed Heart. Image StureLearn

In this article, we analyze the differences between 3D Printing and Injection Molding based on its manufacturing process, cost, materials used, and many other parameters. 3D printing creates the products by using an additive process. In other words, it makes the objects by building them up layer by layer. All the information regarding the products like shape, dimension, and other physical qualities is preloaded into a 3D printing machine. According to the data loaded, thin strands of the plastic substrate are used as raw material to build the product. 

While in Injection molding, plastic material in the form of liquid is injected into the mold of different shapes to make the product. When the raw material is completely injected into the mold, it is allowed to cool, and after assuring its solidification, it is ejected from the mold. 

Difference Between 3D Printing and Injection Molding Based on Costing

Injection Molding of Polymers. Image Source: SubsTech

Injection molding machines are widely used by such industries that already have a good number of customers. Injection molding machines can cost up to thousands of dollars, and after including the manufacturing process, this can go beyond that. The manufacturing process, which includes loading, injection and cooling, and ejection of products, is quite costly. But as an investment of such handsome money in a suitable injection molding machine can provide a decade of usages and returns. 

As this type of machine is custom-built, an industrialist needs to have a large number of customers to make a profit after setting up this machine. This machine involves a molding process in which you need to make molds according to the size, shape, and dimensions which is quite expensive, and hence manufacturers make these molds on a large scale to stretch their money further. 

These molds are made up of copper, aluminum, or steel so that they can bear the heat created during the injection process.

On the other hand, an excellent 3D printing machine can only cost you a few hundred dollars. Its maintenance charges are quite low, and it has an inbuilt custom injection mold that can reduce the owners’ pressure of making customers before setting up the machine. 

Difference Between 3D Printing and Injection Molding Based on Volume

3D Printed Objects. Image Source: All3DP

Now you will think, why invest so much money in injection molding machines when a 3D printing machine is cheaper than an injection molding machine. Let’s find out the reason: Every machine has some positive and negative points. When we talk about several productions, you can imagine a seven-figure quantity that can run at a time in an injection molding machine. And at that number of products, you can earn profit maybe just when the inventory is sold.

3D printing was always used to make a prototype of any object from the beginning of its invention; hence 3D printing machines are always a better choice for creating a prototype of the product and when a meager volume of product is needed. Nowadays, many manufacturing companies prefer 3D printing machines for their products because of their overhead cost and are only required to make spare parts on request or order. 3D printing has now reached a point where it can complete production in no time, making it more viable for low-range production.

Difference Between 3D Printing and Injection Molding Based on Time

Injection molding is better when producing parts in one cycle, but we cannot determine which machine works faster or takes less time on this factor. At the beginning of the process in an injection molding machine, you have to create a mold according to your need by molding steel or aluminum, and that can take you more or less 15 to 20 days. And this alone takes several times of the production. 

After that, you need to wait for machine time, which completely depends on your service provider. In this way, it takes a lot of time to produce a single consignment, and even if it takes a few minutes in baking, all these factors make it a time taking process.

3D printing takes more time to make the actual part, but that also depends on the size and design of the product. But one advantage in 3D printing is that you can input your required size, shape, and dimension of development in the machine instead of making a mold like in an injection molding machine, which saves a lot of your time. It does not require any lead time, so you can get your prototype in a few days by using 3D molding machines.

Advantages and Disadvantages of 3D printing:

Pros: 

1. Low entry cost- As we have discussed earlier, manufacturing objects in 3D printing is much cheaper than injection molding machines. And even if you find it costlier than a desktop 3D printer, filament supply will work for you. There is numerous open-source software available that can reduce the final cost. Since we can make only a product prototype, its materials are also readily available, software and the supply of material is cheaper than injection molding equipment.
2. Easy to make changes: 3D printing has a feature that can help you easily change the design, such as shape, size, dimensions, etc. It has an addictive nature, so if you find any issue in your design, you can fix that issue even when your model is being made. In this way, you will not need to waste the material just for a small problem. Wastage of material can be avoided. Another best part of 3D printing is that it can allow you to stop at any point of a product manufacturing process and continue from the same point later.
3. Easy to support complicated designs: 3D printing is always preferred by manufacturers when it comes to designing complex models. Its manufacturing or printing process is additive, which means that it adds layer over layer to make the product. Hence, any complicated design is easy to make because the precious layer works as a support for it.

Cons

1. Slow object output: Along with many good features of 3D printing, it has a few drawbacks, and one of them is that it has a limit of how many objects it can print at a time. As of now, most 3D printing allows only one to two objects to print at a time.
2. Limited build volume: The arms of 3D printing have a restricted reaching area. Hence printing area is limited in this machine. And if you increase the section that hangs off the edges of the printing area, it will disturb the entire designing process.

Advantages and Disadvantages of Injection molding:

Injection molding. Image source: TWI Global

Pros

1. Large simultaneous output: This machine was designed by keeping in mind the number of objects it can manufacture at a time. This machine can simulate thousands of objects at a time. Hence it is perfect for those who want to manufacture their designs on a large scale.
2. Enhanced object strength: Objects manufactured from the injection molding process have good stability. It is made by a single layer, or the liquid raw material is used and injected in the mold, which provides strength to the object.
3. Minimal scrap produced: As discussed earlier, it uses liquid raw material injected into the molds. It uses a fixed amount of material only that avoids wastages.

Cons

1. Difficult to correct mistakes:  Mistakes in this process are incorrigible, and you will have to go through the whole process again after fixing the issue.
2. High entry cost: Injection molding machines alone are very costly; hence they are designed for industrial use only where products are manufactured in bulk.

Conclusion

We’ve covered the similarities, differences, advantages, and disadvantages of 3D Printing and Injection Molding, two of the leading technologies in the manufacturing industries. We hope you find the article informative. Drop us a line if you have any suggestions or doubts.

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