3D Printing vs Injection Molding, Comparative Guide

Two of the most popular techniques used to create complex plastic parts and components are 3D printing and injection molding. Previously, these two technologies competed in market shares but nowadays, their advantages are fully recognized. Many also agree that the two may be used at the same time to boost production and improve project efficiency. Let’s explore 3D printing vs injection molding; which one works best for your type of project.

About 3D Printing:

3D printing is a process that turns an object into many slices and prints the object from the bottom to the top. The object is printed one slice at a time with each layer sticking together until you have a complete object. Every layer differs in complexity; some printers can make moving parts including wheels, hinges, and gears.

How to use 3 printing

A 3D printer works with a CAD program on a computer. The design is loaded in the printer and the right type of filament is used to create the different layers. A 3D printer creates the object in a three-dimensional manner working layer by layer, applying the filament carefully until the object is complete.

3D printers can use all kinds of filaments including plastic, rubber, metal, graphene, or wood. The filament is softened by heating the material and extruding different layers. You may use one type of filament material, two or as many as you like.

Most 3D printers come with adjustable bed and extruder temperatures to accommodate different types of material. Some 3D printers come with a cabinet where the object may be printed with care while some only have a plain heated bed.

When to use 3D printers

3D printers are for projects that require faster turnaround times as a simple 3D project can take 1 week to complete. This technology is for low volume production of about 100 items or fewer as 3D printing is a slow process.

Projects where frequent design changes are expected work well with 3D printing. Most of the filaments used for 3D printing like PLA may be recycled but only with PLA materials. 3D printing is best in making smaller plastic components or parts.

About Injection Molding

Injection molding is another way to process different products by injecting melted material into a mold. A ram or a large screw-type plunger is used to introduce the molten material to a cavity. When this material solidifies, the mold is opened and the shape is removed.

Injection molding works with a variety of materials including glass, metal, elastomer, confection, and thermoplastics. This process is used in the mass production of different products with difficult shapes. 

How to use

Injection molding uses a special machine that’s developed especially for the kind of product that’s being manufactured. The raw material is fed into a large hopper and passes overheating elements to melt the material. A large reciprocating screw takes the melted material and pumps it into a mold. After the material is fed inside the mold, it is removed from the machine to cool down. Once the mold is cool, it is opened and the finished product is removed.

When to use Injection molding

Injection molding is primarily used in manufacturing plastic products. It takes longer to produce injection molded products even simple components and parts however, it can produce products in high volumes. Typically, an injection molding machine can make 1,000 or more parts/run.

This manufacturing process is for projects that don’t require any final part design or prototyping. It is for projects of any shape, size, and level of complexity.

3D Printing vs Injection Molding

To find out whether 3D printing or injection molding is best suited for your project, consider the following factors.

Project costs

3D printing is a far more expensive technology to use as a good quality 3D printer alone costs a fortune. It also costs more to purchase filaments and 3D printer materials. Meanwhile, plastic injection molding costs a lot initially but the process is simpler and costs less in the long run.

Tool design

3D printing requires a CAD tool to help the machine work on your project. With CAD, working with 3D printers is easier compared to other technologies. In injection molding, a lot of time is spent creating tools or molds. And this is where injection molding makes use of 3D printing technology.

A technician uses a 3D printer to print tools or molds to be used in an injection molding machine. This helps reduce the costs and the time needed to make specific tools for a project. 3D printing can be an alternative to time-consuming and strenuous metal tools fabrication.

However, 3D mold printing may only work in small-scale projects. To create larger and more precise tools and molds, traditional methods are still better.

Customized plastic parts design

So many industries are using 3D printing to create different custom-made plastic parts and prototypes. Take the health and medical industry where doctors use 3D printing to create prosthetics, artificial bones, artificial valves for the heart, implants, dental products, and many more. A breakthrough uses 3D printing to produce organs and tissues.

Injection plastic molding also has its contributions to the health and medical industry. This technology is used to create complex devices and medical components. Injection-molded products like plastic syringes, laboratory equipment, and facility equipment are just some of the most common examples.

Combining 3D printing and injection molding techniques has also become the norm in many industries which is why it’s difficult to say which one is better than the other. OEMs and injection molders treat the two technologies as equals as combining them in many situations can reduce the manufacturing times, improve testing, and enhances outcomes of products.

Last Words

When you’re wondering about 3D printing vs injection molding, the two technologies are incomparable. There are many advantages of using 3D printing or injection molding but clearly, combining the two makes better, more efficient, and high-quality manufacturing processes. These technologies are now used in more and more industries all around the world.


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