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

In modern manufacturing, technological advances have led to the development and adoption of various innovative production techniques. Among these, 3D printing processing and injection molding have emerged as two key processing methods in the plastics molding industry. Both technologies offer unique benefits, and understanding their capabilities is essential to choosing the right manufacturing process for your project.

In this article, we will look at the similarities and differences between these two methods, discuss their strengths and weaknesses, and examine the application scenarios for which they are suitable. 

What is injection molding？

Injection molding is a widely used manufacturing process for producing plastic parts in large volumes. It involves injecting molten material, typically thermoplastics, into a mold cavity under high pressure. The material then cools and solidifies, taking the shape of the mold, and is subsequently ejected as a finished part.

Advantages of injection molding：

1. Cost-effective

Once the initial costs of mold design and production have been taken out, the labor costs of injection molding are usually very low. Being a highly productive method of production, the mold costs are recovered over time. It is, therefore, an excellent choice for producing high-quality, high-volume plastic parts.

2. High productivity

The plastic injection molding process is known for its rapid production speed and efficiency, making the process ideal for mass production. Many aluminum molds have a service life of up to 10,000 cycles, while steel molds have a service life of over 100,000 cycles. This ensures a repeatable, high-output process that meets tolerance and appearance requirements. The speed of output usually depends on the dimension & weight and complexity of the target injection molding part.

3. High precision and accuracy

Modern high-speed injection molding machines are capable of consistently producing precision plastic parts. Machine manufacturers often equip their machines with advanced control systems. These automated systems monitor and adjust process parameters in real-time. As a result, plastic parts can be molded to precise specifications and provide components with uniform quality, tight tolerances, and high dimensional stability.

4. Wide choice of materials and additives

Injection molding is compatible with a wide range of materials and colors. More than 25,000 engineering materials are available, including thermoplastics, thermosets, silicones, resins, and more. These options allow you to strike the perfect balance between the mechanical, chemical, and physical properties of your materials. You can easily combine materials and additives to improve the rigidity, strength, or impact resistance of your products.

What is 3D Printing?

3D printing, also known as Additive Manufacturing（AM）, is a process that creates three-dimensional objects by depositing material layer by layer.

Advantages of 3D Printing：

1. Fast and versatile

3D printing is a rapid prototyping technology. It can be used for accurate and repeatable prototyping, as well as the production of small batches of end-use parts to ensure faster delivery of components. Depending on the prototype's size, 3D printing of an average prototype part usually takes only one hour or less to form, without waiting for the production of the mold.

2. Complex Geometry Design

Generally, additive manufacturing methods offer greater design freedom than injection molding or traditional manufacturing methods. For parts with relatively simple geometries, injection molding or CNC machining may be a more appropriate and cost-effective solution. But for organic and intricate geometries, parts that require multiple iterations, and small plastic parts, 3D printing is the preferred solution.

3. Customised options, small quantities

The flexibility to customize 3D-printed parts is another significant advantage of additive manufacturing. It can be used to produce small batches of end-use parts, including patient-centered medical devices, wearables, and small batches of high-performance aerospace components.

4. Lightweight Parts

The additive materials used in 3D printing offer excellent durability while being lightweight. This is why 3D-printed parts are used in aerospace and automotive.

So how can we make an initial judgement on which plastic molding technology to use? Here is a brief summary：

Both technologies have their advantages. They can complement each other in design and production. SHQD offers injection molding services and has a dedicated partner company to provide 3D printing support. Get in touch now for a project quote.