3D printing or injection molding？Which one do you choose?
Injection molding process
Injection molding is a traditional manufacturing process that produces parts and assemblies by injecting material into molds. The material is usually heated, liquefied plastic, and as the plastic cools and solidifies, it is produced in the shape of a mold and ejected. Injection molding is typically a four-step process. The first steps are mold development, injection, cooling, and ejection. An injection molding machine is generally needed to combine all these small processes into one.
3D printing process
3D printing works differently, not by forming a mold to shape the product, but by doing it in 3D CAD software and then having the machine print it layer by layer. That's why it's also known as additive manufacturing because it adds material from the bottom up. With this process, instead of a mold, a 3D file needs to be made, which the printer can use to guide how to produce the desired model.
The rise of cost-effective 3D printing technology provides a powerful tool for rapid prototyping and an alternative to injection molding for manufacturing plastic parts and products. Injection molding and 3D printing are both versatile, effective techniques, but sometimes, one of the two methods is better suited for your project. Evaluating certain aspects of a project can help determine if injection molding or 3D printing is a better fit.
The rise of cost-effective 3D printing technology provides a powerful tool for rapid prototyping and an alternative to injection molding for manufacturing plastic parts and products.
Injection molding and 3D printing are both versatile, effective techniques, but sometimes, one of the two methods is better suited for your project. Evaluating certain aspects of a project can help determine if injection molding or 3D printing is a better fit.
How big is your production?
Since injection molding requires custom metal molds, it is most cost-effective to manufacture larger quantities of products while spreading the cost throughout the production process. For low-volume production of hundreds or less, 3D printing is often more cost-effective.
What is your production plan?
3D printing has a very short lead time, but the actual production is much slower than injection molding, which is one of the fastest manufacturing methods after a mold is completed.
Do your products have unusual shapes?
Some shapes may be more challenging for injection molding or may require additional tooling, increasing costs. 3D printing may be better suited for designs with spaces, gaps, branches, or complex structures or other elements that make it difficult for the injected resin to properly fill the mold or make it difficult for the part to pop out of the mold.
What are the requirements for the surface treatment of the product?
3D printing may produce slightly rough surfaces or visible delamination. In injection molding, there is no need to worry about molding ridges and molding layers because the material is poured into a single layer with an almost uniform and smooth finish. In addition, injection molded parts can be efficiently post-processed. From the point of view of good surface treatment, injection molding is preferred.
Are there any requirements for the strength of the product material?
Because injection-molded parts are produced in a single step, they tend to be stronger than 3D printed parts, whereas in 3D printing, the part is manufactured layer by layer, which affects its overall strength. 3D printing creates significant bulges and structural defects during the manufacturing process, and is not strong enough where the layers come into contact, which is not typically seen in plastic injection molding.
Are there any requirements for the degree of loss of product materials?
Because injection molding pours as much material as possible to fit into the mold, it uses exactly what is needed for each design. This makes it a very effective way to mass-produce objects without worrying about waste. On the other hand, some 3D printing technologies lose some material when building a support structure, and even though the material powder can be reused, it can only be reused a few times without changing the properties of the material.
3D printing produces very little waste, such as support structures, and failed prints must be removed in post-production, but when it is used to produce individual units or small batches, waste is less important, and for large batches, the waste is significant. Therefore, if you customize a large batch size, you can consider using injection molding and don't worry about material waste.
