The fees for a set of plastic molds may cost thousands or even hundreds of thousands of dollars. What if the products have many styles but with a small quantity? Is it alright to go for 3D printing directly?

Let’s take a look at the differences between plastic injection molding and 3D printing.

Difference on manufacturing principles
The principle of plastic injection molding is like making chocolate. After the raw materials are heated and melted, they are poured into the mold, and after cooling, it will be demolded, and comes out as a finished product. Different pigments can be added to the materials so as to have the finished products with different colors. The biggest difference for 3D printing is that it does not require exclusive molds, just like stacking building blocks, which are stacked layer by layer. Since there is no restriction of the mold mechanism, the products can be made into any shapes accordingly. For example, a closed hollow product can be made by 3D printing while it cannot be achieved by plastic injection molding.

Difference on production efficiency
Although 3D printing may help save mold costs a lot, it is not workable at all when you have to put the order into mass production. Let’s take a pen holder for example, it might take at least 2 hours to get it produced by 3D printing, while by plastic injection could just take less than 2 minutes.

Difference on surface finish
Since 3D printing is stacked layer by layer, it is normal to find fabric-like fine lines on the product surface. Unlike plastic injection molding, it can be made into different kinds of surface finish or specific pattern. Such as mirror finish, optical finish, etc.

Difference on structural strength
Due to the tight combination of plastic materials, Injection molded products are generally more resistant to drops and impacts, while 3D printing can be relatively fragile.

Difference on cost
In the initial stage, the development cost for a mold would be relatively high, which leads to the much lower cost on raw materials and molding process. While 3D printing is a one-time custom cost, it may take hundreds of dollars or more.

In a word, Plastic injection molding would still be a preference when it comes to mass production. If you only need a very small amount of finished products, or just need to verify the product design, 3D printing will definitely be your first option.
What’s more, both 3D printing and plastic injection molding are now actually used collectively to help optimize production efficiency, which means they are complementary instead of competing technologies. Combining these two techniques should be a wise choice for molders as it can ultimately achieve better testing, manufacturing and outcomes.