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

Posted on :Sep 13 , 2022 By  GREFEE

There are two main methods for the plastic products molding. One is through mold injection molding, and the other is through 3D printing technology.

The plastic injection molding refers to melt the plastic material completely thought the stir of the screw bar under a certain temperature, and then inject the plastic into the mold cavity to obtain the ending products after cooling and solidification. The technique was firstly introduced in the 1920s and has a development history of nearly 100 years with a wide application and mature industrial manufacturing technology. Excellent injection molding suppliers can achieve a processing tolerance of 0.005-0.02mm. 3D printing rapid prototyping is a kind of technology based on digital model files, which utilizes fusible materials, such as powder metal / plastic to construct objects by printing layer by layer.

In terms of the molding, this article is going to talk about the difference of 3d printing vs injection molding.

Mode of production

The injection molding process only focuses on the injection mold, then the cost can be reduced and standard and large-scale production will begin. Thus, for traditional, large volume, and large scale manufacturing, injection molding is still the optimal choice so far.

While, 3D printers can be able to directly, automatically, quickly, directly and accurately transform the three-dimensional design in the computer into a physical model in any shapes without traditional tools, jigs, lathes or any kinds of molds. Thanks for the characteristics of the 3D printers, the processing speed of the more complex non solid objects is faster, and it saves more material. Therefore, 3D printing is suitable for manufacturing personalized and diversified products.

The yield depends on the speed. Compared with traditional technology, the speed of plastic 3D printing is still slow. So far, injection molding is still the optimal choice for large volume manufacturing. Even large production lines that adopt 3D printing, it is generally only used to produce molds and test products. However, the core procedure is not additive manufacturing. So, injection molding is more advantageous.

Manufacturing quality

One main limitation of 3D printing is that the components produced do not have the same physical properties, which the traditional manufacturing process outweighs it to a large extent. Although the types of 3D printing materials are increasing, there are still a long way to improve on many aspects compared with injection molding. Therefore, if the 3D printing material is different from the final product, the test can only be carried out around the shape, which is not helpful for the physical performance test.

As well as the surface finish. Although the fineness of 3D printing parts is largely determined on the performance of printing equipment, there is still a big gap between them compared with polished steel injection molds. Last thing is the durability of products. Compared with injection molded parts, 3D printing parts are also slightly underdeveloped.

Manufacturing cost

As the material of injection molding are wide and available, its characteristics of large scale and rapid standardized production are beneficial for lowering the cost of single product. Therefore, in terms of the manufacturing cost, the cost of injection molding is far lower than that of 3D printing.

However, for industrial manufacturing, the real cost saving step in 3D printing is the prototype modification phase. Since only the CAD model needs to be modified, and it can be processed without any manufacturing costs.

While, in the injection molding, if the prototype is steel mold, the modifying cost would be low. However, if it is aluminum alloy manufacturing tools, the cost would be much higher, which is the reason why many individuals and enterprises that work in this industry choose the “Create 3D printer” to carry out printing of mold design.

Application domain

At present, injection molding process can achieve large volume manufacturing of products in the same shape. Therefore, it is suitable for producing large volume and standardized products.

Only by controlling the terminal and input the 3D image, 3D printing can turn the raw material into the real products, or even can be applied into producing the parts or molds to effectively shortens the research and developing cycle. 3D printers have been widely used in makers, architectural design, mold model design and other fields.

Advantages of injection molding

Injection molding has big advantage due to the large volume production, high accuracy and perfect repeatability. When using the plastic injection molding, there are many material selections for you, and each of them involves thousands of changes through adding the additives. Each of them can also result in different characteristics. The weight of material, cost, flexibility are endless in terms of the plasticity and possibility.

As mentioned above, injection molding not only can be applied into large volume production, but also can create very delicate details. Due to the repeatability of the process, adding details on the injection molded parts are easy to achieve. Injection molding makes it possible to produce parts with higher strength. As a matter of fact, injection molding process can use fillers in injection molds.

Advantages of 3D printing

3D printing has many advantages that make it a perfect replacement of traditional manufacturing technology. Firstly, it is suitable for the updates of products. In a long term, it is regarded as a rapid molding technology. The situation is no longer the same as it was before because it has been an reliable manufacturing technology. However, rapid and flexible prototype making is still one of the best advantages of this technology. When using 3D printing technology, you can carry out test with it or use it for the modification of the modeling software, and re-print for the confirmation. The flexibility of this process can effectively save time and cost, and it also improves the design of products.

3D printing is also helpful in saving material. Compared with CNC traditional processing technique, it not only fully utilizes the required material for the whole project to avoid the generation of waste, but also lowers the cost of manufacturing. With 3D printing, you can also improve the management of supply chain to avoid the additional storage cost.


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