Month: February 2022

3D Printing vs. Plastics Injection Molding

By Bozilla
February 8, 2022

3D printing has been available for decades There are several reasons it has only begun to gain traction In this article, we will explore some reasons why has there been so much interest in 3D printing in recent years and how it compares with injection molding

3D printing began as a method of creating a prototype part that could be physically observed in form, fit and sometimes even functionality before large cash investments were made in the manufacturing process The methodology of 3D printing started as a simple layering process with either a liquid or powder polymer-based medium

In the infancy of 3D printing the quality of the printed item commonly could not be utilized as a production part because it had inherent deficiencies For example, the quality of the adhered layers of the part were weak, making the part susceptible to breakage In addition, the part was also very porous and could not be used in applications where porosity was not acceptable Thus, the market for this technology primarily remained in the pre-production hemisphere Yet, with the advent of material suppliers creating new polymers and polymer blends, the quality of 3D printed parts has significantly improved The improvements gained include increased bond strength and decreased porosity

Bond strength of the layers in 3D printing has increased effectively enough so that parts can actually be used for their intended purpose as long as they meet the mechanical demands of the product

Unfortunately, the 3D layering process creates ‘weld lines’ (an injection molding term) between layers which is essentially two layers of polymer that meet The problem with ‘weld lines’ or ‘layers’ is that the polymer sits upon itself and has no way of physically mixing This lack of mixing doesn’t allow the molecules to intertwine and entangle, creating a strong bond Thus, the actual layering process has an inherent flaw

However, additional processes have been employed in order to further strengthen the part such as the inclusion of inserts, fiber in the material, and post printing sintering These additional processes raise the quality of the part up to a level where it can almost compete with the traditional injection molding process Unfortunately, the combined time to 3D print a part and the implementation of the post molding process translates into a long cycle time for each part Manufacturers try to overcome this hurdle by purchasing multiple 3D printers which all print the parts simultaneously This is an additional expense that must have

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