Metal vs. FDM Thermoplastics: What’s Your Application?

By Kelly Judson on

If you are thinking about replacing traditional manufacturing methods with 3D printing, you have likely thought, “Can I replace an existing metal part with a plastic one?” The answer is a resounding “maybe.” It all depends on your application. If the part has requirements that lend itself to metal, like very high-temperature conditions or significant usage cycles, then a metal part may still be required. Our Application Engineers put together a list of five topics to consider when debating between traditional metal vs. FDM technology.

1. Material Properties

color_bottle_yt_with_man.jpgWhat are the expectations for your part? The answers to this question will reveal the material properties that the 3D printed part needs to have. The strength, temperature range, fatigue resistance and chemical resistance are all topics that need to be discussed to determine if a thermoplastic can handle the working conditions in which the part will exist. We often need to remind people that a thermoplastic is still a plastic – and in some working conditions won’t replace a metal part; which is why the part was made of metal in the first place. 

2. Critical Features of the Part

The critical features of the 3D printed part often need to be discussed to ensure that the part can provide the necessary geometry for the end-use application. In most cases, a 3D printed part can print with the required accuracy and geometric dimensioning and tolerancing (GD&T).

3. Life Expectancy

It is important to understand that sometimes plastic is not able to survive in an environment like a metal part would. For example, a mold made from Digital ABS won’t have the same lifecycle as a metal mold and, therefore, is most suitable for low-volume injection molding.

4. Print Time

In most cases, a thermoplastic can work for the replacement of a metal part. Once plastics is deemed suitable for your application, the print time needs to be addressed. Overall, it takes significantly less time to produce a 3D printed FDM part versus a traditional metal part. However, there are many aspects that affect the speed of a print, such as resolution, part geometry, and part fill. 

5. Printing a Plastic Part for Sand Casting a Metal Part

When the answer to the material properties question is that a metal part is still required because thermoplastic won’t meet the requirements; there is an option of printing the part in a thermoplastic and then creating a casting from that printed part. This is most common in sand casting applications. Note: this would be a hybrid approach of using a plastic part to ultimately create a metal part significantly faster than the traditional methods.

If you have questions about replacing your traditionally tooled metal part with a 3D printed part, stream our On-Demand Webinar, Metal Forming with 3D Printing.