Additive manufacturing The five most common misconceptions in 3D printing

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When companies want to speed up production, processes, or product development, 3D printing is no longer a secret tip. However, persistent misconceptions and prejudices about 3D printing still circulate. These are the five most common myths.

High-tech 3D printers are now found in craft businesses as well as in the research departments of corporations. Those who do not want to buy their own printer can use a production platform like Xometry Europe. However, the company has found in customer interactions that despite the growing popularity of this technology, persistent misconceptions and prejudices still prevail. Xometry has identified the five most common myths.

1. "Additive processes can only process plastics."

Customers have Xometry print parts from aluminum, cobalt-chrome, steel, stainless steel, Inconel, or titanium. Among the outputs are dental or orthopedic implants, gas turbines, die casting tools, or spare parts for cars. Alloys are used to give the materials special properties. For example, Al-Si10Mg contains silicon and traces of magnesium and iron in addition to aluminum. This makes the material highly conductive for heat and electricity.

In the aerospace industry, a mixture of chrome, nickel, copper, and steel (stainless steel 17-4PH) is often used for printing. This results in the tensile strength and stiffness demanded in high-tech industries.

2. "3D printing only produces weak parts."

Whether it's toolmaking or medical devices, storage or brackets: Today, what is needed is printed. And these are indeed parts that must withstand high loads. It is not only the selection of the right materials that matters. Design, printing settings, and post-processing also influence the strength of additively manufactured components. Basically, two groups of materials are distinguished: plastics, which are printed using processes such as Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), Stereolithography (SLA), Carbon Digital Light Synthesis (DLS), Multi Jet Fusion (MJF). And metals, which can be processed with Direct Metal Laser Sintering (DMLS).

For example, those with high thermal requirements might choose CE 221 (cyanate ester). This resin has a glass transition temperature of about 225 degrees Celsius and is therefore thermally stable in the long term. High impact resistance, on the other hand, is promised by polycarbonate (PC), a tough and amorphous material. It is used in medical and industrial products, as well as in electronic components.

Among metals, stainless steel 316L is often used for food and laboratory equipment, heat exchangers, nuts, and bolts. It has excellent corrosion resistance and stability against chlorinated media and non-oxidizing acids. Printed components are no longer considered weak.

3. "Printed parts just don't look nice."

This prejudice about aesthetics completely overlooks the possibilities of post-processing. While smooth surfaces are not always achieved immediately with 3D printing, as layering processes are typically used, some technologies are nevertheless well suited for smooth surfaces: SLA, Polyjet, and Carbon DLS. In these cases, the raw materials usually solidify into a homogeneous surface, often resembling glass, especially with Carbon DLS, where plastics such as polyurethane are used.

In post-processing, techniques such as glass bead blasting, vapour smoothing, tumbling, or grinding and polishing have proven effective. Each technique has its specific properties that come into effect with the respective material.

4. "Only small parts can be printed"

Pistons for sports car engines, a complete radiator grille for SUVs, prostheses, or surgical instruments – some examples of parts that are additively manufactured. For example, in the FDM and SLA processes, printing is done up to a size of about two meters. The corresponding machines cost over a million euros. However, a significantly cheaper average system can already build up to half a meter in size. With technical improvements, the application areas are expanding. Therefore, developers' imagination is increasingly less limited in 3D printing.

5. "We can only produce prototypes with 3D printing."

The production costs for additive manufacturing have dramatically decreased within a few years. It is becoming increasingly viable to replace traditional technologies such as injection molding with 3D printing. As the print quality also continues to improve – as mentioned above – the results of both technologies are becoming comparable. For example, TPU can now be chemically smoothed, which was unthinkable until recently.

 For those planning series production, there's a balancing act: a tool for injection molding can quickly cost tens of thousands of euros. If a change to the component is needed over time, a modification to the expensive tool or even a completely new part may be required. With 3D printing, this step is eliminated: updates to the model are digitally communicated to the printer. Therefore, printing can still be worthwhile even if the unit price for production seems high. What matters are the overall costs – and these may be lower here. 3D printing is also an option for complex constructions. If these are not feasible in casting, redesigning may be necessary. In printing, however, even challenging designs can be realized. (jup)