Where 3D Printing Can Be Used and Not

I’m reading a baffling piece in the Harvard Business Review about 3D printing and China.

The piece explains that due to the significant and growing tariff war between the US and China, it may be time to shift manufacturing back to the US by more extensive use of 3D printing technologies.

They say:

“As companies rethink their supply chains, they ought to seriously consider embracing a new manufacturing technology that’s now ready for prime time: 3-D printing.

No longer relegated to trinkets and prototyping, 3-D printing, which is also called additive manufacturing, is now moving into mass production. Printer makers have solved a variety of quality, cost, and speed problems to the point where printers can compete with conventional manufacturers at volumes of tens or even hundreds of thousands of units.”

This is partially true. Some 3D printers indeed are now capable of 3D printing in materials, both metal and thermoplastic, that are suitable for production parts. Early 3D printing technologies typically involved materials suitable only for prototypes and artwork.

But I don’t think this is completely true, as the piece seems to ignore the current difficulties of speed and cost of 3D printing. While 3D printing can rapidly produce small numbers of newly designed parts without the need for expensive tool-ups, it simply cannot compete price-wise for many products and parts against traditional manufacturing technologies.

A typical manufacturing process for example would involve the creation of a master mold, into which thermoplastic is injected. While the cost of mold creation can be significant – and include a number of design iterations to get it right – once made truly massive numbers of identical parts can be very rapidly produced at extremely low cost.

That cost can be many times less expensive than a 3D print.

How much less expensive? Consider the cost of a canister of Stratasys Fortus ABS material, which costs around US$500 for 1.5kg of thermoplastic. That is just the cost of materials for 3D printing with that production equipment – and does not include the cost of the machine, its environment and operation labor. If you made, say, 15 parts with that canister they would each carry a materials-only cost of US$33.

That’s fantastically larger than the cost of a 100g injection molded part any way you want to calculate it.

Even worse, the Fortus print would take many hours to complete, while the injection molded counterpart would take only seconds – and possibly less, as many parts can be made with a single mold operation.

There are only three ways 3D printing can possibly compete against traditional manufacturing today:

Low Volume: 3D printing the number of units being produced is lower than the cost of creating the mold for traditional manufacturing. This is a rising trend, but still an extremely small amount of manufacturing.

Impossible Design: The part can only effectively be made with 3D printing due to an ingenious design. Aerospace has capitalized on this by developing many new low-weight part designs.

Unique Design: One-off parts designed to fit a particular situation or person, typically via a 3D scan. We now see this for some eyewear and footwear applications.

In fact, the HBR article does reference these approaches as success stories for 3D printing, which they are. However, they absolutely do not mean that the same success can be extended to the larger world of mass manufacturing, about which the China issue revolves.

And if such approaches could be used in the US, then they could also be used in China where many 3D printers are now manufactured, still at lower costs than in the US.

Large-scale manufacturing is not going to be replaced with 3D printing anytime soon.

Small-scale, specific manufacturing situations could benefit from 3D printing, but there is no immediate prospect for replacing Chinese manufacturing with 3D printing in general.

Via HBR