The focus on faster 3D printing continues. Many vendors and developers claim fast speeds or development efforts that will increase speed. But what exactly is meant by “fast?”

How fast is fast?

For 3D printing, what is fast enough?

No hard answers are available for these questions. The factors used to define “speed” for 3D printing / additive manufacturing (3DP/AM) equipment are not consistent or even generally agreed upon. For example, does speed only refer to how fast an extrusion nozzle moves around a build bed, or how fast lasers move across a powder bed? Do you factor in preparation time to get the printer ready, and then post-processing time to finish the part?

Different vendors use different criteria when they claim a specific number for speed. For some vendors, speed refers just to the actual time it takes to build a part–from the time you hit the go button until the part is built. For others, build speed begins when an STL file moves into the printer control, the machine is warmed up, all the way through to part post processing or cleaning operations, including build cooling time.

The parameters vendors use matter because of situations like this: a 3DP/AM machine can build a number of small, simple parts in an hour or two. But it may take several days to actually use the finished parts because of the time involved to remove supports and properly finish them. So, what is the build speed here—several hours or several days?

Speed is also affected by a number of factors, some of which users can control in the design. If the part is tall, for example, you can print it vertically along the Z-axis, or lay it down and print it horizontally. Each orientation has a different build time.

The 3D printing process and the build material affect build time. For example, during a build, the material may change state, such as from a solid to a liquid and then back to a solid. The issue here is residual stresses, warping or curling that may be introduced into the part. To avoid these stresses, you may have limited choices for orienting the part.

Printing fully dense parts will increase the build time. Printing fine details takes time too. The fill patterns used in a build will also affect build time—sparse patterns can be done more quickly than a solid fill.

Can you batch your parts? Sometimes, this shortens build time, depending on the technology used.

Other factors that affect build time include the age and state of maintenance of the equipment. For example, lasers can experience power declines, which will affect build time. The age of material is a factor too. For example, if reused powder has been exposed too often to high temperatures, it will affect the build times.

So ask questions of the vendor about how they define build time. “Fast” may not be so fast.

Leslie Langnau
llangnau@wtwhmedia.com