Laser Spot Size

Is there any benefit to going to a smaller laser spot size? I have seen other SLA machines advertising a 70 micron spot.

Smaller spot you can expose a smaller area and get smaller features.

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You should check out this post on SLA vs DLP which goes over some of the reasons why spot size isn’t relevant for many applications. Spot size defines the minimum feature resolution, but it’s largely the positional accuracy of the galvanometers that determines the tolerances of a print. The Form 2 spot size tends to fall in the range of 140um - 200um, and this is fine enough to resolve thin walls and fine rods on most designs. Reducing the spot size increases print time as more passes are required for the walls and interior fill.

So the galvo motion is more important. Would a more powerful laser print faster?

This is highly dependent on material and layer height. Some settings are power limited, and increasing laser power might offer speed improvements for those.

A smaller laser spot could produce sharper corners though as well (that’s why DLP prints often look very crisp). But what could happen eventually is that a printer could have multiple lasers to print faster with higher detail (small laser for the outside, large laser for the inside)

Is that true for anything other than 90 degree corners? For corners that require some amount of stepping, a laser-based setup should win out as the positional accuracy of the galvanometers is generally greater than the diameter of the pixels in a DLP setup.

For things like small lettering you’ll get the sharper corners with DLP. Jewelry printers with small build areas can get the pixel size down to 50 microns or smaller which produces some nice corners. I still prefer the laser though to avoid the X/Y stepping and maintaining the build size without sacrificing quality.