Laser Printer-style Raster Layer Imaging: viable alternative?

Going with the adage “a little knowledge is a dangerous thing” I ask my question. I worked several years in Sharp Electronics’ copier and imaging systems division, and coupled with my later IT experience (cleaning toner-dusty laser printer optics), I am intimately familiar with how a laser printer images a page. It’s fast, very high-resolution, and - most significantly - uses not much different hardware than appears to be in a Formlabs printer. So I got to thinking: short of installing a rotating mirror drum, is there anything to gain or lose by the Form printer imaging each layer using an old-school CRT-style top-to-bottom, left-to-right (or back and forth!) raster style of imaging? If the galvanometers are as precise as stated, the XY resolution could still easily equate one pixel with the laser spot size, and the slicing software should be comparable to that of projector-based printing. XY smoothing could be tackled in the same way projectors do - by anti-aliasing edge pixels with partial laser power. In summary, if a Form printer’s lasers can be hacked to play “Space War”, maybe they can be hacked to do raster-based imaging… maybe as a draft mode for the Form2 since it’s lost its 200 micron setting? Geek with me, people! :slight_smile:

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I don’t think you would get good results that way.
The laser point is around 140 microns, which is quite large for a pixel.
Also, for resin printing, you wouldn’t get smoothed edges using partial power, you would still end up with a pixel shape that’s only partially cured rather than an actual smooth edge. There are other printers that use DLP projectors as the light source, so it’s exactly like what you are thinking, but you end up with stepping on the X/Y directions due to using pixels. That’s one of the benefits to using the laser galvanometer, the X/Y resolution is much much finer since the galvo can position the laser with single-digit steps. And you can get that quality across the whole print volume vs. DLP printers that require you to move the printer closer to make the pixels smaller which makes your build volume smaller.

Zachary_Brackin, then what about running with the ‘spirit’ of what Volguus is suggesting and switch from the current mechanically moving galvanometers to Caltech’s integrated optical phased array (OPA) to very quickly move the laser beam around electronically?

This type of Light Beam Steering (LBS) is used in the new laser pico projectors.

Some math tells me that a 140-micron laser spot, if considered as one pixel, gives just over 180 “PPI” at the printing surface, just beating 24-pin dot matrix printer resolution. Meh.

BUT: that still means the entire 5.7 inch square of the Form2 print bed would resolve to at least 1024x1024 pixels (rounding down slightly to a nice computery number). If the Form’s galvos can raster that entire area in a half-second or less, you might still have a very useable draft mode, limited only by the speed of the peel/wipe motors.

Even further, if the galvos are fast enough, you might even simulate “wobulation” to offset a second series of scan lines by 70 microns (one-half the laser spot width) to double the resolution in at least one axis. Or even 4 sets of scan lines offset 35 microns (720 PPI!). Who knows how much you could lay down before it’s no longer faster than the current laser system?

I think one of the steps in the future might be to have multiple lasers, could increase build size and speed.

If I need a very fast scanner for laser micromachining (say greater than 10 meters/sec) then I use a polygon scanner. This has one rotating mirror with multiple facets and a second ‘galvo’ that only indexes in the other dimension. I’d link to examples, but don’t want to show vendor favoritism. This type rasters the entire field width even if the printable part is small.

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