Great find, thank you!!! I’ll have to look into that for future applications, I’m sure it will come in handy! Ultimately I think the better plan, though, is to outset the airblade with a sacrificial bar and then shape it with needle files. I used to do something similar but formally modelling something to protect the end of the blade is probably better, with an indicating ridge to show where to stop filing. After examining some older prints I think having the windway exit begin on some initial layers after supports is just a bad plan; the areas where the greatest precision is necessary always benefit from being the last layers on a surface, as they have a solid structure to build upon. The airblade at least I can SEE and access relatively easily, whereas squinting down a slightly tapered 0.03" high slot to see if there is a deviation near the end is just painful.
I used to do these in two parts, allowing both surfaces to point “up” (aka toward the pool of resin), but found the indexing to be yet another source of error. There’s a reason these instruments are typically made using stock tubing sizes and clever milling tricks rather than going for the acoustic ideal - they’re just hard to make, and the more you can outsource the precision to the suppliers of your raw materials, the better.
For the devs, though, here’s a perfect example of what I’m talking about:
Figure 1 here is fine - nothing is occluding the windway exit.
Figure 2 here is unacceptable - this instrument would be unplayable if the supports were clipped flush, and having to scratch into the windway to adjust the bit left over is a real workflow problem. ANY pitting caused by support removal kills the instrument permanently.
If Formlabs wants to be taken seriously in the industrial/engineering space, the ability to nudge those supports off of key features is an absolute must.