Can we change raster engraving to go top-down, to avoid smoke discoloration?

So I’m not sure if you’re describing the same motion. On the Glowforge the air is pushed back-to-front from the head area, then the exhaust sucks it out the back. So it kinda shoots the smoke to the front makes a u-turn to the left, and exits. Since the engrave is front-to-back, the smoke always passes across your fresh engrave.

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Thats similar to what it does on mine…on Monday I’ll do 2 vids…one etching front to back and the other back to front…
Generally the back to front is not as clean…

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I think the reason it does it bottom up is that you can see the engraving emerge. If it was top down it would be mainly covered by the head and gantry until the end. So I think it was done to make videos look more impressive.

So it might need to be an option as it seems to be on other machines. A bit more work to add a tick box in the GUI, but still trivial in the GUI frameworks I have used.

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Could very well be the reason. Sure hope that option makes it in and quickly.

Could also be to keep the laser and cables out of the way if your project would catch fire

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Hmm, yes that could be a reason.I think there is metal between the cables and the fire though. The main things that seem to be exposed are the lenses and the head cam.

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Doesn’t this also mean that if an engraved part remains hot by continuing to blow air assist over the just engraved stuff you continue to cool it?

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I agree with most of what you said, except this part. We don’t know enough about their codebase to make any sort of judgement about how trivial or not any change would be to implement. Nor do we know anything about their software qualification or release processes.

I think your choice of language here is part of why people get riled up. Your choice of phrasing takes what is a straightforward and pretty uncontroversial observation that reversing the direction of engraving of raster images is likely to reduce the smoke contamination, and layers a value judgement about how long it should take Glowforge to implement it. Riding along with that judgement is what could easily be perceived as an implication that they’re somehow neglecting us if they don’t prioritize such a trivial change – after all it should only take a few minutes.

For the record, I don’t think that’s what you meant by your statement and I believe that you’re genuinely trying to provide context from your experience. And it’s interesting context for me! I have spent 20+ years building software but I don’t have any experience in image processing so I enjoy reading your insights. I also don’t think that you were intentionally trying to cast any aspersions on the Glowforge team’s efforts to improve the system. Still, I have to go out of my way to remind myself of my belief that you’re just trying to provide helpful context when I read language like that in order to read it in the best possible light rather than assuming that it’s a passive aggressive attack.

Thanks for your contributions to the forum, I really do appreciate them. I hope you’ll read this in the spirit of constructive feedback that I intend!

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I think the Y axis advances so slowly that it would still have time to cool things.

In doing those cedar coasters, there were some smoldering going on on already engraved parts until the air assist hit it a second time (although that stuff is akin to engraving gasoline)

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Yes but when the head returns back the same X coordinate it will make no difference if Y has advanced a minute fraction or retreated a minute fraction. To move any appreciable distance X has made many passes. If it hasn’t cooled by then it is probably on fire for good anyway.

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Wouldn’t that be exactly like fanning a flame?

Well it’s a balance between providing oxygen to the flame vs cooling. If cooling wins it goes out, if oxygen wins it gets hotter.

Ultimate example of wind putting out fire (albeit with water which also should make this worse) but just the shear volume…

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Thanks for the suggestion! Putting in the hopper (cc @Tony).

  1. Nothing gets built without going through the hopper
  2. We’re pulling things out of it all the time, e.g. when we touch code for another reason that makes it easy to pick up a good idea from the hopper
  3. The hopper is for consideration, not implementation, and it’s a neverending wellspring of improvements
  4. The hopper will never be emptied.
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Sounds like a list for fight club lol

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Happy cake day @dan :grinning:

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For what it’s worth, this is the only issue I have seen in the 3 days since I got mine. I’d love to have this option.

Thanks for the feedback! There’s no way to do this now, but we’ll put it in the hopper.