A year ago, it was said that this was impossible. Has this changed at all, by chance?
It would be nice to not have the smoke perpetually blowing across what I just engraved. It isn’t so much a problem with most masked materials, though it would make it easier to clean up the residues from the finished piece. It definitely presents a problem when working on 2-color acrylic sheets, like the ones from Inventables, as the top color gets blasted off, but the hot dust from each new line redeposits on the still-warm core from the lines before, sometimes actually fusing back into the material.
If the laser drew the image from the top down, the dust/smoke would blow across untouched (and probably masked) areas, with much less depositing and would probably just get obliterated by the laser passes anyway, which would make the final cleanups a hell of a lot easier and effective.
It’s a feature that lots of other lasers advertise, and seems like something that could be done, since it’s an operational issue, not a physical/hardware issue.
I don’t recall that being stated by any authority. Last I heard it was a viable option that could be considered one day. I would definitely love to see it happen.
I don’t believe we’ll ever see this one implemented. While it’s a pain in the tush to have the smoke and resin residues blow across the area that you have already engraved, if you were to reverse it and engrave from the top down, you will be blowing resin and smoke across unengraved area, and the beam will not penetrate as far into the material when it gets there. So you wouldn’t get an even engrave if it’s going the other way.
(The air assist is always going to be blowing towards the front on this machine. Other machines that have the feature to engrave from top down might not have a front facing air assist.)
As I recall it was a switch to make it bottom up. I remember a post by Dan a long long time ago where he mentioned it possibly was implemented due to a suggestion by Bailey that it made for better photos/video
If the air blew the other way, a top-down engrave would have the same exact problems we’re currently having. If it were a matter of having multi-directional air sources, then the engrave would be fine to run just the one way. But being as adding another air source direction would be a physical/hardware option, it would be damn near impossible to implement, whereas the direction of the engrave could be solely controlled in the software and implemented across the board on Glowforge’s end.
While residue and dust are likely to accumulate a little bit on the unengraved surface, generally, those surfaces are flat, so it would have much less of an encumbered path as it was blown off the board, and be way less likely to snag and build up, as it does with the grooves and textures of a fresh engrave.
Obviously, both scenarios have potential problems, but it would be nice to have the tool as an option, to allow us to solve the problem as it arises, as we see fit.
I dunno…I think it might depend on the material and the operation. Plywoods, MDF and draftboard with a lot of glue tend to stick, and even with a flat surface there can be significant buildup. Resinous woods are even worse. (I’ve been running a lot of deep 3D engraves lately, and the crap builds up on flat surfaces as well.)
I believe it would impact the depth of the engrave, because something as thin as the QR sticker on the masking will affect it. (If you want to test it, run an engrave over the sticker sometime.)
Anyway, just my theory. The resin buildup can be cleaned out if it has already been engraved, but if it gets in the way of the engraving, there isn’t any way to deepen the shallow areas without running it again, and then you’d have the same problem.
If the resin buildup under the current system is bugging you, you can do a cleanup pass afterward at high speed and low power to burn it off…that actually works pretty well, and I use it to keep from raising the grain on some of the hardwoods that I’m testing when it comes time to clean it up.
this is true. on the universal PLS6 (and maybe other models?), the air assist points straight down. you can choose different attachments that give you different direction options. we have an attachment that points straight down and focuses the air assist directly on where the laser is cutting. very helpful for things that tend to flare up. but you can buy one that rotates and change it to point in any direction you want.
Like I said, it would be nice to have it as an option.
The proofgrade woods and materials are less an issue in this regard, but it really jumped out at me when I tried to engrave some of the 2-color layered acrylic from Inventables. It was black on top with a white core. As the black layer was getting blasted off, its dust was redepositing on the tacky still-warm white core of the fresh engrave and fusing to it. No amount of wiping or scrubbing could un-grey the final piece. The specs on the material recommend top-down engraving, but it can’t be done on the GF, and without it, it seems like perhaps this material is more or less unusable.
I’m not giving up on it altogether, so I suppose I will try a low-power cleanup pass and see where that gets me. This particular design is a small but intricate piece with an already hefty cut time that I’m trying to not exacerbate.
Tom!
