New thought on a rotary concept

in the last months I have had request to etch wine glasses. while doing one offs would be easy to do with a vinyl stencil and sandblast. the last request was for a winery to do and order of 1000. The glass they will use is almost 4 inches in diameter. I know this will not fit in the the forge. but I have been thinking about the problem. with a background in mechanics and lack of electronic know how I came up with this

my theory :
the gantry travels in X ( right and left) and Y ( front to back) if you disconnect the rubber tracking band from both sides of the gantry you will eliminate the Y moment. The wine glass will need to rotate at the needs speed of what the gantry would travel. this can be done by doing the math and using gear size. So why could we not build the rotary system to harness/tap into the rubber tracking band. So when the GF thinks its moving the gantry it would actually be rotating a gear set that in-turns rotates the wine glass.
completely mechanical rotary system using the GF itself to power it. simple manual alignment would be needed to start. then allow it to run itself.
I know this does not solve the problem of the depth of the forge

Thought on this from people that like to think out side the box.

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So why bother continuing the thought? It’s a nonstarter until you solve that.

Peole have wildly speculated about using a mirror to redirect the laser.

People have made manual rotary indexers (and posted them here).

The bottom line is that the glowforge is not designed for this, and you’ll always beat yourself against a whole list of bad compromises.

If you ask me, if you need a thousand units, just design it and farm it out to another commercial laser engraver, charge a design fee/slight markup, make some cash off it, and move on. The glowforge is just not he right machine to make a thousand engraved wine glasses, you’re going to destroy any hope of profit by trying to rig something up, it’ll take a very long time, and you aren’t likely to get a good result in the end.

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The other component you haven’t considered is that the machine uses head location (specifically the logo on top of the head) to perform initial head location tracking (centering) under the camera - without Y-axis movement, it will never complete that process, and will stay stuck on that process during startup.

… unless you were planning to also write your own firmware.

challenge accepted.

yes I could farm the order out. but what if I was the person people farm the orders out to.
THINK out side the box big picture. creating space under the forge is the easy part

thank you for pointing that out. I believe by placement of the gantry so that when the laser head makes is X moment for alignment it will be under the camera. moving on that thought the Y motion the GF makes to get to this point is a very fast movement so it may toss any item off of the rotary system. possibly a build in inertia clutch. think cap on

thanks for the positive insight

If you cut the bottom out you will probably also be cutting yourself out of any sort of future hardware support from glowforge.

I’m just saying that sure we could come up with ridiculous workarounds all day long, I just fail to see the point.

You wanna be that person that gets farmed out to? Buy a proper rotary engraver and profit away. The Glowforge just isn’t your machine for that.

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This phrase and attitude has led to some awesome stuff, some stupidly awesome stuff and hangovers galore. I have no problem rooting you on - go for it.

However, the glowforge is a hobby machine. As a business machine its best use case is as a complement to a business or a gateway to a lasing business machine. There are lasers out there with four inches of z-depth and rotary attachments that are meant to handle 1000 units. There are probably sand blasting cases set up to do batches of glassware.

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Theoretically Glowforge could do a useable rotary since they have a removable head. They could make a head that reflects the laser forward instead of down and mount a rotary unit in front of it without the tray. They would have to get control to the rotary unit and then the concern of laser beams flying around but theoretically…

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the end goal is to move into more space and yes upgrade to industrial set up… I may end up not doing the wine glass but I would like to be able to do rolling pins. small shot glasses and a have the ability to do shorter this that will work with in the 2.5 inch clearance. with out having to cut the floor of the forge.

fify.

Shot glasses work fine.

I have not looked at the idea of the removable head. that’s another bunny trail to chase. down that maybe the answer to wine glasses. still use the same set mechanical set up to allow the forge to do the rotating of the object

I like the out side the box idea thanks

I would like to do larger etching and maybe wrap all the way around the glass with out having to do multiple manual resets.

I bet you would get a 4" piece in it too.

You really want to get this granular on building your own engraver, you ought to look at a lasersaur. You’re wasting your time trying to make a glowforge do this, there are just too many very large stumbling blocks.

As an economic argument, buy a k40 and have at it. Less than a grand all in even with upgrades and you won’t have destroyed your glowforge trying to do it.

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No it’s not. Glowforge is inextricably tied to their laser head design because of how the head homes (which is basically what eflyguy already tried to tell you). Writing a firmware is not trivial. Go over to openglow and see how far they’ve gotten, and they have years headstart on you.

Even if (big if) you figure out a way to somehow make this work, properly aligning your gantry after you do whatever crazy hackery you are talking about is going to be much more difficult than it’s worth. You’re very likely to wreck your machine trying this and have nothing to show for it when you’re done.

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your comments are appreciated. Thank you for the negative vibes.
instead of listing all the ways this will not work have fun and think out side the box of the ways it can work… I know its a problem. WE all know its a limit the GF has. instead of saying its not going to work because of this be positive and say hay your going to have issues with this and give a theory of how to work around it

Oh man, negative vibes, I’ll feel really bad about myself later for that. Hang on, I gotta go find my eyes, they rolled right out of my head.

You just aren’t listening. The workaround is not to use the glowforge for this, it’s a nonstarter idea, and I am trying to save you the trouble. I’m not just idly speculating, I’ve seen this topic come and go several times and put some thought into it and it is a loser. But here you are, with your (no doubt) impressive resume that includes some Deep Authority™ on the matter (wow us with it, come on!), so I await your incredibly practical solution. Sometimes people just want to keep digging, so go you! I look forward to your inevitable post where you’ve destroyed your machine and are outraged that support won’t help you. You’re exactly the kind of guy who will think “I’ll rig something up to make vinyl cutting safe with my glowforge!” Just wait for me to get my popcorn, I want to get a good seat for this.

Don’t ask people who have been here for a while for an opinion on heavily-trod ground and then get upset when you don’t like the answer.

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Okay. Where to begin.

What you are referring to is the GT2 belt on the left and right side of the unit. Which are connected to a GT2 pulley on each side. The issue is that the unit is internally configured to move a specific distance per step. This is how it knows how to move 1mm or 25mm. To translate that to a controllable/predictable rotation in degrees is complex and eats up space.

The easier method is to keep the unit stock and move/rotate the object underneath it.

But the main issue is even with the tray out, there is not a lot of space to have a rotary and have it hold an object more than 1.10" (while keeping the head a set distance so the focus can work correctly.) The rotary itself would have to be super low profile and still have a stepper motor, controller and a means to power it in that short foot print.

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If I had a guaranteed order for 1000 wine glasses, that will pay the totality of a Trotec, Universal, etc. unit that already comes out of the box with the ability to do the job, no muss and no fuss. Then you have a new machine, completely paid off, with much more capability and potential… plus a glowforge that’s still very capable.

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I built a prototype rotary that would use the whole height and work without disconnecting anything. Obviously you would be restricted to height limits, but it wasn’t too hard to do. I was going to refine and sell the design in the shop when they started letting users sell things, but they never did.