Double sided cut


You’re killing me. I honestly can’t tell whether that’s a question, or by adding the smiley face intended as a humorous comment. I’ll give two responses…

  1. Ha! yes.
  2. Only explaining the automatic double sided cut feature unique to the Glowforge. A capability that no other laser system has without jigs or adding reference marks. No clue how well it will work once complete. “Eyeballing it” is always an option for those that prefer.
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I think we all understand the situation. I was just goofing around, my friend. :grin: Yes, it’s something we can do manually on any machine if we’re careful enough, but it’s also an instance that the Forge’s “double sided cut feature” has trouble with.

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A toddler can easily tell the difference between a funny smile and sarcastic smile. Me, never been the smartest person in a room. :no_mouth:



We’ll, you’re usually head and shoulders above me. But those are the best rooms to hang out in!

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@rpegg is spot on, as usual. Cut one side, flip, engrave and cut through the reverse. If you have something that starts out perfectly circular, you can’t align it when it’s been turned over - although there are some good ideas here for the hopper to try!



Challenge accepted!:relaxed:

I am looking at just this situation. Getting closer all the time to getting a feel for the positioning routine, but the circle flip over is special.

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:slight_smile: I wouldn’t bother for now, although you’re welcome to - the Glowforge won’t do anything special that any other laser wouldn’t do to, until we release double sided cutting.

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question on the circle thing. Maybe I’m being a bit thick on this one, but if I have a 2" circle that it’s center of origin is 3 inches in from the left side, and 4 inches down from the top. On the one side I engrave whatever message I want and then cut/engrave the circle into the material 1/4". When I flip it over, wouldn’t the software recognize the corner flip and now draw a 2" circle with it’s center 3 inches from the Right side, and 4 inches down from the top?

Why is a circle so hard? you don’t have to get the rotational positioning correct at all, only the x and y location. Out of most the shapes I would think the circle would be one of the easiest, until you have interior shapes/letters/designs that you want to cut out. But then again, it would be registered off of the edges/corners.

Even in the situation where I’m cutting out a circle from a current circle, as long as both circles have the same point of origin (center), it’s just an offset from the circular edge. The only issue that I see is if you wanted to cut out a circle that does not share the center origin of the larger circle.



I’m back! It’s the initial material that needs to have defined edges/corners. Not the design or the cut.

The grey rectangle represents the material you drop onto the laser bed. Cut anything you want from that material. The hello world coaster or any design of your choosing. The Double Sided cut feature needs to know how the original material is oriented so that you can flip it and a mirror image will be cut on the back side perfectly aligned and positioned.



Yes, what you are showing is why I think a Circle shouldn’t be too hard, it’s all relative to the edges. And as long as you are only engraving a design on one side of your circle, when you flip it over, you don’t even have to account for any inadvertent rotational ‘distortion’ of the image.

I think you and I are agreeing, what I’m asking is why Dan keeps saying that circles are so difficult. As long as you have an edge/defining feature to reference off of for position and rotational accuracy, I think a circle is certainly possible.

Potentially the worst case scenario might be in using an oversized piece of material where the corners are not within the bed area where the Laser Head can find them. At that point, it would have no way to tell where the circle should be precisely placed (but that would also ring true for any shape at that point) without another “feature” to reference off of.



I think part of the confusion is switching between talking about a circle still on a bigger rectangle, as in @rpegg’s example, and a circle like a pre-cut coaster or something with engravings on both sides.



Yes. The only time Dan said regognizing circles was hard was in reference to the original material shape. Not your end result or design.



But, going from what @takitus points out, with a nice tight jig/fixture you can convert a pre-cut circle into a circle inside a bigger rectangle.

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Just a guess:

indexing -

  1. vertical “stick” taped to bottom side of the pre-cut circle or medallion
  2. horizontal stick taped to the top side
  3. engraving and cut jig on the right

Cut the jig and remove the center.
Engrave the text on one side of circular medallion.
Flip medallion along vertical axis and remove the vertical stick on the top.
Engrave the text on the other side.

i think what @dan was referring to with the circles, was that if you try to engrave on both sides of a pre-cut circle without indexing it in some way, the text might be rotated away from where you want it placed on the medallion on the back side



Remember that the primary benefit of the double cut capability (as advertised) is that you can cut deep (1/4"+) into one side, flip, and finish all the way through (1/2"+) material, The two cuts will be perfectly aligned and appear as if you cut all the way through from one side. Thereby doubling the maximum cut depth. If all we want to do is engrave something on both sides on any material then you don’t really need the double sided cut capability because alignment is generally not critical.



I would say something like that, but Id cut a circle that fit around the thing youre cutting, with the spokes sticking out of it so there wont be any height variance. Then just tape to prevent rotation inside the jig.

Crude drawing:



Yep! That would be even better. :slight_smile:



have there been reports from beta testers or the pre-releases that allow you to set an absolute X/Y starting position? That way if you make a jig for your double sided cut/engrave, you can bypass any limitations of the unit by doing the alignment yourself



Want to be clear, since other lasers don’t allow you to automatically perform a double sided cut, it is not a Glowforge limitation. Apples and Oranges. Now there are of course limits in how the capabilty can be used.

Separate subject… Folks have argued here, at length, about the benefits and limitations with respect to a Glowforge home or set 0,0. There has been discussion with one of the operators about testing it on a pre-release unit. Suggest you start with these topics. Good luck because it is very long and all over the place. Sorry I can’t give you a direct answer that won’t devolve into the same back and forth.



Reason I asked was because I read all the forums, and I do not recall a decisive answer on this item.

I recall things like positioning using keyboard vs mouse, but nothing else.

Part of the problem with the forums is that there so much speculation on the questions that is hard to pick out any hard information