Dual side prints

qa

#1

Say, for example, I want to make wooden playing cards. I would start with a 20" x 12" piece of material and have many cards on that piece. I would etch one side, flip it over, then etch + cut the cards out. The problem (traditionally) is that aligning everything once the board is flipped over is pretty much impossible. I know the GF will have the ability to flip and continue a cut that was started on the first side - is there a plan to leverage the same technology to support two-sided-prints where such alignment is important?


#2

I’m sure it will be, worse case you could either cut a small shape in the corner of the sheet to use as alignment. But if they can manage doing half a cut and flip it and continue the half cut without much to go on then I don’t see why not.(I plan to do the same as you)


#3

You can fix your material on the bed, etch one side and also cut out the cards, then flip each card and place back in the cutout. Etch the second side. That will give you registration with error no greater than the size of the kerf.


#4

Except that you would need to visually ensure that the design of the other side is lined up for each already-cut-out card. I think it was stated correctly in @Brandon’s initial post–cut the cards on the second side.


#5

That’s easy. For example in Inkscape, create the outlines to be cut in one layer, copy to another layer, and switch line color to one that won’t be cut. Line up your engraving art the same way on both sides (e.g., center in cutout). Run the job using the layer with cutouts and engraving, flip pieces, run a second job using the layer with the engraving and the outlines that won’t be cut.
The problem with cutting on the second side is that you have to flip the entire sheet, instead of each card. That means you have to mirror the template, plus when you flip the whole board you may not get it back in exactly the same place. And (assuming you are flipping it left - right) if the distance to the edge of the material from your art is not exactly the same on both sides it will be offset.
Using the cutout material to register the flipped cards gets around all those issues.


#6

I don’t think you quite see his problem. the reason why he and many people want to cut the 2nd side nto first is for 2 reasons:

  1. more flipping involved…
  2. each playing card has to be individually picked up by the software(position and orientation, that this doesn’t work for other situations where you have 10 different shape pieces) or you have to manually re-register each piece or “help” the software with each piece.

#7

Additionally, the pieces may not be symmetric and therefore cannot be ‘flipped’ within the cutout. (not the place for playing cards, but perhaps it is for other pieces)


#8

Yes, there are cases where the approach I described will not work (asymmetric pieces, for example). But I was responding to Brandon’s original post where he gave the example of playing cards, and said alignment of the second side was pretty much impossible. I provided a possible approach for that example.


#9

@whitehill - I do like your solution for some cases. Very simple and elegant!


#10

Can’t take credit, I’ve seen the idea a few different places :smile: There are lots of other ideas from woodworking and other endeavors that can be adapted to laser cutting projects.
Thinking about it, this technique could work for some asymmetric objects too.
Basically, flip the outlines in the duplicated layer, and offset them from the cuts in the first layer. You can view both layers at once to do this. Place the engraving art in them - will need to flip that too. Engrave and cut the first orientation. Remove pieces. Cut and engrave the flipped layer. Remove those pieces, flip and insert in the first cuts. Take the pieces that were cut first, and put them in the second set of holes. Now engrave both layers (no cutting).
The key to making this work is ensuring that the piece of material you are cutting from does not move throughout the process, as the “waste” is what registers the pieces you want.Note that once you remove the waste piece it can’t be used again unless you have a way of returning it to exactly the same position in the machine’s bed, and even then only if the laser always sets itself back to precisely the same home position. The lasers I’ve used need to have the home position re-calibrated each time the machine is turned on, and even with a red dot pointer it’s really hard to hit the same point accurately enough. If the Glowforge has the precision to do so it will be a huge time and material saver.