Anyone try this?

[Todd Schwartz]

Here is one I have not been asked before. Has anyone tried lasering halfway through the material and then flipping it over and lasering the exact mirror? The scenerio is that we want to laser a 13/16" thick material. My laser can get through a 1/2" on a good day so the thought is to go as deep as I can in one run and then hit it from the other side and hopefully meet in the middle. I know registration is key to line everything up. Or , another thought is to make one run focused on the top of the material and then make a second run focused 1/2" into the material. I am not too optimistic either of these will work, think I will get a treamendous amount of charring and residue, but had to ask.

Thanks,

Todd

[jason harris]

No, never tried it but I have only had the laser for a week :)

Not sure how easy it would be to line it up accurately. I do that often on a mill, using my dial indicators for setup and getting things square but the mill has an advantage of being able to put something in the spindle to center the head on something. The laser has no such thing and I think getting things aligned well enough would be tricky.

[Rodne Gold]

It's possible with much difficulty , but in reality you are using the wrong tool for the job.....
I would make a sub board with 2/4 dowels , drill the oversize material to fit on the dowels do one side and then flip it over for the other side.

[Dennis Rech]

Here is one I have not been asked before. Has anyone tried lasering halfway through the material and then flipping it over and lasering the exact mirror? The scenerio is that we want to laser a 13/16" thick material. My laser can get through a 1/2" on a good day so the thought is to go as deep as I can in one run and then hit it from the other side and hopefully meet in the middle. I know registration is key to line everything up. Or , another thought is to make one run focused on the top of the material and then make a second run focused 1/2" into the material. I am not too optimistic either of these will work, think I will get a treamendous amount of charring and residue, but had to ask.
Todd

I do it all the time. I have a FSE 40 watt laser and although it will cut 1/2 inch acrylic (slowly) there is usually quite a bit of wedge from the tapered laser beam.
Alignment is pretty easy. I vector cut one side of the acrylic half way through, then remove the acrylic. I then lay a piece of white paper in the machine and vector cut it at about 3% power ( just enough to mark the paper). Now I turn the acrylic over and looking through it, I align the previously cut acrylic with the pattern on the paper and then laser through the second face. This lets me cut up to up to 3/4 inch acrylic with 40 watts. The center seam is barely noticeable.
With opaque plastic and wood, I first draw a cross of horizontal and vertical lines on the piece and then transfer the lines around the edges.
I then laser a set of longer crossed lines on white paper on the honeycomb, align the cross on the work with the cross on the paper and laser half way through, flip the work, realign and laser the rest of the way. I can only cut about 3/8" wood before the charring gets too great.
The white paper trick also works well when you have removed an item from the machine and then discover that more work needs to be added. An example would be cutting out a number of items and then wanting to engrave them later. Just lay the paper on the honeycomb, burn the outline into the paper and then align the work with the burnt tracing.
Hope this helps,
Dennis
229970

[Gerd Spatz]

"The white paper trick" -> Thats a really good idea!

[jason harris]

Yes, thanks Dennis, as a newbie to lasers I think I will use one of those tricks, it's not one thats usable on my other machines so it's good to learn for this one.