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How to - laser cutting and engraving designs

There aren't many things to remember really, the image on the right is a link to the full size original, it was taken from Rhino, which happens to be my personal favourite CAD software, and it shows the EL Butterfly, namely the butterfly we use here as a standard demo piece.

Now, right away, by selecting an area of the drawing, we can see an issue.

The laser will basically follow every single line it "sees" in a file, if you overwrite / overlay one line on another so you can only "see" one, the laser will follow both, in effect running the same track twice, possibly with different settings for each track, this is not a good thing.

Because the laser will follow every single line it "sees", what it will see in the drawing on the right, as highlighted by the yellow lines, is a whole lot of separate curves, it may "look" like a complete drawing to the human eye, but to the computer, and therefore to the laser, it is just a collection of "open curves" or individual lines, so that is what the laser will treat it as, and that gives a very sub-optimal performance from the laser and affects the output quality, in short, it will produce crap.

What needs to be done is all those individual lines need to be "welded" together in the software to form complete CLOSED curves, only closed curves can be raster engraved, open curves can be cut, closed curves can be cut, but only closed curves will be correctly nested and processed in the correct order by the software.

So the outline of the butterfly, for example, should be a closed curve, and the software will detect that it is the outermost closed curve, so it should be done last.

As well as the segment of the outline, the yellow lines show another group of lines that also need to be made into a closed curve, or welded, in software parlance.

This drawing was 2,891 open curves, after welding it was just over 40 closed ones,

At this point, we have options, while an open curve can only be cut, a closed line, which in reality should be 99% of all lines and curves in everything we get, can be cut or engraved... as you can see from some of the samples in the demo gallery, in some cases the pattern on the right butterfly wing was engraved before the outline was cut out, in other cases the pattern on the right wing was cut out as well.

What we need from you, is to know which is which, and the best way to do this, once you have cleaned your drawing up, removed all hidden lines, everything that shouldn't go to the laser, etc etc, and welded and closed all open curves, is really quite simple, just set everything that you want to be cut to one colour, and everything you want to be engraved in another.

As you can see in the image on the right (again, a link to full size) in this case we happen to have set red for cut and blue for engrave, but the colours do not matter, you can use any colours you like, as long as they are obviously visibly different, and as long as they are just colours, don't do anything fancy like dashed or dotted lines, or that is what the laser will cut, and cut only, as they are not closed curves, and only closed curves get engraved.

The final image is the simulation screen output from the laser itself, and as you can see, everything inside the closed blue curves has been raster engraved, and the closed red curve has been vector cut.

You do not have to use "our" colours or anything else, all you have to do is send us a file where all the curves that need to be are welded, be aware that any shape to be raster engraved *must* be a closed curve, although cutting can be done on either open or closed lines, and separate and denote what you would like to be engraved from what you would like to be cut by giving each a separate line colour, or specifying in words in an attached txt file if you like.

Please also ensure your drawing dimensions are correct.