Shared borders

[Ron Deweyer]

Noob here with zero experience (yes zero, I don't even have my laser yet, 2 more months to wait) but am already using the RD works program to create a library of things to make.
My question is, when cutting out multiple bits, should I share the borders (maximum use of material) or "explode" the items, see attached pictures.

[Gary Thompson]

I'm new myself Ron and it's a problem I've encountered. I think (and I'm happy enough to be corrected) it depends on whether the borders are drawn as one line or two. I've tried both options and, if the shared border is effectively two lines then the laser performs two cuts leading to a poor edge on acrylic - a similar effect to using too much power/too little speed.

I tend to separate the items by a couple of mm and take the slight loss of material.

[Gene Uselman]

My usual spacing is .050- 1.5mm. Getting too much into savlng material can be expensive.

[Jeffrey Aley]

I'd say, "it depends". There's a certain amount of material that is removed by the laser. On a saw, we would call this the "kerf". If you don't mind having your little rounded squares being a little bit undersized, then I'd butt them up against each other. If you delete the overlapping lines, you can reduce the amount of time it takes to cut them out.

You could, of course, draw them slightly oversized to compensate for the laser kerf.

Or you can leave a little bit of space between them, and tell RDWorks that it's an "Out Cut" (w/ the appropriate "Sew [kerf] compensation") and it'll take care of the kerf for you, resulting in exact-sized pieces.

[sebastien laforet]

My question is, when cutting out multiple bits, should I share the borders (maximum use of material) or "explode" the items, see attached pictures.

if you share the borders, and do nothing special about it, they will be cut twice. basically, this is bad because either you will have burn marks, or even you will destroy pour piece (for example a piece will be completely cut and will "fall" on the grid and move laterally, and the next passage of the laser will cut on the piece!

so, either you move the piece to avoid sharing the border, or you use RDworks to remove overlaps --> this will detect duplicate segments and keep only one. this is also possible in lightburn.

be careful : in RDWorks, the segment is "really" deleted from the file, so if you move later one square, it will be missing parts!!! also, the segment is removed before the path optimization, so RDWorks will not detect any more closed shapes... this might pose a problem if you expect to cut inner parts first automatically.

in Lightburn, the path optimization is done first, then the overlaps are removed from the cutting path, but not from the drawing. this is far better.

[Doug Fisher]

>>in Lightburn, the path optimization is done first, then the overlaps are removed from the cutting path, but not from the drawing. this is far better.<<

Agreed. One caveat - If you are doing very small pieces that require very high precision, the delete overlapping lines function works best when you have straight angled corners versus the rounded ones like shown in the picture in the initial post.