Perfect inlays

[Joe Hillmann]

Can anyone here explain how they make perfect inlays with the laser.

I have done a few of them but they always have small gaps in areas when I raster out the area that will be replaced with the inlay I draw a .005 white line around all of it which helps a lot but it still isn't perfect, I have tried making the line thicker.006 and .007 and then the inlays don't fit.

The way I am doing them now is ok and customers love them but I know by looking at others work here that the joints can be made better.

[Scott Shepherd]

Make a positive and negative using the same file. Raster the pieces into the work, then on the inlay material, reverse the image, engrave all around it, leaving a thin web holding it together. Glue it in, once the glue dries, sand it smooth, sanding the web off and the two materials on the same level. It'll be dead perfect with no gaps. You can do very very detailed work like that.

[Joe Hillmann]

That is how I am doing it now but I end up with half the thickness of the kerf of the laser or about .002 gap all the way around. I tried adding and extra outline to get make up for the gap but it isn't working.

[Craig Matheny]

What you are dealing with is the gap the laser leaves when cutting. What I did was cut a 1" square measure the square and the hole find the difference lets say .04 so cut in half .02. so .02 is the true width of the cut from the laser. Now take the art create the two sheets the inlay and the main sheet. Now the difference is .02 gap for the beam cut the .02 in half to .01 so on the inlay do a contour to all the inlay parts increasing them by .01, now on the main sheet that the inlay goes into decrese each opening by .01 using the contour tool. This will give you a nice tight fit no gap light sand and finish. good luck

[Scott Shepherd]

How deep are you cutting it? Normally the pieces are angled opposite each other from the beam , so you get a really great, tapered fit, that fits better as you go deeper.

Somewhere on here there's a post with photos I did years ago of some very detailed, small stuff. I think it had sharks on it, with a dime in the photo to show how small it really was.

[Craig Matheny]

I overlay the item with the main veneer that is cut save tons of time from engraving and hoping it is deep enough

[Gary Hair]

The only way you'll get a "perfect" inlay is if the pocket and inlay are slightly angled \\___// - that way they don't have to be exactly the right size. It's very easy to do with my cnc router and a 45 degree bit, not so easy with a laser. One way that will help though is to laser the inlay upside down, the natural angle produced by the beam can give you a slight angle that will simulate the router bit. It's also helpful to vector the pocket, that will create the same angle. It won't be perfect but it should be better.

Gary

[John Noell]

We do quite a few of these and I have found that I often do have to 'contour' the inlay just a bit to get a no-gap-at-all fit. On real small parts, I use .01mm and increase that for bigger parts. When you have both fine detail and larger chunks, it can take a bit of adjusting (aka "a lot of work") to set the contours appropriately.

[paul mott]

Hi Joe,

CAD/CAMs such a Vectric allow a vector profile to be cut on the inside or the outside of the line (for the purpose of cutter radius compensation). By creating a tool with the diameter of your anticipated kerf then creating two images or toolpaths – the outer parts of the pattern cut on the inside of the line and the inner or inlay parts of the pattern cut on the outside of the line the parts will then fit without gap.

Paul.

[Mike Null]

I have done some inlays that I'd call perfect by rastering the pattern then vectoring the inlay from the back side. The thicker the inlay the more difficult a perfect fit will be.

[Scott Shepherd]

Here's the thread from some time ago showing some samples. See if this is the type of fit you're looking for....

http://www.sawmillcreek.org/showthre...(needed)/page2

Look at the sharks at the bottom of the page.

[Ric Taylor]

Scott,

I can't get the link to work.

Ric

[Scott Shepherd]

That's odd, it's a link to another page on this forum. Search for "Marquetry 101" and look for page 2 on that thread. The photos are near the bottom of page 2.

[Glen Monaghan]

It doesn't like the Page2 part... Deleting that gets you to the 1st page of the thread.

-Glen

[Richard Rumancik]

Joe, are you vector cutting the inlay portion (insert) and rastering the pocket to fit it in? Or the procedure that Scott was describing that involves 2 raster generated pieces, one male and one female?

. . . I draw a .005 white line around all of it which helps a lot but it still isn't perfect, I have tried making the line thicker.006 and .007 and then the inlays don't fit.

Joe, what dpi are you using to raster the pocket? Suppose it is 300 dpi. What this would mean is that for a shape such as a square, you would only be able to adjust the pocket size in .0033" increments (one step). Perhaps this is what is causing it to go from a loose-fit to no-fit condition. If you used 1000 dpi to raster, then you would have more control to change the size, as you could adjust the pocket in .001" increments. So if you are using low resolution, increasing dpi may help.

Unfortunately with a random shape it will not behave as nicely as a square, as the vector to bitmap algorithm needs to add as many dots as it can inside the shape.

If you are vectoring the insert piece, then you should also check the scaling on your laser i.e. if you draw a 10" x 10" square does it actually measure 10.000 x 10.000? If not, then you may need to add compensation somehow. (One way is by stretching the drawing.)

It might not be a bad idea to experiment with a simple rectangle inlay to see if you can shed some light as to the source of the problem. You could laser 3 consecutive pocket sizes and measure them, as well as measure the insert piece. Once a rectanglar inlay is debugged you could try and apply the knowledge to irregular shapes and see what kind of success you have.