I want to use the laser to reduce the thickness of specific areas of a piece of horn before I cut a shape out it. I can successfully cut through the 6mm horn (with about 4 or 5 passes) but I want to reduce the thickness of some areas by about 1mm or 2mm first, ideally graduating so there is a curve across the surface.
I wondered if anyone has ever done this successfully in either engraving mode or cutting mode?
I don’t want the thickness to be even across the whole piece or I’d use a manual ‘thicknesser’ first. I was thinking of creating a simple shape where I want to reduce thickness and have it ‘engrave’ this shape, then repeat this several times, with a smaller shape over the areas where I want it to curve in.
Any suggestions would be welcome, I will post the result if it works.
This really depends on the controller and software you have and use. Stock nano/moshi controllers will take more work than a DSP/smoothie and the appropriate software.
I’d suggest testing a gradient engrave bitmap, with the curve profile you want based on the scale of greys. May or may not work as well in practice as it theoretically should.
I have the basic controller that comes with the K40 but maybe this is the excuse I need to upgrade to a Cohesion3D. Iwill see if I can figure our how to do grey scale in CorelDraw 
@Phillip_Meyer it’s not possible to do true gray scaling with the stock controller. What people do however is to use dithering to create a gray scale effect by varying the density of engraved dots. It maybe possible to do some profile engraving but it’s going to be a step profile where you have a series of engrave elements and you engrave sequentially with increasing power or slower speed.
Hmm, then I need a new controller, thanks. The Cohsion3D looks good and relatively easy to fit to a K40. I think I will have to buy one.
@Phillip_Meyer What you could do with the stock board is create a series of rectangles, each progressively smaller than the previous. Engrave the biggest rectangle first, then the 2nd biggest, then the 3rd, & so on. Do them all at the same power level & it should give you a 45 degree transition. Not perfect & would be a hell of a job to setup each operation. I think the C3D is probably a good way to go to get the results you’re after.
Oh, just realised Ned said the same thing about the series of engravings.
I’m finding it hard to do that with CorrelDraw. I tried exporting a planar surface from rhino as a png and imported it but when I tried to engrave with it, it just threw up an error. Maybe I need to do something in CorelDraw to have it engrave the solid png image?
@Phillip_Meyer CorelLaser will only do black & white. So on & off. Any gradiented image will just laser as all black for any variation away from white. There’s 2 options that I envisage may work. I’ll draw some examples & add them to the post in a minute.
I managed to reduce thickness consistently using engraving but still need to experiment with a gradient pattern. I think it might be best to just get a better control board for the laser as I find CorelDraw so frustrating (not to mention the fact I have to keep rebooting my Mac to run windows)
@Phillip_Meyer That looks to be a great result. Did you engrave that whole depth into the material?
I totally agree on the frustrations with CorelDraw. It seems a very clunky interface & made it difficult to work with the laser for me (as last time I used CorelDraw was over a decade ago).
With controller upgrade you will be able to run natively in OSX, so that will be an added benefit for you as well as the improved performance/capability.
Hi, yes, engraving seemed to cut about .45mm deep so I ran 5 passes. I tried different size boxes first to try and give a graduated depression but the steps were very obvious (an about 0.5mm apart) so it would have required more sanding that manually filing the additional grooves. I have a cohesion3d board on order, hopefully that will give me more control.