how to Clean engrave middle path / setup wont generate

[doncawley]

I am attempting to engrave about 40 small labels and am testing the process with a single label. I almost have it all down but I am running into the challenges listed in the title. I imagine this would be very easy with a larger scale model or a much smaller bit ( the forum help / YouTube I've found would be more helpful at least) but these are my project restraints. I would love any help / suggestions; in particular, any suggestion that keeps in mind I will need to make 40 unique labels and don't want to hand click hundreds of letters would be greatly appreciated.

the current engrave setup i have works great but leaves an ugly raised middle section, you can see it in the CAM but I have attached a real photo as well.  My labels are 1.25" x .5" x .0625" and my only chamber tool is something like a 20deg (Fusion input) v bit.  Ultimately all I want to do is remove this middle section / make the letters as smooth as possible.  I was under the impression engrave would do this but I've gathered I need to do a secondary path, possibly 2D pocket or 2D adaptive.  I THINK I have setup my 2D pocket path correctly but when I attempt to generate it stalls at 9% no matter what I do.  So now I am stuck.

I could absolutely be going down the wrong road here, so just tell me if I should change directions.

--- the REALLY ugly tag was my best attempt at using my laser, you can obviously ignore that.

[Richard.stubley]

Hi @doncawley 

I have taken a look at your project.

The reason why the engrave pass leaves bits in the middle is the bottom height of the toolpath is stopping the cutter going deep enough to touch both sides of the geometry.

Looking at the cutter you have and the material thickness I don't thing just increasing the bottom height will work as you almost cut completely through the material. 

Options if you wanted to would be to just a larger angle V bit so it doesn't have to plunge so deep in. Or make the geometry you are cutting thinner to stop the tool going as deep.


If that V bit is the only tool you are going to you Ideally you will need to do one of the 2 above as you will be there forever trying to get flat floor on the letters with a pointed tool. 

Also where did the sketch come from with the lettering? 
If you use the text command in Fusion design to create the lettering, you can then select the text in the manufacture workspace and you only need to do one click. 
If you have special characters like the Ø symbol you can just enter these as the ALT codes in Fusion design.

[doncawley]

Thanks for your time richard!   The text is from an illustrator file I made as the the font is futura ( a font not available within fusion).

It makes sense that the angle of the bit is too steep to hit both sides of the geometry.  while a perfect floor for the letters would be ideal, i undertand thats not possible.  The most simple idea i can think of, and be happy with the result, is adding a single path in the center of the geometry, perfectly hitting the tops of the extra "mountains".  This would instead leave two half high hills on each side, however I believe it would be small enough to not be as noticeable. The only way i know to accomplish this would be to create offsets of EVERY letter in the design workspace and then a trace setup on that line, but that seems absurd.

[Richard.stubley]

I just had a play, Its a bit of a hack but if you duplicate your tool 2 times and make another tool at 35 degrees and another at 30 degrees.

Give them the same tool number so it will just run one after another on your CNC.

Now duplicate your engrave toolpath so you have 3 of them, and change the tools for the first 2.
Do the 35 first, then the 30, then the 18. 
Doing this will force the tool into the centre of the letter. Again you wont have perfect floors but it might get you what your after.

If you were to actually model the lettering then you could use other toolpaths to do this. But because we are driving it from a sketch our options are limited. 

[doncawley]

Thanks Richard, that defiently looks good in the simulation, ill run in through the CNC later today to see how it works in practice.  I do like this hack though as there isnt any added work for a larger group of models.  A little worried the generated simulation only "looks good" because we cheated the bit and itll look much different when i CNC it all with my real 18ish deg bit.   

Lookingt at the paths it has generated, could I get away with removing one of those extra engraves?   It seems both the 30 and 35 "bit" paths are almost identical and in the middle.

If there is an easier way with a fully modeled design I can absoultly do that!!  The only reason I didnt reccess the lettering in the 3D model is because it was extra time consuming to click the proper sunked geometry and i figured just changing the bottom height would be easier.  

[doncawley]

It definetly worked better than the 1st but the D and O is still fairly noticeable.  If you could share your idea for a fully modeled design that would be great!

I would also happily invite any other ideas the community has while we work on this.