CNC Router Artwork Prep macro

We use Coreldraw to prep our artwork before we cut something out on our CNC Router. One of the things we have to check for everytime, is that the router bit is going to fit everywhere around the letter (inside and out) as it cuts it out. Basically we do that currently by drawing a circle the diameter of the bit, and dragging it around to the narrow areas of the letter, and seeing if it fits. we will then change the artwork to reflect that and send the customer a proof. So for instance:

The circle represents the size of the tool (which does vary, so that would need to be adjustable) and it isnt going to fit through that narrow area. So we would need to show the customer what it would look like if we cut their artwork as is.That obviously doesnt look very good, so generally the customer would request for us to alter the artwork so that it looks better after being cut. We also will fillet all the inside corners because the tool cannot get all the way to the corner as shown below
So if the customer is expecting that deep cut, it isnt going to happen, it will look more like this
Which isn't usually a problem as long as they are expecting it.
So to sum up this post, we need a macro that we can specify a tool size, have it check for any areas around the letter that it wont fit through, and close those areas up as shown. And then add a fillet to all the inside corners (any corner less than 180 degrees. all outside corners will turn out fine) of the radius of that selected tool. I have tried a few different things on my own, and come nowhere close to making this happen. I know that is a lot of info in this post, but i hope it made sense. Is it possible to do this? or is it just wishful thinking? It would save an incredible amount of time.
  • Just thinking aloud on this ...

    It will help if you first find a manual method of steps that would predict the result, then try to automate those steps with a macro. The first step would be to eliminate manually dragging around the circle, because that's not easily automatable.

    I'm not sure if this will work in all cases, but here's something to try ...

     

     

    The black is my test object. For the moment I'm assuming just a filled object. If it had an outline, you would need to convert that to an object before beginning,

    The red is a construction line created as a 2mm contour hair outline without fill, then broken apart from the original. It represents the path that the cutter will take.

    The green is a duplicate of the red, given a round pen with a 4mm diameter. It represents the material that will be cut away and needs to be arranged behind the red.

    The yellow is a 4mm outline of the original black. The outline needs to be converted to an object and placed behind the other objects, in order to highlight the uncut material.

    - - -

    Next step would be to see what happens with multiple objects. I think in principle the inital boundary should work around the multiple objects, but I know people have reported cases where the boundary does not work.

     

     

    • Applying that to a more complex case also seems to work.

      Here's an example:

       

      Or slightly neater, with the green changed to white and the yellow to red...

      • I can see where a macro would be handy for that. It would be nice to have a dialog to choose the diameter of the cutting blade too.

        Myron

        • I hadn't considered that approach. mine was more complicated :) I was trying to use the blend tool around the outside to get those paths. I have no idea why i didnt think of it that way. I think you are on to something.