One of the family of parts I design and manufacture is extrusion dies for Polin Depositors. One of the recent designs is one you have seen in other posts as the Guitar Die. Soon if you go to the Music City Arena in Nashville you may just find a guitar crouton next to your salad or maybe a chocolate chip cookie made with this die for the Polin Depositor.
Now this part has presented problems before with finishing where the corner round goes into the cavity. The way I have had to deal with this to prevent stair stepping in the past has been to basically create three or four cut paths to accommodate varying degrees of slope.
Besides the Volumill routine in CAMWorks for Solid Edge (CWFSE) my second favorite tool path is constant step over. This gives me a constant step over based upon the distance across a face and not just in “Z” or “X-Y” as was my previous fate in life. Now a word of warning here. This tool path follows contours it assigns across your part for maintaining this constant step over. This can result in gouging if you are using this path to cut down to a face. The way to avoid this is to create a contain or avoid feature and this will stop the tool path from gouging the floor of the part.
Is this not a beautiful thing? It did not matter where I looked in these cavities all the tool marks were completely concentric. I used a sketch profile around the cavities for containing and picked tool on the profile and I have a perfect blend going into the hole and then completely down to the bottom. Now keep in mind the finish can be as fine as you want it to be if you are willing to spend the cutting time to get there. This quality of finish is good for this type of application and requires nothing finer.
I can see that many of my 3D parts will require two tool paths only. Volumill with intermediary step cuts at sufficiently small cut amounts to allow for going directly into the constant step over finish tool paths.