Oval form cutter

[tony1001]

I was experimenting with an oval form cutter and can't seem to figure something out. I used a parallel toolpath to do the 10° taper and used the radius and floor surface as avoidance geometries in the collision control tab. For the tool axis control, I used surface with tilt, follow surface iso direction, and a tilt angle at side of cutting direction set at -78° (+78° made the cutter come from underneath the part). I get that it is locked at that tilt angle, but what type of tilt control do I need to do to make this cutter reach into the corner where there is still a gap? Can it be done in one toolpath or do I need to make it a separate tool path with a different tilt control?

 

Thanks,

[Chally72]

There are a few ways to get after this. I attached an example file. 

Toolpath 1 is just to show our starting point and what we have to solve. We have a side profile that we need to cut down to the fillet, but starting off with a cut pattern that contacts in the middle of the Oval form profile, we can see how far past our "floor" it would have to travel to respect where we want to start the oval form cut. So, this is what we will attempt to mitigate in the next steps.

Toolpath 2 shows a very simple change- Rather than setting up our floor and fillet with a Trim strategy in collision control, set them to a Tilt to avoid strategy. This will maintain the same contact point on the oval form tool until we start to get into the interference area, and then it will tip the tool farther and farther onto the nose in the last few passes to clean the surface up. Don't be afraid of the blue path lines doubling back on themselves here- remember that they represent the tip position of the tool, and NOT the actual contact position of the tool flute against the surface- which still maintains its nice even parallel spacing.

Toolpath 3 shows a way to feather in this nose tip tilt over the entire path- turn on the TO field in Tool axis control and it will tell the path to enact a gradual FROM/TO contact point change over the course of the entire path. The value in this box is a 0 to 1 value that corresponds to 0 to 100% length of the flute, as an approximate desired contact point. So in this case, I start off at the top of the wall with my oval form cutting roughly in the center of the profile, and feather the contact point towards the tip over the length of the path, so by the time it reaches the floor fillet, the Tilt to Avoid strategy doesn't really have to do any adjusting, because I've already removed the gouge while mostly maintaining the benefits of a big stepdown with small cusp that Oval forms give me. 

This method will also make it harder to pick out a visual discrepancy in surface finish from rapid angle changes or rapid effective cusp width changes that would occur when we suddenly start adding large tilt to the path like we do in Toolpath 2.

Example of Oval tilt.mcam

[tony1001]

Great, thank you for taking the time to look at that!