Problems with 5 axis parallel toolpath

[b.mcg]

Hi all

I'm having problems with this parallel toolpath and was wondering if anybody had a solution. I'm currently using parallel with multi axis enabled driving it from a curve, the toolpath itself works, however when running the toolpath on my Hermle C20U, as the tool reaches the summit of the part, rather than rotate round and follow a curve it spins at the top leaving a blemish in the part.

As you can see from image 1 that is the toolpath that fusion has generated, image 2 is a closeup view of the toolpath and you can see that the tool axis vectors are doing an unwanted motion which is resulting in the tool spinning at the top of the part. Has anyone had this problem before, or better yet got a solution?

Thanks in advance

Image 1

Image 2

[b.mcg]

I think I've found a solution, however I'm not 100% understanding of how this works. I thought that directing the tip of the tool towards a curve would mean that the curve would have to be below the part in order to direct the tip of the tool around the part, however driving the curve from above the part has fixed my previous issues with the unwanted motion at the top of the part. Could anybody shed some light on this? 

[seth.madore]

It's going to be hard to counsel you on the behavior without seeing the toolpath itself. Could you share your Fusion file?

File > Export > Save to local folder, return to thread and attach the .f3d file in your reply