Clarification on radial thickness use for Offset Finishing

[Edwin.Elston]

I have a need to leave a small amount of material when performing Offset Finishing, I believe this should happen using Radial Thickness. The image shows a simple rectangle pattern using a 0.05 mm stepover and 0 Radial T, the distance from the orange pattern is exactly 1/2 stepover (0.025 mm).  My expectation was that this first offset from the pattern would be cutting tool radius but that doesn't seem to be the case - this would be better if I knew how to force radius rather than 1/2 stepover for 1st offset.  Can someone comment as to why the 1st offset is 1/2 stepover rather than 1/2 diameter?

So to increase the 1st offset, I thought I could add Radial Thickness, as an example the image below shows a value of 0.04 mm but the toolpath does not change at all.  What do I misunderstand here please?  If all worked as I expected, the outermost path should have been offset by 0.04 + 0.025 mm from the pattern, right?

Thank you for any input.

Ed

[Sean570]

The radial thickness is to keep the toolpath away from the model radially, not the pattern. The pattern is only need if you want to define the shape of the offset that is projected onto the model, it does not use the pattern to limit the boundaries of the toolpath.

[Sean570]

The help menu shows how this is used pretty well.

[Edwin.Elston]

That part I understand, but we frequently use patterns that were created from a model and those are selected in the Offset Finishing drop down. So when you say it does not use the pattern to limit the boundaries of the toolpath, we actually were instructed to copy the pattern we want to a boundary which we use in the limit section. I'm trying to find a simple way to leave a small amount of material so I think we must re-think our approaches.

[Sean570]

I guess I don't understand the reasoning behind your process? Is there a wall in your part at the edge of your pattern that needs to be avoided, or are there surfaces to avoid in the real world that aren't modeled? I just don't think it's clear what you are trying to leave thickness on?

And if you really need to have the boundary changed to leave thickness (which seems odd to me?) you could copy the pattern as a boundary, and just offset your boundary inward by a certain distance.