Mill window does not follow reference part accurately

[Spikaart]

Hi NC guru's. I'm trying to figure out why my mill window does not follow the outside of my reference part accurately. It seams to smooth out one corner that makes for inaccurate sequence for milling. See attach file showing a picture of how the mill window looks.

Are there settings to increase how "tightly" the window follows it's parent?

Thanks in advance for any help you can offer.

Steve

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[DanielSantos]

Hi Steve,

Have you tried to use absolute accuracy for both <u>reference part</u> and the <u>MFG assembly</u>?

Config.pro option: enable_absolute_accuracy = yes (Hidden option)

It will force Pro/NC to consider the value you entered as the smallest geometry in your part. It's very useful to get better results for arcs in trajectory milling, profile milling and toolpaths that are written to work with ruled surfaces.

Your issue it's interesting. Please let us know if this solves your problem.... or if not so that we can understand the source of your problem...

HTH

Regards,

Daniel Santos - Sr. NC Programmer / CAM Support

Liebherr Aerospace Brasil

[Spikaart]

Thanks to everyone for their responses. Below is a summary of what I found out.

1.Accuracy settings have no effect on the mill window.I generally use .0005 absolute but tried other settings with no change in the window.2. Mill Windows do not follow the geometry of the part precisely. They are not intended to. They generally have a slight offset from their reference part but in some cases can cut accross corners etc... If there is a smaller surface present then the mill window will adjust to capture that surface (I added a radius to the corner that the window was cutting accross and the window then followed around the part properly). There is no known problem with milling sequences seeing the appropriate surfaces even when the window violates the part slightly. According to Lee G. at PTC there are no options to tighten the mill window. Lee pointed out that trying to drive a trajectory sequence using the mill window's curve would not work (which is what I was trying to do).3. Lee also pointed out that there is a feature called a silhouette curve which would probably work for driving a trajectory sequence around the outside of a part. This is only available in the Tool Design option (which I do not have). That would make a pretty nice enhancement to NC!What I was trying to accomplish was getting some trajectory milling sequences to go around the outside of a block in such a way that we could re-use the sequence with derivative parts and the trajectory would automatically update to follow the outside of the block regardless of it’s shape. Sounds like maybe the Silhouette Curve could do that but I can’t pay for the Tool Design option just to get that capability. In the mean time we’ll build a curve in another way and the NC programmer will just have to make sure it’s right before using it.

Thanks for all the input!

[DanielSantos]

Thanks for your feedback Steve,

We all learned something new here...

Regards,

Daniel Santos - Sr. NC Programmer / CAM Support

Liebherr Aerospace Brasil