finish parallel

[Jmick]

When I use finish parallel on a solid model it seems like it will just come up short at the end of its toolpaths leaving a small radius at the end of the cut. What I mean by that is if I'm machining a small 10 deg. slope on the end of a part it should generate enough code to continue the cut beyond the ball endmill geometry leaving the last cut almost in air. What am I doing wrong?

My step down on the .250 ball is about .0045

[strabe]

I always extend my surfaces to avoid this problem.

[Jmick]

That will work but that seems like a work around.

Shouldn't it be easier then that.I mean it seems like youshould be able to work directly from a model without making extra surfaces.

[strabe]

Well I guess that's true but an extended surface guarantees or "forces" the cutter past an edge or whatever. I hope one of the guru's chime in on this cuz I'd like to know why it's this way too.

[Jmick]

Well I'm out of here for A LONG WEEKEND hopefully someone has the answer we need. Thanks again Strabe. I'll check back Monday.

[Redfire427]

More info is needed to answer your question. Lets take a rectangular planer surface tilted at 10 degrees. If you are cutting to the centre of a boundary which is the outside perimeter of the surface, then the area on the low side of the surface will not be cut.

A way to cure this is to set "only between surfaces" under the advanced settings tab. Keep in mind that there is a chance of gouging adjoining surfaces if they are not chosen as check surfaces. You would also not use any boundaries.

Another option is to use the c-hook " create boundary" and make a cutter contact boundary.

 

There are many ways to accomplish what you are trying to achieve.

[Colin Gilchrist]

If the surface is "open" at either end, in other words, you don't care if the endmill travels beyond the edge of the surface you are cutting, there is an option to extend the toolpath motion beyond the edge of the surface.

 

Go into "Gap Settings", under the 'Motion < Gap size, keep tool down section, you can use 4 options: Direct, Broken, Smooth, and Follow surfaces.

 

The first three options will allow you to use the "Tangent line length" extension options.

 

This will allow your tool to travel beyond the surface edge...

 

I like smooth the best...

[MotorCityMinion]

Open at both ends is more appropriate when using Gap settings as the line length extension starts before and after the surface edge using the same value for both sides of the surface.

 

The direction tab at the bottom of the page offers up more options for controlling the entry and exit independent of one another. Works good for creating a start/entry point when you need to control where the cutter starts and exits,

 

I think a mixture of the two will work also.

 

[ 07-23-2009, 09:18 PM: Message edited by: MotorCityMinion ]

[Josh T™]

+100 to Colin

 

I almost always do exactly what he just mentioned on all Surf Finish Parallel Paths that are open. The Tangetial Line Length extention works great.

 

Josh

[Tyler Robertson]

I do the same thing as Colin, even with robots.

[Jmick]

Thanks guys. I use tangential line length all the time and it works great on the start and finish ends. This surface is open on all 4 sides. Is the only way to get it to extend on the non start and non finish(tangent)sides?

[Mike-T]

Options are limited with working with the solid,

When I need to, I'll create a surface off the solid, then un-blank the parent and create a boundry. Another way would be to create a fence surface at the edges of the surface you want to extend.