Profiling a radius with back side of key cutter

[pwolfe]

I have a boss extruding from a wall. It is down inside a part no other way to get to it but with a key cutter style tool. I need to profile a concave radius on the underside of the boss. Mastercam wants to machine a convex radius, putting the cutter on the wrong side of radius, coming thru part not on the inside.

[Guest]

Moved to the correct forum

[Greg_J]

You need to change your surface normal, it's under the edit tab at the top of the screen then when that menu opens it's at the bottom of that menu.

 

I use surface finish flow line.

 

If you can control how the tool will move on the surface in the flowline button.

 

Click on Step direction and make the tool start at the bottom of the part.

 

If your toolpath is on the wrong side click the offset button.

[pwolfe]

This seems to be the way to go. But i can only cut with leading edge of cutter, and when I try using cutter that I defined so that it will use trailing edge it doesnt work. There is no tool path preview.

[Matthew Hajicek - Singularity]

You may need to do a wireframe toolpath and shift it's drive geometry down by the thickness of your key cutter.

[Rotary Ninja]

I have never tried it, but can you use a lollipop tool and define the tool using the custom geometry to be the shape of your key-cutter? I've never used a lollipop but I have always wondered if that would work or not for this type of surfacing?

[MotorCityMinion]

The keyway cutter WILL work. No custom tool is needed. If the geometry is circular and consistant in size throughout it's path, FLOWLINE is the ticket. Surface normals must be correct. Use the directional controls to lead-in and lead-out. The keyway cutter will cut with both sides of the cutter without shifting geometry or doing any wierd mathamajical calculations. If only the leading edge of the cutter will do it, something else is wrong.

[pwolfe]

Went back and used a standard key cutter and everything works great. Thanks

[Illuminator]

I've used surface finish contour with success undercutting angled models etc when nothing else would come close to working. only problem is setting correct containment for shank etc. Then you can utilize the lead in and outs to clear protrusions.

[Chris Rizzo]

Late to the game here, but:

 

Check your surface normal. Edit > Set Normal.

 

Surface finish contour (or rough, they are the same) and flowline are the only toolpaths to support undercuts. Contour has fantastic control for extending the toolpath and lead-in's and outs. Also if needed, use the advanced settings button and select roll tool "only between surface edges".

 

hth

[Guyinthedesert]

Late to the game here, but:

 

Check your surface normal. Edit > Set Normal.

 

Surface finish contour (or rough, they are the same) and flowline are the only toolpaths to support undercuts. Contour has fantastic control for extending the toolpath and lead-in's and outs. Also if needed, use the advanced settings button and select roll tool "only between surface edges".

 

hth

 

I just did a part where I has to surface the underside of a flange with a full radius keycutter. I tried different toopaths, and had the best luck using morph between curves set to 3 axis.