5 axis swarf question

[Jim at Gentex]

I have a vertical wall that is a surface projected onto another surface. I tried to select a swarf 5 axis path with the walls as surfaces instead of chains, and the bottom surface as the tip control surface instead of the lower rail, but the outcome was strange. If I selected the top edge of the wall surface when prompted, the toolpath would write 'upside down'...a common error. However, when I went back in and tried again selecting the bottom edge of the wall surface, clikced on OK, and nothing happens. No toolpath is generated. I tried several times from scratch with the same result.

 

I ended up creating splines on the top and bottom edges of the wall, and defining the walls as chains and the lower rail as the tip control, and it works fine...but I am wondering why it didn't work correctly with the walls defined as surfaces. Any thoughts?

 

Thanks in advance.

 

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Jim teh dyslexic NCN Mogprammer.

[Guest CNC Apps Guy 1]

Dunno. I ALWAYS use chains. You get more Sync control that way.

 

I'd be willing to bet the surface normal flips. One problem with using surfaces for walls is that a trimmed surface will give you a different result from a Coons Type surface.

 

James teh HTH

[crazy^millman]

I agree with James I always use chains for 5 axis swarf but I will create points along the chains and then sync using the points. If doing a part as you described I would look at 5 axis curve and then create some tool path control lines and think you might fine this does a really good job.

 

HTH

[Jim at Gentex]

Thanks for the responses.

The part I'm machining is a polycarbonate lens for a flight helmet. I've used 5-axis curve toolpaths in the past, but the walls of the lenses would sometimes have material removed where it shouldn't be due to the fact that there is no tool axis control (or I didn't utilize it properly)when following the single spline that traces the trim line of the lens. I like the idea of the swarf toolpath because it gives me EXACTLY what the model shows since we can use the vertical wall as the tool axis control feature, thus ensuring no undercuts. The thickness of the lens is only .090, so any deviation in the tool axis vector is negligible over such a short distance, but I like to be as accurate as possible. (We are all kind of anal that way, aren't we?) And since the wall is a surface, it would be simpler for me to pick it instead of creating edge curves and splines. But if I must...I must.