Surfacing issues

[Scareyguy]

Having limited success programming the radial ramp of this part (see attachment). We don't have a 4th axis on the mill, so looking for advice on best way to program. We've tried Surface Finish Flowline, had a little success with Surface Finish Parallel, but even with max. stepover @ .001" , the part isn't looking good.

Any suggestions?

 

Thanks very much!

[Rotary Ninja]

Try a Surface Finish Blend.

 

[uncle_dolan]

Having limited success programming the radial ramp of this part (see attachment). We don't have a 4th axis on the mill, so looking for advice on best way to program. We've tried Surface Finish Flowline, had a little success with Surface Finish Parallel, but even with max. stepover @ .001" , the part isn't looking good.

Any suggestions?

 

Thanks very much!

 

What problems are you having with surface finish flowline? I would probably be trying to use this toolpath. That Blend Toolpath looks quite nice too Kevin

[Rotary Ninja]

Lil' something I learned in group from MCM

[Rotary Ninja]

I would probably offset the inside chain out a couple thou for the surfacing path to stay off the wall then drive a 3D contour using the upper breakout of the rad to finish the wall.

[Colin Gilchrist]

I would probably offset the inside chain out a couple thou for the surfacing path to stay off the wall then drive a 3D contour using the upper breakout of the rad to finish the wall.

 

3D contour doesn't support offsetting the tool tangent to a surface. So you can get gouging on the surfaces. I'd do the blend, then use project to creat the final pass. This usually involves taking the floor surface, and extending it out so that you have something to "project" onto.

[Rotary Ninja]

Huh? You lost me.

 

I meant offset the inside chain of the blend toolpath out a couple thou so the blend toolpath doesn't actually finish the wall. This is actually .025" for clarity...

 

I should add that I offset the green geometry you see in the first picture I posted here. The arrow in this pic looks like I am pointing to the 3D chain but I am just illustrating the distance the toolpath stays off of this chain.

[Rotary Ninja]

Then use the 3D contour to finish the wall. Chain the upper contour, in linking parameters set the depth to incremental and give it a -.250" for half of a 1/2" ball endmill.

 

Here I used multi passes and one finish pass. Ya can't really see them though because it was a .002" stepover.

[Rotary Ninja]

Better view...

[MotorCityMinion]

Some surfacing tomfoolery.

 

Create dummy drive surfaces, extending the ear by your tool rad. (Green in the picture using a .25 ball). This will assist in keeping the tool down and can be used in a 3D roughing strategy where the tool enters the cut in a sane fashion, cutting with the side of the tool at full depth.

 

Run a flowline path in the corners. While in back plot, save that as geometry to a new level. Change the color on the set of curves produced at the outer most cut to a new color but not the lead-in or lead-out. (Flowline saved picture). That will be used as your second drive curve in a SF Blend tool path. Create the first Blend curve using the true outermost radius of the ear and remember to extend it (.125 min.) far enough to allow the tool to get to the bottom of the part.

 

Now create a SF Blend tool path before the flow line path. Use depth limits (deepest radius point plus half the ball) on the flow line path as we don't need to machine the entire vertical area of the ear near the bottom. Apply direction control to both tool paths accordingly.

 

HTH, MCM.

[Scareyguy]

Many thanks to all for your help! There are still some issues to work out as we're switching from stand alone MasterCam & learning MCam for Solidworks, but looks like Surface Finish Blend & 3D Contour should do the trick.

 

Cheers!

Steve

[brandon b]

Blend is my choice. I recently starting using blend.Its an awesome toolpath.

 

Didnt even need to program it for you. rotary did exactly what I would do.

[drafting3]

i worked through this using rotary's method. my 3d contour kept gouging the part slightly. (probably .001") any idea why this would be?

 

 

MCM, that toolpath is beautiful. I am going to work through your method next.

[Brewster]

The gouge is because the 3d contour tool path doesn't compensate for the tangency of the ball end mill.

[Colin Gilchrist]

i worked through this using rotary's method. my 3d contour kept gouging the part slightly. (probably .001") any idea why this would be?

 

 

MCM, that toolpath is beautiful. I am going to work through your method next.

 

The reason is exactly what I mentioned above. 3D contour does not compensate properly when cutting down a radius like the one you've shown. You need to use a Surface toolpath, which is designed to properly compensate for the tangent point of the tool. Plus 3D contour has no support for anything like a Check surface, which you can use to keep the tool away from an area.

 

Check out this example file. There is a .125 radius on the angled bosses, that blends into a .093 radius. This .093 radius blends into a .03 radius on the floor.

 

If you just try and use Wireframe with 3D Contour to drive this path, then it will take a lot of work to get anything close to correct, and you'll spend a huge amount of time tweaking the geometry to get it to work. It is much easier if you just use a Surface toolpath like Project.

 

In this example, I've created a 2D contour above the part, and used that as the "source" for the Project toolpath. Notice that the tool is able to drive all the way around the circular boss, and compensate properly in Z for the varying surface depths...

 

Hope that helps,

 

Colin

SURF PROJECT VS 3D CONTOUR_VARIABLE FILLET.zip

[MotorCityMinion]

Saving the flow line as geometry shows how the path compensates for the tangency of the ball end mill. This is about as close to tangent as your going to get. Using this as a drive curve for the blend tool path eliminates wasted moves, over lapping, or not cutting enough. I had to use surfaces as the solid produced hops and waves in the blend tool path. Exlax.

[Oscar R.]

i worked through this using rotary's method. my 3d contour kept gouging the part slightly. (probably .001") any idea why this would be?

 

This ^^^^ is because of this VVV

 

The gouge is because the 3d contour tool path doesn't compensate for the tangency of the ball end mill.

 

When I need to get a surface profile like that I'll try blend but prefer a projected toolpath with accuracy setting on high and using some tweaked geometry as mentioned by others.

[Rotary Ninja]

3D contour doesn't support offsetting the tool tangent to a surface. So you can get gouging on the surfaces. I'd do the blend, then use project to creat the final pass. This usually involves taking the floor surface, and extending it out so that you have something to "project" onto.

 

I see what you are saying now Colin. You misunderstood my original post. If you read it I mentioned stay off the wall a couple thou with the "blend". I think you thought I meant to offset the 3D contour, which is not what I said. In my example that multi-pass on the 3D contour would leave a gouge. I only did the multi-pass in my example because I offset the blend .025" for clarity. My mistake.

 

But on an actual part I would offset the blend geometry by a thou or two and surface both ears. Then I would run a 3D contour all the way around the part as long as there was enough room to do so. I don't like to surface right up to a vertical wall. At zero offset a 3D contour would work just fine and look much better IMO.