Finish Blend Vs. Finish Flowline

[NeilJ]

Is there anything Finish Flowline can do better than Finish Blend?

[Colin Gilchrist]

Yes, it can machine a single surface without having to create any wireframe geometry.

 

It will also do a good job on a set of surfaces, if all the surface U,V curves flow in the same direction...

 

Blend is much better for sets of surfaces, but it does require you to generate two chains (can be as simple as two lines, or even a rectangle and a point...).

 

There is also no "roughing" option in Blend...

[NeilJ]

Is there a way to change the surface U, V curve flow in Mastercam without creating new surfaces?

[YoDoug®]

This is one that I actually like X3 for. I prefer using the 2D high speed blend then project that NCI onto the surfaces being cut instead of the finish blend. It gives you better lead in/outs and the ability to use the map to highfeed function instead of rapids.

[Colin Gilchrist]

I've looked into it quite a bit, but no, not really...

 

The general rule of thumb is to use blend when it is a problem that flowline can't handle.

 

There is a button on the flowline interface called "single row only" that trys to force Mastercam to evaluate all your surfaces as a "single row" and eliminate the gap retract moves at the surface edges, but it is hit and miss...

 

Your choices are to build wireframe and use blend, or to attempt to rebuild the surfaces and try to get flowline to work...

 

Most of the time I just use Blend, or sometimes Surface Finish Contour, depending on the shape I need to machine.

 

HTH,

[NeilJ]

Thanks Colin, thanks Doug.

[cobra95kev]

Thanks for the tip Doug, I had never done that one before.

 

 

[Trevor Bailey]

if you want to change the UV of a surface, use the MAP.DLL. not the greatest tool, but it is a good starting point.

[NeilJ]

What problems does MAP.DLL have that I should be aware of? Are there any tutorials available on how to best use MAP.DLL?

[Colin Gilchrist]

Hi Trevor,

 

I've played with Map quite a bit, and from what I can tell, it maps surface curves from one surface to another. I have yet to find a way to get it to actually swap the directions of the UV curves on a surface.

 

The best application for Map that I've found is for flattening surfaces and mapping the wireframe geometry from the curved surface to the flattened surface. This tends to be a long and quite involved process.

 

Here is the help file entry for the Map.dll Chook:

Use this C-Hook to map a surface curve from one surface to another. It creates the new curve by copying the u, v coordinates from the selected surface curve to the new surface curve, and connects it to a new parent surface. You can optionally choose to swap the U and V coordinates. The shape of the new surface curve is a function of the U,V coordinates of the selected surface curve and the shape of the new parent surface. Generally, this results in the surface curve "morphing" from the first surface to the second surface.

 

This C-Hook is often used together with the surface flattening C-Hook (Flatsrf) to map curves from the flat to the original surface. You might also consider using the ConsToSpline C-Hook to convert the surface curves into splines.

 

After starting the C-Hook, you are prompted to select the surface with the surface curves. Select the surface, not the individual curves, and press [Enter]. Then, select the surface or surfaces to map to. You can select several surfaces to create more than one set of curves. Press [Enter] when you have finished selecting the surfaces.

 

Mastercam then displays the Map C-Hook dialog box. Select from options that let you swap the U/V coordinates and create points along the mapped curve. Click OK to create the curve and close the dialog box. Or, click Apply to create the curve and leave the dialog box open so you can select other curves. Use the Select button to select the new curves.

 

 

This is exactly what I've encountered...

 

You take existing wireframe and use the Create | Curve | Create Surface Curve command.

 

Mastercam prompts you to select curves that you want to turn into surface curves. This take existing wireframe and turns it into a "Surface curve" entity type. Now you can use Map to transfer the surface curve from one surface to the other. Then you use "ConstoSpline" Chook to convert the mapped surface curves into splines. Needless to say, this is pretty complicated and you really have to have some knowledge and skill to get it to work right. It may work fine in a tutorial sample, but in the real world I have success maybe 70% of the time.

 

Jon, I don't think I've seen any tutorials on using Map. It really won't do what you want it too...

 

Your best bet is to rebuild the surface, which may or may not work for your flowline toolpath...

 

I'll go over this proceedure in a bit...

 

Thanks,

[NeilJ]

Colin, have you or anyone else tried using a product like Rhino (or another product) to solve this problem with using the Flowline toolpath when the U, V curves run in different directions?

 

I asked this question about Rhino:

 

One of my CAM program tool paths wants all the surfaces U, V curves that I'm going to machine to flow in the same direction. If I bring a file into Rhino where surface U,V curves flow in different directions does Rhino have the tools to easily change the existing surface U, V curves so that they all flow in the same direction?

 

 

I got this answer from a McNeel employee:

 

"You can use the Dir command and the command line options there to manipulate the U and V and normal, but in V4 only one surface at a time I'm afraid. In V5, you'll be able tweak multiple surfaces UV at once. For now, it might help to set up a new display mode with the U and V directions indicated by isocurve color.

 

To do this, open Options> Appearance> Advanced Settings> and in the list there select, say, Wireframe and click the Copy button. Then, call

it UV Wires or something and edit the settings on the Surfaces page of this new display mode- you will see a setting for Isocurve Usage where you can change the isocurves to display differently in U and V. Then in this mode, you'll be able to see which surfaces need it, and how to align the UVs in the Dir command."