[JoeCraftsman]

Some features are angled (along Z) with a radius edge break.

For speed I would like to do straight milling instead of using a ball end mill on the entire part.

For the couple features that are angled and have a radius edge break I set a boundary which is usually away from the feature less than 1/2 the tool diameter... This prevents the end mill from traveling down the finished wall and speeds up the operation of milling the radius along the edge.

Now, what's the best way to mill radius on a part that is complete and has sharp edges that are not 'flat' (angled)... yet keeping the ball end mill from touching your finished surfaces... such in this example on the 15 degree surface:

[aldepoalo]

I like this part! Great sample, I am not at a computer right now otherwise I would dive right in. I have some ideas about how I would approach this. Is there anyway you can pm me your contact information so we can talk tomorrow?

[jrmach]

Sander and a file make quick work of it.
A 3D Engrave may work with a Round-Over tool.You will have to "lie" to the software about the tool size so as to position the tool in its sweet spot to cut full radius without gouging.Another possibility is see if chamfer is acceptable,that would be the best...Damn Engineers....

[JoeCraftsman]

LOL, I agree... Putting on a nice radius edge break by hand would work but there is a large qty (aluminum) and they are 8"+ long. Unfortunately the smooth edge needs to be there for the application and also required by the customer.

When profiling the sides completely with a ball end mill there is no problem cause it generates a nice radius as shown... but takes sooo long! I've got other stuff to do but just does not make since when I've got a 5/8 end mill with 15deg angle and the .125 corner radius built in (for the larger radius in corner) that will take it in a few passes.

Only problem is having the machine still do the radius edge break without hitting the finished surface.

If BobCAD just had a feature that you could click on the .031 radius and it would only mill that surface and stay away from nearby features (collision).

I've messed around with engraving but nothing has come close yet.

[jrmach]

Yeah,I think for Round-Over tool to work you would have to modify(grind) it.
Well use those tolerances to your benefit.3 place decimal +or- .005 or .010????

[jrmach]

Joe,can you post back on what you decide to do.Am curious,as I have that situation sometimes,although not a big quantity of parts.

[SBC Cycle]

LOL, I agree... Putting on a nice radius edge break by hand would work but there is a large qty (aluminum) and they are 8"+ long. Unfortunately the smooth edge needs to be there for the application and also required by the customer.

When profiling the sides completely with a ball end mill there is no problem cause it generates a nice radius as shown... but takes sooo long! I've got other stuff to do but just does not make since when I've got a 5/8 end mill with 15deg angle and the .125 corner radius built in (for the larger radius in corner) that will take it in a few passes.

Only problem is having the machine still do the radius edge break without hitting the finished surface.

If BobCAD just had a feature that you could click on the .031 radius and it would only mill that surface and stay away from nearby features (collision).

I've messed around with engraving but nothing has come close yet.

I was playing with the multi-axis demo this week, I believe there is a new toolpath that will do exactly what you are asking, including using what BobCAD calls a "Check Surface". Pick the "Drive Surfaces" to machine, choose the surfaces you don't want to machine as Check Surfaces and off you should be. You could probably swing around there a few times and generate that nicely.

[JoeCraftsman]

So, I let the part run as programmed previously with Z-Level Finish and ball end mill, so all my edges were rounded nice but it took a long time.

It was mentioned below to try engrave - I experimented with engrave some more. With 'Mill 3 Axis' then 'Engrave' and using a modified corner-radius tool might get me real close next time. The tool path does follow the geometry on the corner radius that I click.

Also, It does look like the multi-axis is the ultimate solution with a lot more milling options and a couple in particular that will address what I'm trying to do... I'll just have to wait until we have a larger demand for it to justify the purchase.

Thanks everybody for your input... It has been very helpful.

[SBC Cycle]

Yep, if you grind a slight angle relief on the top corner of your corner round, it might get you close enough and it will look nice.

[SeanDa]

3D Engrave will work perfect for this part. I have show an example file of the tool path run through Predator with a modification of the tool type to a radius tool. The path came out exactly as I was expecting it to. I have provided the NC code, the .bbcd file, and a video of what it did in Predator after I made the change to the header tool type.

I have a link below to the file is to large for CNC Zone.

https://docs.google.com/file/d/0ByWS...it?usp=sharing

[jrmach]

Sean getting error when trying to download from your link.

[SeanDa]

Sorry let me get a new link. This time I will use drop box instead of google drive

[SeanDa]

Here is a new link if you can't access the Google drive account

https://www.dropbox.com/s/1emr39sqqp...%20Engrave.zip

[jrmach]

There is something worth mentioning here about the 3D Engraving.There is no comp.Which means that in order for this to work for this particular situation you will have to offset the tool path in cad to be in "harmony" with the "sweet "spot of the modified corner rounding tool.A little of work,but I think doable.

[SeanDa]

Cool thing about when working with the 3D Engraving Toolpath, is that when you have the fillet already defined in the geometry, many times if you work off the bottom edge of the fillet, the corner rounder actually follows that path and gives you the appropriate fillet for the corner. This is only true, however, when the tool being used is the appropriate rounding tool for the radius of the fillet.