Stumped by the simplest stuff

[GregHeumann]

This is a 1/2" thick 2.375 brass flywheel to be. I pre-drill 2 holes per slot with an 11/32 drill bit - then I want to REST finish it with a 1/4" end mill. I've tried a bunch of strategies but can't get it to work. The 2D Contour warning is that there is "No rest material is left by rest tool(s)." But there is. Does REST not work after a drilling operation? 

[Anonymous]

Hi @GregHeumann , try 3-D Adaptive with rest machining. Also 2-D coutour with a ramp may work good. I attached a file.

Jason

[DarthBane55]

Rest material in 2d operations are not what you think here.  It does not know that you used a drill before, 2d operations are not aware of the model/volumes.  What it does, is that it lets you put a tool diameter for previous tool used, and it considers the same operation would have been done with that tool, so what would be left with the bigger tool would then be cut with the smaller tool.  So in a pocket, if you have inside corners of R0.25" and you rough with a 3/4" endmill, when using rest for the next operation, you input 0.75 as previous tool diameter, and it would then know that there is material left in the corners accordingly.

In your case, if you want the path to know what is left after the drills, you will have to use 3d operations.  Those are fully aware of what has been cut, when enabling rest machining.

If you are stuck with 2d operation, you would probably have to draw sketches to make it work.

[engineguy]

@GregHeumann 

Just to confirm what the other guys have said 2D operations are not "Model Aware" so the "Rest" option doesn`t work for them.

You were pretty much going the right way with the 2D contour which works fine without trying to use the Rest, see the screen cast below and file attached.

 

[GregHeumann]

Thanks, Fellas- 

Darth, good explanation of REST in 2D . But even with the 3D tool path - the tool path appears to just plow through a lot of material left by the drilling operation - which kind of defeats the purpose (like where I've circled in red.). I couldn't find an "Optimal load" setting in the 3D toolpath to ensure I'm not trying to remove more than 20% of tool diameter. (I know with the shallow ramp it would probably work fine, it just isn't what I expected. I know I could just treat the whole thing like a pocket and not drill at all. But I have been told "the fastest way to remove a lot of material is via drilling" and so I wanted to try that. Am I missing something or is this just "the way it is?" Would YOU just pocket it the whole way with a single end mill and skip the drilling?

[DarthBane55]

To answer your last question, in brass I would just mill is with ramping, yes.  Nothing wrong with what you are trying to do tho, if you want to try it, go for it.  Did you try the "predrill position" in the last tab of your 3d operation?  It should allow to plunge in the hole.