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View Full Version : Need Help! Need some ideas on how to machine this part please



FoxCNC1
04-20-2015, 03:30 PM
Hello everyone,

I have not done much 3D in RhinoCAM and my wife has asked me to make her a small frame.
I constructed the model of it, got an approval ;) and now I need to make it.

I decided to machine each other 4 side separately and profile them to a crisp 90 angle and then glue them together.
I am at a loss on how to machine the top slanting face below. If I can please get some help I would appreciate it.

The entire part is 0.25 tall. The length of the part is 5.5". Its a very small frame for one of her craft projects.
Thank you

PS: IGES file attached.

http://i10.photobucket.com/albums/a146/Profoxcg/3dview_1_zps0mheu268.png (http://s10.photobucket.com/user/Profoxcg/media/3dview_1_zps0mheu268.png.html)

awerby
04-20-2015, 03:45 PM
If it were me, I wouldn't bother trying to machine the miters; I'd just machine it straight and cut those later with a saw. You never get a very good cut routing wood against the grain like that. If your machine is big enough, you can probably cut all 4 pieces at once. In any case, it's good to leave something at the ends to hold onto while you're routing on the middle. As for the slanted face (which I assume is on the underside in your illustration) I'd cut that in a separate 3D machining operation, using a ball-end endmill so as not to get the "stairstepping" you'd get with a flat-end endmill.

Andrew Werby
ComputerSculpture.com ? Home Page for Discount Hardware & Software (http://www.computersculpture.com)

FoxCNC1
04-20-2015, 04:41 PM
actually the bottom is flat. the slant is the top part. I see where the confusion is : I chose a poor angle to post.

hub
04-20-2015, 05:01 PM
Maybe make a slanted part below to match the angle, then just cut normally.

FoxCNC1
04-20-2015, 05:32 PM
There is not slanted part below. The only face that is slanted in the one that is selected. (curves).
everything else is orthogonal.

I attached the file in hope some can look at it and help me figure it out. I am not sure what operation to use. I have tried to use a horizontal finishing on the slant with a ball end but the curves seem to limit the cutter. Its almost as if I need a "facing" operation on 3 sides at an angle.

There is a "Projected pocketing" But doesn't seems to clean it up properly. Let me play with it a bit and I will report. I think I just need to add some "clearance planes" and just extend the face I want to mill.

PS: What is the rule of thumb is any when choosing a 0.25" ball end versus 0.125" etc?

hub
04-21-2015, 04:01 PM
There is not slanted part below. The only face that is slanted in the one that is selected. (curves).
everything else is orthogonal.

I attached the file in hope some can look at it and help me figure it out. I am not sure what operation to use. I have tried to use a horizontal finishing on the slant with a ball end but the curves seem to limit the cutter. Its almost as if I need a "facing" operation on 3 sides at an angle.

There is a "Projected pocketing" But doesn't seems to clean it up properly. Let me play with it a bit and I will report. I think I just need to add some "clearance planes" and just extend the face I want to mill.

PS: What is the rule of thumb is any when choosing a 0.25" ball end versus 0.125" etc?

What I meant was to add a slanted part below, like this: (The part being the red one)
277550

That way the surface would be easy to machine.

FoxCNC1
04-21-2015, 04:55 PM
oh I see.. good idea.
I found the at least in the simulation, a 3d projected pocket works. I will have to try physically.