4Th axis help

[bhorstTGM48]

I am trying to cut the face of this part, it is close to what I want. I want it to make a complete revolution 360 degrees while ramping down in Z. It currently only goes 1/2 way and then back the other way, thus climb and conventional cutting. How can I get it to just climb cut?

[chris.coleQDYFL]

Hello, bhorst.

Long time, no speak. I'm still around, but they keep me in the basement where I just sit among the boxes and mumble about my red stapler.

If you want to use a groove, you are just going to need a much longer curve. In order to be continuous, the groove would have to be long enough where the ramping never has to change direction at that 5-degree ramp angle. But then you will run into more problems. At some point, FeatureCAM will think you will have run out of flute length, so it will start changing your ramp angle accordingly. Actually, I couldn't get it to work correctly with a groove.

Here's another idea using an Flowline surface mill toolpath. Please take a look at this file. I think it's pretty close to what you want. If it looks good, let me know if you have any questions and I will walk you through the steps. It's a lot to explain, so I might just send you a video.

[bhorstTGM48]

Good to hear from you. I hope it is a good thing that you are still around?  😁  I only have FC Premium, I am not sure if that is a problem but when I open your file it appears to have fallen apart. I can see the feature you created, and open it up but it does not have anywhere to select a tool? 

https://www.screencast.com/t/5lZaf74C

[chris.coleQDYFL]

Oh, man. I have been out of tech support for too long. That's the first question I should have asked - my solution requires Ultimate. Let me keep scuffling with it and see if I can come up with something else.

[chris.coleQDYFL]

OK, tell me how this looks. I decided to give the groove another try, but use a different curve. With a simple groove, your curve doesn't have to be flat in the XY plane.

So, knowing that, I used some construction geometry to construct a hypotenuse that extends off in the positive Y direction and use it as the profile curve. This will allow your tool to descend in Z. Wrapping that curve creates a spiral. You can adjust the pitch of that descent by moving ln7. Since I snapped the hypotenuse to the intersections of the rectangle, moving ln7 will take the feature curve with it.

Let me know how this goes!

[chris.coleQDYFL]

Try this file instead - I found a mistake in that last one.

Same solution applies. Just change the endpoints to adjust the pitch and the depth.

[bhorstTGM48]

Very interesting, When you say change the endpoints do you mean the angle of the line? What controls the total depth of cut? How did you come up with the total length of that line? The code very interesting, 4 ish lines of code?

[chris.coleQDYFL]

The depth of the groove feature is somewhat arbitrary, because the spacing between the passes is determined by the angle of that line. If you change Y value of the upper end of the line, it will become steeper or shallower. That will control the tightness of the helix. If you want more "coils" make the Y larger - less, make it smaller. The more coils, the smaller the stepdown.

The Z value of that endpoint controls how deep the tip of the tool goes (+ the depth of the groove.) In this case, if Z=0, then the tip of the tool will go past center by the depth of the groove.

For the origin of the line, you will just set Y to 0 and Z to the height that you want the tool to start (minus the depth of the groove.)

For both endpoints, X will be the finish position minus the tool radius.

Clear as mud?

[bhorstTGM48]

in think it all makes sense and you have answered all of my questions except the total length of the line. How did you come up with this value?

[chris.coleQDYFL · Accepted solution]

It's trial and error - at least for me. I measure between the toolpaths to try to get an idea of the stepdown, and adjust accordingly. For example, a Y endpoint of 500 gave me a stepdown of approximately .320.

Of course, you are going to have to be very careful with this since the tool is over the center of rotation. It's going to be tough to keep material from being jammed up into the center of the tool.

[bhorstTGM48 · Accepted solution]

If I zoom in on the simulation this is what I am seeing, is there any way to fix this?

https://www.screencast.com/t/Hya0koScWkNe

[bhorstTGM48]

What I am seeing is that if I keep tweaking the line it will get rid of this. Thanks for all of your help. I will keep you posted once I am making chips.