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View Full Version : Newbie 4-axis milling not working as in tutorials ?



dwneumann
11-18-2012, 01:35 PM
This is my first attempt at 4 axis milling. I am trying to follow the 4-axis milling tutorials to the letter, but my MadCam v4.3 isn't behaving like this tutorial "www.youtube.com/watch?v=wOYNC_abRTw"

Is the procedure shown in that tutorial still correct or is it obsolete?

I have a 3D model that I want to mill from different sides just like in the tutorial. But no matter which world view I set the construction plane to, it always mills from the top down. The only difference that I can see between my setup and the tutorial is that I have Z=0 at the top surface of the stock (not through the center of the stock as in the turtorial) and Y=0 at the front edge of the stock (not through the center of the stock as in the tutorial) so that I can touch off my cutters to the top of the stock in order to locate Z=0 and so that I can probe the edges of the stock to locate X=0 and Y=0.

So... am I doing this right? How do I get it to cut from different directions (and have the clipping plane set to the centerline of the part no matter what direction it's cutting from) ?

thanks for all your help...... this forum is awesome.

svenakela
11-19-2012, 06:45 AM
Haven't watched the clip you linked to, might be old though.
Here's how I do indexed 4-axis. I always rotate the model instead (I rarely change Cplane).
MADCAMCNC: 3D toolpaths for 4-axis indexing (http://madcamcnc.blogspot.se/2012/06/3d-toolpaths-for-4-axis-indexing.html)

dwneumann
11-19-2012, 12:36 PM
thanks svenakela, I will try the rotate method rather than the c-plane method.

I'm confused about two things in your video however (sorry :-)

1) how do you get MadCam to emit G code that rotates the A axis between the three toolpaths (or do you do that manually)?

2) you define Y=0 and Z=0 to be in the center of the part. Since your zeros are not on the surface of the stock how do you edgefind a reference datum to locate the workpiece, and how do you touch off to locate Z=0 at each tool change? (do you manually enter a non-zero value into the DROs to locate the stock and again for Z after each tool change?)

Will it work to model the part so that X,Y,Z=0 are at the surface of the stock (the A axis is parallel to X but offset from it) and then rotate the stock around the world origin rather than around its center?
thanks....
dean

svenakela
11-19-2012, 02:42 PM
You can have the zero point where you like.
I prepare all the tool paths as normal 3-axis CNC and in the end of the clip you'll see that I change the machine setup to a 4-axis. That will let the simulator and post processor add the rotational movements (indexing) for you.

I home to absolute coordinates and touch off at a given position. I know by then where the mid of the rotational axis is. But as I wrote, you can have zero where it works best for you.

dwneumann
11-20-2012, 11:37 PM
thanks for your help svenakela. I'll keep plugging away trying to use your method but my program isn't behaving the same way yours is ...