MCX6: Using 4th Axis for Rotary Indexing

[ccs86]

Hi guys,

 

I think I'm on the right track here, but would love a little insight...

 

I am going to manufacture a connecting rod, and to avoid multiple part setups, I would like to use the 4th axis and machine from round bar like this:

 

 

My general strategy has been:

 

- Start with WCS/Tool/Comp planes all set to top, do the top paths

 

- In subsequent tool paths, change the Tool/Comp planes to Bottom, Front, and Back, respectively, leaving WCS as Top.

 

- Also enabling Rotary Axis Positioning about X in each tool path.

 

 

In verify, everything looks great. The tool attacks from the intended orientation for all 4 tool planes. However, in the G-code generated (Haas 4 axis, for use on a VF-2), I noticed something weird. It starts with A0, moves on to A180 (great), but the final two setups call A-90 and A-90 again. I was expecting an A90. Also, it seems to be creating a new WCS for each, ie G54, G55, G56.

 

Is it possible that I can have everything coded in G54, just using A0, A90, A180, A-90 to index the part?

 

Thanks so much for any help!

[Jayson Kramer]

For starters the bottom default WCS will not work as it flips about the Y axis so you need to great one.

A quick easy way to lock the offsets is go into the view manager and set all the WCS planes you are using to off sets of 0 this wil be a start.

 

PS are you an instructor?

[RayD]

You have to create a "new bottom" and "new back" plane, the easiest way is to use rotated planes. Mastercam sees the default Bottom, Back, and Left Planes looking through the part.

 

You don't have to use "Rotary axis positioning", setting WCS=Top > Tool Plane="New Bottom" > Comp Plane="New Bottom" will result in A axis positioning of 180 when you post.

[ccs86]

For starters the bottom default WCS will not work as it flips about the Y axis so you need to great one.

A quick easy way to lock the offsets is go into the view manager and set all the WCS planes you are using to off sets of 0 this wil be a start.

 

PS are you an instructor?

 

 

 

So, are you saying I should have a new WCS assigned for each orientation?

 

I haven't used offsets before. What will setting them to 0 do? Does that keep the machine orientation correct when switching WCS?

 

Nope, I'm a student. Why do you ask?

[ccs86]

You have to create a "new bottom" and "new back" plane, the easiest way is to use rotated planes. Mastercam sees the default Bottom, Back, and Left Planes looking through the part.

 

You don't have to use "Rotary axis positioning", setting WCS=Top > Tool Plane="New Bottom" > Comp Plane="New Bottom" will result in A axis positioning of 180 when you post.

 

 

 

I did notice that the Back and Bottom planes have a reversed X axis orientation. Is that part of the issue you are talking about?

 

Well, that is a little simpler. So, what is that rotary axis positioning for then?

 

Thanks guys!

[Rotary Ninja]

Setting the offset setting to 0 for each view you are using forces G54 to be output for each of your rotations.

 

Here is what I do when I start a part like this. Especially when I know I have to machine at A0, 90, 180, and 270...

 

For starters I usually try not to alter my main views i.e. Top, Front, Bottom, Right etc. I copy the Top and Front to a new view and rename them accordingly. Top is A0 and our front view is A90.

 

Open your WCS (bottom-right corner of the screen). Right-click on the top view and select copy. Name it A0. Do the same for the front view. Depending on which way your rotary rotates and which way your machine is setup name this view accordingly. I think the default is A270 or A-90 whichever you prefer.

 

For the back and bottom view use the Dynamic WCS function. Switch to Isometric view. Click the WCS icon in the bottom-right corner of the screen again but this time select Dynamic WCS. Place the gnomon at the origin. Click the letter "Z" on the gnomon and rotate to point the -Z- axis toward your back view. Click OK. Name your view with the appropriate rotational angle (our back is A270). Put a check in the box under Work Offset and set it to 0. Make sure "Set new origin" is unchecked. Click OK.

 

For the bottom rotation (A180) do the same. Just rotate the -Z- axis of the gnomon to the bottom.

[ccs86]

Rotary Ninja, you are awesome!

 

I'm going to work on this today and hopefully cut tonight.

 

Thanks everybody for your help!

[ccs86]

Which plane do I set the Work offset to 0 for? I tried it with all planes I use, but get errors about that.

[Rotary Ninja]

Ignore the errors. They are just telling you that work offset is already being used for a different view. Just click OK each time.

 

Edit, I usually set it to 0, then hit enter 3 times. Just a habit

 

If you already have toolpaths created before you set the work offstes to 0 you may need to set this in the toolpaths themselves. Do this by selecting all the toolpaths, right-click them, select "Edit selected operations>>Renumber work offsets". Set both text fields to 0 then check both check boxes and click OK.

[ccs86]

Awesome. Thanks again!

 

I set up the Back and Bottom planes as instructed, locked all Work Offsets to 0, generated NC code, commented out a few unneeded A0's and it ran beautifully.

 

I didn't have the material yet, so I test ran the code with foam. Came out beautiful.

 

[Rotary Ninja]

Good job. Looks just like the pic