wcs problem on 4 axis setup

[prettygoodnotbad]

I'm finally getting around to testing the rotary axis on our new machine.

The machine is a legacy woodworking Maverick (https://lwmcnc.com/cnc-mills/maverick-4-x8/) and uses Mach3. I've been using the Mach3mill post processor for everything that is 3 axis without any problems.

So I'm now testing a part that uses the turning center of the machine, and it seems to work in that the A axis was turning with the spindle, except the spindle was working on the total opposite end of where the 0 offset of the turning center is actually located.

So I'm assuming it's a coordinate problem in my setup.

This is illustrates it:

This is the wcs I set up, which is essentially the same as I would do for the 3 axis parts, except I'm taking the center point rather than the bottom left corner:

It could be a matter of inverting those coordinates but I don't really want to try something without understanding the logic first.

[daniel_lyall]

ou will need to post the model that has this problem it could be anything, To attach a file Go to File -> Export and save as a .F3D Archive File and attach it to your next post, if you can not post the file you can PM it to me or say in your next post you can not post the file and one of the Guys that do NDA work will help.

[prettygoodnotbad]

yes here is just the simple test I was doing. Never mind the actual tool path choice I'm sure there are better ways to machine this.

[daniel_lyall]

I can not find why it is starting at the other end.

I have done an example of another way to do it so you can do it in one toolpath.

watch these videos for how to do it https://www.youtube.com/channel/UCrx-8M8nRa-rNlkwIowx6Kw

[prettygoodnotbad]

The mach3 version I'm using is something Legacy customizes to be specific to their machine, it has a "turning" button that you press before launching a code that is meant to use the 4th axis. The point is that it sets the offset to the proper position to machine a part along the 4th axis.

So what I've discovered:

First off, there is no specific problem with the turning offset, if I click "turning" and then send the machine to offset it goes where it should. The problem happens when I start cycle, the spindle goes to the wrong place.

However, if I don't activate the "turning" option and manually set my XYZ 0 coordinates to the center of the 4th axis and then send the code the spindle seems to be working in the right spot. 

So it leads me to believe that whatever Legacy has setup with "turning" must be more than just the offset, something else goes haywire with this turning thing. So I think I will contact Legacy, but this is somewhat unknown territory for me, does this sound like something that would have to be adjusted in the post processor or something that needs to be adjusted in Mach3 settings, or something else? 

[prettygoodnotbad · Accepted solution]

ok so it looks like what I needed to do was manually input offset number 6 in the post processor tab in setup, this is the offset the machine uses for the turning center.

[daniel_lyall]

That is good that you have it going now.😀

[prettygoodnotbad]

Well I was pretty happy about it but now as per my other post 

https://forums.autodesk.com/t5/fusion-360-manufacture/rotary-axis-moving-too-slow/m-p/9390317#M77825

my a axis is rotating too slow, i think it’s a post processor thing, not sure if it’s something I’ll be able to solve.

[daniel_lyall]

In mach3 you have to have the A-axis feed set to at least half more than what the other axis are set to so if X is set to 1000 A should be 1500 - 2000, it is something to do with how the motion planner works since it is time of flight.

As an example, a Velox CNC machine I do the programming for sometimes X is set to, velocity 100 and acceleration 20

the A axis is 800/400 this works really well for this machine and in toolpath config, rotation is set to use radius for feed rate.

[prettygoodnotbad]

Hm not sure I know what you mean, do I set it in mach3 or fusion and are we talking ipm or degrees per minute, or are those just arbitrary numbers as an example? 

[daniel_lyall]

Have a look at my edit to the post.

[prettygoodnotbad]

So I finally found the settings, it is in motor tuning correct? Currently X is set to 600/18 and A is set to 100020/2500 so definitely over half more. I'm assuming these are the settings configured by the company who builds this machine, which must work for them.

[daniel_lyall]

Yes, correct with those setting it should be fine you will need to try with inverse time on and off in the post.