5 axis machine rotary position help.

Reezenenuff · Aug 18, 2011

Can anyone give me the procedure for setting the center of the A and C axis center of rotations on a Variaxis. I am pulling what little hair I have left out trying to get the machines to index into the correct position. What I am doing is just not accurate enough.

scojen · Aug 19, 2011

You are going to have to come up with some more info what machine, control and a bit more on exactly what it is you want to do, find home position maybe ?.

Scott

Reezenenuff · Aug 19, 2011

We have Variaxis machines with both the Matrix and M640 control. I need to find the center of rotation on the C axis(rotary axis)and A axis(tilting axis). I have to know the exact position of these points for the WPC SHIFT command to be accurate, as well as Mastercam.

Ox · Aug 19, 2011

A Co-Ax should git your there eh?

Use it to indicate flat (sqr?) first, and then co-ax the center hole. If a trunnion mount - you should have the value to C/L in a manual somewhere, but you could also spin it 90* one way and touch off, and then spin it 90* the other way and touch off. Divide by 2 and you know your distance to C/L eh?

No?

------------------

Think Snow Eh!
Ox

Joe788 · Aug 19, 2011

Ox said:
A Co-Ax should git your there eh?

Use it to indicate flat (sqr?) first, and then co-ax the center hole. If a trunnion mount - you should have the value to C/L in a manual somewhere, but you could also spin it 90* one way and touch off, and then spin it 90* the other way and touch off. Divide by 2 and you know your distance to C/L eh?

No?

------------------

Think Snow Eh!
Ox

That's where the fun part comes in, Ox. The A axis goes -110 one direction, and +30 the other, so you can't go 90 degrees each way. :willy_nilly:

Reezenenuff · Aug 19, 2011

Joe788 said:
That's where the fun part comes in, Ox. The A axis goes -110 one direction, and +30 the other, so you can't go 90 degrees each way.

Exactly! I just recieved a custom macro from one of the application guys at Mazak. I will try it and see? Makes sence but I thought the way I was doing it made sense also. If anyone has any info please let me know.

IAMATT · Aug 19, 2011

THATS 140 DEGREES GUYS, you only need 90 degrees not 180 degrees.

Joe788 · Aug 19, 2011

IAMATT said:
THATS 140 DEGREES GUYS, you only need 90 degrees not 180 degrees.

You need 180 degrees if you want to go 90 each way to find the center in the Y axis. If you can only go 90 in one direction, the center you're finding in the Y axis is effected by the Z length of the tool you're using.

It seems simple, but once you really start wrapping your head around it, you'll realize it's big PITA.

IAMATT · Aug 19, 2011

Joe788 said:
You need 180 degrees if you want to go 90 each way to find the center in the Y axis. If you can only go 90 in one direction, the center you're finding in the Y axis is effected by the Z length of the tool you're using.

It seems simple, but once you really start wrapping your head around it, you'll realize it's big PITA.

Geez I dont know many people with trunnions that use that 180 degree advice or even have 180 degrees. Like mentioned above 0 degrees to 90 degrees is all you need to find the center of rotation. Finding the center of any rotating axis takes only 90 degrees of rotation. 180 degrees if your lazy or you think your need 180 to find the center. How does the rest of the world with trunnions do it without 180? They do it with 90.

JMC · Aug 19, 2011

Unless I am missing something....this is not tough to do. Cut a diameter at A0 using your C axis (rotate a part on the table into an endmill & cut the diameter that way.) Indicate that diameter in and it will be at the center of rotation. One you have that, tilt the table 90 degrees and edge find the table. The number in your Y axis (assuming it is a A-C machine) is the distance to from your pivot point to your table. (for an A-B machine it would be the X axis number)

Now to find the error between the 2 axis's, (Center of rotation never projects perfectly to tilt center), things get a little more complicated.

Joe788 · Aug 19, 2011

IAMATT said:
Geez I dont know many people with trunnions that use that 180 degree advice or even have 180 degrees. Like mentioned above 0 degrees to 90 degrees is all you need to find the center of rotation. Finding the center of any rotating axis takes only 90 degrees of rotation. 180 degrees if your lazy or you think your need 180 to find the center. How does the rest of the world with trunnions do it without 180? They do it with 90.

LOL. Like I said, once you get out there and start trying to do it, things become a little more fun.

Don't forget, you need Z AND Y center of rotation numbers. Neither of them is any good without the other, and either of them can be challenging to get without the other.

IAMATT · Aug 19, 2011

I think I did it 10 times last year Joe. Keep thinking and youll get it.

Joe788 · Aug 19, 2011

IAMATT said:
I think I did it 10 times last year Joe. Keep thinking and youll get it.

Oh don't worry about me. I've already done it so I know exactly what's involved.

There's a reason the procedure is 5 pages long.

IAMATT · Aug 19, 2011

Z and Y or Z and X is easy to get with the right tool. Then rotate 90 degrees and your there. I dont know why it should be extremely difficult for some but we nail it within .0001 which is more than good for what we do.

Xjenderfloip · Aug 19, 2011

IAMATT said:
I think I did it 10 times last year Joe. Keep thinking and youll get it.

How do you do it?

Ox · Aug 19, 2011

OK - so you have found Zero of the platten (?), if you dial it up 90* in whatever direction, the distance from your previous ZERO point to the table @ 90* would be your offset.

Follow that?

---------------------

Think Snow Eh!
Ox

fpworks · Aug 19, 2011

Lol...Matt, you must be missing something. I'm with Joe on this one...finding center of tilt axis is not easy...especially on a machine with a 20" diameter table. It is a 2-3 hour job for me on a Variaxis. It took the Renshaw guy over five hours. It its even more fun when the center of A and center of C don't actually intersect. I'm about to set up our new Variaxis and I expect to spend a full day with it AFTER Mazak is done...and that is to get it within .001 of positioning accuracy through only 90° of A and 360° of C...forget .0001!

IAMATT · Aug 19, 2011

How much will you pay me to come over and do your job for you? :Yawn:

Its a tough job when you dont set the trunnion on the table correctly. Beyond that its as easy as basic geometry, and indicator and a touch probe. Its not like you cant use a notebook to write your starts down and then a little drawing if you arent used to computing the numbers. A and C never line up..at least thats been my experience. They are always off at least a couple tenths to a couple thou.

Reezenenuff · Aug 19, 2011

Help please? :crazy:

Hansdie · Aug 20, 2011

Joe788 said:
There's a reason the procedure is 5 pages long.

5 pages seem a bit too long ours is about 1 page.

IAMATT said:
Z and Y or Z and X is easy to get with the right tool. Then rotate 90 degrees and your there. I dont know why it should be extremely difficult for some but we nail it within .0001 which is more than good for what we do.

I'd like to hear how you do it within .0001 by only rotating 0 to 90??

Anyway the way we do it, if from scratch, with a table-table 5 axis is indicate the table flat, thats A0. In Z axis touch the spindle nose to the table, thats the distance to the table. Machine a bore or boss by spinning C axis, thats X and Y center. Now swing the A axis up in the - direction as far as it can go thats equal to the + direction so 30 degrees probe a spot in Y. Swing the A axis in + direction, again 30 degrees dont move X or Z and probe again in Y, divide by 2 then you have the distance to the pivot point.
After that we either run a macro program to fine tune the numbers to get it perfect or we use G451.

all our machines can swing at least +/-90 degrees so it makes it easier and more accurate.

5 axis machine rotary position help.

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