To each his own(;-), Why would the rotary axis be any different than any other axis (;-) It is based on perceived tool tip travel not just the direction of table/chuck motion.

Your mileage may vary, (;-) TP

Why would the rotary axis be any different than any other axis

Because it is a ROTARY axis, not linear.

If you want to see conventional rotary axis direction demonstrated, take a look at Mach3

If you want any axis to move in a non conventional direction on your machine, then go for it. No one is going to take away your birthday.   

I'm going to shut up now. 

This is interesting. Good rule illustration Greg.
"A" set up with the thumb facing X+, the Y and the A are identical as far as + and - directions go. (relative to the tool)
"A" set up with the thumb facing Y+, the X and the A are opposite, ie a pos. A move will be the tool going to the left instead of right.

Considering a standard knee mill. Would a gantry router be similar ?
Does mach know the difference ?

  

It is all about the perceived movement of the tooltip NOT the table or gantry or rotary axis. (;-)

Rule of thumb from long ago.

IF the "table" moves then table will move opposite of tool tip
IF the "spindle" moves then the table movement will be the same as tool tip
Rotaries are counted as part of the table.

Just a thought, (;-) TP

It is all about the perceived movement of the tooltip NOT the table or gantry or rotary axis. (;-)

Rule of thumb from long ago.

Rotaries are counted as part of the table.

Then perhaps you had better tell Art and Brian.    All these years they have had it wrong in Mach and did not realise it.     

You do realize we are describing the same thing right? Only you are describing tool tip motion and I am describing Table motion to get proper tool tip motion as defined in MACh3.

Just a thought, (;-) TP

You do realize we are describing the same thing right? Only you are describing tool tip motion and I am describing Table motion to get proper tool tip motion as defined in MACh3.

No I am not talking about the table at all.  Has nothing to do with the table.  Different beast all together.

Talking about conventional direction of rotation of a rotary axis.  As described by the right hand rule as shown above.  

Rotary positions are described by angle, not cartesian coordinates.

You can have YOUR rotary axis set up however YOU want.  Just pointing out what is conventional and followed by Mach and the CAM software that I have used.

So I will wish you well and leave you with it.

Quote from: BR549 on March 23, 2013, 01:18:07 PM

It is all about the perceived movement of the tooltip NOT the table or gantry or rotary axis. (;-)

Rule of thumb from long ago.

Rotaries are counted as part of the table.

Then perhaps you had better tell Art and Brian.    All these years they have had it wrong in Mach and did not realise it.    

im inclined to like this one.... cus to me, that gear/spline wizard looks wrong if displayed rotations are opposite to actual table rotations.

probably the thing that started this whole mess!


oh, fanuc, fanuc....

I wanted to leave this alone but am concerned that misinformation can be taken by forum readers to be correct.  As demonstrated by the post above.

So I devised as simple a demonstration as I can of CONVENTIONAL rotary axis direction (right hand rule) as displayed in Mach3

Rotary axis positions are measured and described by ANGLE.  Not to be confused with X Y positions described by cartesian coordinates.

The right Hand Rule describes the direction of the chuck or job movement. NOT the apparent tool movement.

Two pictures of simple profile toolpaths of lettering on a cylinder, displayed my Mach. Showing that Mach follows convention with rotary axis direction.

 I have tried to make them from the same perspective. Included is the 3D compass for reference.

The first is toolpath set to cut correctly with CONVENTIONAL direction of the CHUCK. Displayed in Mach3. You should be able to see the visual display is correct.

The second is toolpath set up to cut correctly with rotary axis direction set up for APPARENT tool tip movement.  Opposite to chuck movement.  As per Terry's argument.

As I hope you can see Mach displays rotary toolpaths as per CONVENTIONAL rotary axis direction.  And has done for as long as I have been using it.

I can not remember any user over those years who has cried "Mach has it wrong"

I assume that you are refering to Baxis in you example as it is inline with Y SO your chuck is moving CCw?


OK now show the point of origin of your code  is it lower left?  IF so then B positive would be to the right which would be CW tool motion or CCW chuck motion. Facing the chuck. YES?NO?

NOW there IS no real standard for the placement of the chuck on rotarys I know just as many that run it on the left as on the right as A axis. the exception being the B where MOST run it outboard to clear the column (mills).

NOW as to physical Chuck rotatation IF I swap from left to right I must rev the direction of the chuck to maintain toolpath orientation.

Just a thought, (;-) TP