Messages

61

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 27, 2013, 07:48:02 PM »

............SO your chuck is moving CCw?

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.

This is a perfect example of why I keep banging on about the Right Hand Rule.   

CW and CCW,  "which end is the chuck??"  "Facing the chuck. YES?NO???"  "Is the sun over your left shoulder??" 

The explanation possibilities are endless, as are the opportunities for misunderstanding those type of explanations.

The Right Hand rule simply explains any and all situations.  Stand in front of your machine and do it.

Make a fist with your right hand, thumb extended and pointing in the positive direction of the axis you are interested in. Your fingers curl around in the direction of positive rotation.

62

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 27, 2013, 07:29:47 PM »

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

Terry that is a B axis toolpath.  To keep the explanation simple, I should have made an A axis example. 

My mistake.  Here is my fix.

Same basic example.  Showing the same conventional direction, but this is an A axis toolpath.

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.

63

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 26, 2013, 10:32:47 PM »

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"

64

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 24, 2013, 07:19:58 PM »

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.

65

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 24, 2013, 03:03:04 AM »

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.     

66

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 22, 2013, 10:37:14 PM »

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. 

67

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 20, 2013, 07:39:42 PM »

................ on rotarys you have to consider which way the tool tip moves NOT the chuck.

Not going to argue about.......but I disagree.

Rotary axis direction IS the way the chuck moves.

68

Mach Screens / Re: reversing "A" axis rotation on toolpath display?

« on: March 20, 2013, 06:26:45 AM »

Conventional direction is best described via the Right Hand Rule.

Doesn't matter from where you look or which end is the chuck.

69

FAQs / Re: What does 'A-Rotations Enabled' mean?

« on: March 13, 2013, 10:35:59 PM »

"A-Rotations Enabled" tells Mach that the toolpath is of a rotary type for visual display purposes.

You must select this and the correct "Axis of Rotation" for the display to correctly represent the rotary toolpath..

Note;  you must also set the "Rotation Radius" DRO to represent the distance that the Z axis origin is offset from the centre of rotation.  Or the displayed toolpath will be out of whack.

Also note; only A axis toolpaths will display.  Not B or C.

Greolt

70

Mach Screens / Re: Another screen size question

« on: February 27, 2013, 07:51:51 PM »

Bob

This is a very old thread. 

I have progressed through steadily larger screens on my machines.  Each time, I redo my screen sets to suit the monitor they will be displayed on.

Nowadays I use Klaus' MachScreen for screen set building / modifying.  Set the frame size to requirements and layout control elements within that.

I always leave room for the standard Windows task bar at the bottom.

Greolt