Boxford TCL 160

[Saracen]

5mm dowels arrived and have been inserted into the turret. Definitely no play now when trying to rotate the turret by hand, which was noticeable before.

I've written some Gcode scripts to perform tool changes, and am still struggling with getting the turret to a known safe position before initiating a tool change. As the parting / grooving tool stands so proud of the turret, it will hit the Z axis slides if the turret is rotated with the X axis at anything other than near the +ve limit. Still waiting to hear back from Planet-CNC as to why G53 moves are apparently affected by tool offsets, which is why no progress recently.

The TNMC inserts arrived today, so I'll be able to repopulate the original Boxford threading tool, as that is left handed and is easier to accommodate in the gcode I'm writing, and requires less material to be removed to make space for the tool head.

Adrian.

[JAZZCNC]

Still waiting to hear back from Planet-CNC as to why G53 moves are apparently affected by tool offsets, which is why no progress recently.

When you say affected by tool offsets what exactly is happening.? Your not using it in incremental(G91) mode are you.? G53 can only be used in absolute(g90) mode and cutter radius should always be cancelled prior to move.

[Saracen]

The details are all laid out here:

http://forum.planet-cnc.com/viewtopic.php?f=5&t=1846

This is the test program:

%

G18               ( Force XZ Plane )
G21               ( Force Metric Dimensioning )
G40               ( Force Tool Nose Compensation To OFF )
G80               ( Cancel Any Modal Motion )
G90               ( Force Absolute Coordinate Positioning )

G53 G00 X60 Z100      ( Move Turret To Safe Position For Tool Change )
G04 P10            ( Pause For 10 Seconds To Allow Notation Of Axis Locations )

G91               ( Force Relative Coordinate Positioning To Stop Turret Reversing To Location )
G00 A16            ( Rotate To Tool Position 3 )
G01 A-2 F100         ( Rotate Back Against Pawl At Feed 100 )
G90               ( Force Absolute Coordinate Positioning For Machining Passes )      
T3               ( Force Tool Change For Tool 3 )
M6               ( Force Use Of New Tool )
G43 H3            ( Force Use Of Tool 3 Offsets )

G00 X30 Z60         ( Simulate Program Moves )
G04 P10            ( Pause For 10 Seconds To Allow Notation Of Axis Locations )

G53 G00 X60 Z100      ( Move Turret To Safe Position For Tool Change )
G04 P10            ( Pause For 10 Seconds To Allow Notation Of Axis Locations )

G91               ( Force Relative Coordinate Positioning To Stop Turret Reversing To Location )
G00 A46            ( Rotate To Tool Position 1 )
G01 A-2 F100         ( Rotate Back Against Pawl At Feed 100 )
G90               ( Force Absolute Coordinate Positioning For Future Machining Passes )      
T1               ( Force Tool Change For Tool 1 )
M6               ( Force Use Of New Tool )
G43 H1            ( Force Use Of Tool 1 Offsets )

M2               ( End Program )
%

I start the machine off with no offsets on any tools. Tool Offset is set to "Not Used" in the Tool Change settings page. Before every pass, the tool is homed using the limit switches, which leaves it at X65, Z105.

What I'm seeing is that the final absolute position at the end of the program is the "G53 G00 X60 Z100" commanded position, but minus the Tool 3 X offset value. That in itself is odd, but it's also affecting both the X and Z axes, by the same amount. In other words, the final Z position is minus the T3 X offset, not the T3 Z offset:

To get a safe automated tool change, I need to be able to get the carriage to a known safe location, and at the moment I can't do that. Changing from G90 to G91 also seems to have the side effect that the next movement control, on any axis, caused motion on all axes. This usually results in the machine going out of limits, but has also caused a couple of turret/chuck interfaces.

Adrian.