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lathe -g28 moves x before z
« on: April 11, 2012, 12:12:01 PM »
Hello all ,

Please help with a lather problem

If I enter G28 mach3 homes  the z axis before it homes the X axis.( moves left to right before front and back)

I would prefer to home  the x axis first before the z axis

haw can i set this up?

many thanks

fred
think of the trees-- use both sides of the computer paper
Re: lathe -g28 moves x before z
« Reply #1 on: April 11, 2012, 12:53:26 PM »
TP offered some excellent info in your earlier thread.
Quoted below.


IF you use a G28 X0 Y0 call then you get a straight traverse move (combined) to home. the X will NOT move first both move at the same time.

To get what you need (IF the G28 and G30 positions are the same) I would use

G30 X0

That will Home X first THEN home Z. That way you have Safe clearnance for all axis to travel.

Other wise you would need to do

G28 X0  (home X)
G28 Z0  (home Z)

Just a thought, (;-) TP
Re: lathe -g28 moves x before z
« Reply #2 on: April 14, 2012, 11:18:51 AM »
thnaks overloaded and tp

(Using mach3 turn on lathe with the standard screen)

I opted to try the G0 X0 option and this is what i did

( I used a .tap that i wrote called turndownod.tap)

After swirching on I used home switches to "set home X"" and "set home Z"

I jogged the x until it took a cut .

I measured the cut and entered that value into the X axis dro in top left of screen.

I touched the face with the tool tip and zeroed the Z axis at that position

i went to auto prep screen and loaded my turndownod.tap

(I had previously put this line in first
G30 X0 ( in your suggestion))

I did a single cycle and when it got to that line it rapid ran the tool to
X0 when I had wanted it to go to x home

What did i do wrong ? ( apart from breaking the tooltip ( LOL )

regards
 fred



 
think of the trees-- use both sides of the computer paper
Re: lathe -g28 moves x before z
« Reply #3 on: April 20, 2012, 08:14:54 AM »
for reference of others-- the g30 did not work for me
now I use g53 and that works fine
the following line
g0  g53 x0 rapids the tool away from the job as far as the home position
g0 g53 z0 rapids the tool to that home position

best regards

fred
think of the trees-- use both sides of the computer paper