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How do you home a Bridgeport with Fanuc 0T

shanghyd

Aluminum
Joined
Aug 15, 2008
Location
San Antonio, TX
Got a Bridgeport Romi 35E Centur lathe. Problem is trying to home the x axis. I don’t know how to home the lathe so I’m doing g28 x0 in the mdi.
The x axis will over travel and error.
The position screen shows distance left around 4900.
I manually move the x and z to machine position zero and get the same result with g28 x0
G28 z0 works perfectly.
I’m just learning about this machine. I’m not a machinist by trade. This is in a home shop. Any help is appreciated
 
Got a Bridgeport Romi 35E Centur lathe. Problem is trying to home the x axis. I don’t know how to home the lathe so I’m doing g28 x0 in the mdi.
The x axis will over travel and error.
The position screen shows distance left around 4900.
I manually move the x and z to machine position zero and get the same result with g28 x0
G28 z0 works perfectly.
I’m just learning about this machine. I’m not a machinist by trade. This is in a home shop. Any help is appreciated

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usually there is a zero return button then cycle start.
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some machines need
G53 G28 X0. (G49 G40 needed if tool comp is active to turn tool comp off)
some use G91 G28 X0. (incremental mode and X0. from intermediate position)
some machines will alarm if G28 and G53 used
work offset G53 is machine coordinates (after it wont stay in G53 it normally returns to previous work offset used) and if successful the green light on X axis indicates at zero return position and display will read a combination of current work offset from zero return position for example if

G54 X10. is on work offset screen then at zero return position and no tool comp active it should read like X-10. (usually opposite from whats on G54 work offset screen)
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so unless the G54 work offset screen shows all zeros at zero return position it will show something other than zero. on work offset screen there is often also a common offset that effects all other offsets (they are added together)
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common work offset often used to compensate for a attachment on a mill like a horizontal head. on a horizontal mill its often used so zero is center of table and table top when all other work offsets are all zero. on a lathe is might be used so face of chuck is zero
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i usually look to see if i got a green light at zero return confirmation part of control panel. when its on you are at zero return. if display doesnt read zero there is usually a work offset active and or a tool offset active and or a common work offset is active
 
Appreciate the input which kind of answers my next problem about work offset.
There are a lot of threads with different answers so I'm not starting a thread.
 
On a Fanuc controlled lathe it's G28 U0 W0

G28 X0 Z0 should go to the programed zero then go to zero return. This may cause issues like you described.

Brent
 
On a Fanuc controlled lathe it's G28 U0 W0

G28 X0 Z0 should go to the programed zero then go to zero return. This may cause issues like you described.

Brent

that why usually its G91 G28 X0. as it goes to current X position THEN to zero return position cause its in incremental not absolute mode (X0. absolute mode position it might crash into something at X0. absolute then go to zero return position)
obviously got to give a G90 to put back in absolute mode next line normally
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usually a cnc has a zero return button might be called home1 button (home2 might be tool change position) and when you activate it and press cycle start it does zero return and reset position display if G54 work offset all zeroes then at zero return it should read all zeros too. obviously if G54 work offset is not zero then it will usually read the G54 work offset usually opposite direction X10. becomes X-10.
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its possible to go to zero return position but unless the cycle was active it wont reset the display. sometimes G92 on a mill and G52 ? on lathe will shift the coordinates to what ever you want you can give gcode and current position can become X0. no matter what is on G54 work offset screen. when you do zero return cycle it goes to zero return and lights up the zero return position lights and RESETS the position display if a coordinate shift was done by G92 or G52 (different on mill compared to lathe normally)
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i have seen some cnc where you press a button and you can make current position all zeroes or input what you want display to read at current position. annoying if thats not what you wanted to do. but normally just run zero return cycle to put it back
 








 
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