Newbie- HELP!!!!!!

[mazda]

hi everyone!

Ive just started a new job and found that they program their mcs (lathes)totally different to the last place i worked at. Im not a programmer only an operator.

Theres a few things that i just dont understand,


1... What does the G99 at the begining of every op/tool change mean?


2... Why do they have T0 then T0100 T0101 at the begining and then T0 and T0100 AGAIN at the end of every op/tool change?

Although i understand what the codes mean, Cant you just bring the tool in with its offset and then cancel it just once at the end without bothering with the T0 at all?


3... Why do they send the tool to U0.0 W0.0 "home" at the begining AND again at the end of every op/tool change?


Again i understand sending the tool "home" or to a tool change position but cant it be done just the once after the op?


Is it a safety issue?
Because i have asked these questions but have been told
"It has to be done like that"

Please help????

THANKS IN ADVANCE!

[dcoupar]

On a Fanuc and many others, G99 is feed per revolution. This is a safety code to ensure the feedrates are not feed per minute.

I've never programmed a machine with T0, but I have programmed those which indexed the turret with T0100 then approached the part and activated tool offsets with T0101. And after each tool a T0100 to cancel the offsets.

A G30 U0 W0 is usually followed by an M01. Then to ensure the X and Z are in the correct position in case the operator restarts a tool, G30 U0 W0 are programmed at the start of each tool.

Safety, safety, safety.

[CNCBoss]

Sounds to me like their programmer likes to be very sure the machine is in position and offsets cleared. I know on older model Fanuc, like our 6TB, you can not start a program in any other position than machine zero. Some of this sounds like a little over kill but in my book better safe (and sure) than sorry - a.k.a CRASH!

[mazman]

G99 is feed per revolution, so feeding if depend of RPM
G98 is feed per minute, so feeding is constant

T0100 means use tool number 1 and use offset in offset no0
T0101 means use tool number 1 and use offset in offset no1

In turning must be use G28 U0.W0. to back to zero position for safety, use incremental mode U=X positioning (U=incremental)