How to use G50 on a CNC lathe
Category : Fanuc Turn Haas Turn Mazak Turn Siemens Turn
CNC Turning Basics G50 Speed Clamp
How to use G50 on a CNC lathe
How to use G50 on a CNC lathe.
G50 in a turning program is a speed clamp. The machine accelerates up to the speed you set (G50 S2000) and will not go any faster.
Now before I get arrested by the “Correct Word and Grammar Police” I know it’s not actually a clamp. The truth is it’s just what everybody calls it, so get off my fuckin case.
![](https://www.cnctrainingcentre.com/wp-content/uploads/2018/03/dog-3043576_1920.jpg)
Anyway if I start to call it something else all my CNC mates (and I do have some) will be confused.
Just check me out on LinkedIn. Anyway as I was saying my mates wouldn’t know what the fuck I was on about.
You must program a G50 before each tool and at the beginning of the program for safety reasons which I will explain later.
It’s Modal
G50 is a modal G code (it stays active). If you have a program where you do not want to clamp the speed you must still put the G50 at the beginning of the program (set the clamp to the machines maximum RPM).
Otherwise it may pick up the G50 from the last program and you may not get the RPM you want. It can have the effect of slowing down production because the speed is being restricted and you didn’t realize.
Don’t use someone else’s G50 get your own.
You wouldn’t wear someone else’s dirty pants. (Americans call underpants underwear I think)
These are mine (sorry I din’t get time to wash them).
Modal G code explanation here.
Now Here Is Something You May Not Know
Historically G50 was used to set the machine datum. This still works so do not put any X or Z figures on this line. You will get some weird shit happening if you do. Oh and you will probably trash your 100 grand machine.
Anyway how to use G50 on a CNC lathe
G50 S2000 (SPEED CLAMP 2000 RPM)
Some G code systems, or depending on parameters, may use G92 instead of G50. This is not very common but it works exactly the same way.
On a Fanuc control they are called A type and B type G codes and depends on machine tool builder. Most of the G codes remain the same but proceed with caution.
It is particularly useful when you are facing a part using G96 (constant surface speed). When the tool reaches the centre of the part the machine will be running at maximum RPM. This could be very dangerous on large or out of balance components. When you set a G50 speed clamp, once the machine reaches the clamped speed it will go no further.
Here is a tutorial video about G96 and G97
RULES
- Use a G50 at every tool-change
- Use a G50 at the beginning of a program (even if you think it’s not needed)
- G50 S2000 (Only G50 and speed on one line, nothing else)
- There is no rule 4
- Never eat yellow snow.
This is a Toshiba VTL (Vertical Turning Lathe).
If you want to buy one or fix one go to Leader CNC
Now imagine this revolving too fast you would soon need their services oh and a good trauma team.
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5 Comments
Ravi Ashok Yadav
September 1, 2020 at 6:36 amThank you gentlemen for sharing such a valuable informations. from india
Ricardo Reyes
September 3, 2021 at 10:26 pmHAAAAHHAHAHAAH this G50 explanation made my day . “never eat yeloos snow” noted
David
September 4, 2021 at 9:19 amglad it’s of use Ricardo
Patrick Brennan
September 16, 2021 at 2:33 pmInformative and entertaining as ever!
David
September 16, 2021 at 4:00 pmThanks Patrick