G96 Constant surface speed not working correctly for me.

dbohm · Post by **dbohm** » Mon 04 Sep , 2006 21:16 pm

The unit is a Novaturn 99 vintage. fully updated firmware and VR software.

When programing a G96 CSS it works perfectly on the first tool no matter what tool number or offset but on the second tool it runs extremely slow (like 150rpm)

Any combination of tools or offsets do this. Here is an example.

First G96

N180 G96 F0.008 S200 (in SFPM) works perfectly
runs through code

Second tool

N1070 (END TOOL)
N1080 G00 G40 G20
N1090 G28 U0.
N1100 G28 W0.
N1110 M00
N1120 (MDJNR 12-4B RIGHT)
N1130 T0101
N1140 G96 F0.008 S20

Runs super slow. I can program all succesive tools in RPM with a G97 and then works fine, but its like the controller cannot update itself after the first G96 that comes after an offset/tool change.

Kinda of an odd question to add to this. This unit was brand new when I purchased it and has been updated to the latest firmware and VR turning but it is still very quirky. For instance, sometimes when zeroing the Z axis it holds onto some number from before and wont completely zero. If I disconect the machine in VR turning and reconect it zeros right out. That is just one of multiple quirks I have found. Is there some way to reset the controller or something? Is there a newer controller that is more reliable that I can purchase?

I thank you for any ideas you may have about the G96 issue

dbohm · Post by **dbohm** » Mon 04 Sep , 2006 21:17 pm

That code at the end should have read a SFPM of 200 not 20. Sorry. I double checked and that is not why its running slowly. Has been exhibiting this behaviour for some time.

Post by **Denford Admin** » Tue 05 Sep , 2006 14:09 pm

I've never seen this, before, but I'll need to know exactly what versions of VR turning you are using, and what the controller type is (is it a RED 7-segment display, or a Green one on the Baldor control card ?)

If its a RED 7-seg display, I'm guessing that the mint file is not up to date.
Otherwise, I'll try and reproduce the problem here.

As to the machine position not zeroing - I think you may be seeing the result of rounding errors - as the position display has a resolution of 0.001 (1 micron), but the machines actual step (stepper) resolution is only 0.005

Triac whizz · Post by **Triac whizz** » Tue 05 Sep , 2006 15:37 pm

I'm only familiar with Fanuc's version, but don't you have to tell it the max speed first?

have a look at
https://www.answers.com/topic/g-code-1

But then if its the post processor thats putting that out you would expect it to be right

dbohm · Post by **dbohm** » Tue 05 Sep , 2006 16:23 pm

The version of VR Turning is 1.15.2.425

It is the red segmented display

The DenMint chip reads 2.0B/10/S/B19-JD5

The speed on the machine has been acting oddly lately. The speed of the lathe does not match the display (verified by a laser tachometer). Now that the box is open I can vary the speed control to match them out (I have been lazy) but I remember the SFPM working correctly in the past. Maybe something has become corrupted?

To Triac whizz. I think you are right. I should be including a Max spindle speed in the intial code, maybe with a G50? but still, why would the first tool run correctly and then the second so slowly?

Thanks again for your time.

Triac whizz · Post by **Triac whizz** » Tue 05 Sep , 2006 17:08 pm

Yeah with G50 I believe.

I see your second tool is T0101, I guess this is a boo boo in typing it? unless the first tool wasn't T0101

Has it always been like this? or something that's happened now?

Since it's related to the distance from the centre of the job it sounds like it's an offset problem

Post by **Denford Admin** » Tue 05 Sep , 2006 17:11 pm

Ok,

Just to be sure you don't have an old mint file running on your machine, follow these instructions (as long as VR Turning is the very latest version - 1.16 I think at the moment):

Firstly - make sure any other Denford software is closed and disconnected from the machine
Then run the file: MintMan.EXE which is located in the VR turning installation directory (C:\Program Files\Denford\VRTurning)
Go to menu Setup -> Comm Port
Set the parameters to:
COM 1 (whichever machine is plugged into)
Baud: 19200
Parity: None
Data bits: 8
Stop bits: 2
Handshaking: none
Press OK
Press Upload Version button
If it connects to control OK and finds the mint version, you can now download the .mnt file for your machine
Click Download Mint
Should be: C:\Program Files\Denford\VRTurning\NovaTurn.mnt

This is like the firmware for the machine and stays on the board permenantly - if its never been updated since 1999, then I'm positive there will be problems with the old mint file and the newer vrturning.

If the problem remains, I'll try to reproduce it here this week and find out what the problem could be

dbohm · Post by **dbohm** » Sat 16 Sep , 2006 23:12 pm

thanks you for your help.

The root of this issue, I believe, is the main cause of almost all issues. Human error.

I think I was just screwing up. I had not only the offsets incorect but considering the diameter of the part I was turning and the SFPM I had set, this was the correct RPM

Post by **Denford Admin** » Fri 29 Sep , 2006 9:55 am

Nobody is perfect

Denford Software & Machines

Denford Software & Machines

G96 Constant surface speed not working correctly for me.

G96 Constant surface speed not working correctly for me.