Feed speeds displayed incorrectly.

[MAX THE MILLER]

When executing a part program VR Milling displays the feed speed. I assume it derives this from the F (feed speed) parameter in the part program.

However the speed is often incorrectly displayed possibly because the software is reading the wrong parameter. I've attached screen shots of two examples. In both cases programmed feed speed was 0.875 inches per minute. With no manual speed override the display showed 39 inches per minute for both programmed and actual speed. If the manual feed speed control pot is wound up to 150% the displayed speeds are programmed 39 ipm and actual 59 ipm.

If material override is selected incorrect values are still shown.

I've also attached the .fnc file which was being run.

Any chance of a fix?

Thanks, Max.

[TDIPower]

Hi, so is it just a display issue and it is moving at the correct speed (matches the program) or is it moving at the displayed speed e.g. 39ipm

Is this happening with all files?
DO an 'air cut' but change that feed speed F0.875 to say F10 and see what it does.
Have you tried any of the 'demo' FNC files included with VR milling.

Pete

[Steve]

Try turning turbo mode off as the program reads ahead as far as the next modal change. The feed displayed will be the feed where's the program has read ahead to.

If you turn turbo off the machine will display the feed of the actual currently exicuted line.

[MAX THE MILLER]

Hi, so is it just a display issue and it is moving at the correct speed (matches the program) or is it moving at the displayed speed e.g. 39ipm

Is this happening with all files?
DO an 'air cut' but change that feed speed F0.875 to say F10 and see what it does.
Have you tried any of the 'demo' FNC files included with VR milling.

Pete

I believe this is a display problem. I'm pretty sure that the feed rate is that in the F parameter as modified by the setting of the manual feed rate potentiometer or overridden by selecting materials override. The axes certainly aren't moving at 39 inches per minute! I think that's beyond the machine's capability.

The original part program had a feed rate of 1 and the same thing happened ie speed displayed as 39. I changed the feed rate to 0.875 in order to investigate.

I'll try some demo programs when I next use the machine.

[MAX THE MILLER]

Try turning turbo mode off as the program reads ahead as far as the next modal change. The feed displayed will be the feed where's the program has read ahead to.

If you turn turbo off the machine will display the feed of the actual currently exicuted line.

Point taken and I'll try it. However the only feed rates used in the part program are 0.875 and 0. The latter sets the feed rate to maximum during rapid traverse.

I think the software is actually displaying the retract height of 1mm (0.3937 inches) which it rounds to 39 and multiplies by 100.

[MAX THE MILLER]

After carrying out a few experiments I think I know what's going on here.

For some reason the DWG import function puts F parameters in the generated Gcode with a value of zero ie F0 or no feed. I have no idea what this means or how the machine interprets it. The help file is not helpful where F0 is concerned.

When running in non-turbo mode the display shows the last feed rate programmed, but rounds it to the nearest inch. I don't know whether it rounds up or down, but it seems inconsistent. F0 is displayed as a feed rate of 1 ipm. Sometimes the programmed speed is rounded one way and the actual speed, as set by the override pot, is rounded the other way. A more accurate display rounded say to two decimal places would be better.

If the last feed rate was set by a GO Gcode (rapid traverse) the display shows 39 ipm in the case of the Z access which appears to be the actual speed. It's sometimes a case of blink or you'll miss it, for example if the cutter is retracted 1mm from a shallow cut.

When running in turbo mode the displayed speed is ahead of the actual machining so the rapid transfer rate of 39 ipm is often displayed.

Max.