VF-4 vs VF-5: Z travel woes...

Well, crap. Just got in a brand new VF-5 and we moved the programs and fixtures over from the VF-4 to run a job and kept getting Z overtravel alarms. Just figured out that the spindle face can get to within around 4" on the VF-4, but only around 8" on the VF-5! I fudged the parmeter that controls the max number of steps from 26,638,271 to 27,470,720 and bought myself an extra .75" of travel, but that didn't help much. Any more than that gave me a servo error alarm. I'm guessing the idea was that with the VF-5 being a bigger machine people are expected to cut bigger parts on it so getting close to the table wasn't a priority. Unfortunately I'm cutting the same sized parts, just more of them on the larger table. I know there's no fix for this other than to make my fixtures taller or use longer tool holders, so I'm just posting this as a warning. Also posting it in case my little parameter fudging is going to cause my machine to explode, and maybe a Haas guy will warn me before it happens. :)

That is a bummer. Guess you should have checked the specs first

Haas VF-5/40 | Haas Automation, Inc. | CNC Machine Tools

:stickpoke;)

If your getting servo errors now at the bottom, you will blow something up. Ballscrew or something else is now binding.

I would set the the params back to where they were originally. Underthetire is right, the ballnuts could be at the end of the travel and binding. You want to leave some breathing room for fast decelerations.

Most machines of this size class have a similar spindle-nose to table minimum distance. I agree it's pretty annoying, but it is what it is.

Yes, change your maximum travel parameter back to what it was.

It is not likely anything bad will happen the way you have it when the controller is doing a rapid or feed move because it keeps track of the axis position.

HOWEVER if you rapidly spin the jog wheel to bring the Z axis down it can overshoot and if you don't have a bit of room for some overtravel you can cause damage.

Don't ask me how I know this.:o

Mark,
This is why I bought the VF4. I wanted the bigger table a 5 represented but the spindle nose to table was to much. There is an answer for that from Haas and they sell a table to put on your table to reduce the height. Around $3600 as an option if I remember right.

I also figure that what I gained in table size I would lose in cut speed productivity with the VF5 compared to the VF4.