Need Help!- Ballscrew question? Haas TM-1

[CJH]

Hi guys,

I need a liitle assistance with something. We just got the Y Axis spring cover on our '03 TM-1 replaced. The Tech came out last Friday and did the work. Unfortunately I wasn't able to be around when he did it, and another co-worker of mine was.

So today was the first day the machine was back on and hasn't been moved since the day the tech was in. I started the machine up this morning and did all the usual, power up restart, and sent the machine to home. All looked good as usual, I turned on the safety switch override to run full CNC as usual. Warmed it up and loaded my first program for the day, I'm cutting very low density foam right now, and got about 30 seconds if that into the first op and the Y Axis came to a screaming halt, and spiking the load meter till I could hit the E-stop. Believe me when I say screaming, it sounded like a banshee chewing sand and screaming at the top of it's lungs.

Thankfully I was only about 4 steps from the machine an I could dive for the E-Stop. After hitting the E-Stop, and looking at the Alarm page, had nothing other than the usual first start up alarm with the servos as being off and the additional alarm of the E-Stop being triggered. So I hit reset and popped out the Stop button and manually jogged the mahcine from the control, nothing sounded out of the ordinary, so I sent it home at slow speed, and tried the program again. Same result, I tried a similar program run last week with success before the service of the machine, and same result. So I left the E-stop punched in this time annd turned the hand wheels on the mill, and the X Axis glides like a warm knife through butter, no problem. The Y Axis however seems to be stiff and gritty. The tech had to remove the ballscrew to put on the new cover and did an inspection of the screw and seals, etc. he said was all OK and passed muster. From what my co-worker, who shares the maching duty, said the tech seemed to have a bit of trouble getting the backlash readjusted. I don't know how this was done or tested so I can't speak to this.

I put in a rather frustrated call to 2 of our service reps this afternoon trying to track down answers and also get a tech back in the morning, since I have a back log of work that needs done. Every hour the machine is offline it costs. You guys know the deal.

So I'm wondering if there is some misallignment on something after the service, or he tightened up the ballscrew nut too much. Quite frankly I'm clueless and feeling lost on this.

So I'm asking for help in troubleshooting this and looking for some suggestions on questions I should be asking when the next tech comes in. I'm not apt to really want to fire the machine up till I have I have a tech in front of me. I really think I could do more harm than good.

The other thing is what about the cost of the possible new repair? My feeling is that the company servicing the machine should be making good on the service even though the warranty is up on the machine. Since this is a possible direct outcome of the service call last week, I think that they should be doing this as a freebie. The only real wrinkle to this thinking is we are not a big client in quantity, since we only have 1 machine and our router deal fell through the cracks a few months back. So I really don't feel I have any leverage on this.

Any thoughts and help you could give on this would be greatly appreciated.

Thanks,

CJH

[HAILINHAAS]

The ballscrew was probably not put back together properly. ask them to run a ballbar plot on the machine after they have everything put back and working. Compare it to the ballbar plot you have in your manual .. in the back of the manual. Check parameter 27 ... it should be no more than 30. Place a magbase and indicator on the table and set the indicator against the spindle. You can check backlash this way by jogging both directions and making sure the machine repeats back to zero on the indicator.

[HAILINHAAS]

... they put the hand wheels back on .. right? because if they didn't ... the machine will make a bad noise. There are parameter values that need to be changed if the hand wheels were taken off.

[CJH]

Thanks for the info. I was able to locate the problem. Found 3 issues.... The first was the connection between the servo and the ballscrew. The collar on the ball screw side wasn't tightened back down, I doubt this was the issue. But I tightened it back up anyhow. So my co-worker shot some more grease back into the ballscrew nut and it seemed to glide a whole lot better. I figure the tech didn't put enough in when he put the screw back in. The 3rd and what I figure was the problem, was we had a small shroud we made to keep coolant from dripping down behind the Y axis optical switch. I guess the tech either removed it and put it back in the wrong place/angle, and the Ball guideway on the table was hitting and binding the movement, causing the increased load. So I removed it, since it's now bent. I ran the machine through a series of manual jogs and semmed to be OK. So then the real litmus test began. I went back and started the program I was running the day before when the issue happened, and things cut and ran perfect.

I don't know how I could have over looked something as simple as that. I'm just glad it's back up and running, and we don't need another repair bill.

So thanks for the advice and I'll look at having them come back to do the ballbar test.