Need Help!- Servo 300 Barfeeder not repeating

[CNCMAN 83]

I am trying to get a job going that requires a double push. We machine the front of part close to the chuck and then push the part out to 4.750 and turn and part off the part. My problem is the lengths are all over the place. Does anyone no what the push repeatability is?

[Haas_Apps]

Please call us at the factory 805-278-8500

[ChsBrown]

Let us know what they tell you. My barfeeder is repeatable to @ .05. I use the double push with a collet and had to turn the chuck pressure WAY down. The problem I have with that is turning, If I take a heavy cut or over feed it stuffs the pardt back into the collet.

[swain]

I have been using the 300 barfeeder for 10 years on my Sl-20.

I would have to say mine repeats within about .010 to .020 at the most.

The only time that it has every given me fits is when I was doing small bar and pipe, and the material was sliding a bit when the barfeed stopped pushing and the chuck closed. On most everything else...it repeats consistantly.

Swain

[double a-ron]

I blew out new push rod brackets for my 300, as well as replacing the stock
push rod with a .5" hardend stainless piece. I also swaped the plastic bushing for a bronze one. With theese simple mods I hold +-.005. I also make my own spindle liners that fit the spindle bore and material alot beter then the $100.00 piles of poo HAAS is selling.

[roundman]

I had the same problem and I had fits trying to get it just right. I have not run the job again probably because we lost on that job big time. Why we did not just use a bar puller instead of buying this thing is not understood by me. I can use a bar puller now with no problems and it is easier to set up. For long runs yes it is good (servo 300) but the double push thing is something I need to work on. I really mostly run 16 pieces at a time and thirty to fifty or more would be a big run. Our company has not gotten enough work to really pay for the thing and I am dissappointed in myself to see that because I have used it enough to know that once we get the hang of it and have work to justify it this thing will do a superb job. The manual by the way is very confusing to me also (my opinion). Please let me know what you find out from Haas I really would like to solve that problem. I have called the rep on occasion when I have had issues and get the feeling he hates dealing with the bar feeder. Of course its probably just me..... Here it is you bought it. I am envious of people who have gotten the hang of this and have good work for it and they make it all look so easy.

[double a-ron]

Ok so this week I got an order for "a hundred of everything". So this is my first big run on this machine. Total number of parts needed is 600. I noticed
that sometimes the bar feeder would under push by about .1. This is not normal for my machine as I said in my other post. After a lot of hair pulling I saw that the push rod was retracting before the jaws were completely closed, so the draw tube was pulling the material back as it should but the push rod wasn't there to stop it. I called Haas and asked the apps guy if I can change how long the push rod stays in position before it goes to its min retract position after a push. His response was not helpful at all so I scanned the parameters list and found parameter 249: chuck clamp delay. It was set at 1000 (1 sec.), after doubling it to 2 sec my problems went away and I'm back to holding +/- .005. Maybe this will help. I mean the bar feeder should hold at least that, I would have thought it would be better considering it can move in tenths.

[ChsBrown]

According to my Haas service tech, The minimum diameter for stock in the 300 is a quarter inch. We routinely run .199 and occasionally .187. We have to shim the tray a little and the first piece is almost always a throw-away. I have to turn the chuck pressure way down or when the collet opens it will throw the stock way out and the bar feeder will be off mathematically as a result.