[thebodger]

Good luck TerryG
I'm going to watch this thread

[Machineit]

Yes, this is where it all started. Was running a job, everything was going perfect. After a hundred parts or so my 1/8" EM snapped. Purchased two new ones, they both snapped within 1" of feed.

After inspecting the cuts on the parts where the EM snapped, I noticed a large burr (even on the new EMs). This was very unusual since all my cuts in the past have been very clean.

After checking the runout on the tool, it was way out. Then I removed the cutter and checked the collet seat of the toolholder for runout. This was also way out. Checked a few more tool holders and the same thing. Then checked the spindle as Haas recommended, and it was better than .0002" which is within spec.

The drawbar pressure was next on the list of things they said need to be checked. I also changed pull studs with no results.

That's how it ended up from breaking an 1/8" cutter to now!

I think you missed the point of my comment and my humor. If the drawbar was so loose as to break an eighth inch endmill, other tools would have been literally jumping out of the spindle.

Unless all of the washers collapsed at once, I think you have another problem. Have you just tried to put a pry bar or big screwdriver between the tool and the spindle and see what kind of pressure it takes to move the tool out a little?

Mike

[Terry G]

Yes, I did miss that. Once thing lost with messages and e-mails!

I did try and pry the tool holder out when I was first looking at this, but it would not budge. There is suppose to be 900 to 1300 foot lbs of force on the tool holder, so not sure I would get it to move without damaging something first even it was below spec.

I did the push and pull tests Haas recommended with a length of drill rod sticking out of the tool holder. I forget the tolerances, but with a gauge on it, it should deflect about .0005" at the holder, and something like .001 or .002 6" down (please don't quote me on those numbers, I am trying to remember off the top of my head). But it did check out when I had the numbers in front of me.

Only reason the draw bar came up was because Haas said it needed to be checked. And this was the next step on their list of troubleshooting. Don't have enough experience with this type of troubleshooting to say otherwise.

I totally follow you though. If it were so loose that it wobbled enough to break an 1/8" EM, then when I put my 1/2" EM running at 112 IPM at .200" DOC you would think the tool holder would just pop off. I often run my 1/2" EM close to 100% spindle load, and the finish and cuts look great.

My original thinking was this problem / runout issue was so minor that only the small EMs would be affected due to the runout version EM diameter ratio. But my thinking could be wrong.

I do push those little cutters pretty hard, probably right to their limits, but it had been working great for 1000's of parts, and then they just started breaking (these were the high helix aluminum cutters). Though with my SGS double sided standard cutter, it is hanging in there with about 500 parts under its belt since this issue started. Same feeds and speeds as before with no changes to the program. Just leaves a little extra burr than what it used too.

It's one of those things that is minor enough to where you can almost convince yourself that maybe this is how it always worked. But I know something changed in the machine. So hopefully when it gets inspected something will show up.

I only have about 2 years with this particular machine, but I do have a good feel for it since most of the parts we manufacture are similar using the same tools, feeds, and speeds in the same material.

I'll definitely post back what ever I find out.

Thanks.

[Bloy2004]

It's one of those things that is minor enough to where you can almost convince yourself that maybe this is how it always worked. But I know something changed in the machine. So hopefully when it gets inspected something will show up.


I'll definitely post back what ever I find out.

Did you find out? I mean, why you suddenly started having problems? Is your sudden problem with the machine all worked out now?

[Terry G]

Sorry for not posting back in a while. Been super busy.

YES, the machine is working great now. Couple of minor issues that were resolved by the Haas tech.

1. Machine was actually twisted a bit. When moving the Y axis front to back with a machinist level on the x axis, it measured about .002" difference. The left rear foot of the machine was actually off the ground! Looks like my concrete slab settled a bit.

The tech adjusted the machine to within .0002" twist. And now I check it once a month, and adjust as necessary.

2. The tech also added a bit more backlash compensation. He was very familiar with this machine and has worked on it since it was new. Also very reputable in this area. So I trusted everything he did.

3. I also had no idea on this, but my memory was at about 90% full with a bunch of programs. The tech said I should never have more than 20% or so in memory. Not sure if this made a difference, but I'll only keep the programs I am running on the machine form now on.

The machine is cutting very well and the finish of the parts look excellent.

There were no run out issues. And my draw bar pressure was well within spec. He also listened to the bearings, etc.. with his trained ear and said everything sounded great.

As far as the 1/8" end mill have not broken any since the initial two I broke in a row. Still running the same feeds and speeds pushing them pretty hard and all is good.

Terry

[Matt@RFR]

That's great. A minor tune up and all is well.

[MetalZilla]

19.5 inches per minute plunge at 6000 rpm seems high to me. Works out to be .0033 inches per revolution. I would lower that feed and use a G73 peck cycle to start at a lower feed rate.