HAAS Belleville Washers

First off, I would like to say hello to everyone. This is my first time posting on your forum.

I have a customer that has two HAAS VF-5 50 taper machines that have been running pretty much 24/7 for the last year. They have been running the same part. My company did the programming for the customer and had the machines running up to 9500 RPM's during some of the operation, but not all of it. Maybe 10 minutes out of a 30 minute cycle was at 9500 RPM. There were about 20 tools, so there were 20 tool changes every 30 minutes.

The machines are now in need of service because the drawbar holding pressure was only around 600lbs. The belleville washers need replaced because of the high number of tool changes and they are just worn out, but the customer wants to attribute them wearing out to us running the spindles at almost maximum RPM.

My question is, does anybody have a source of information about these belleville washers and maintainence of them? The wear of the belleville washers vs. spindle speed? The wear of the belleville washers vs. number of tool changes? I need to put a report together for the customer that says we investigated the and can explain to them why these belleville washers are failing and that it is not because of running the machines close to maximum RPM.

Thanks for any and all information I recieve back from this post.

First welcome to the forum.


I'm sure this is not the answer you want, but...

If I were in your shoes I'd call Haas directly and ask them why the Belleville Washers failed prematurely. For me they have always been the best place to get my questions answered. Aside fror Haas the factory I would speak with service techs at your HFO.

Hass Belleville Washers

I would be asking, are the washers broken, are the washers just worn out, or are the washers just not being held tight enough anymore. Maybe the adjusting nut that is adjusted to create the tension has backed off. Seems the springs can be flexed time and mtime again but you pull a toolholder out of the spindle when it is clamped and the springs will be broken right then and there.
Just some thoughts.
Regards Walt...

I'm FAR from being an expert on the subject, so take this with a grain of salt, but I'm not sure why spindle speed has much to do with the life of bellville washers.

From what I've seen, the washers are somewhat of a consumable item, and 24 hours a day for a year is a lot of hours.

From what you say, that's somewhere in the neighborhood of 960 tool changes per day... maybe 300,000 some tool changes in a year?!

I guess I'd be really surprised if things weren't wearing out after that many tool changes and hours!

I built and rebuilt spindless at Ingersoll Milling for about 6 years of my career there. Replacing the bellville springs was a standard repair. Our spindles were mostly slow and big 50/ 60 cat taper, 6000 rpm , being about as high as the standard spindles went. That many tool changes sounds like a good life.
Another product line at Ingersoll used hydrostatic bearings in the spindles. These spindles were 25000 rpm/ 65 hp. They had hsk 63A spindle tapers but the gripper/drawbars were a pretty normal bellville spring configuration. I wouldnt attribute very much wear to the spindle speeds.
Low pull force? Are the gripper fingers set to the proper dimensions? We checked that with the gripper full open, no tool. Walt at SGS might know a bit more about the different dimensions and strokes of the drawbars.

I haven't worked on a Haas 50 taper, but we have HS-1 10k, 2 VF-2, and 2 VF-3 all with 40 taper. Only have had to replace a drawbar when we did the spindle. The HS-1 runs a lot of aluminum and spends a lot of time above 7500 rpm. Only put in 1 spindle and drawbar in 10+ years. The VF's aren't bad to put in only a couple of hours, and Haas is real reasonable on new drawbars $wise, so put in a new one. The 50 tapers are heavier but I don't think that they should be that much more difficult.

Thanks for the info guys. I was HAAS Demo Days yesterday and spoke with the Service Manager there. We spent about an hour talking about the issue. From what he was telling me, the spindle speed does not effect the belleville washers. The drawbar pressure is set to be around 1800 pounds of pressure. If that goes below 1700 pounds of pressure, they replace the drawbar. I dont believe that any maintainence has been done on these two machines which expalins why I am in the situation I am in. I will be going back to my customer shortly to let t hem know what I have found out. Thanks for the replies.

The first item in the machine "wellness check" here is about belleville washers:

http://www.parllpcs.com/wellness.php

Hello Keijus68.


WE have 2 VF1s and 2 VF4s

The max speeds we run is 6500 ( that too for just 20 seconds ) per cycle.

BUT the Haas VF1 makes about 2000 tool changes in 24 hours and about 28 days a month.

And I can assure you that speed has nothing to do with bellevelle springs failing.Its the number of tool changes that cause it ( the DRAWbar) to FLex.

I all I must have replaced the drawbar on all the HAAS s ( one in six months or so for some and about once in 8 months for the others)



I purchased 2 drawbars from haas .

I take out the low force ones ( VF4 and VF1 have the same DRAW bar) fit the new and service the old . usually we find a few 4 or five cracked ones )

I also purchased a 'CLAMPrite' FOrce gauge - just type that on google to get more details...

I have a weekly check sheet pasted on all the VMc, not just the HAAS where my maintenance technician has to write down the force reading .

We catch the ones going faulty and replace them immediately.

I got some replacement disc springs and change the springs myself. (

I have posted some drawings somewhere on this forum will link it to you....

Good Luck
MJM

Well HEre it is .
And I just noticed I didnt reply to the last question.. missed it completely !!

http://www.practicalmachinist.com/vb/showthread.php?t=162552

MJM