Fadal Low Speed Belt Slipping

[mattpatt]

Hi All,

I have a VMC3016 and it seems to be suffering all the problems this thread describes.

I sorted out one problem which was the hydraulic rams for the RPM high and low ranges, but I have the awful clattering, and it appears from reading this thread that my motor mounts are worn/dead.

I look at them and they're squishing out from the sides of the mount, and a dude at Fadal recommended that these will need changing. Part# MTR-0068 he says.

I read here that maybe solid mounts are the way forward. If so, what material are people using? I was thinking of making my own, but the motor seems to wriggle about a fair bit so I don't want to upset this with solid mounts.....maybe!

Carbidecraters mentions the tensioner cable. I think this is what has caused my grief as when the so called technicians changed my belts they didn't adjust this, even though I kept pointing out that it said in the manual that it needed adjusting.

Does anyone have any advice? I'm scared to use the machine as it sounds like it's about to fly apart!

Yours in need......

Matt.

[ThatguyDave]

To address Bob's curiosity. The unused belt is constrained by two curved profiles consisting of 180deg radiuses a bit larger than that of the pulleys. The untensioned belt expands into these profiles so its not like they're just floating around dragging aimlessly on the spinning pulleys. Simple, relatively effective, and certainly something anyone could replicate cheaply.

I second the opinion that a buildup of crud could certanly cause all kinds of issues, particularly is the better part of a deceast belt or two is still hanging around. The hydraulic hi-lo seems to work reasonably well even if it isn't perfectly bled. I went nuts trying to get mine perfect and finally gave up but it continue to work fine.

[Neal]

Mattpratt--
The motor is probably moving because the vulcanized mounts are worn out. You can replace them with solid mounts. Yes, the tension cable should have approx .015" tension on it. It does help to stqablize the spindle motor.

Neal

[Delw]

One other thing to add,
if you dont have an air filter on the top of your spindle motor your going to have a few problems.
If you face mill alot your belts will last about 8 months to a year.
if you dont face mill you can get about 1.5-3 years out of them.
if you use junk coolant or run a thick coolant 6months -1 max life.
if you use a water system with your coolant the belts will last 3-7 years.

coolant build up is the worse thing for the belts as well as the mist. Make sure you have all your covers on the z axis, make sure you have a air filter on the spindle motor.
recomended when using coolant clean the tensioner rollers every 6 months, I use keroseen on a rag at a very low RPM just use some common sence.
One other thing that I have noticed, in the mornign when you run your spindle warm up, make sure you call up low gear than high gear, I have found that if you just start the spindle like I do( right after you turn the power on to machine) its in high gear however the tension isnt always right maybe from the lack of runing the the belts sit over night? so I cycle the gears run low for about 10 seconds then run high for the remainder.

Theoretically you should run a program with equal time on both high and low gears for warm up, this will keep the belts even in tention.

when you do change the belts make sure you clean everything including the pulleys the gunk and crude builds up pretty fast.

again the main thing is the air filter thats most important especially when face milling.

Delw

[mattpatt]

Thanks for the replies.

One thing is that I'm in Thailand, so I won't know until Monday exactly how quickly I can get the parts.

Can anyone suggest a material to make solid mounts?

Cheers,

Matt.

[Neal]

Matt--
Check with Mitracom in Bangkok. They are our Thai distrubutor.

Neal

[mattpatt]

Neal,

Thanks for your reply. We purchased the machine from Mitracom. I spoke to them this morning and we're discussing the sequence of events that lead up to this..........

[mattpatt]

It seems as if spindle belt life is going to be a major issue. You can see from my last post that only a couple of months has passed since we changed the motor mounts and the belts, and now I have problems again.

Dewl recommends a motor filter etc. Well, I've tried various guards, filters etc to keep coolant out of the belt area, but it seems it's not doing a good enough job, as when I pulled all the covers off there's a fair amount of cutting fluid around.

I pulled the belts off and cleaned everything meticulously with kero, and dried it all off, but there's still a problem. I can see that one of the belts has lost it's flat shape, which is causing the pulley to drag the 'free' belt around, thus making the noise.

So far we've just used FADAL genuine belts, but I have some others ordered from Kmac-parts, so we'll see how we get on with those when they turn up. Much better I hope.

For the record, 99% of my machining is aluminium parts, so always plenty of coolant flying around. Maybe I need to come up with a cunning shield of some sort to stop the coolant splashing upwards and into the motor area.

Anyway, that's all for now.

Any suggestions as to what I may be doing wrong, or if in fact this is normal!

Regards,

Matt.

[BobWarfield]

Matt, since its the low speed belt that gives trouble and you use the high speed (presumably?) for aluminum 99% of the time, I wonder if that's your trouble. Maybe you want to cycle in the low speed a little bit during your warm up routine.

Fadal works by tensioning the belt being used and leaving the other slack. Maybe leaving the one slack all the time is the trouble.

Just an idea.

Best,

BW

[SBC Cycle]

Originally Posted by mattpatt For the record, 99% of my machining is aluminium parts, so always plenty of coolant flying around. Maybe I need to come up with a cunning shield of some sort to stop the coolant splashing upwards and into the motor area. Anyway, that's all for now. Any suggestions as to what I may be doing wrong, or if in fact this is normal! Regards, Matt.

Another local shop here that has Fadal's and does a lot of high speed aluminum cutting fashioned a plexi-glass or lexan cover that goes over the top of the machine. It just has a cutout for the Z axis to go up and down and it does a damn good job of keeping the mist to a tolerable level.

I'm still on my original belts on all my machines. Some are 12 years old now. I'm surprised at the seemingly frequent periodical belt replacement I'm seeing here.

[mattpatt]

Thanks for your replies.

Interesting about the low speed belt not getting use, so causing the trouble. Some how that may actually make sense!

I've made a cover, so let's see how we get on.

12 years on a set of belts! that's pretty good going.