[mattpatt]

Guys,

Just replacing a belt on my Fadal 3016. I noticed strange wear on the belt. When I checked the height of the pulley with a setting block, the block doesn't fit. The pulley is low by about 1mm.

Now I know it was correct as I fitted the pulley myself, dropping it onto the setting block and allowing it to cool.

Anyway, the next thing I have found is that the spindle moves up and down inside the cartridge. I just measured it at 0.12mm.

Surely this can't be right as I was under the impression that the whole thing was preloaded when it's put together.

I do have to say that the spindle has been rebuilt.

[ASIGuy]

MattPatt,

First, check your motor mounts. They are made with vulconized rubber sandwitched by two pieces of steel. The overall height is exactly 1". Generally they tend to compress and the rubber breaks down, this throwing off the alignment of the motor and spindle pulleys. I suggest you replace them and start there if you can see the rubber squishing out from sides beyond the width of the steel top and bottom. We stock these at $80 each. Use PN: MTR-0068. We ship internationally daily, so no worries about shipping. You can follow this link to order:

Fadal Parts Online

Just search for MTR-0068 and you can follow the checkout process from there.

As far as the spindle preload, you are correct. You can try taking the nose cap off and tightening the lower preload nut such that when you press the tool in/out button with an indicator zero'ed off the nose of the spindle, the movement should be around 3 to 5 tenths of an inch, or .0003 to .0005". You do risk setting the preload incorrectly and killing the nose bearings, especially if you have drawn in contamination from a faulty air purge system to the nose bearings. You just never know, but this should have been set properly by the spindle rebuilder and certainly not something you should have to address on the machine.

I've attached a photo of the motor mounts so you know what you are looking for.

Cheers!

Brian D.
FadalCNC

[mattpatt]

Brian,

Thanks for your info.

I can say that the vulcanized rubber mounts went to the wall a while ago and it now has solid motor mounts.

I don't think I mentioned that it's an air/oil spinde.

To explain more of what I mean, I can actually use my hand to lift the spindle up and down inside the cartridge 0.12mm. If I use a length of wood on a block to act as a lever, then put all my weight on it I can see about 0.15mm movement. I'm 70kgs and the lever was about 5:1 so exerting about 350kgs force upwards.

Just now I did the tool release test you mentioned. It shows the spindle dropping down 0.09mm (0.0035"), which is well outside the spec you gave. However, when I then force the spindle up with my wooden lever (as I said above), then reset the dial gauge and hit the tool release the difference is now 0.25mm (nearly 0.10").

I also just found this in the manual with regards to preload adjustment using the tool release method and 1000lbs:
15,000 / 10,000. 0014-.0017 (Can Not be adjusted) Air/Oil

I can see the nut on the top of the spindle, just below the pulley. I wasn't away that there was also one at the nose. How can I hold the spindle while trying to tighten it?

Cheers,

Matt.

[ASIGuy]

Brian,

Thanks for your info.

I can say that the vulcanized rubber mounts went to the wall a while ago and it now has solid motor mounts.

I don't think I mentioned that it's an air/oil spinde.

To explain more of what I mean, I can actually use my hand to lift the spindle up and down inside the cartridge 0.12mm. If I use a length of wood on a block to act as a lever, then put all my weight on it I can see about 0.15mm movement. I'm 70kgs and the lever was about 5:1 so exerting about 350kgs force upwards.

Just now I did the tool release test you mentioned. It shows the spindle dropping down 0.09mm (0.0035"), which is well outside the spec you gave. However, when I then force the spindle up with my wooden lever (as I said above), then reset the dial gauge and hit the tool release the difference is now 0.25mm (nearly 0.10").

I also just found this in the manual with regards to preload adjustment using the tool release method and 1000lbs:
15,000 / 10,000. 0014-.0017 (Can Not be adjusted) Air/Oil

I can see the nut on the top of the spindle, just below the pulley. I wasn't away that there was also one at the nose. How can I hold the spindle while trying to tighten it?

Cheers,

Matt.

Matt,

I better understand. The spindle cartridge is held in place by SOCap screws around the flange of the spindle that you can see clearly if you lay on the table on your back and look up at the spindle. These must be tight obviously. Other than the entire head moving up with your block of wood, I am not sure what else can be moving other than what I discussed in the last post.

Your preload is too loose and needs tightened, but my guiding rule of thumb is this: If it's not broken, don't fix it. You chance damaging your spindle trying to set the preload now after the spindle has been in and running for a period of time as per the contamination discussion above. If this is not the source of the movement you are expressing, and the bolts around the spindle nose flange is tight, the movement must be in the head.

Verify this and I can help from there.

Brian D.
FadalCNC

[mattpatt]

Hi Brian,

The head is not moving and those cap screws are most definitely tight.

I mounted the dial gauge on the head and I can clearly see movement in the spindle.

As it is, the spindle doesn't make any strange noises, the finish is still good and it'll hold good accuracy (as good as I need it on my parts anyway).

The air into the spindle runs through a handful of filters and an air dryer before getting to the spindle, and all the filters for the spindle oil are clean.

I'm sort of tempted to leave it as it's one of those things that may have been like that for ages and could go for years, but it obviously isn't right.

Cheers,

Matt.