Hurco Spindle Orientation - belt failure

We've had a belt go out on our VM20i again (2014 model, WinMAX control), and rather than pay $2k for the Hurco guys to come fix it, I'm going to do it myself. If I understand correctly, the only tricky part is getting the spindle correctly oriented after the belt change. Does anyone have the procedure for this they can send my way? Any tips on changing the belts before I dive into it? Thanks!

Hi,

I had belt slip by couple teeth on my vm10, it moved enough so the tool changer couldn't grab tools correctly. Machine is still under warranty, so I called technician to come in.

He literally set the spindle by eye to where it's supossed to be and then changed some values in the yasnac drive. He did explain to me all the steps, but I didn't write them down.

I'll try to email them Monday and will come back to you if they give me any valuable info.

Kamil

I did something sim to this. Replaced belt and tried to index turret. Feed hold or estop, do not remember. Loosen belt tension and rotate by eye and repeat. Main spindle of a mill should be easier because "spindle orient" would tell you where it thinks it needs to be, adjust belt to suit.

At a minimum, you need the pendant / operator panel for your spindle drive. If it's there you're good to go.

Like Kamil said, you just slip the belts until it orients in the right place, but if you need to fine tune it (which you very likely will have to do) then you need to do so at the spindle drive.

It's not complicated, just changing a parameter on the drive. Assuming your drive is Yaskawa, the manual can be easily downloaded from their website where you can look up which parameter and how to change it.

If you don't have the pendant / operator panel, you can look up the part number from the manual and likely pick one up on ebay for very little.

Sorry, I did mean Yaskawa not Yasnac drive :P sounds similar. My drive has inbuilt screen and buttons, so the pendant musn't been necessary in this case.

I dug into the machine a little and found the Yaskawa A1000 drive has a screen/buttons built-in in the cabinet. I suspect it's the same as Kamil's. I just need to figure out what to do with it! The Yaskawa manual leaves a lot to be desired as far as telling us how to adjust the spindle orientation.

They sure didn't make changing the belts easy, everything is really tight and difficult to get to! Any tips on that? And how is the belt tension adjusted? It looks like it's done by moving the entire motor over in some slots, but there's nothing for tuning the adjustment, just slots and bolts that tighten down...

This is the second time I've had to replace a belt (first time I paid the techs to do it, but it was over $2k!), and the machine has just under 1000 spindle-on hours. Is this normal? We haven't had a big crash, and the spindle load rarely goes over 60%, so this seems odd to me.

I have a hurco vm1, had to
Adjust the belts a few times and it’s very easy. You need to fine tune on the yaskawa drive, (I’m not good at this stuff but it’s really easy) I think I have the page folded in my book If you need help. Another option is call hurcos tech support, the guy who usually answers is very helpful and got me out of a few jams without a tech.

I sent an email to my reseller, who forwarded it on to Hurco. They responded back quickly with the following:

Replace belts
Remove sheet metal on head
Loose 4 bolds on motor mounting plate (10mm hex socket easiest with rachet and long eat)
Slip motor fwd
Remove unclamp cyl
80% of the time you can slip belts ove top of spindle and on motor pully
Other 20% you have to drop spindle a couple inches
Tighten belt.
Run 20 min retighten belt
Set orient

Click to expand...

He also called and left a voicemail with saying basically the same thing and that the belt failure is probably caused by the belts being too loose. I've been out with the flu, but hope to get back on this in the next couple days. I'll post an update once I give it another shot.

Got everything back together and up and running again!

Replacing the belts was fairly straight-forward. It's clear they didn't design this with easy belt replacement in mind, but it wasn't too bad. The most annoying part is getting a good tension on the belts. There's no jack screw or other provision for tension adjustment, you just shove the motor back in the slots and tighten it down. That leaves a lot to be desired...

Spindle orientation was pretty easy once I got the correct instructions. Here are the instructions for that (Yaskawa drive) in case anyone runs into this issue:

1. Calibrate machine axis and tool changer.
2. Set P2-02 Market Offset 1 on the A1000 inverter = 0 first.
3. From the Manual screen, press the “Orient Spindle” softkey, and then Cycle Start to orient the spindle.
4. After the spindle is oriented, press the “Spindle Off” button.
5. Turn the spindle in CW direction a minimum of two revolutions and stop it at the actual orient position (I marked this before removing the belts, which really helped!).
6. Monitor U7-02 Dist From Marker on the A1000 inverter to view the current orientation encoder counts.
7. Set parameter P2-02 on the A1000 Inverter (0~4095) as viewed in U7-02 to adjust orient position and then escape to Dataset.
8. FOR 10K SPINDLE NON 1:1 Ratio ONLY F1: Set N95:214 to 1, force rotation before orientation. (not necessary for me)
9. Turn on the spindle CW or CCW in manual mode and perform the orientation several times to check the orient position.

Overall this took me a couple hours, but when I have to do it again it should go much faster, plus I bought extra belts for when the time comes.