Issues with Homing

[[email protected]]

A few weeks ago we ran into issues with our CMM not homing correctly in the x axis.
When it goes to its zero points during the startup homing it over travels in the x+ direction after hitting home.
so it hits home but keeps moving in the x+ direction for a few inches then stops.
that's all fine and dandy except we are running some parts right now that take up the entire table and I've had to modify all my programs around this issue.
And now today we are dead in the water on a part that will be needing checked tomorrow because there's just not enough room to run it now because of this issue.
I've checked all over for reasoning and can't get this resolved.
The scales look good, we clean them by dusting them off with a horse hair brush.
never chemically.
It's a Global 9*12*08 Brown & sharp.
with the gold scales.
Also along with this homing issue we have lost our probe rack position over a dozen times.
It seems to have straightened up this week, I haven't had to relocate the rack but dang!
What the heck is going on with the X?

Is there a way to adjust the home position manually? So that we can continue?

[bfire85]

A few weeks ago we ran into issues with our CMM not homing correctly in the x axis.
When it goes to its zero points during the startup homing it over travels in the x+ direction after hitting home.
so it hits home but keeps moving in the x+ direction for a few inches then stops.
that's all fine and dandy except we are running some parts right now that take up the entire table and I've had to modify all my programs around this issue.
And now today we are dead in the water on a part that will be needing checked tomorrow because there's just not enough room to run it now because of this issue.
I've checked all over for reasoning and can't get this resolved.
The scales look good, we clean them by dusting them off with a horse hair brush.
never chemically.
It's a Global 9*12*08 Brown & sharp.
with the gold scales.
Also along with this homing issue we have lost our probe rack position over a dozen times.
It seems to have straightened up this week, I haven't had to relocate the rack but dang!
What the heck is going on with the X?

Is there a way to adjust the home position manually? So that we can continue?

Have you contacted Hexagon about this?

[[email protected]]

No I have just been reaching out to the forum for help.

[KIRBSTER269]

Re-clean those scales and make sure they are clean and dry, had that happen in the Z rail before, it went up, then went down, down, down or scale is minutely off. It's to do with the scale, but that's all I got good luck

[[email protected]]

what can I clean them with? I just used a soft cloth and wiped it down thoroughly
powered it all down and re homed and still the same issue

[louisd]

so, from what I understand, home pulse on B&S Global's is via a hall sensor and a magnet. the home pulse can vary up to 1/4" each time. there's really nothing that can be done about this other than implementing a robust master probe and re-calibrating your master any time you re-home. this should also mitigate losing your probe rack cal.

make sure your readhead is clean as well. you might have a horse hair laying over your readhead..

other contributors: your motor, a bearing, or a drive belt can be on its way out, feel the carriage that holds the Z axis while traversing in X.... Does it have more vibration than if you feel, while traversing in Z or Y?

[Peter Fuller]

Just the limit is a hall effect sensor, the home pulse should be a digital mark on the scale.

[[email protected]]

I even took air duster and blew on and around the scale sensor for dust bunnies or anything else that might be blocking it

[acgarcia]

Got to use a lent free cloth and 91% medical alcohol. Using a lesser percentage still leaves a residue on the scales. This happens to our tigo quite often because the x axis keeps getting dirty.

[michaelwildschutz]

never use that high percentage of Alcohol always 70% alcohol or less..To high % Alcohol can destroy the etching on the scales

[acgarcia]

That is what I was told by hex hardware support. They said alcohol with a less percentage has other chemicals that leaves a residue.

[acgarcia]

The Machine has to home on its own in order to open programs. It got to a point where cleaning the scale didn’t help and it still wouldn't home so Hex had to remote in and run some test over the web. They can home each axis individually make sure it’s the axis you’re having problems with. Ended up replacing a X scale and it’s encoder. Spent a Saturday with a tech to get it up back and running. No issues since.

[KIRBSTER269]

I buy these to clean the scale, and no I'm not advertising.

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[JEFMAN]

KIRBSTER269 : And you use it to look at the hour, but you're not advertising ?????? LOL

calypso.jpg

[FMC.QC]

Check your encoder... we had the same issue with the X-Axis... found the magnet in the encoder had shattered / deteriorated somehow.

[[email protected]]

Anyone know how to home the machine without having to powering it down?
it would save some dang time!

[RIDER]

Do you have access to the FDC website? You can home from there.

[RIDER]

Firmware for Distributed Control. If you don't have a shortcut to it on your desktop or browser, you should be able to call tech support (assuming your SMA is up to date) and let them take over your computer to put it on there.

[Disal]

Check your encoder... we had the same issue with the X-Axis... found the magnet in the encoder had shattered / deteriorated somehow.

Hi-i know this is an older post-but where is the encoder and how does it look like? my machine won't home and cleaning scales didn't help

[FMC.QC]

It's the piece that rides on the glass scales.

[louisd]

So a READHEAD is the piece that is closest to the glass scale, mounted to the moving side of the CMM, that should have a little square piece of glass pointing to the scales (if scales are glass, some shop floor CMM's don't use glass scales). This is also more generically called the encoder (there can be different flavors of encoders aside from the commonly used CMM optical readheads).

The device that produces the HOME PULSE (AKA LIMIT SWITCH) for most CMM's is a magnetic hall sensor. However, this varies by CMM. If your CMM has a little black box (less than 0.200") with an "N" on it, located adjacent to the scale really close to where the CMM HOME location is, that's the hall sensor magnet. The hall sensor itself is a non-visible component inside the readhead sensor.

Hall Sensor Readhead is visually depicted as the top sensor in this wikipedia page: https://en.wikipedia.org/wiki/Linear_encoder

[louisd]

Here's that STEVEW guy flagging again... Where is the spam, Mr "I flag everything, but post nothing"?!! I see zero spam in this post, ya jackwagon!

[KIRBSTER269]

Admin2 that Steve guy is spamming our forum again. Can you please remove him from the forum.

[bfire85]

STEVEW If you are going to flag posts from almost 6 months ago, I'd appreciate it if you would post something as well. At this point, you seem to me like a social justice warrior, getting mad at everything but doing absolutely nothing. I hope you don't melt since the heat is being applied. Please justify your reason for flagging rather than just saying "spam post" without reading the context of the post. KIRBSTER269 has helped more people on this forum that you even know and has the rep to show for it.

[KIRBSTER269]

Your making me blush bfire85 .

[Disal]

Thank you guys, will be looking at it tomorrow