FARO Arm

What are your impression/experience with FARO Arms (Gage Plus)? I am looking to get a FARO Arm for some on Machine (lathe, man. mill, and VMC) measurements and inspection room CMM reports. Documentation shows that the machine is accurate to .0002".
Thanks,
Chazsani

I just do not believe in .0002" accuracy from an articulated arm CMM. I used an old Romer with about .004" accuracy and I used a Faro Gold with about .002", those were my observed errors from measuring known items. These were both solid touch probe machines.

I believe the Gage Plus has a pretty limited range, doesn't it?

FARO Arm Range

The arm can do 48"... 24" from the base.
Chazsani

I have a small faro arm, one of their demo units. (Not the gage, one of the mainline arms.)

Certified to 15microns or better than 0.001.

If you measure something like a gauge block and get all of the p's and q's lined up, you can get a number that is good to several places. But of course, you know the dimensions of the gauge block to start with...

I think articulated arms CAN be very accurate, but a salesman for Romer admitted to me that they get better answers when the support the arm.
And a short arm should have less grief than a long arm.

Also, what are the alternatives? You probably cannot fit your machine tools inside a CMM, and arms are very good at reaching around and into things.

(Also see the other thread about using probing on the machine to do measurement.)

I sell a lot of metrology equipment and the .0002" accuracy that FARO claims is correct, if taken in context.

If you take the arm and measure a feature, remove the arm, and remeasure that SAME feature they are saying the second reading will be within .0002" of your first reading.

.0002" does not apply to taking a reading at one end of your measurement envelope and then the other end.

So, the .0002 is right, but you have to read the fine print.

How accurate would you expect it to be on say a 24" bore or OD?


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Think Snow Eh!
Ox

PerryMill said:

I sell a lot of metrology equipment and the .0002" accuracy that FARO claims is correct, if taken in context.

If you take the arm and measure a feature, remove the arm, and remeasure that SAME feature they are saying the second reading will be within .0002" of your first reading.

.0002" does not apply to taking a reading at one end of your measurement envelope and then the other end.

So, the .0002 is right, but you have to read the fine print.

Click to expand...

That sounds more like you're describing good repeatability.
Accuracty is a different story altogether.

You don't have to tell me that I'm just repeating what I was told by multiple other reps about Faro's stuff. The point is that they're not so forthcoming with real numbers.

Anyone know where I can get a used Faro Arm for under 15K?

Thanks,

Smart Metal

A 2004 Faro "Guage" with 18" reach from C/L sold for $12K I think on Ebay the other day. FWIW

The newer "Guages" have a 24" reach from C/L tho.

The "Arms" are 48" reach, with less accuracy. I assume you would want a "Guage"?


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Think Snow Eh!
Ox

Our shop neighbor has a Faro Gage that we just used to reverse engineer one of our motorcycle frames. I got to know it pretty well.

Gage, stand, surface plate, software (not the laptop) included.

The guy wants to sell it, too. He never used it. If you want details send me a PM.

Our shop just purchased a FARO arm, brand new.
I'll report back if it's a boondoggle.

We just demoed a Faro Titanium they let us use it for 2 weeks the are good the shorter you keep the arm the greater the accuracy, but a the laser option is better for reverse engineering. They should let try one out, for around
$80,000 a test drive would be nice?

I have used the FARO Gage daily for about 7 months now in many different environments. The accuracy is actually a +/- .0002". I can confidently say that measuring to .0002" is not a problem with a good setup. The advantages of this system are that it is an ultra portable, fully functioning CMM. This being said, sometimes the environment is not ideal like it must be for a bridge style CMM - therefore you open the door to incure some error. If I am setup solidly on a CMM's granite I would have no problem going head to head against its accuracy. Have a great day and happy measuring!

Its great to be accurate with your measurements, and your only limited by your budget when it comes to the equipment you can purchase. But do you need that level of accuracy? what are your tolerances on your blueprints? Are those tolerances achievable with your manufacturing equipment?
We had this discussion at my work a few months back and it came down to being good at what we do and transition to new levels as needed not rushing to the very top, there is no point in wasting 2 hours setting up for 0.01 mm accuracy for turning a metal peg which will get whacked into the ground.

We looked at a FARO arm and came to the conclusion that our current Metrology was sufficient for the components we make but do see a use for it in the future.

Pazuzu71 said:

Our shop just purchased a FARO arm, brand new.
I'll report back if it's a boondoggle.

Click to expand...

And .......????



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Think Snow Eh!
Ox

Hmmmm...... must have missed this the first time around.....

A client has a faro arm....... not at all sure which version.

Apparently the USER has as much if not more effect than the actual machine..... We needed a decent model of a part, actually the mounting surface vs the spindle of a wood router spindle motor (old one) that we wanted to use to drive a test setup at medium RPM (a bit under 20k rpm).

We wanted the dimensions accurate to make the holder to support the motor and position the collet where it needed to be to couple to a shaft (via a somewhat compliant coupling). Actually, the client's guys were going to make the model and draw the parts, but we needed to approve.

Anyway, the client's in-house machinist used their Faro arm to get the relationship dimensions.

For whatever reason, the results were no better than 0.002, and not always that good. A few were out far enough that their draftsman and I were very puzzled. I assume their guy messed up, and possibly their unit was not the best one.

We ended up doing better by measuring. Their draftsman, who is good, could not use the data that came off the arm, because it wasn't internally consistent. He and I measured the unit with mics and calipers, etc, and got some very different numbers.

He used our numbers to draw up the support, and the result fit perfectly. Indicating off the shaft of one part to the shaft of the other at two levels showed we were well under 2 thou error, and the coupling could take 6. So we were good.

I don't know what would have happened with the arm's measurements.

I also don't know why they were so bad, but they sure were. So just using the arm won't get you perfection, by any means. You have to do it right, and THEN maybe you get the results mentioned above......

It is far best to not trust what is said about the accuracies of most arms as experiences shows they usually greatly over-stated.
Sometimes the reps simply forget to mention that little + or - statement, sometimes it's just wishful thinking.
If you're really interested in a gage like that and if the rep is really honest, a GR&R study should be no problem.

JST seems to have a good experience of Faro Arm. I am totally disappointed with our FARO gauge. It is not good for batch machining, as you dont always have a good setup on or nearby your machine to get all these things working perfectly. Expect a max repetability of 0.001" on your Faro. Conventional CMM's are always great.

We've got a 6ft. Fusion Arm that we purchased new last May to replace a 10 year old Gold arm and we absolutely love it. For this particular arm the calibration certification states a single point 2 sigma accuracy of 0.051 mm and a linear displacement 2 sigma accuracy of +/- 0.071 mm. I've been told by a FARO rep that based on the required calibration procedure, these accuracy numbers are the worst that the arm could be operated at (the best that I've been able to calibrate mine at is +/- 0.0006 in.). Just like any other precision measurement tool, accuracy and repeatability are dependent on setup. The arm needs to be mounted to a very SOLID and RIGID surface, we purchased the granite table / roll cart that FARO has available for the arm.

Of course FARO manufactures Arm's with much greater accuracy such as the Quantum and Gauge but for the price and required accuracy the Fusion arm meets our needs. We use our arm primarily for Reverse Engineering work and occasionally for some Quality Control work and have been absolutely thrilled with the results.

As a matter of fact the week before last I attended training at FARO's facility in Lake Mary, FL for their new CAM2 Q software for use with the FARO arm and Laser Tracker. The new software is much more user friendly and I believe a lot easier to use than the previous versions.