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Good Table for Faro Arm ?

a2t

Plastic
Joined
Jul 16, 2018
Looking for a work stand to mount my faro arm on.

Ive looked at the rolling faro cart and its really nice, but $2600 and weighs 800 lbs

I used a 4' faro USB in my home office so I need something good to mount it to but not granite.

Does someone make a steel table or cart with casters on it that I can just buy and mount the arm to for reasonable accuracy ? I know it wont be perfect if not mounted on granite but what are some good lower priced options better suited to a home office ?

Thanks,

Paul
 
Good suggestion re: optical table. Also, check McMaster's offerings of machine tables.
 
ok thanks for the suggestions guys. The optical table seems like a great option for me. I have my faro arm already mounted to a 6" x 6" machined steel mounting plate so I can bolt it down to any table with threaded holes, so I don't have to use that circular faro ring mount if I can get away with a less expensive option.

Just browsing ebay I can see a bunch of threaded breadboards and complete optical tables. None near Atlanta, sadly so I will have to just buy it online and hope for the best...

I could go the route of just buying a table with leveling feet, then buy a threaded breadboard and somehow attach the 2. Or buy a complete optical table ready to go. Since this is going into a home office and will be sitting on laminate floor, Im not going to be too concerned with dampening. The temperature is reasonably controlled. I obviously wont be measuring down past say +/- .005" with this faro anyway, so Im not looking for a big bucks pneumatic dampened set up here or anything. Just basic and simple but solid and reliable.

For a 4' Faro I was thinking 24"x24" table would suffice, let me know your thoughts on that. Maybe I could go 24" x 36" ? Im putting this into a home office so constraining the size and weight are important.

The last thing I will need is a basic fixture kit with standoffs and angle blocks to actually fixture the parts I'll be inspecting. If anyone has any suggestions on where to get a basic, inexpensive fixturing kit that works well on a variety of small parts, I'd also very much appreciate the input.


Looking forward to getting this Faro P4 up and running and getting good data.


Paul
 
What about something like this ?

36" KINETIC SYSTEMS VIBRAPLANE OPTICAL TABLE T-SLOT BENCH breadboard lab laser | eBay

I could machine a base with the right hole pattern to bolt the Faro arm down to.

Would this be rigid enough to support the arm and not bow in the middle ? I could mount the arm off to 1 side.

Also, found a few from Optical Breadboard, Optical Table, Optics Table, Optical Bench, Isolator and Vibration Isolation - could do either 1" thick or 2" thick boards and they sell the tables for them as well. Would 1" be thick enough to just use to measure, or should I go with 2" ?
 
The table in your E-Bay link looks good.

Stiffness of deep honeycomb cores is almost unreal. 4" thick core should be plenty to avoid bowing unless you put something silly heavy on it. Track back to the table makers data. Should be details about loading and bow. For a 4" core a conservative and very, very rough rule of thumb will be under 5 micro inches per pound point load at the centre of table like that on solid legs. In a practical world nothing you can lift on is going to worry it.

I'd put the Faro arm over one leg.

Clive
 
ok was thinking more like a 2" core to save $. Think that would be OK ?

Im not planning to load an engine block on the table or anything. Max weight would be like 100 lbs but mostly 10 lbs max. I could also recalibrate the faro arm if I did load a heavy object like an engine head on.
 
Tables I worked with were 12", 16" or more deep so no real experience of 4" or 2" core ones. Although I have used equipment built on 4" tables that seemed plenty stable enough. Of course this was high precision relatively long throw optical work where even a micro inch shows up.

All I can say is that I never saw anything built on 2" core table tops of any size. My gut feeling is that you need a certain care and engineering nous to use 2" cores on the things I was involved with but 4" ones are pretty well behaved. Just not as stiff as the big boys. Of course in my world we were more concerned with vibration et al rather than bow which has a whole different dependance on stiffness. Unfortunately all the easily accessible data seems to be written from the vibration analysis side of things. Understandable because if the vibration is under control the thing will be way more than stiff enough. The thinner the table the more important correct support becomes.

You really need to get data from the folk who make them but I'd be unsurprised to discover that a 2" core table properly supported would be adequate for your needs. Properly supported covers multitude of sins of course.

Clive
 
ok the difference between 2 and 4 inch cores is pretty negligible.

Vere makes a decent 24x36x4 breadboard with 1/4-20 on 2" centers, as well as a nice stand for it with casters and adj height. Would be about $1600 delivered, seems like a pretty good deal to me. Its also shipped in parts so would be much easier to transport into a home office as compared to 800 lbs Faro rolling cart. Think I will pull trigger on it.

Another question I had was regarding fixturing - is there a good place to get a decent kit of stand offs and such that I will to fixture the parts ? Some of those kits can exceed the price of the table! Any help there would be much appreciated.

Last question - I think I will get my 4' Faro P4 recalibrated. anyone know what that service would cost ?
 
That Vere table seems very good value. Suggest you ask them about bending stiffness and best way to mount your Faro arm before buying. I imagine other folk have had similar needs in the past. With precision work the devil is always in the detail and often seemly trivial variations make big difference.

Clive
 
Suggest you ask them about bending stiffness and best way to mount your Faro arm

The faro arms can impart some significant unbalanced forces into the platform they're mounted on due to the counterbalance system.

The point accuracy of the faro arm depends on the base of the arm being fixed rigidly in space. Any displacement due to flex in the platform directly impacts the accuracy of probed points.

That's why most dedicated platforms for faro arms tend to be very stout, and also why having the arm and the workpiece mounted on separate platforms is common.

I am not familiar with the tables you are discussing, but rigidity under dynamic loads is the main concern for mounting a counterbalanced arm. Are these tables up to that?
 
I am not familiar with the tables you are discussing, but rigidity under dynamic loads is the main concern for mounting a counterbalanced arm. Are these tables up to that?

Rigidity and stability under dynamic and vibration loads is what optical tables are designed for. The big boys are always floated on air suspension legs or similar systems around 1/4 length & in from edges to decouple them from outside influences. With significant unbalanced loads, much more than a Faro arm, you may need to adjust the support positions to compensate. The thinner tables are often mounted on an external frame rather than fully isolated. Although the frame may have isolation legs. Not familiar with the implications of that for unbalanced loads. Gut says solid legs on and edge mount frame will be fine.

Honycombe core optical tables beat the pants of granite for sure. At Vere prices can't see what anyone would choose granite. Optical tables have got much, much cheaper in relative prices than when I was buying.

Clive
 
Not to derail your thread but I was skeptical when these came out on the market years ago I guess that makes me an old school CMM guy. How useful is this arm ? Has it worked out well in your shop ? Has it taken the place of your CMM or found it's own place as another way to get the job done. I spent some time on the Website and was impressed.

Make Chips Boys !

Ron
 
Here is ours on an optical table, retractable casters make it easy to reposition.

This right here is pretty much what I ordered from Vere.

233935d1532449915-good-table-faro-arm-faro_optical.jpg


Its a 24x36 breadboard with 1/4-20 on 2" centers. The core is 4" thick. They said it would not deflect up to 1200 lbs so should be plenty for what Im doing in my home office.

I really havent had much chance to appreciably use my 4' faro arm yet, currently its clamped to my wooden work bench, lol. However, it seems capable of taking basic touches. It will be tricky and perhaps tiresome to move the arm by hand, press the stylus against the part without moving it, and press the green button to take the point. I did set up on a basic part and it seemed to be able to do this although I didnt really test the accuracy as its irrelevant when mounted to a wooden work bench.

I'll show a picture and perhaps video of the set up once I get the table here.

Can anyone suggest a decent fixturing kit for me ? Or give me a heads up where to be looking for 1 ? These seem to range in price from 100 to 1000 or more. I'll be working with mainly small parts, so I need a good way to hold them rigid while I manually touch the part with the stylus to gather data.

By the way, thanks for all help thus far. Pretty excited about setting up an inspection lab in my home office. Im also searching for a decent optical comparator, as we seem to be getting more and more into small gears and such. The iterations are killing me, if I had a good optical comparator I would be able to measure the teeth on these tiny gears very accurately. Calipers and eyeball arent cutting it!


Paul
 
@Dupa3872 - I've never owned a CMM, but do have a faro that's gotten a little bit of use of the years. I don't view as much of QC/QA device. Rather, my uses were all for reverse engineering or interface engineering. (e.g. reverse engineering something not to replicate it, but make something that fits to it.)

In the age of the web and way more drawings for things readily available, this some less of an issue than it once was.

At least in the era I got mine, faro's marketing was heavily driven towards tasks like reverse engineering molds and other tooling (where for whatever reason no model or drawing was available), or making a model from a mockup someone made by hand. (e.g. People make clay model of something like a car, then scan that to make models)

Just my (rather limited) experience and observation.
 








 
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