Clamping X-Y Stages together
Clamping X-Y Stages together
(OP)
We have built an X-Y mothion stage, that moves a fixture aroung. Travel is 40inches x 24 inches. Max velocity is 1.5meters/sec. The upper stage(24") weighs approx 60 pounds, the fixture about 10 pounds. Stages and saddle below are anodized aluminum, stages are secured with 4x 12.9 Grade M8 Socket Head Cap Screws, torqued to 40N.M.
When the tables are run into the hardstops, they slide on each other.
Can anyone suggest an interface material or joint surface preparation that would prevent slippage?
We currently are using some drywall sandpaper pads, but that is only a temp fix.
Thanks
Paul Labelle
When the tables are run into the hardstops, they slide on each other.
Can anyone suggest an interface material or joint surface preparation that would prevent slippage?
We currently are using some drywall sandpaper pads, but that is only a temp fix.
Thanks
Paul Labelle





RE: Clamping X-Y Stages together
Or, modify your program to not run into the stops. Frankly, running into stops doesn't sound like something that one should be doing.
TTFN
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RE: Clamping X-Y Stages together
Assemble, align, torque normally.
Apply a few drops of Loctite 271 (green, low viscosity, wicking) to each joint interface. Give it a few hours to set up if you can.
Be careful to not get the Loctite into any crevices that you don't want >>permanently<< bonded.
Mike Halloran
Pembroke Pines, FL, USA
RE: Clamping X-Y Stages together
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Sometimes I only open my mouth to swap feet...
RE: Clamping X-Y Stages together
Table accuracy needs to be within 5 microns, banging into the hard stops produces some linear translation, but also some rotational.
Drilling and pinning after assembly is not an option, no room to get in.
Will this green loctite come apart if necessary?
Thanks
Paul
RE: Clamping X-Y Stages together
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Mike Halloran
Pembroke Pines, FL, USA
RE: Clamping X-Y Stages together
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Clamping X-Y Stages together
I suppose the idea of installing shock absorbers on the end stops is unnaceptable, and redesigning the bolted joints properly is also unacceptable?
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Clamping X-Y Stages together
In a similar situation before (not the hard stop scenario, but did need ensure that there was no tranlation and/or rotation between the X and Y stage) and what I was able to do was use drill and taps that were the side of each stages interface plate to mount restraining plates.
If the stage you have doesn't have these drill and taps, would it be possible to dis-assemble the stages and add them? If so you may be able to add 6mm braces on all four sides
Kevin
“Insanity in individuals is something rare, but in groups, parties, nations and epochs it is the rule” Nietzsche
RE: Clamping X-Y Stages together
Kevin
“Insanity in individuals is something rare, but in groups, parties, nations and epochs it is the rule” Nietzsche
RE: Clamping X-Y Stages together
We are considering the loctite solution, but are still looking for a non-messy mechanical solution.
Dis-assembly to drill and tap is not an option for the unit in the field, it is installed in a clean room.
We have slowed down the table speed on this unit, as a precaution, however, they table can still hit the hardstop and be sent out of calibration.
Paul
RE: Clamping X-Y Stages together
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Clamping X-Y Stages together
Kevin
“Insanity in individuals is something rare, but in groups, parties, nations and epochs it is the rule” Nietzsche
RE: Clamping X-Y Stages together
RE: Clamping X-Y Stages together
Please expand on your statements about dowels not working in shear. I don't understand.
Thanks.
Lcubed
RE: Clamping X-Y Stages together
RE: Clamping X-Y Stages together
Same with keys in shafts, where you should use a spline or a taper or a friction face to transfer the torque.
This is assuming efficient design of course, if you are not trying to exploit the maximum capacity of the material then you can use pins. But that is carpentry, not engineering.
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Clamping X-Y Stages together
No dowel, no key, and a friction joint that you have to send a tech across an ocean to realign after a bump is ... unfortunate.
Mike Halloran
Pembroke Pines, FL, USA
RE: Clamping X-Y Stages together
In the type of application that you (pal00) are designing the dowels are all about location, location, location (as any good house seller will tell you). There are any number of reasons to take an x-y stage assy apart, but only one way to get it back together to its calibrated position....dowel pins. However, if you are hitting your end stop with enough force to overcome the friction forces generated by 4 bolts, then you are in a bad place. If you do have dowels in this assy then they are either being deformed into a lovely S-shape and/or destroying their mounting holes rendering them useless.
Some further suggestions/things to look at.....
1. Are the bolts holding the stages together tightened to the correct torque settings?
2. Are you sure that the damages to the slide is from the impact and not from over-running the system on the end stops?
3. I would get your techies to check the drive and gearbox to make sure your crash hasn't damaged them as well.
Kevin
“Insanity in individuals is something rare, but in groups, parties, nations and epochs it is the rule” Nietzsche