Loctite Inspection?
Loctite Inspection?
(OP)
Is there a way or a device to inspect for anaerobic loctite application on a screw threads after installation?
The assemblies I'm involved in building require loctite on every screw, followed by thorough cleaning which removes any traces of excess loctite. The method I have set up to assure that loctite has been applied is making the assembly operators record loctite cure start time on each part's mandatory history log. This is merely a "warm-fuzzy" rather than a mistake-proof method.
The assemblies I'm involved in building require loctite on every screw, followed by thorough cleaning which removes any traces of excess loctite. The method I have set up to assure that loctite has been applied is making the assembly operators record loctite cure start time on each part's mandatory history log. This is merely a "warm-fuzzy" rather than a mistake-proof method.





RE: Loctite Inspection?
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Loctite Inspection?
Mike Halloran
Pembroke Pines, FL, USA
RE: Loctite Inspection?
"Art without engineering is dreaming; Engineering without art is calculating."
Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of these Forums?
RE: Loctite Inspection?
It would be nice to have something that can measure the difference between an installed screw with and without loctite.
RE: Loctite Inspection?
Mike Halloran
Pembroke Pines, FL, USA
RE: Loctite Inspection?
"Art without engineering is dreaming; Engineering without art is calculating."
Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of these Forums?
RE: Loctite Inspection?
RE: Loctite Inspection?
yOu might do this immediately afer assembly before the parts are cleaned.
RE: Loctite Inspection?
Mike - your idea of buying preapplied thread locker is practical and I will investigate further.
btrue- I am limited to using the materials approved by the customer. Right now, using the green penetrating loctite is out of my control. The witness idea is good but I feel that the loctite cure start time recording we have in place now is just as effective
unclesyd- I have investigated using our UV lights. However, our cleaning process is so thorough that it completely removes all trace of such fluorescent material. I am trying to avoid adding an inspection step after installation and before cleaning because of the sheer amount of non-value added work.
Does anyone know if ultrasonic technology can be useful for this application?
thanks again for the help
RE: Loctite Inspection?
KENAT,
Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at http://eng-tips.com/market.cfm?
RE: Loctite Inspection?
Actually, what might change is the resonance of the assembly. Quasar/Magnaflux/ITW provides equipment to do this, but I believe it would be prohibitively expensive for this application.
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Loctite Inspection?
You say you need to have Loctite on every connection yet an inspection step to insure this is true is of is of no value.
A question would be why inspect at all?
It seems to me that a simple automated inspection step after the fabrication but before the wash would be better than using the Ford principle of inspection, only count the rejects that get back to factory.
If you can't inspect for all the reasons you hae stated I would certainly go with MikeHollran's suggestion of using a pre applied Loctite. Not only would this insure that all screws had Loctite, it would take away one step in your process where someone has to apply the Loctite to each fastener.
RE: Loctite Inspection?
I agree that it is best to build the quality into the assembly rather than inspect for poor quality. That's why I like the pre-applied loctite idea.
Thanks
RE: Loctite Inspection?
Start by holding a stand-up all-hands meeting, where the purpose of the time recording is emphasised (QC check that it gets applied). Then single out your maverick employee, make an example out of him. Severely reprimand him, make him sweep floors and clean toilets (at least figuratively) for a week, in full view of the remaining crew.
More effective when the 2nd-pair of eyes technique is used, and the signatures are actually controlled stamps with employee numbers on them (harder to fake times, fake signatures).
But, all of that nasty cr$p goes away if you use pre-applied loctite. The problem with that approach is convincing the purchasing dept. not to skimp and buy off-brand stuff that doesn't work, or is surplused because it passed its pull date. Or, it sat past its pull date on YOUR shelf.
RE: Loctite Inspection?
Your first approach is now equilibrated to taking one out to the woodshed for an attitude adjustment. The HR people would be on you like the proverbial "Duck on a June Bug".
You would have to spend a couple of weeks in all kinds of management classes and take all manner of tests.
RE: Loctite Inspection?
The message to other employees is clear and you get to miss the management training
Does it have to be pre-applied loctite or equivalent? This never seems to work out every time I look at it however the nylon patches on screws I have seen work.
KENAT,
Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at http://eng-tips.com/market.cfm?
RE: Loctite Inspection?
http:/
RE: Loctite Inspection?
KENAT,
Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at http://eng-tips.com/market.cfm?
RE: Loctite Inspection?
Are you saying preapplied thread adhesives have not worked for you, but preapplied thermoplastic inserts/patches do work? There is no reason for that to be true.
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Loctite Inspection?
I personally prefer the fourth alternative, microencapsulated liquid threadlocker, because patches, strips, and pellets all require so much initial torque that hand assembly is impossible.
Mike Halloran
Pembroke Pines, FL, USA
RE: Loctite Inspection?
I agree with Mike and Cory, the pre-applied Loctite is lovely stuff. But there are knock-off products for sale that look like, but don't quite work like, the name-brand stuff.
Nylon patches are a one-time use, IMO - the second time used, the patch has taken a "preset" and no longer locks as tightly as the first time.
Of course, the OP could always use option #5 and lock-wire all fasteners...<running for cover>
RE: Loctite Inspection?
As to the Nylon Patches, we used them on bomb tails that got dissassembled several times, flown around in very aggressive environment etc. with no problems. If to the MIL std they are rated for 5 time use as I recall and in practice are OK for more than that in most applications.
KENAT,
Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at http://eng-tips.com/market.cfm?
RE: Loctite Inspection?
ITW used to be good at providing samples for testing and prototypes.
http://itwmc.com/content/default.aspx?cID=82