Inge


As a Nuke we too are under stringent guidelines for crimping.  At a minimum before crimping we attend a 1 week class, with job performance measures (graded) for "Nuclear Grade" LOW VOLTAGE (<600V) splicing and crimping and the use and installation of Ray-Chem heat shrink as well as environmental splices and Grayboot installation.  HIGH VOLTAGE is a whole different can of worms.  This is repeated every other year.   We also have specific classes for Triaxial and coaxial cable installation, as well as for Fiber, and Ethernet connections.  Each connection is installed and then verified by a qualified peer and by QC with a whole laundry list of failure criteria.   We have a specified engineering installation drawing series for EVERY type of connection, and we have to update that drawing for each new type of installation, before we do it, with attendant engineering, vendor, and QA reviews.   Each and every crimp is logged as to the lot# of lug used, the lot# of heat shrink (if used), which nest was used, and the calibration number and date of crimper used, and all must be independently verified.  Each and every crimper is calibrated and verified annually and may only be used on the lug it was specified for by the manufacturer, and in the correct nest.
Crimpers are considered as test equipment with strict calibration requirements, including pull testing as well as go, no-go gap gauges, jaw compression pressure, lug deformation, ratchet release pressure and distance ..... 
 
 If anything fails then all of the installation crimps done with that tool are replaced.  

It's a wonder sometimes how we get anything done.    

Make the monkey sounds here!!!! 

One of our former managers made the comment, "I&C techs are a dime a dozen, I can go to any Greyhound bus depot and get all I want".   
 
Pat  
   

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord
Sent: Thursday, December 06, 2012 8:58 AM
To: [log in to unmask]
Subject: Re: [TN] Crimp tensile strength

We have spent hours and hours on crimping. People did not take the quality requirements seriously. Just 'simple' crimping. A monkey can do it, as said one boss. Series of tests gave an image that shocked the involved, and we dedicated two MSE guys to work 100% for one year with crimping. Resulted in a bunch of updated assembly directives. Among many background papers we used Hans Danielsson's inches thick report from the car industry. He demonstrated how connections and contact joints were the far most common source in car electronics..

Inge

On 6 December 2012 16:23, Gerald Bogert
<[log in to unmask]>wrote:

> December 6, 2012
>
> One important crimping consideration in addition to verifying tensile 
> strength is to confirm that the crimp tool used was used in a manner 
> to ensure full ratchet action of the tool was achieved as required by 
> the IPC workmanship standards.  Some air operated crimp tools can be 
> set to different pressure settings.  Normally, for air operated crimp 
> tools, to achieve full ratchet action the tool is set to a specific 
> pressure depending on the tool used (e.g., 90 PSI).  However, if the 
> tool is set at a lower pressure (e.g., 60 PSI) you will get a crimp 
> that is not fully formed but it may or may not still pass tensile 
> testing, depending on the type of wire and lug used.  The lower 
> pressure setting would violate the IPC standards since less than full 
> tool ratchet action would occur.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Landman
> Sent: Thursday, December 06, 2012 9:59 AM
> To: [log in to unmask]
> Subject: Re: [TN] Crimp tensile strength
>
> Molex crimping tool instructions include information on measuring 
> crimp tensile strength.  I haven't checked but would expect Tyco/Amp 
> also to have the information.  It's the only way to verify a "good" 
> crimp has been made.
>
> One item of interest: we recently had a problem with consistent crimps 
> of a Molex terminal.  The documentation was of no help.  The 
> technician noticed that the "V" grove that the terminal is placed into 
> prior to closing the handles of the tool seemed worn.  There are two 
> such groves in the tool and the other one (for smaller gauge wire)  
> had never been used so that made it obvious there was a problem.  The 
> terminals would roll a bit to one side or the other before the tool closed.
>
> The documentation says nothing about the groves but clearly they are a 
> significant feature of the tool.
>
> A few minutes with a triangle file restored the grove.  The tool again 
> yielded 100% good crimps.
>
> Bob Landman
>
> On Dec 6, 2012, at 1:48 AM, Inge Hernefjord <[log in to unmask]>
> wrote:
>
> > JF, je vais vouz envoyer offline " The Crimping Handbook". /Inge
> >
> > On 30 November 2012 14:03, JF <[log in to unmask]> wrote:
> >
> >> Hi all,
> >>
> >> I'm trying to find a chart to evaluate crimp quality. This chart 
> >> was about "Crimp tensile strength". Can't remember what it was.
> >>
> >> Thanks for any help!
> >>
> >> JF
> >>
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