Forums

MLCC soldering and dielectric cracking damage

Started by Mr.CRC October 23, 2011
StickThatInYourPipeAndSmokeIt wrote:
> On Sun, 23 Oct 2011 10:12:55 -0700, Joerg <invalid@invalid.invalid> > wrote: > >>> ... Assembling CPU coolers onto PC motherboards is always a >>> treacherous experience! I wonder how many MLCCs survive that experience. >>> >> That one I don't understand. How can such coolers stress the caps? >> >> -- > > Learn to read idiot. It is the act of ASSEMBLING CPU coolers onto PC > motherboards that this guy does wrong, and you fail to discern. He is > obviously striking then physically somehow. Your diagnostic capacity is > like nil.
No, "he" doesn't strike anything. Look at langwadt@fonz.dk's response above. That person understands. -- _____________________ Mr.CRC crobcBOGUS@REMOVETHISsbcglobal.net SuSE 10.3 Linux 2.6.22.17
On Tue, 25 Oct 2011 09:53:19 +0800, "Dennis" <jon.dough@ithemorgue.com>
wrote:

> >ass chad = santorum? >
Voter card chad... hanging chad... ass chad... DINGLEBERRIES! You stupid, convoluted fucktard!
MK wrote:
> On 24/10/2011 04:51, Jon Elson wrote: >> Mr.CRC wrote: >> >>> Hi: >>> >>> I frequently assemble PCBs by hand soldering MLCCs of the 0603, 0805, >>> 1206, and a few larger ones (and other parts too--as those >>> capacitor-only circuits aren't much fun!). >>> >>> My hand soldering technique is to use 0.015" wire solder, >>> 1. first adding a tiny bit of solder to one pad. >>> 2. Then I flux both pads, and tack the part to the pad with the added >>> solder. >>> 3. Sometimes at this point, I put my tweezers on top of the part to >>> create a downward force, and reflow the tacked joint to make the part >>> seat squarely on the pads. >> I do a lot of these, on small-volume projects. I have been doing this >> for probably close to 15 years. I have encountered no more than >> 3 or 4 cracked capacitors in this time, and I have used up several >> 10,000 part reels and many smaller reels. >> >> I put a dab of solder on one pad, place the component gently with >> tweezers >> while reflowing the already-soldered pad, and then solder the other pad. >> I don't use flux, other than what is in the flux-cored solder wire. >> >>> The question is this: How much should I worry about thermal stress >>> cracking or otherwise damaging the MLCC dielectrics? >>> >>> I have heard that using a pre-heated PCB, and soldering the MLCCs both >>> joints at once using hot air is the preferred approach, to avoid damage. >>> >>> Also, that MLCCs with thinner dielectrics are more susceptible, like >>> high values in small sizes. >> Yes, the smaller the caps, the more fragile. I don't use anything >> smaller than 0805 just because they are harder to deal with. >> >> I have straightened warped boards with the parts on them without >> damage, but that is really asking for trouble. But, I never had >> any problem with it, either. >> >> Jon >> >> > I use a very similar technique (to Jon's) with pointy stainless steel > tweezers and I'll do parts down to 0402. Over the last 10 years I have > put down between 5000 to 10000 capacitors an have temperature cycled > many of the boards. I have never seen a short circuit cap (since I guess > about 50% of caps are decoupling I might have missed some open circuits). > Recently I've done quite a few bigger ceramic caps like 22uF 16V in 1210 > or 1206 packages - these are about 2mm thick but I've seen no problems. > I only do prototypes and very small runs (like perhaps 4 boards) like this. > The suggestion that you can solder an 0603 part touching only the pad > and not the parts sounds like boards with very large pads or theory not > yet contaminated by contact with reality. > > Michael Kellett
I design my pads for hand soldering, usually with a minimum 0.016" excess on each side beyond the max part dim. For larger parts, it scales according to the vertical lead thickness. -- _____________________ Mr.CRC crobcBOGUS@REMOVETHISsbcglobal.net SuSE 10.3 Linux 2.6.22.17
On Mon, 24 Oct 2011 20:44:09 -0700, "Mr.CRC"
<crobcBOGUS@REMOVETHISsbcglobal.net> wrote:

>Then you really went off the rails!
Probably another retarded Ford owner.
On Tue, 25 Oct 2011 03:46:31 -0700 VioletaPachydermata
<PurpleElephant@thebarattheendoftheuniverse.org> wrote in Message id:
<2r4da7lpvug0efrqc44s3aacdfr55ghntr@4ax.com>:

>On Mon, 24 Oct 2011 20:44:09 -0700, "Mr.CRC" ><crobcBOGUS@REMOVETHISsbcglobal.net> wrote: > >>Then you really went off the rails! > > Probably another retarded Ford owner.
You know... it suddenly occurred to me that you have a personality that only a cadaver could love. This, no doubt, explains why you count so many of them amongst your sexual conquests.
On Tue, 25 Oct 2011 08:03:56 -0400, JW <none@dev.null> wrote:

>On Tue, 25 Oct 2011 03:46:31 -0700 VioletaPachydermata ><PurpleElephant@thebarattheendoftheuniverse.org> wrote in Message id: ><2r4da7lpvug0efrqc44s3aacdfr55ghntr@4ax.com>: > >>On Mon, 24 Oct 2011 20:44:09 -0700, "Mr.CRC" >><crobcBOGUS@REMOVETHISsbcglobal.net> wrote: >> >>>Then you really went off the rails! >> >> Probably another retarded Ford owner. > >You know... it suddenly occurred to me that you have a personality that >only a cadaver could love. This, no doubt, explains why you count so many >of them amongst your sexual conquests.
Probably another retarded Ford owner. It is obvious. This JW fucktard calls his sexual encounters "conquests". Yeah, perverted fucktards like you are what made the perverted fucktard mentality twits we have running around today. Good job, fucktard. NOT! Nice try at a jab, but a lowlife fucktard like you has a long way to go before you could even grasp my coattails, boy.
On Tue, 25 Oct 2011 03:46:31 -0700, VioletaPachydermata
<PurpleElephant@thebarattheendoftheuniverse.org> wrote:

>On Mon, 24 Oct 2011 20:44:09 -0700, "Mr.CRC" ><crobcBOGUS@REMOVETHISsbcglobal.net> wrote: > >>Then you really went off the rails! > > Probably another retarded Ford owner.
I had a Fiesta once. It was pretty good, for the first 14 years at least. John
On Tue, 25 Oct 2011 10:19:08 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>On Tue, 25 Oct 2011 03:46:31 -0700, VioletaPachydermata ><PurpleElephant@thebarattheendoftheuniverse.org> wrote: > >>On Mon, 24 Oct 2011 20:44:09 -0700, "Mr.CRC" >><crobcBOGUS@REMOVETHISsbcglobal.net> wrote: >> >>>Then you really went off the rails! >> >> Probably another retarded Ford owner. > >I had a Fiesta once. It was pretty good, for the first 14 years at >least.
I had a Granada, way back. Other than having to replace the carb every year or two ($60) it was a great car, for the first 14 years. My wife's Sable has been excellent for its first 11 years as has my Ranger, for 10. The '74 Rustang-II was on the other end of the scale, though. The other thing Ford has going for it is that it's *not* Government Motors.
On Tue, 25 Oct 2011 12:28:44 -0500, "krw@att.bizzzzzzzzzzzz"
<krw@att.bizzzzzzzzzzzz> wrote:

>On Tue, 25 Oct 2011 10:19:08 -0700, John Larkin ><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>On Tue, 25 Oct 2011 03:46:31 -0700, VioletaPachydermata >><PurpleElephant@thebarattheendoftheuniverse.org> wrote: >> >>>On Mon, 24 Oct 2011 20:44:09 -0700, "Mr.CRC" >>><crobcBOGUS@REMOVETHISsbcglobal.net> wrote: >>> >>>>Then you really went off the rails! >>> >>> Probably another retarded Ford owner. >> >>I had a Fiesta once. It was pretty good, for the first 14 years at >>least. > >I had a Granada, way back. Other than having to replace the carb every year >or two ($60) it was a great car, for the first 14 years. My wife's Sable has >been excellent for its first 11 years as has my Ranger, for 10. The '74 >Rustang-II was on the other end of the scale, though. >
We rented a red Mustang convertible a few years back, sort of by accident. What a heap-o-junk! Incredible garbage. Getting the top up/down was almost impossible. The retro tiny round instruments were unreadable. The turn signal sound was a loud, tacky, synthesized fake of an old thermal clicker. We have rented a few 4wd Explorers for ski trips. They weren't bad. John
LM wrote:

> Because if you have only two hands hands, you cant hold the part, > solder and the solder iron all at the same time. I have tried. > Evolution is not fast enough to grow the third hand.
You hold the solder in your mouth. Please learn to bottom-post. Thanks! Rich
>> > My hand soldering technique is to use 0.015" wire solder, >> > 1. first adding a tiny bit of solder to one pad. >> >>Why not soldering the part onto that pads right away? That how I do it. > > >> Tweezers are metal, can scratch and stress the part. I use a toothpick, >> usually. A fresh one :-) >> > Heh