Favorite SMD chip removal method

Are you trying to claim that an insulator has no triboelectric effect?

It was first discovered from observance of the interaction between two insulators.

Insulators also charge Leyden jars.

I see fibers.

Concatenate into a single line.

No, I'm saying that there is no danger of a triboelectric current larger than the protection network can stand. But nice try.

Completely irrelevant.

(A) That isn't a Dremel wheel, and (B) fibreglass is still an excellent insulator, as I said already. Circuit boards are made of it, in fact, even high voltage ones.

And your creative snipping avoids all the actual physical explanation.

You'd be very lucky to get more than a hundred nanoamps of triboelectric charging at the most from such a small area, there's no opportunity for a rapid discharge, and the available capacitance is too small to matter even if there were.

In other words, you're making all of this up.

Cheers

Phil Hobbs

Think about building a tiny version of one of those electrostatic generator things, a Wimshurst sort of thing, as a Dremel accessory.

John

It most certainly is. It even has the mounting stalk (shaft) right there with it.

Second, the "cut-off wheel topology is industry wide, and they are what are used to cut off hardened steel linear gantry shaft media, etc.

So, yer nuts. It IS a dremel wheel and that IS how they are made.

You explained nothing other than your flawed guess as to what TE is.

All that is required is CONTACT and then RELEASE between two physically separate mediums. So the edge of the wheel dragging along the lead DOES impart charges into it. It is absolutely no different than rubbing synthetic cloth on a surface and seeing it collect charge from the same effect.

It really is that simple. You can test it with a steel bar (or any metal bar) and the same wheel. You can test it with leads that have already been cut off. There are many ways to test and prove it. A simple ESD field strength meter would do it, for sure.

It is neither negligible nor trivial, and the protections are not meant to be exercised, they are there for events which MAY occur AFTER the delivery of the product. They are not meant to allow nor foster casual, haphazard behavior in any part of the manufacturing process.

We are killing the chip here, so *it* doesn't matter, but elements attached to the leads being abraded (more proof when thinking of the actual word) can receive the charges. Not to mention the fine, conductive particulate (which WAS also mentioned btw).

My point exactly. Charges accumulate. Modern chips do not like certain subsequent events that arise from such accumulations, regardless of what you might think, and ESD failure modes do not always manifest as a failure immediately upon introduction of the damage.

Pretty funny then that there is an entire industry segment making personal discharge devices and "protection gear" for users of cut-off wheels and the handheld drives the run them due to problems associated with static accumulation and static discharge.

In other words, you are not thinking straight today. Knowing that this is rare behavior for you, I'll give you a pass... for at least one more post. Maybe you should do some research for a few moments of reflection on one of the first things we get taught in this realm.

Here is one for you... Why do photons not repel each other?

You have no idea what you're talking about. Exactly where are the charges going to accumulate to a level that can cause damage?

Cheers

Phil Hobbs

For a Dremel grinder on IC pins? Let's see a link. (Of course Monster Cable would be all over that one if they thought folks were that silly.)

Cheers

Phil Hobbs

All you have are unsupported assertions, which lack physical plausibility. You hide behind a nym, so there's no chance for your fine professional reputation to make me take you seriously, and so I don't.

Can I be wrong about this? Sure, I'm wrong often enough that I'm quite used to it. Show me, don't just tell me.

Cheers

Phil Hobbs

I'm always glad to be given the benefit of the doubt, even when I don't think there is any.

Because they're bosons with zero charge and zero baryon number. According to QED they do interact, but only at extremely high energy and/or extremely high number density. Why do you ask?

Cheers

Phil Hobbs

AlwaysWrong does have a pretty "solid" professional reputation, as does a sixty-year-old toothless streetwalker.

Let's see, perhaps Hobbs is wrong or could AlwaysWrong be wrong? Such difficult questions!

"A Monkey" is no doubt a nym for AlwaysWrong. Ignore, unless, of course, feeding trolls is the best conversation you can arrange ;-) ...Jim Thompson

Yeah, well, we live in 'opes. Our discussion is pretty polite, all in all, so it's a gentlemen's disagreement at this point and not troll-baiting or flame warring.

Cheers

Phil Hobbs

I push current into ESD diodes all the time, like clamping a big signal swing into 3.3 volt logic. Most parts spec the allowable ESD diode current, and I believe them. It's a diode, after all. Nowadays most people design chips that don't do the SCR latchup thing, and say so.

Cutting leads with a Dremel isn't going to ESD-damage chips.

Some chips still latch up if you forward-bias the ESD diodes when power is on. The manufacturers like to hide the fact, and you have to look for hints in the specs and application circuits. LM34/35/45 is notorious. Mixed-signal parts, like DACs, can be bad. Old CD4000A series parts would latch at the tiniest provocation.

John

Hmmm, let me think about that for a few nanoseconds....

John

Jim Thompson wrote in news: snipped-for-privacy@4ax.com:

don't you folks have killfiles and filters? why even bother with such people?

discourse with them just keeps them coming back for more,and also brings you down to their level more than anything else.

I certainly do!

Ask Hobbs and Larkin and Fields... they seem to rejoice in bantering with idiots... repeating myself: "feeding trolls is the best conversation you can arrange?"

As I keep saying, feeding trolls provides them with a podium, and BU pimps and has-been physicists thrive on that ;-) ...Jim Thompson

He's being polite, which I'm pleased to encourage, because I don't define people's value by their engineering expertise.

We have a lot of superannuated seventh graders trying to rule the roost here, but it doesn't work very well for them because nobody's fooled. Bragging and trading cheap insults isn't how you get respect from adults.

Cheers

Phil Hobbs