MLCC Sorting clarification.

When you think you know then you understand that perhaps you do not know.

Background.
I have been using an ordinary magnet for sorting MLCC. Non magnetic have been saved and magnetic thrown away.

On day then cleaning the workshop I find a little box with MLCC. My memory tells me they were non magnetic but before I put them in the good MLCC box I test them with a ordinary magnet. To my suprise like 95 % was magnetic. Had my memory totally failed me? I was quite sure they tested non magnetic before. But in action cleaning the place i dumped the magnetic ones in the waste bin.

The incident have popped up now and then in my brain. Then I read a thread were somebody (anachronism?) stated that a ordinary magnet was not enough. There should be a distance of some mm between the magnet and the MLCC.

I have done some tests. Some MLCC seems magnetic but can be shaken away from the magnet while others sticks to the magnet even if i shake. This done with the magnet I uses now (from loudspeaker). Before i had an other magnet that I lost. Then testing the MLCC i sorted out with the old magnet, as non magnetic, a large share now were attracted to my new magnet (loudspeaker). These can most often be shaken of the magnet and are not stuck as hard as newer Fe type.

Now i am pretty convinced that I do not really know how to sort MLCC. I am pretty sure i have thrown away good MLCCs due to too strong magnet even if a ordinary one. Magnets are of diffrent strength. This seems to complicate the sorting with magnet. If so I will not be the only one to throw away good ones.

Anyone that have a good guideline how to sort and a good specification on what magnet to use? What about this with a distance between magnet and MLCC? ( can not find the thread were I read about it)

Hi Jens.
I dont know for sure in your case, but my memory sometimes play havoc with what I thought to be fact
Nevertheless I use a hard drive neodymium magnet and if it don't stick to that, I save it.
But since I haven't processed any yet, I'm in the dark about the effectiveness of this excersise :wink:

Yggdrasil, you are for sure dumping good ones by that method. The Nickel in the MLCC sticks to a neodymium magnet even if no Fe present. Thats why to use a "normal" magnet. The question is how "normal" it have to be.

Well, not many failed, if I remember correctly, so it should not be that bad.
And of course, nothing has really been throwed away, just denoted to a scrap pile
Anyway I had gotten the impression that the MLCCs with PMs would not contain nickel.
Obviously it may not be that simple.
I have some of the old good ones, stowed away too

It seems to be the ends that can contain nickel. As I mentioned. I just found out that just a common magnet is not enough for sorting MLCC. My new magnet is stronger than my old. Due to this it it attracts more MLCCs than my old did. If these additional, that my new magnet attracts, contains pm then I sort out good one with it. These additional do not stick very hard to the magnet and falls of when shaking the magnet. Newer Fe type MLCC sticks on hard and do not fall off when shaking. So my conclusion is that a stronger magnet, of common type, might attract pm containing MLCCs.

I am very keen to find the thread were I read about a spacing between the magnet and the MLCC to be tested. It seems to be the way to go if a stronger magnet.

Quit sorting and just process all of them.

Seriously.

T


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snoman701 said:

Quit sorting and just process all of them.

Seriously.

T


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Agreed.

you can never tell the exact makeup unless you can get the manufacturing data.

crush add silver and melt stir. (over simplified but the idea)

Eric

I love me some MLCCs

snoman701 said:

Quit sorting and just process all of them.

Seriously.

T


Sent from my iPhone using Tapatalk

Click to expand...

Now that was a hands on advice that I will follow. Thanks!