HI, STM32F746IEK6 MCU dimension in the datasheet, The A value should be between 0.460mm and 0.600mm, but we measured several pieces all excess 0.6mm, Our measurement results are 0.610mm, is within an acceptable range?

[Imen.D]

Hello @cxi.1​ 

I would like to understand the measurement method. How you measured these 10µm differences?

Is it on one package, several? Is it an average value collected from a quantity of x samples? is it performed on one ball, all balls?

I will escalate your request internally to the expert in packages for help.

Imen

[cxi.1]

HI Imen

We used electronic digital caliper,We took 30 samples from one package,But most of them measurement results are 0.610mm,Small measurement results are 0.600mm,We want to know is within an acceptable range?

The electronic digital caliper like this

[Imen.D · Accepted solution]

Hi @cxi.1​ 

These measurements are totally not relevant.

The manufacturer of this tool and the measurement tolerances are shown below (AliExpress).

This instrument is not enough accurate and does not have the required precision to measure such dimensions ranges.

It’s then not appropriate to notice a dimensions deviation of 10µm with a measurement tool which accuracy is about +/-30µm or +/-40µm.

You can contact your FAE for double check, if you want to return back these parts, we have a QA team to answer to such a request.

Thanks

Imen

[cxi.1]

Hi Imen

OK,we will use instruments with higher accuracy for measurement.

Thank you very much

vike