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Solder Paste Volume measure in SPI

Views: 3479

#80065

Solder Paste Volume measure in SPI | 25 March, 2018

Hi experts,

Is it normal that a stencil of 0,1mm would produce 45% solder paste volume being printed over the board?

Or is a property linked to the solder paste?

thanks in advance

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#80069

Solder Paste Volume measure in SPI | 26 March, 2018

Usually this is caused by too much solder mask.

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#80071

Solder Paste Volume measure in SPI | 26 March, 2018

I realize that I wrote wrong. Sry

The stencil of 0,1mm of thickness is printing 45% more volume. I know this becouse the SPI is setup with the stencil gerbers and the messurements have a median of 145% of volume.

what do you mean with excesive solder mask?

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#80077

Solder Paste Volume measure in SPI | 27 March, 2018

Hello, can you tell me your SPI machine brand? Some brands have Bare board teaching for getting the best data when measuring paste. Even then it is normal to have more paste than 100%. So you can check your average and see if you are getting this on all pads or on some pads. Additionally what is the finishing on your PCB's? HASL makes measurements to variate because it usually has thickness from 2 to 50 microns.

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#80083

Solder Paste Volume measure in SPI | 27 March, 2018

Occasionally when circuit boards are manufactured, there may be issues with solder mask coverage. It is not uncommon to re-run back through this process to fix missing or thin areas. This can causes the traces to become higher which in turn raises the volume of solder deposited.

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#80218

Solder Paste Volume measure in SPI | 11 April, 2018

Diego,

the first question you have to answer is "Is the paste volume too much in real?" How does your paste look? To check that, I would say you measure bare board with your SPI and see if your SMT pads show you zero, or may be not? If your value for bare board is 20um and your stencil is 100um, you should set your value in SPI 120um and not a 100um. If the paste is more, than you should go over your print process and PCB examination.

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#80227

Solder Paste Volume measure in SPI | 11 April, 2018

YES to the first question in some points of the board. Bulky, to the second question when it is not in short.

What you say about the PAD height, helped me to understand why the SPI shows weird values for other measurements. I am currently doing tests with an SPI of VI tech. After trying to measure the height of the Mask solder resist, I noted that the CERO level measured is not the top surface where the stencil is placed.

If the PAD height is negative, it would add to the height of the paste brick.

Is it normal that the SPI's perform a CERO calculation? How standard is this calculation?

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#80232

Solder Paste Volume measure in SPI | 12 April, 2018

Diego, I dont know how this machine works. Maybe they patented some way of measuring. But the idea of Mr. Evtimov is very good. Measure the pad only and see its value. If it is not 0, you have to know why, maybe ask the machine supplier. Also like Mr. Evtimov said, there is difference in height and in volume. On some pads even 100um more paste will be okay, it is depending...

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