FEDEVEL
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JohnsonMiller , 04-14-2023, 03:27 AM

In AD, do we have a chance to check the solder past? If so which design rule can do the task?
Suppose that in the library and during pad setting designer make a mistake and set it to the manual, the solder paste opening is not enough or completely closed, if the manufacturer uses the solder paste layer for stencil creation, it will cause manufacturing issues and that pad will not be soldered, since there is no solder.
By default, AD is not doing any checks related to the solder paste layer, and above mentioned problem will pass to the manufacturer, and we should keep our fingers crossed that the manufacturer notices it and call the designer for correction, otherwise...
I was wondering if we can add a solder paste check to design rules and prevent this issue. Or if there is any library check that inspects this issue for each component.

qdrives , 04-14-2023, 01:01 PM

I would not know how to define such rule and, by default, there is no such rule.
I always manually check the paste mask in 3D by showing the paste layer (50% transparent) and hiding the 3D bodies.

JohnsonMiller , 04-16-2023, 12:25 AM

Thank you!
Wondering which tool the manufacturer using for these types of checks?

qdrives , 04-16-2023, 01:28 PM

Are you talking about the fabricator or the assembly company?
I do not think that the fabricator checks it.
The assembly company may, because they (sometimes) change (tweak) the design. Hence, they might discover the mistake.

JohnsonMiller , 04-17-2023, 01:44 AM

In our case, the PCB manufacturer and assembler are the same, I was wondering which software they are using to check GERBERS. A friend of mine introduced CAM350, but not sure! Is it for manufacturing tests?

qdrives , 04-17-2023, 03:25 PM

When you sent the gerbers to be used to produce the (bare) board, a lot of tweaks are done compared to what you output.
A short list:
- Silk screen clipping
- Trace width adaption (more on outer layers due to plating)
​- Solder mask expansion
- Paste mask expansion (and dividing for larger area's i.e. QFN thermal pads
During this process, they may discover that some 'pads' do not have paste mask. However, that too would (often) be a manual 'discovery'.

How would one detect it automatically?
A pad = copper without solder resist?
Add the rule solder paste. What about:
- Fiducials?
- Solder thieves
- Test pads
- Edge connectors
- Programming connections (like the ones used with https://www.tag-connect.com/ )

robertferanec , 04-18-2023, 08:26 AM

I always check this in gerbers - you just enable pads + paste and you immediately see if there is a problem. This has to be manually checked anyway as often there are some places you don't want to have paste or the paste shape is special (e.g. thermal pads, gold logo or text, ....),

PS: Even if you find out too late, making a new stencil is not expensive.