[sdiy] JH goes PCB - Copper ring size for PCBs?

[Seb Francis]

P.S. When spec'ing hand soldered analog PCBs it's generally better to go 
a fair bit bigger than the manufacturer's minimum specifications.


Seb Francis wrote:
> A couple of things:
>
> Normally manufacturers assume the size you specify is the finished 
> hole size, not the actual drill size.  So you shouldn't need to think 
> about the thickness of the plating through the hole, only about what 
> size component legs you want to push through the finished hole.
>
> However just be confusing, the manufacturers I know spec the minimum 
> annular ring width with regard to the Production Hole Diameter (the 
> drill size itself).  The actual minimum annular ring width will vary 
> from manufacturer to manufacturer, but a typical value is 0.15mm.  
> Thus your pad diameter must be 0.3mm larger than the Production Hole 
> Diameter (drill size), or 0.4mm larger than the finished hole size.
>
> So Hole = 0.9mm, Pad = 1.5mm sounds easily ok (but do check the 
> minimum annular ring specs of your manufacturer)
>
> Seb
>
>
> JH. wrote:
>> I'm editing some library elements of my Rimu PCB layout tool for the 
>> use with Olimex:
>>
>> Olimex web site says that final hole diameter will be 0.1mm smaller 
>> than drilled because of plating of the holes, and consequently offer 
>> "odd" drill diameters as a standard, like 0.9mm and 0.7mm, to get the 
>> "standard" holes of 0.8mm and 0.9mm.
>>
>> So, ist it ok to increase the hole size in the library without also 
>> increasing the pad diameter?
>> Specifically, is the combiantion
>>
>> Hole = 0.9mm, Pad = 1.5mm ok ?
>>
>> (Talking of double sided boards - I know it's probably not large 
>> enough for single sided ...)
>>
>>
>> Hmmm, yes ... I think I'm going to make pcbs again after many years 
>> of Veroboard-only.
>> And I hope it will be for the benefit of the DIY comunity, too! :)
>>
>> And I just found that I *might* get the whole lot of filterbanks and 
>> envelope detectors of a Sennheiser vocoder
>> on a single 320 x 200 mm board, when I completely redesign the 
>> circuit topology ...
>>
>> JH.
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>>   
>