Homebrew PCBs

kabowers@... pravi:
> On Mon, 21 Jun 2010 19:00:45 +0200, you wrote:
>
>   
>> I'm print grid over entire page.
>> The error is randomly spread over entire lenght of paper.
>> ..and near same amount with print on thick or thin paper.
>> .. just seems that paper shrink. When I print onto kimoto foil (looks 
>> like semitransparent plastic) the random error is stil present but 0.5% 
>> shrinkage drop to under 0.1%. but random error (wigling) stay near same 
>> in both. I think that transport gear's teeth are uneven and that cause 
>> that's problems.
>> Of course when printing text nobody will ever see that here is some 
>> missalignment. But long row of connector can be out of order just 
>> enought to prevent conector to be installed.
>>
>>
>>
>> Andrew Villeneuve pravi:
>>     
> I apologize if this is a dumb question, but do you
> have every stage of the print stream set to 100%. In the
> past I have goofed and had "fit to page" enabled in either
> the board software or Windows printer driver configuration 
> and gotten similar results. This can easily be hidden if one dimension
> of the board is close to one of the paper dimensions.
>
> May also be dirty/glazed drive rollers in the printer.
>
> Keith Bowers WB4LSJ- Thomasville, NC
>
>   
All are set to 100%
The 0.5% shrinkage is probably caused by moisture in paper. But the 
nonconsistent error can't be result of moisture.
As I already say I print grid (10x10mm squares) onto paper and measure 
each axis.
The X (width) has consistent error of about 0.5%
The Y is not consistent! ie
row 1 is 0.3%
row 2 is 0.5%
row 3 is 0.6%
row 4 is 0.5%
row 5 is 0.3%
and so on. The walues are random but way (increasing / decreasing) seems 
periodic. So I think the gears can be problem.