← Back to team overview

kicad-developers team mailing list archive

[PATCH] - PCBNEW - implement PS plotting width correction.


>Hi Alexander,
>It would have been nice to explain your strategy and why you chose this over possible
>other alternatives.
>Can you pllease explain:
>What is width correction?
>Why do you need it? That is, what is wrong with the original width that it needs
>Why is the original width wrong?
>Thank you very much,

Hi, Dick!

First of all, i'm not shure my message will be posted in the proper thread :(.
Please, be so kind and show me where i can read about interaction with kicad developers mailing list.

Let me try to explain some problems of DIY PCB designers and why i suggest the 'width correction` feature
(maybe you would like to suggest another feature name). Most of home-made PCB designers take advantages
of technologies like toner transfer or photoresit one. They don`t use gerber plots in most cases, because they
have no photo-plotters. Usually DIY designers use laser or inkjet printers as PS plotters.
The problem is that the final plots has some width errors, especially tracks and pads.
For example, my HP LaserJet 2300L enlarges tracks and pads for nearly 0,0025" (0,06 mm).
I don't know why, maybe because of rasterization of vector plots? This fact makes almost impossible to produce
DIY PCB with modern packages, such as LQFP one (0.25 mm tracks and 0.25 mm clearances).
Even if there will be no LaserJet plot errors, there is a track width etching and it is very important for RF PCB designers
because of impedance matching.

Thank you very much and sorry for my english,