Hi Pete,
Inconsistencies of scale have been a problem with every printer I've ever used. I don't make a lot of pcbs, let alone double sided, but the problem also shows up when you print schematic diagrams that are divided among several pages horizontally, or vertically, or worse, both. The lines are close, but there can be vertical or horizontal gaps where they should meet. My printers over the years have been either HP inkjets and IBM Laserjets.... no off brands.
However, I have printed things to "scale" using the free graphics viewer "Irfanview". When printing, the size of the image can be adjusted in width or length by hundreths of a centimeter or inch. After printing something I need to 1:1 scale, I will measure the print's dimensions and use the software to adjust one or the other until it is right. Recently made some "actual size" outlines of two GI7B Russian triode tubes from an image on a "spec sheet", glued them to cardboard and cut them out. Needed to check the clearances in a proposed rf amplifier chassis; turned into a "tight" fit, but doable. Much easier to visualize where everything is supposed to fit, including clearances because of the high voltages.
You might be able to do the same. Start with one side and print it on normal paper, adjusting the dimensions until they are "right". Then do the same for the other side of the board, but hold them back to back against a light source. Adjust the second layer to match the top layer. Incorporating registration marks at the corners of the layers may help; usually its a "plus" sign by itself or in a circle.
Normal computer paper is dimensionally stable enough for you to check your work. Make sure the printer's paper handling tracks and rollers are clean, too.
Now, if your pcb is bigger than a full size piece of computer paper, this method won't work!
Jimmie
--- In Homebrew_PCBs@yahoogroups.com, "godzilera" <yah.5.peteben@...> wrote:
>
> Although I have been making successful single-sided PCBs for a while now, I just recently decided to try making a double sided board with SMD (.5mm TQFP) parts. So, I went out and bought a new inexpensive Samsung ML-2165 printer. The problem I am having is getting the scaling right. It's inconsistent and varies from print to print. Plain paper works pretty good, but the Pulsar paper comes out too short. I tried adjusting the scaling in the Kicad print dialog, but it seems to come out either too wide or too short. Very frustrating, and I have wasted four sheets of TTS paper so far.
> I have a couple of boxes of HP glossy photo paper, so I may try that.
>
> Any advice?
>
> Thanks,
>
> Pete
>