Wicked Minds Electronics

HOW TO: Super simple double sided PCB pattern alignment

1 post in this topic

I've been meaning to post this somewhere for awhile now, figure this is as good a place as any :)

In the past I have read a lot of tips on how to align patterns on double sided boards and overcoming the simple problem that you can't see through the board. Everything I read would work sometimes and still required a bit of finesse to accomplish with average results. After some experimentation, this is what I came up with. Maybe others have figured this out to but maybe I can save some people the headaches of doing it the hard way.

Step 1

Before printing your design add a cross mark to all sides of the board. They do not have to be any specific distance from the board nor do they need to be a certain size. Keep the line width thin but visible and give yourself a minimal margin between the cross and the board outline.

The additional lines shown connecting the crosses are not required but aid in cutting and folding later and for this demonstration. Cut one pattern down as shown on the left and leave the pattern for the other side with some margins as shown on the right.

doublesidedstep1.jpg

Step 2

Working with the pattern you trimmed down, turn it print side down and fold each cross in half as shown on the left. Your folds do not need to be accurate or perfect.

doublesidedstep2.jpg  doublesidedstep3.jpg

Step 3

Place the folded pattern face down on the pattern for the other side. Align the unfolded axis of each cross as shown here, as long as all four lines are touching, you are in alignment. As you can see, it is only important to align the upright axis of each cross, the alignment of the crossbeams (the line of the crosses you folded) does not matter. While looking straight down at your patterns to ensure good alignment, tape two sides in place.

doublesidedstep4.jpg

Step 4

Gently slide your blank board in between the patterns and proceed to laminate/iron.

doublesidedstep5.jpg

Can't help but love how well sugar paper transfers toner

:)

doublesidedstep6.jpgdoublesidedstep7.jpg

This green foil works great for filling in micro pits in the toner!

doublesidedstep8.jpg

Here is the final result after etching and everything lined up great :)

doublesidedstep9.jpg  doublesidedstep10.jpg

I have been using this method for awhile now and the only time I get bad alignment is when I am sloppy with the laminator and the patterns slip.

NOTE: I get my sugar paper from here (also available from DigiKey) and have never had a pattern fail to 100% transfer to a properly cleaned board. The pcb shown here was made using scissor cut pcb. Because it is so thin, it causes almost no issues with alignment and board thickness, plays nice with the laminator and etches quickly, not to mention it results in these cool looking see through boards :)

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