Homebrew PCBs

Stefan,

Before I got the mechanics straightened out, I did damage the drum in 
2 places, but since then there hasn't been any. Granted I've only run 
boards through a few dozen times, but so far, so good. I replaced the 
toner cartridge and since then have been carefully smoothing the 
edges of the boards with a 3M pad and rounding the corners a bit with 
a fine file. I've also been using .031 (1/32) board, though I have 
run some 1/16 inch board through with no problems. The board is only 
in the printer for 1.3 inches.

The mechanics of my printer enable boards as small as 1.5 inches to 
be fed through without a carrier. If I were to use a carrier, I could 
probably obviate the drum damage problem by having the carrier always 
in position so no edges are seen by the drum. This would take some 
doing because you can't feed the board till the drum is charged.

The toner density seems fine to me - it certainly resists the enchant 
in my experiments, so far. The toner seems TIGHTLY adhered to the 
board. In fact, you can put the board on it's side and rap it against 
a desk top without dislodging the toner.

I do have some mechanical issues. As you can see from the photo, the 
drive roller steel rod doesn't go all the way across the printer, 
limiting the width of the board. The board doesn't print well near 
the edges of the drum and at the sides of the board. It works best if 
the settings print the board at the center rather than to the right 
side (it can't reach the left). The board should also be somewhat 
wider than the desired image to keep away from the board edges. I can 
fix most of this by changing the rollers to provide a much wider path..

Mark

At 01:54 PM 4/5/2008, you wrote:
>Hi Mark,
>
>I'm perfectly happy to keep this on the list so everyone may benefit.
>
>One of my questions is about the mechanics. If one sends a rigid PCB
>through a laser printer i would expect the edges to eventually damage
>the sensitive coating on the drum. Even with careful de-burring
>potential for damage seems high.
>
>Another thing is toner density. When i tried printing on metal foil i
>noticed i can only achieve 50% of normal toner density, because the HV
>that normally holds the toner is shorted out. I did not consider it
>possible to achieve enough toner density to resist the etchant.
>
>Generally i much prefer laser printers, i hate the messy ink business.
>But with an inkjet the head moves some distance from the surface, so
>that is no problem.
>
>Did you use some type of carrier sheet or was the PCB large enough to
>be transported by the printer?
>
>Thanks
>
>ST
>
>
>On 4/5/08, Mark Lerman <mlerman@...> wrote:
> >
> >  Or do you want to take this off list?
> >
> >  Mark
> >
>
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