Homebrew PCBs

The board I did on the new hot plate, between the clothes iron and the hot plate, preheated for 3 min @ 160C worked good.

Tried that on the next one, and got bad trace adherence and transfer.

Paper is turning brown. When I overcooked and smoked the paper it turned real brown...

Decreased temp to 150C and run a board. OK but not great. Still loosing traces.

Decreased temp to 140C. Much better, very little browning, good "stickage" and transfer, even of the fine alignment lines. But still some traces didn't adhere.

Got to thinking. Yeah, I know, a dangerous thing. I got really good results at 160C and 3 minutes, but only moderately good results at 150C and 140C for four minutes. Got to wondering if I was actually "cooking" the toner. Damaging the plastic with the heat.

Broke out the tiny type-K probe that came with the multimeter and a stop watch. Soldered the probe tip to the edge of a board, and had someone call out 10 second intervals as I wrote down the temperatures.


Heated between the good aluminum top hot plate and the clothes iron, both at 140C, the board reaches full temp in less than 60 seconds....

So any time I spend on the preheat, with my setup, beyond 1 minute is just overkill, and is probably baking the toner and making it non-sticky. 


I figure run it for like 90 seconds, give everything time to reach pre-heat temp, then run it through the laminator.

Thoughts?

--- In Homebrew_PCBs@yahoogroups.com, "rlspell2000" <rls@...> wrote:
>
> The board I did on the new hot plate, between the clothes iron and the hot plate, preheated for 3 min @ 160C worked good.
> 
> Tried that on the next one, and got bad trace adherence and transfer.
> 
> Paper is turning brown. When I overcooked and smoked the paper it turned real brown...
> 
> Decreased temp to 150C and run a board. OK but not great. Still loosing traces.
> 
> Decreased temp to 140C. Much better, very little browning, good "stickage" and transfer, even of the fine alignment lines. But still some traces didn't adhere.
> 
> Got to thinking. Yeah, I know, a dangerous thing. I got really good results at 160C and 3 minutes, but only moderately good results at 150C and 140C for four minutes. Got to wondering if I was actually "cooking" the toner. Damaging the plastic with the heat.
> 
> Broke out the tiny type-K probe that came with the multimeter and a stop watch. Soldered the probe tip to the edge of a board, and had someone call out 10 second intervals as I wrote down the temperatures.
> 
> 
> Heated between the good aluminum top hot plate and the clothes iron, both at 140C, the board reaches full temp in less than 60 seconds....
> 
> So any time I spend on the preheat, with my setup, beyond 1 minute is just overkill, and is probably baking the toner and making it non-sticky. 
> 
> 
> I figure run it for like 90 seconds, give everything time to reach pre-heat temp, then run it through the laminator.
> 
> Thoughts?
>


I never do any preheating. I just set the laminator to 160C which is as high as it goes and then run the board through a couple of times. perfect transfer every time.

Interesting. I run the laminator at 180C, and still need pre-heat.

In fact, I was running it at 220C (until the rollers failed) and still needed pre-heat.

I use OEM HP P1006 toner and Hammermill Laser Gloss paper.


--- In Homebrew_PCBs@yahoogroups.com, "James" <jamesrsweet@...> wrote:

>
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, "rlspell2000" <rls@> wrote:
> >
> > The board I did on the new hot plate, between the clothes iron and the hot plate, preheated for 3 min @ 160C worked good.
> > 
> > Tried that on the next one, and got bad trace adherence and transfer.
> > 
> > Paper is turning brown. When I overcooked and smoked the paper it turned real brown...
> > 
> > Decreased temp to 150C and run a board. OK but not great. Still loosing traces.
> > 
> > Decreased temp to 140C. Much better, very little browning, good "stickage" and transfer, even of the fine alignment lines. But still some traces didn't adhere.
> > 
> > Got to thinking. Yeah, I know, a dangerous thing. I got really good results at 160C and 3 minutes, but only moderately good results at 150C and 140C for four minutes. Got to wondering if I was actually "cooking" the toner. Damaging the plastic with the heat.
> > 
> > Broke out the tiny type-K probe that came with the multimeter and a stop watch. Soldered the probe tip to the edge of a board, and had someone call out 10 second intervals as I wrote down the temperatures.
> > 
> > 
> > Heated between the good aluminum top hot plate and the clothes iron, both at 140C, the board reaches full temp in less than 60 seconds....
> > 
> > So any time I spend on the preheat, with my setup, beyond 1 minute is just overkill, and is probably baking the toner and making it non-sticky. 
> > 
> > 
> > I figure run it for like 90 seconds, give everything time to reach pre-heat temp, then run it through the laminator.
> > 
> > Thoughts?
> >
> 
> 
> I never do any preheating. I just set the laminator to 160C which is as high as it goes and then run the board through a couple of times. perfect transfer every time.
>

--- In Homebrew_PCBs@yahoogroups.com, "rlspell2000" <rls@...> wrote:
>
> Interesting. I run the laminator at 180C, and still need pre-heat.
> 
> In fact, I was running it at 220C (until the rollers failed) and still needed pre-heat.
> 
> I use OEM HP P1006 toner and Hammermill Laser Gloss paper.
> 
>


I'm using a fancy Unilam 1200 that has variable feedrate, so I can have the board crawl through at a slow pace. The better laminator made a huge difference, if you can replace the feed motor with something that you can slow down I suspect that would fix your issue. If the feed is too fast you don't get enough contact time for the PCB to heat up.

I use a Fellows SPL 125. It has speed settings, I run it on the slowest setting. Takes like 10 seconds for the board to go through.

Actually, almost all my boards are double sided. The preheat makes the paper stick to the board, so both sides are lined up when I stick it in the laminator.


--- In Homebrew_PCBs@yahoogroups.com, "James" <jamesrsweet@...> wrote:

>
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, "rlspell2000" <rls@> wrote:
> >
> > Interesting. I run the laminator at 180C, and still need pre-heat.
> > 
> > In fact, I was running it at 220C (until the rollers failed) and still needed pre-heat.
> > 
> > I use OEM HP P1006 toner and Hammermill Laser Gloss paper.
> > 
> >
> 
> 
> I'm using a fancy Unilam 1200 that has variable feedrate, so I can have the board crawl through at a slow pace. The better laminator made a huge difference, if you can replace the feed motor with something that you can slow down I suspect that would fix your issue. If the feed is too fast you don't get enough contact time for the PCB to heat up.
>

--- In Homebrew_PCBs@yahoogroups.com, "rlspell2000" <rls@...> wrote:
>
> I use a Fellows SPL 125. It has speed settings, I run it on the slowest setting. Takes like 10 seconds for the board to go through.
> 
> Actually, almost all my boards are double sided. The preheat makes the paper stick to the board, so both sides are lined up when I stick it in the laminator.
> 
> 
>

I suspect the difference comes down to toner, I lucked out and the stuff in my current printer seems to melt at a relatively low temperature and bond very well to copper. Some toners don't work nearly as well and unfortunately this isn't something you can typically find out without actually trying.

For double sided boards I get excellent results by cutting the paper for one side a bit smaller than the other, lining it up perfectly and then taping around 2-3 sides to make a sandwich into which I slip the board. If you have trouble with the board shifting, folding it between a sheet of plain paper and running the whole package through the laminator can prevent that.