Thomas,
If you can put your press back togther you can probably sell it on ebay for
enough to buy a few good hot roller laminators! The 210M is a great press
for artwork -- I used one in college for mounting photos, but could never
afford one of my own. The 210M sells for $250 - $800 on ebay.
I use a HeatSeal H200 for toner transfer -- you can get a brand new one
online for $85. It won't do the same size as the SEAL, but if you're doing
∗that∗ many boards, you may want to look at cheap offshore fabrication (e.g.
olimex.com) or something from barebonespcb.com.
Of course if you want to trade your 210M for my H200. . .
-Alex
[Alex Hay] -----Original Message-----
From: Thomas P. Gootee [mailto:
tomg@...]
Sent: Thursday, July 15, 2004 9:13 PM
To: '
Homebrew_PCBs@yahoogroups.com'
Subject: [Homebrew_PCBs] Anybody tried a large flatbed laminator for toner
transfer?
I was looking for a better way to make larger lots of pcboards at a time
when I remembered that several years ago I had "accidentally" purchased a
fairly large laminating machine at a gov't surplus auction. It's a
"Commercial 210M" model, made by Seal. The bed and heated lid/press's
mating surfaces are flat and measure about 18 x 22 inches.
I am wondering if anyone has found a way to make these types of machines
work well, for making pcbs with the toner transfer method (laser printed
pattern on common glossy paper). It sure SEEMS like it OUGHT to be able to
work well. And it SURE would be ∗NICE∗ to be able to fill an 18 x 22-inch
area with boards and do them all at once!
This thing is heavy! It has an external frame composed of two 1/2-inch x
2-inch (cross-section) steel members on each side, holding up the bed and
the lid's axle, with 3/4 x 1 1/2 steel c.s. members on each side comprising
the lid/press's support and the lever/cam/closing mechanism, that rotate on
a 1/2-inch diameter steel axle in the rear. And there's a 3 5/8 x 2 inch
U-beam going from one side to the other, between those, from which the lid
is suspended, by adjustable "swinging" 1-inch-diameter hollow bolts (so the
lid can self-level as it closes). The levers'/cams' large handle goes all
the way across the front of the unit and is connected to the opening/closing
mechanism by steel members that measure 3/8 x 1 inch c.s.. The handle swings
about 180 degrees between the closed and fully open positions, which raises
the front of the lid about 10 inches and the rear about 2 inches.
It has a temperature control knob and a temperature gauge (thermometer),
which go from 150 deg F to 350 deg F. It's rated at 1350 Watts, 11.3 Amps,
115 Volts.
The inside surface of the heated lid seems to be made of something like
hard rubber. In the base, where the lid touches when closed, there was a
smooth "cushion" about 3/4-inch thick, which sat on what looks like a sheet
of asbestos-type material (no lectures on asbestos, please).
My first experiment was just to place a pcb with a toner transfer pattern
sheet in the press (see my pcb toner transfer web page at
http://www.fullnet.com/u/tomg/gooteepc.htm , for specs of paper used, etc),
which was set for just under 300 deg F, and close the lid for three minutes.
No good. The toner rubbed off quite easily.
So I decided to try to go for higher pressure and placed a sheet of
1/4-inch-thick wood on the press's pad and put a pcb and toner pattern on
top of the wood. That made closing the press significantly more difficult,
and, I assume, applied more pressure to the pcb. The results were a lot
better, but were spotty. Apparently the inner surface of the lid is either
not evenly flat, or maybe not evenly resilient, or, it's being deformed
irregularly by the pcb, or something.
So, I tried placing a 1/16th-inch-thick sheet of aluminum on top of the
pcb and toner pattern paper, just before I closed the lid, in an attempt to
even-out the pressure from the heated surface. The results were better, but
not consistently great.
I then pulled out the cushion/pad from the base and replaced it with a
couple/few of sheets of 1/4-inch-thick plywood, to which I later added a
1/8-inch sheet, all in an attempt to get more pressure applied, and in a
more uniform manner. The wood looked smooth and flat, but I put a 1/16"
thick sheet of aluminum UNDER the pcbs, as well as on top of them, just in
case. Eventually, I had it all set up so that closing the lid required
quite a bit of force on the handle; probably well in excess of 50 pounds for
the last few inches, to get it to the fully-closed position. I did make
some excellent boards, with toner that could not be rubbed off with fingers
or with a stiff toothbrush, no matter how hard or fast I rubbed on it. But,
whenever I tried to put more than one board in the press, the results were
spotty again, with maybe one out of four boards being good. And,
occasionally, even with only one board in the press, there would be small
areas where the toner was not fused well-enough and it could be rubbed off
by my thumb or by the toothbrush.
I assume that the solution involves either more pressure or a better way
to get the pressure distributed. I was sandwiching multiple boards between
two 6x18 inch pieces of 1/16th" aluminum (two halves of a "kickplate" made
for the doors of houses. And I did have the boards separated by a couple of
inches. But perhaps if I used separate pieces for each board (or maybe even
NO aluminum sheet on top of the boards, since the pressure is now much
higher), it might work better; or MAYBE even a ∗thicker∗ (i.e. stiffer)
sheet of metal, covering the whole inner (heated) surface of the lid. But,
I had boards that had to be made and shipped (for the Curve Tracer kits that
I sell; see
http://www.fullnet.com/u/tomg/gooteect.htm ), and work to do. So
I have gone back to using the clothes iron, for now... Sigh...
Any suggestions? I need something that works perfectly every time. A
handheld iron does that, for me. But I'm on a continuing mission to
automate or streamline as much of the process as possible (I've got a nice
etching tank, with two 50 Watt heaters, digital thermometer, and a 250 gph
submersible pump that pumps sodium persulphate across the boards at high
speed, which works very well. And for drilling I'm converting a small x-y
milling table to CNC and mounting a surplus z-axis over it, "real soon
now"...)
If anyone can suggest something else I should try to get the laminating
press to work well, I'll really appreciate it!
Thanks.
Regards,
Tom Gootee
tomg@... http://www.fullnet.com/u/tomg -----------------------------------
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