I would also presume a roller process would be a lot less prone to getting bubbles under larger areas.
PG
Sent from my phone, anything lewd or incomprehensible is probably autocorrect and not my fault.
----- Reply message -----
From: "Donald H Locker" <
dhlocker@...>
To: "Homebrew PCBs" <
Homebrew_PCBs@yahoogroups.com>
Subject: [Homebrew_PCBs] Toner transfer temperature?
Date: Tue, Nov 15, 2011 3:25 am
Make a roller version then. The advantage of a roller over a flat plate is that the pressure is applied where needed, relatively uniformly, with relatively low force requirement. To achieve 200psi with a roller requires a few pounds (35+/-) of force - the contact area is extremely small (estimate 0.030x6.0 inches). Over a 4x6 inch surface, a plate would have to be loaded with a force of 4800 lb to achieve the same 200psi, and the uniformity of application is far from guaranteed. A hot diaphragm with a 200psi hydraulic chamber behind might be able to provide sufficient uniformity, but would have to be at least twice the size of the maximum working area (to reduce edge effects) with support to prevent blowout of the diaphragm.
Temperature seems to depend on the toner, but somewhere around 275F to 325F seems to work pretty well, near as I can tell.
HTH,
Donald.
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----- Original Message -----
> From: "Stephen" <squirrox@...>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Monday, November 14, 2011 10:53:15 AM
> Subject: [Homebrew_PCBs] Toner transfer temperature?
> Hi Guys,
>
> What temperature should I be trying to achieve to achieve a good
> transfer of toner to PCB? I have access to a good workshop (machine
> shop in the colonies!) together with metal and I am thinking of making
> a heated press to provide a uniform hot surface and pressure rather
> than clowning about with steam irons or modifying a printer or
> laminating machine.
>
> Regards,
>
> Steve
>
>
>
> ------------------------------------
>
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