Browse Prior Art Database

Liquid Medium Autoclave

IP.com Disclosure Number: IPCOM000101235D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Fuller, BW: AUTHOR [+2]

Abstract

It has been demonstrated that autoclave lamination improves thickness control and dimensional stability when used to manufacture high performance circuit boards. However, autoclaves are usually not economically competitive with conventional multi-opening flat bed presses. One serious autoclave disadvantage is longer cycle time because heat transfer occurs only through convection. Energy cost is also higher because a large volume of gas must be compressed, heated, cooled and then dumped to the atmosphere. The subject concept could greatly eliminate both of these problems while maintaining the other advantages offered by the autoclave process.

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Liquid Medium Autoclave

       It has been demonstrated that autoclave lamination
improves thickness control and dimensional stability when used to
manufacture high performance circuit boards.  However, autoclaves are
usually not economically competitive with conventional multi-opening
flat bed presses.  One serious autoclave disadvantage is longer cycle
time because heat transfer occurs only through convection.  Energy
cost is also higher because a large volume of gas must be compressed,
heated, cooled and then dumped to the atmosphere.  The subject
concept could greatly eliminate both of these problems while
maintaining the other advantages offered by the autoclave process.

      The concept is basically to replace the gas used in current
autoclave equipment with a liquid medium, preferably a water soluble
medium such as glycol, or a high temperature oil, thus reducing total
process cycle time through better heat transfer and reducing
operating costs by saving energy.

      Product-filled bags would be loaded onto a rack, evacuated and
the autoclave closed.  Next the preheated liquid medium would be
pumped from the upper storage tank displacing the air out the exit
valve at the top of the tank.  When all the air is gone, the valve
is closed, and the chamber is pressurized with the upper hydraulic
pump. The internal recirculation pump and small heating element are
activate, keeping a constant temperature in the chamber and shutting
off when the heat cycle ends.  Next, both hydraulic pumps activate,
p...