Kelly I Perkins

US Patent:

44966970, Jan 29, 1985

Filed:

Aug 24, 1982

Appl. No.:

6/411111

Inventors:

Andrew Zsolnay - Manhattan Beach CA
Kelly M. Perkins - Anchorage AK
Leiv H. Blad - Van Nuys CA

Assignee:

Lockheed Corporation - Burbank CA

International Classification:

C08J 300
C08J 324

US Classification:

526 60

Abstract:

This invention is directed to a method of automatically controlling curing of a thermosetting polymeric material. The method comprises the steps of (a) applying heat to the polymeric material to initiate curing; (b) measuring a selected characteristic of the polymeric material at various times during the cure cycle thereof; (c) generating a set of signals corresponding to the measurements made; (d) determining from the signals the optimum time for applying pressure to the polymeric material; and (e) automatically applying pressure to the polymeric material at the optimum time, in a closed-loop system. The selected characteristic measured may be the capacitance or the dissipation of the polymeric material. In general, the pressure is automatically applied immediately after the minimum capacitance level is reached but before hardening of the polymeric material.

US Patent:

43991009, Aug 16, 1983

Filed:

Dec 29, 1980

Appl. No.:

6/220369

Inventors:

Andrew Zsolnay - Manhattan Beach CA
Kelly M. Perkins - Anchorage AK
Leiv H. Blad - CA

Assignee:

Lockheed Corporation - Burbank CA

International Classification:

G06G 758
G01N 2722
G01N 3344

US Classification:

422 62

Abstract:

The invention is directed to an apparatus and method for curing polymeric materials by use of a closed-loop, automatic process control technique. A dielectric monitoring device (15) senses the electrical characteristics which are analogous to viscosity changes taking place in an uncured or partially cured polymeric material (10) while heat is applied thereto. The generated analog signal, which changes in response to variations in the capacitance and dissipation of the polymeric material, is fed into a microcomputer (21) which determines from the direction and amplitude of the generated wave form both the maximum and minimum levels of capacitance and dissipation developed. When a predetermined condition is reached, the microcomputer (21) sends a control signal to processing equipment (24,25) to apply pressure, heat and/or vacuum to the polymeric material (10) at or near the onset of gelation but prior to the hardening point. The microcomputer (21) is programmed so as to discard random electrical signals and questionable data such as from short-term burst noises. The system can be used for curing various polymeric materials having differing characteristics.