摘要 |
A vacuum chuck (34) for holding thin sheet material, particularly during high-temperature manufacturing processes, and an apparatus (10) for forming a substantially uniform coating of a substance on a thin sheet material. The vacuum chuck includes a chuck body (36) having a gas-permeable support surface (38) for supporting the thin sheet material to define a vacuum chamber (49) having an inlet (54), a valve member (56) for controlling fluid flow through the vacuum chamber inlet, and a locking shim (58) for holding the valve member in the vacuum chamber inlet. The locking shim is responsive to the vacuum chamber inlet being coupled to a vacuum source for permitting the valve member to partially withdraw from the vacuum chamber inlet, to permit drawing of a vacuum in the vacuum chamber, supporting the thin sheet material on the gas-permeable support surface in a substantially flat position, and is responsive to the vacuum chamber inlet being removed from the vacuum source for inserting the valve member more fully into the vacuum chamber inlet, to seal the vacuum chamber and retain the vacuum therein, holding the thin sheet material on the gas-permeable support surface. One vacuum is attained, temperature excursions during the deposition process will cause the locking shim to press against the valve member with more force. Assuring a sound vacuum through the entire process. The manufacturing apparatus includes a conveyor (12) on which the vacuum chuck is conveyed, with the thin sheet material held thereon, and a source (60) of coating substance.
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