Method and apparatus for producing a hermetic vacuum joint at low temperature

A method for producing an article by welding a first piece to a second piece, the method comprising:

• providing the first piece, which comprises an open cavity and a first sealing surface,
• providing the second piece, which comprises a second sealing surface,
• providing a chamber, which has controllable internal pressure,
• closing the chamber such that the first piece and the second piece are inside the closed chamber,
• changing the internal pressure of the chamber so as to cause a flow of a gas from the open cavity,
• closing the open cavity by moving at least one of the pieces such that the first sealing surface forms a partially gas tight preliminary joint together with the second sealing surface, and such that the first piece and the second piece define an interface,
• opening the chamber after the preliminary joint has been formed, and
• forming a welded seam by focusing a laser beam to the interface after the chamber has been opened,
• wherein the partially gas tight preliminary joint is not hermetic before the welded seam is formed,
• wherein the first sealing surface and the second sealing surface are planar, and wherein a time period between opening the chamber and forming a hermetic seam is less than 100 s.

A method for producing an article by welding a first piece to a second piece, the method comprising:

• providing the first piece, which comprises an open cavity and a first sealing surface,
• providing the second piece, which comprises a second sealing surface,
• providing a chamber, which has controllable internal pressure,
• closing the chamber such that the first piece and the second piece are inside the closed chamber,
• changing the internal pressure of the chamber so as to cause a flow of a gas from the open cavity,
• closing the open cavity by moving at least one of the pieces such that the first sealing surface forms a partially gas tight preliminary joint together with the second sealing surface, and such that the first piece and the second piece define an interface,
• opening the chamber after the preliminary joint has been formed, and
• forming a welded seam by focusing a laser beam to the interface after the chamber has been opened,
• wherein the partially gas tight preliminary joint is not hermetic before the welded seam is formed,
• wherein the first sealing surface and the second sealing surface are planar, and wherein a relative pressure difference between external pressure and the pressure of the closed cavity is greater than 90% when the chamber is opened.

A method for producing an article by welding a first piece to a second piece, the method comprising:

• providing the first piece, which comprises an open cavity and a first sealing surface,
• providing the second piece, which comprises a second sealing surface,
• providing a chamber, which has controllable internal pressure,
• closing the chamber such that the first piece and the second piece are inside the closed chamber,
• changing the internal pressure of the chamber so as to cause a flow of a gas from the open cavity,
• closing the open cavity by moving at least one of the pieces such that the first sealing surface forms a partially gas tight preliminary joint together with the second sealing surface, and such that the first piece and the second piece define an interface,
• opening the chamber after the preliminary joint has been formed, and
• forming a welded seam by focusing a laser beam to the interface after the chamber has been opened,
• wherein the partially gas tight preliminary joint is not hermetic before the welded seam is formed,
• wherein the first sealing surface and the second sealing surface are planar, and wherein the temperature of the surface of the cavity remains lower than 80° C. during forming the welded seam.