Method for the dimensionally controlled bonding of surfaces
This invention introduces an improved method for bonding two surfaces using silk-screen printing technology. The method according to the invention reduces possible occlusion of the screen, thus improving the print quality of the deposited cement film. This is accomplished by adding particles to the print medium. In addition, by selecting the size of the particles it is possible for these, serving as spacers during the bonding process, to define the thickness of the cement layer. An additional procedural step describes the controlled mutual approach of the bonding surfaces.
1 . Method for applying a structured cement film on the surface of an element, encompassing the following steps:
preparing the surface of an element on which the structured cement layer is to be applied;
preparing a silk-screen printing system with screen and doctor blade, said screen encompassing sealed and unsealed regions;
applying a print medium on one side of the screen;
positioning said surface in non-contacting fashion near the screen in a manner whereby the screen is situated between the print medium and said surface;
squeezing the print medium through the screen using the doctor blade by brushing the doctor blade across the top of the screen, causing it to locally press the screen onto said surface and the print medium in the unsealed regions to be deposited on said surface;
characterized in that the print medium contains cement components as well as spacers.
2 . Method as in claim 1 , characterized in that a print medium is employed whose volume includes a spacer component at a concentration of between 0.5% and 80% but, preferably, approximately 5%.
3 . Method for bonding at least 2 elements, characterized in that a first element is provided with a structured cement film according to the method described in claim 1 or 2 , and that the surface of a second element is brought up to that of the first element to within a distance defined by said spacers, following which the cement film is allowed to cure.
4 . Method as in claim 3 , characterized in that the first element is provided with perforations leading to the surface to be bonded, that during the approach a gas flow is first generated in the direction of said surface which gas flow is reduced to zero during the approach and that, upon contact of the structured cement film with the surface of the second element, a negative pressure is generated in the said perforations in a manner whereby the ambient atmospheric pressure presses the second element against the first element.