Method for screen printing of paste

A method for printing onto a surface of a board through a screen comprising the steps of:

• feeding paste into a chamber of a dispenser from a paste supply device via a tube connected to the dispenser;
• kneading the paste contained in said chamber by a rotatable means provided within said chamber so that the paste can have a desired degree of viscosity for printing;
• adjusting temperature of the paste contained in said chamber by temperature adjusting means attached to the dispenser so as to maintain said temperature at a predetermined value;
• dispensing the paste onto a first side of the screen and onto the surface of the board from the dispenser through a slit-like aperture therein;
• removing residue from the first side of the screen by a scraper means projecting forwardly downward from a lower portion of a front wall of the dispenser;
• removing residue from a second side of the screen by a transversely extending blade means extending from a cleaning apparatus so as to be in contact with the second side of the screen;
• and
• sucking and transporting the residue adhered to inner peripheral surfaces of openings in said screen as well as the residue being removed from the second side of said screen by a vacuum means connected to the cleaning apparatus.

A method for printing solder paste onto a surface of a printed circuit board through a screen comprising the steps of:

• feeding solder paste into a chamber of a dispenser from a solder paste supply device via a tube connected to the dispenser;
• kneading the paste contained in said chamber by a rotatable means provided within said chamber so that the paste can have a desired degree of viscosity for printing;
• adjusting temperature of the paste contained in said chamber by temperature adjusting means attached to the dispenser so as to maintain said temperature at a predetermined value;
• applying a pressure against the paste contained in said chamber by said rotatable means to facilitate the paste to be dispensed onto a first side of the screen from the dispenser through a slit-like aperture therein;
• dispensing the paste onto the first side of the screen and onto the surface of the printed circuit board from the dispenser through said aperture;
• removing residue from the first side of the screen by a transversely extending blade means extending from first cleaning apparatus so as to be in contact with the first side of the screen;
• removing residue from a second side of the screen by a transversely extending blade means extending from second cleaning apparatus so as to be in contact with the second side of the screen;
• and
• sucking and transporting the residue adhered to inner peripheral surfaces of openings in said screen as well as the residue being removed from the second side of said screen by a vacuum means connected to the second cleaning apparatus.

A method for printing solder paste onto a surface of a printed circuit board through a screen comprising the steps of:

• feeding solder paste into a chamber of a dispenser from a solder paste supply device via a tube connected to the dispenser;
• kneading the paste contained in said chamber by a rotatable means provided within said chamber so that the paste can have a desired degree of viscosity for printing;
• closing a slit-like aperture communicating with said chamber by actuating means mounted on the dispenser when the dispenser is in a non-printing position, said slit-like aperture being formed between a fixed front wall and a movable rear wall of the dispenser the rear wall of which is movable toward and away from the fixed front wall;
• opening said slit-like aperture by said actuating means when the dispenser is performing a printing operation so that the paste contained in said chamber is permitted to be dispensed onto a first side of the screen during each pass of the dispenser;
• applying a pressure against the paste contained in said chamber by said rotatable means to facilitate the paste to be dispensed onto the first side of the screen from the dispenser through said slit-like aperture and through a space between a pair of blades extending from the dispenser on opposite sides of said slit-like aperture for contact with the first side of said screen;
• moving the dispenser in a direction of travel thereof so that a trailing one of said blades urges the paste dispensed from the dispenser through openings in said screen and onto the surface of said printed circuit board.