| 摘要 |
A method and apparatus for carrying out the deposition of a paste like and/or viscous material, such as solder paste, on a substrate through the apertures or openings of a stencil are provided for use, for example, in screen printing in the mounting of components on a printed circuit board. A hollow receptacle for the material is provided with a lower aperture which is orientated towards the stencil. The lower aperture of the receptacle is delimited defined such that its length is adjusted to the dimensions of the substrate and that its width is a function of the speed of execution of the screen printing. This delimitation is implemented by sealing members preferably comprising two wipers on respective sides of the aperture, transverse with respect to the direction of displacement of the receptacle, orientated one towards the other and inclined with respect to the horizontal between the wipers at an angle of between 120° and 180°. The wipers are transversal and intersecting with the section of the receptacle. A pressure is exerted upon the viscous material in the receptacle. This pressure pushes the material towards the stencil between the wipers to distribute it over the stencil, and pushes the product upon the wipers, applying pressure to the wipers in order to push the wipers onto the stencil. The receptacle is displaced across the stencil at the same time that the pressure is exerted on the material. |
