Screen printing head, method of screen printing and printing blade

Abstract

A screen printing head for and method of printing deposits of a print medium onto a workpiece through apertures in a printing screen, the printing head comprising a main support body 3 for attachment to a screen printing machine; a support member 5 to which a printing blade 7 is in use attached; and a vibration unit 9 which couples the support member 5 to the main support body 3 to provide vibration of the support member 5 and hence the printing blade 7 when attached thereto. The printing blade 7 may be vibrated at at least one frequency in the range of from about 20 kHz to about 200 kHz and with a displacement of at least about 0.4 µm. The printing blade 7 may also comprise a blade element (201, Fig.12) which includes a plurality of disruptions (203, Fig.12) at spaced location therealong, which act to isolate applied vibrational energy into respective segments (204, Fig.12) of the blade element (201, Fig.12).

Description

technical field [0001] The present invention relates to a screen printing head and method for printing a printing medium onto a workpiece via a printing screen (often alternatively referred to as a stencil) for printing a deposit of the printing medium. Typically, the printing medium may be a solder paste such as in the manufacture of electronic components or a silver paste such as in the manufacture of wires in eg solar cells. Background technique [0002] As electronic components and constructions continue to be miniaturized, many of them utilizing screen printing processes, there is a need to be able to print finer pitch deposits with smaller area ratios with acceptable transfer efficiency and area coverage. [0003] The area ratio is the ratio between the open area of ​​the printing hole and the area of ​​the wall of the printing hole. Therefore, when the area ratio decreases, the static friction between the printing medium and the wall of the printing hole will increase...

AI Technical Summary

Problems solved by technology

[0004] Achieving acceptable transfer efficiencies is particularly problematic where deposits ranging in size from standard-sized structures to ultra-fine-pitch structures are required because standard-sized structures require the use of relatively thick printing screens, typically 100 μm thickness in order to provide the necessary amount of printing medium, but the consequence of using a relatively thick printing screen is that the printing holes for finer pitch structures necessarily have a low area ratio, which reduces the deposits printed by these printing holes transfer efficiency

The transfer efficiency of finer pitch holes can be improved by reducing the thickness of the printing screen, but this has the consequence of reducing the amount of print media that can be deposited from standard size holes

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