Apparatus, system and method for determining a match condition for a printed circuit board to a stencil

A system for conducting solder printing on a printed circuit board, comprising:

• an apparatus for determining the condition of a printed circuit board, including:
• a stencil database for storing a plurality of stencil data files corresponding to stencils of different dimensions;
• an image capturing device having an area where the printed circuit board is laid thereon for a surface profile of the printed circuit board to be captured for generating a surface data file of the printed circuit board;
• a condition determination module that compares data from the surface data file with data from a plurality of stencil data files as a nominal reference via matching to determine the condition of the printed circuit board based on a set of categories, the condition includes at least one match-successful condition and at least one match-failure condition;
• a knowledge database for storing the surface data file of at least one printed circuit board, and a knowledge module interfaced therewith;
• and
• a solder printing machine for applying solder paste over one or more pads of the printed circuit board;
• wherein the condition determination module compares diagonal length dimension data of the surface data file of the printed circuit board with diagonal length dimension data of each stencil data file, for one stencil data file that falls within a diagonal length tolerance to then be further compared with the surface data file of the printed circuit board in terms of position offset between aperture coordinate data of the stencil data file and the pad coordinate data of the surface data file;
• wherein the match-successful condition is determined when the aperture coordinate data of the stencil data file and the pad coordinate data of the surface data file of the printed circuit board are within an offset tolerance, in which the printed circuit board is matched with the corresponding stencil of the stencil data file for solder printing therewith by the solder printing machine;
• wherein the match-failure condition is determined when the aperture coordinate data of the stencil data file and the pad coordinate data of the surface data file of the printed circuit board fail to be within the offset tolerance, in which the surface data file of the printed circuit board with the match-failure condition is stored in the knowledge database and then be used by the knowledge module to generate a new stencil data file that is in correspondence therewith, for the new stencil data file to be stored in the stencil database for a future matching.

A method for determining condition of a printed circuit board, comprising the steps of:

• capturing a surface profile of the printed circuit board by an image capturing device for generating a surface data file of it;
• comparing data from the surface data file with data from a plurality of stencil data files stored in a stencil database as a nominal reference via matching executed by a condition determination module, each stencil data file corresponding to stencils of different dimensions;
• and
• determining the condition of the printed circuit board based on a set of categories by the condition determination module, the condition includes at least one match-successful condition and at least one match-failure condition;
• and
• storing the surface data file of at least one printed circuit board, by a knowledge database, in which a knowledge module is interfaced with the knowledge database;
• wherein the condition determination module compares diagonal length dimension data of the surface data file of the printed circuit board with diagonal length dimension data of each stencil data file, for one stencil data file that falls within a diagonal length tolerance to then be further compared with the surface data file of the printed circuit board in terms of position offset between aperture coordinate data of the stencil data file and the pad coordinate data of the surface data file;
• wherein the match-successful condition is determined when the aperture coordinate data of the stencil data file and the pad coordinate data of the surface data file of the printed circuit board are within an offset tolerance, in which the printed circuit board is matched with the corresponding stencil of the stencil data file for solder printing therewith;
• wherein the match-failure condition is determined when the aperture coordinate data of the stencil data file and the pad coordinate data of the surface data file of the printed circuit board fail to be within the offset tolerance, in which the surface data file of the printed circuit board with the match-failure condition is stored in the knowledge database and then be used by the knowledge module to generate a new stencil data file that is in correspondence therewith, for the new stencil data file to be stored in the stencil database for a future matching.