US 4,501,770 A · Method for removing solder from the drill holes of empty printed circuit boards coated with solder

Abstract

During the pre-soldering of printed circuit boards, as a rule, also the drill holes or bores and, in particular, the through-metallized drill holes are filled in an undesirable manner with solder. This solder must be removed before mounting the electrical components or elements upon the printed circuit boards. A simple method is disclosed for this purpose, affording a faultless de-soldering of the drill holes, without deleteriously affecting the properties of the solder material. The printed circuit boards, in a condition where the solder applied during the pre-soldering operation is still molten, are accelerated at least once and thereafter suddenly brought to standstill in such a fashion that the excess solder is knocked or propelled out of the drill holes. The apparatus for accomplishing the method contemplates guiding the printed circuit board essentially horizontally in a frame and accelerating such printed circuit board in a guided vertical drop or fall in the direction of an impact location, so that upon concussion of the frame at the impact location the excess solder is downwardly knocked or propelled out.

Claims10

Dependent claims

A method for the removal of excess solder out of drill holes of a printed circuit board not yet equipped with electrical components, each of the drill holes having an axis and primarily serving to receive and electrically connect the terminals of electric components to metalized conductor tracks on the surface of the printed circuit board, comprising the steps of:

mounting the printed circuit board on a frame;
accelerating at least once said frame including the printed circuit board in the direction of the axis of the drill holes while in a condition in which the solder applied to the printed circuit board is still in a molten state;
and
after a predetermined travel of the accelerated frame including the printed circuit board bringing to a sudden standstill the accelerated frame including the printed circuit board in a manner such that excess solder is simultaneously propelled-out of all of the drill holes of the printed circuit board.

1 more element

A method for the removal of excess solder out of drill holes of a printed circuit board not yet equipped with electrical components, each of the drill holes having an axis, comprising the steps of:

mounting the printed circuit board on a frame;
first accelerating at least once the frame including the printed circuit board in a direction normal to the axis of the drill holes while in a condition in which the solder applied to the printed circuit board is still in a molten state;
after a first predetermined travel of the accelerated frame including the printed circuit board bringing to standstill the accelerated frame including the printed circuit board in a manner such that at least excess solder flowing downwardly along the surface of the printed circuit board is simultaneously knocked-off from the printed circuit board;
subsequently accelerating at least once the frame including the printed circuit board in the direction of the axis of the drill holes while in a condition in which the solder applied to the printed circuit board is still in a molten state;
and
after a second predetermined travel of the accelerated frame including the printed circuit board bringing to standstill the accelerated frame including the printed circuit board, in order to thereby remove any excess solder which has not been removed in the preceding accelerating and bring-to-a-standstill operation.

3 more elements

Dependencies are inferred from the claim text.

Method for removing solder from the drill holes of empty printed circuit boards coated with solder

Life of this patent

Method for removing solder from the drill holes of empty printed circuit boards coated with solder

Life of this patent

Abstract

Claims10