Solder-coating apparatus

Claim 2

A multiple station apparatus for applying a protective coating of solder over the conductive portions of a printed circuit board wherein the conductive portions are present on one or both sides of the board comprising: a preheat station for receiving the circuit board to be coated; a soldering station positioned to receive circuit boards from said preheating station for applying the protective coating of solder; said soldering station including means to contain a bath of molten solder; means defining a path of travel through said bath of molten solder, which path of travel includes a portion beneath the surface of said bath; means positioned above said bath of solder to contact the upper surface of a printed circuit board as the latter travels along said path of travel through said bath of molten solder; said last named means cooperating with said bath of solder to form an infeed nip receiving the circuit board from said preheat station as the latter enters said path of travel such that the path of solder urges the printed circuit board into contact with said means which contact the upper surface of the printed circuit board, means to move said contact means and circuit board in contact therewith along said path of travel and the portion thereof beneath the surface of said bath as the molten solder exerts an upward force against the circuit board to maintain the latter in contact with said contact means, and means cooperating with said soldering station to receive a circuit board therefrom to remove excess solder from the circuit board.

Claim 3

The apparatus of claim 1 including means to produce a flow of molten solder within said path of travel which moves in the same general direction as the movement of said contact means and circuit board as the circuit board moves through and beneath the surface of said bath.

Claim 4

The apparatus of claim 1 including means to collect solder which is removed from said circuit board.

Claim 5

The apparatus of claim 1 wherein the means to remove excess solder from the circuit board includes air knife means directing a band of compressed heated air against the surface of said circuit board.

Claim 6

The apparatus of claim 1 wherein said path of travel is defined by spaced apart members, and said contact means travelling between said members.

Claim 7

The apparatus of claim 5 wherein said solder flows between said spaced apart members and in a direction generally the same as the direction of travel of said contact member.

Claim 8

The apparatus of claim 1 further including means to apply a flux to the circuit board prior to passage of the board through said path of travel through said solder bath.

Claim 9

The apparatus of claim 1 further including a speed change conveyor means positioned between the pre-heat station and the bath of molder solder to increase the rate of speed at which a board travels as it leaves the pre-heat station.

Claim 10

The apparatus of claim 1 wherein each of said spaced apart members is arcuate in configuration to define an arcuate path of travel through the bath of solder, and wherein at least the lowest region of said arcuate path is below the surface of the solder bath.

Claim 11

The apparatus of claim 9 wherein said contact means travels in contact with that one of said spaced apart members which forms the upper of the two said members.

Claim 12

Apparatus for applying a protective coating over the conductive portions of a printed circuit board comprising; a precoat station receiving circuit boards and applying a precoating to at least one surface thereof; a preheat station positioned to receive a circuit board from said precoat station for heating the board to a predetermined temperature; means forming a bath of protective coating material and receiving the boards from the preheat station; an upper and lower spaced apart member defining an arcuate path of travel into and beneath the surface of said bath and out of said bath; endless belt means having a path of travel such that a portion thereof passes between said spaced members; said belt means being spaced from said lower member and in contact with said upper member such that the portion of the belt in contact with said upper member travels in an arcuate path; means to feed circuit boards into the space between said upper member and said belt such that one surface of the board contacts said endless belt while the other surface is spaced from said lower member and the protective coating material beneath the board operates as an upward buoyant force urging the board in contact with said belt; means to advance said belt along said path of travel to carry circuit boards in contact with said belt along said arcuate path and below the surface of said protective coating material whereby protective coating material deposits on at least the portions on one or both surfaces; and means to remove the protective coating material deposited other than on the conductive portions on one or both surfaces of the circuit board.

Claim 13

Apparatus for applying a protective coating over the conductive portions of a printed circuit board comprising; a precoat station receiving circuit boards and applying a precoating to at least one surface thereof; a preheat station positioned to receive a circuit board from said precoat station for heating the board to a predetermined temperature; means forming a bath of protective coating material and receiving the boards from the preheat station; an upper and lower spaced apart member defining an arcuate path of travel into and beneath the surface of said bath and out of said bath; endless belt means having a path of travel such that a portion thereof passes between said spaced members; said belt means being spaced from said lower member and in contact with said upper member such that the portion of the belt in contact with said upper member travels in an arcuate path; means to feed circuit boards into the space between said upper member and said belt such that one surface of the board contacts said endless belt while the other surface is spaced from said lower member and the protective coating material beneath the board operates as an upward buoyant force urging the board in contact with said belt; means to advance said belt along said path of travel to carry circuit boards in contact with said belt along said arcuate path and below the surface of said protective coating material whereby protective coating material deposits on at least the portions on one or both surfaces; and means to remove the protective coating material deposited other than on the conductive portions on one or both surfaces of the circuit board.

Claim 14

The apparatus of claim 11 wherein said means to remove the protective coating material includes at least one air knife means positioned transversely of said path of travel.

Claim 15

The apparatus of claim 12 further including means to heat the air prior to flow thereof into said air knife means.

Claim 16

The apparatus of claim 11 wherein said spaced apart members include a weir at the outlet end thereof and defining a zone of bright solder metal which contacts the printed circuit board as it exits from said spaced apart members.

Claim 17

The apparatus of claim 14 wherein said means to remove the protective coating material is positioned transversely of the path of travel and includes air knife menas to remove the protective coating material deposited other than on the conductive portions on one or both surfaces of the circuit board after the circuit board exits from the weir of said spaced apart members.