METHOD FOR AT LEAST PARTIALLY CLOSING A CHANNEL-SHAPED OPENING

Abstract

A method for closing a channel-shaped opening with a cross-sectional area and a passage length, more particularly through-bores or plated through-holes in printed circuit boards, using a liquid curable or curing filler material. The opening is closed by a digitally controlled application method with two discharge heads arranged opposite one another, preferably in an inkjet method with two discharge heads designed as print heads and arranged opposite one another. The two discharge heads are controlled such that the opening is filled with the filler material from both sides through the two ends simultaneously. The filler material is discharged by the two discharge heads such that the quantities of discharged filler material meet inside the opening.

Claims

1. A method for at least partially closing a channel-shaped opening (1) with a cross sectional surface area and a passage length and two opposite ends, in particular through-holes or through-platings in printed-circuit boards (6), with a liquid, curable or curing filling material, wherein the closure of the opening (1) is carried out by means of a digitally controlled application method with two discharge heads (2, 3) which are arranged opposite each other, preferably with an ink jet method with two discharge heads (2, 3) which are arranged opposite each other and which are in the form of print heads, wherein the two discharge heads (2, 3) are controlled in such a manner that the opening (1) is filled with the filling material from both sides by the two ends at the same time and the filling material is discharged from the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening (1) so that the discharged quantities of the filling material meet each other inside the opening (1).

2. The method as claimed in claim 1, wherein the two discharge heads (2, 3) are controlled in such a manner that the filling material is discharged from the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening (1) so that the discharged quantities of the filling material meet each other at least approximately in the region of the center of the passage length of the opening (1).

3. The method as claimed in claim 1, characterized in that wherein the two discharge heads (2, 3) are controlled in such a manner that the filling material is discharged from the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening (1) so that the discharged quantities of the filling material meet each other at least approximately in the region of the center of the cross sectional surface-area of the opening (1).

4. The method as claimed in claim 1, characterized in that wherein the two discharge heads (2, 3) are controlled in such a manner that the filling material is discharged by the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening so that the cross sectional surface-area of the opening (1) is completely closed.

5. The method as claimed in claim 1, characterized in that wherein the two discharge heads (2, 3) are controlled in such a manner that the filling material is discharged from the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening (1) so that the opening (1) is completely closed.

6. The method as claimed in claim 1, wherein the filling material is a melt adhesive.

7. The method as claimed in claim 1, wherein the filling material is a UV-curable and/or electron-beam-curable and/or thermally curable ink.

8. The method as claimed in claim 1, wherein the filling material is free from solvents or contains at least one solvent.

9. The method as claimed in claim 1, wherein the filling material is free from particles or filled with particles.

10. The method as claimed in the preceding claim 9, wherein at least some particles, preferably all the particles, are in the nano-scale size range.

11. The method as claimed in claim 9, wherein at least some particles, preferably all the particles, are thermally conductive.

12. The method as claimed in claim 9, wherein at least some particles, preferably all the particles, are electrically conductive or dielectric.

13. The method as claimed in claim 9, wherein at least some particles, preferably all the particles, are magnetic.

14. The method as claimed in claim 1, wherein the two discharge heads (2, 3) are orientated in such a manner that the trajectory of the filling material which is discharged therefrom is orientated vertically or is redirected only slightly from the perpendicular or is orientated horizontally or is redirected only slightly from the horizontal.

15. The method as claimed in claim 1, wherein at least one of the two discharge heads is operated with the continuous and/or drop-on-demand method.

16. The method as claimed in claim 2, wherein the two discharge heads (2, 3) are controlled in such a manner that the filling material is discharged from the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening (1) so that the discharged quantities of the filling material meet each other at least approximately in the region of the center of the cross sectional surface-area of the opening (1).

17. The method as claimed in claim 2, wherein the two discharge heads (2, 3) are controlled in such a manner that the filling material is discharged by the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening so that the cross sectional surface-area of the opening (1) is completely closed.

18. The method as claimed in claim 3, wherein the two discharge heads (2, 3) are controlled in such a manner that the filling material is discharged by the two discharge heads (2, 3) taking into consideration the respective performance data of the two discharge heads (2, 3) and the respective spacing of the two discharge heads (2, 3) from the opening so that the cross sectional surface-area of the opening (1) is completely closed.

Description

[0044] FIG. 1 shows a first method according to the invention,

[0045] FIG. 2 shows a second method according to the invention and

[0046] FIG. 3 shows a third method according to the invention.

[0047] In all the Figures, corresponding reference numerals are used for identical or similar components.

[0048] The Figures illustrate three different methods for closing a channel-shaped opening 1 in a printed-circuit board 6 by means of a liquid, curing filling material.

[0049] In this case, the closure of the opening 1 is carried out by means of a digitally controlled application method with two discharge heads 2, 3 which are arranged opposite each other, wherein an ink jet method is used and the discharge heads are in the form of print heads which are arranged opposite each other.

[0050] In this case, the discharge heads 2, 3 are controlled in such a manner that the opening 1 is filled with the filling material from both sides by the two ends thereof at the same time. In this case, the filling material is discharged from the two discharge heads 2, 3 taking into consideration the respective performance data of the two discharge heads 2, 3 and the respective spacing of the two discharge heads 2, 3 from the opening so that the discharged quantities of the filling material meet each other inside the opening.

[0051] As a result, the filling material which is injected into the opening by the discharge heads 2, 3 does not fly through the opening 1 but instead meets the filling material which comes from the other direction, whereby the filling material sprays away to the side and accumulates on the wall of the opening.

[0052] In the method shown in FIG. 1, the two discharge heads 2, 3 are controlled in such a manner that the filling material is discharged from the two discharge heads 2, 3 taking into consideration the respective performance data of the two discharge heads 2, 3 and the respective spacing of the two discharge heads 2, 3 from the opening so that the discharged quantities of the filling material meet each other in the region of the center of the passage length of the opening 1 near a wall 4 of the opening 1. Taking into consideration gravitational force, this may preferably—as shown—be the lower wall 4 of the opening 1.

[0053] Then, initially an accumulation of filling material which abuts a region of the wall 4 of the opening 1 is formed and gains height until the opening 1 in this region is closed by a type of dividing wall 5. This is particularly advantageous in the case of complete filling because initially a dividing wall 5 which is arranged at the center of the passage length of the opening 1 and the two blind holes which thereby result can then be further filled by the associated discharge head 2 or 3, respectively.

[0054] Alternatively, as shown in FIG. 2, such a dividing wall 5 can also virtually be obtained in one step by discharge heads 2, 3 with a plurality of nozzles. The further filling is also then naturally less time-intensive.

[0055] Furthermore, the discharge of the filling material by the discharge heads 2, 3 can also be carried out as shown in FIG. 3, wherein the discharged quantities of the filling material meet approximately in the region of one end of the opening 1. Consequently, the opening 1 can be closed at one side in a flush manner, whereas it remains open from the other side and unfilled.