METHOD AND APPARATUS FOR SELECTING A PASTE STENCIL FOR PASTE PRINTING AND FOR APPLYING PASTE ONTO A SUBSTRATE BY MEANS OF THE SELECTED PASTE STENCIL

Abstract

A method and an apparatus for selecting a paste stencil (10) for paste printing onto a substrate (20), the paste stencil (10) being selected on the basis of a stencil thickness (h), in the case of which an area ratio of a small through opening (11a, 11b) of the substrate is greater than or equal to a setpoint area ratio. Furthermore, the present disclosure relates to a method and an apparatus for applying paste material (30) onto a substrate (20) for at least one small component (21a, 21b) and at least one large component (22) which is larger than the at least one small component (21a, 21b), paste material (30) being applied for the at least one small component (21a, 21b) and the at least one large component (22) by means of a paste stencil (10) which is selected according to the invention, and additional paste material (30) being applied onto the paste material (30) for the at least one large component (22), after paste material (30) has been applied by means of the selected paste stencil (10) for the at least one small component (21a, 21b) and the at least one large component (22).

Claims

1. Method for selecting a paste stencil for paste printing onto a substrate, the paste stencil having at least one small through opening for paste material for at least one associated small component on the substrate and at least one large through opening for paste material for at least one associated large component on the substrate, and the at least one small through opening having a smaller opening cross section than the at least one large through opening, and the at least one small through opening having a first area ratio and the at least one large through opening having a second area ratio which is greater than the first area ratio, characterized in that the paste stencil is selected on the basis of a stencil thickness (h), in the case of which the first area ratio is greater than or equal to a setpoint area ratio.

2. Method according to claim 1, wherein the paste stencil is selected on the basis of a stencil thickness (h), in the case of which the first area ratio lies between 0.3 and 0.7, in particular is 0.5.

3. Method according to claim 1, the paste stencil having at least one smallest through opening for paste material for at least one associated smallest component on the substrate, and the at least one smallest through opening having a smaller opening cross section than at least one small through opening, the at least one smallest through opening having a third area ratio which is smaller than the first area ratio, characterized in that the paste stencil is selected on the basis of a stencil thickness (h), in the case of which the third area ratio is greater than or equal to a setpoint area ratio.

4. Method for applying paste material onto a substrate for at least one small component and at least one large component which is larger than the at least one small component, the method comprising the following steps: applying paste material for the at least one small component and the at least one large component by means of a paste stencil which is selected by way of a method according to claim 1, and applying additional paste material onto the paste material for the at least one large component, after paste material has been applied by means of the selected paste stencil for the at least one small component and the at least one large component.

5. Method according to claim 4, wherein the additional paste material is applied by means of a dispenser, in particular by means of a jet dispenser.

6. Selection apparatus for selecting a paste stencil for paste printing onto a substrate, the paste stencil having at least one small through opening for paste material for at least one associated small component on the substrate and at least one large through opening for paste material for at least one associated large component on the substrate, and the at least one small through opening having a smaller opening cross section than the at least one large through opening, and the at least one small through opening having a first area ratio and the at least one large through opening having a second area ratio which is greater than the first area ratio, wherein the selection apparatus is designed and configured in such a way that the paste stencil is selected on the basis of a stencil thickness (h), in the case of which the first area ratio is greater than or equal to a setpoint area ratio.

7. Selection apparatus according to claim 6, wherein the paste stencil is selected on the basis of a stencil thickness (h), in the case of which the first area ratio lies between 0.3 and 0.7, in particular is 0.5.

8. Selection apparatus according to claim 6, the paste stencil having at least one smallest through opening for paste material for at least one associated smallest component on the substrate, and the at least one smallest through opening having a smaller opening cross section than at least one small through opening, the at least one smallest through opening having a third area ratio which is smaller than the first area ratio, characterized in that the selection apparatus is designed and configured in such a way that the paste stencil is selected on the basis of a stencil thickness (h), in the case of which the third area ratio is greater than or equal to a setpoint area ratio.

9. System for applying paste material to components of a substrate having at least one small component and at least one large component which is larger than the at least one small component, the system comprising: a selection apparatus according to claim 6; a paste printing apparatus for printing paste material for the at least one small component and the at least one large component onto the substrate by means of a paste stencil which is selected by way of the selection apparatus; and a dispenser for applying additional paste material onto the paste material for the at least one large component, after paste material has been applied by means of the selected paste stencil for the at least one small component and the at least one large component.

10. System according to claim 9, wherein the selection apparatus, the paste printing apparatus and the dispenser are connected to a controller, by means of which the application of the paste material can be carried out in an automated manner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Further measures which improve the invention result from the following description relating to different exemplary embodiments of the invention which are shown diagrammatically in the figures. All features and/or advantages which are apparent from the claims, the description or the drawing, including structural details and spatial arrangements, can be essential to the invention both per se and also in various combinations.

In the drawing, in each case diagrammatically:

[0032] FIG. 1 shows paste printing by way of a paste stencil according to a method of the prior art,

[0033] FIG. 2 shows paste printing by way of a paste stencil which has been selected according to one method of the present invention,

[0034] FIG. 3 shows a first work step of paste printing by way of a paste stencil which is selected according to the invention,

[0035] FIG. 4 shows a second work step of paste printing by way of a dispenser which is actuated according to the invention, and

[0036] FIG. 5 shows a substrate with components which are arranged on paste material in a system according to the invention.

DESCRIPTION OF EMBODIMENTS

[0037] Elements with the same function and method of operation are provided with the same reference numerals in FIGS. 1 to 5.

[0038] The paste printing which is shown in FIG. 1 has already been acknowledged in the introduction of the description and is not to be explained again at this point.

[0039] FIG. 2 shows a substrate 20, onto which paste material 30 has been applied by means of a paste stencil 10 which is selected according to the invention. The paste stencil 10 has a smallest through opening 11a, a small through opening 11b and two large through openings 12. The smallest through opening 11a and the small through opening 11b can be considered in each case to be the at least one small through opening 11a, 11b according to the invention. As can be seen in FIG. 2, both the smallest through opening 11a and the small through opening 11b in each case have a smaller opening cross section than the respective large through opening 12. In the case of the uniform stencil thickness H of the paste stencil 10, both the smallest through opening 11a and the small through opening 11b therefore have an area ratio (a first and third area ratio, respectively) which is smaller than the area ratio (second area ratio) of the respective large through opening.

[0040] The paste stencil 10 which is shown in FIG. 3 has been selected on the basis of a stencil thickness h, in the case of which the area ratio of the smallest through opening 11a is greater than a setpoint area ratio, as a result of which the paste material 30 can flow through all through openings 11a, 11b, 12, without forming residues in the through openings 11a, 11b, 12.

[0041] With reference to FIG. 3, FIG. 4 and FIG. 5, a method for applying paste material 30 onto a substrate 20 will be described in the following text for two small components 21a, 21b and two large components 22 which are larger than the small components 21a, 21b.

[0042] In a first step, paste material 30 for the two small components 21a, 21b and the two large components 22 is first of all, as shown in FIG. 3, applied onto the substrate 20 for this purpose by means of the paste stencil 10 which is selected as described above. To this end, paste material 30 is pressed onto the substrate 20 through the through holes 11a, 11b, 12 in the screen printing method by means of a squeegee 61 which is moved over the paste stencil 10 in the arrow direction. Here, the squeegee 61 is a constituent part of a paste printing apparatus 60.

[0043] In a second step, as shown in FIG. 4, selectively additional paste material 30 is then applied onto the paste material 30 for the small component 21b and the two large components 22 by means of a dispenser 40.

[0044] FIG. 3 and FIG. 4 likewise show the system 100 according to the invention having a selection unit 50, a paste printing apparatus 60 and a controller 70. For more comprehensible illustration, the selection apparatus 50, the paste printing apparatus 60 and the dispenser 40 have been shown in different figures. However, the system 100 according to the invention is to be understood in such a way that the selection apparatus 50, the paste printing apparatus 60 and the dispenser 40 are arranged so as to belong to the system 100. Thus, the system 100 can be configured, for example, as a soldering paste printer having the selection apparatus 50, which soldering paste printer has, furthermore, a paste printing apparatus 60 which is configured as a screen printing apparatus, and, in an additional processing region, a dispenser arrangement having from 1 to n gantries with respective dispensers 40 which can be deflected in each case in the x, y and/or z-axes.

[0045] In the system 100 which is shown by FIG. 3 and FIG. 4, the selection apparatus 50, the paste printing apparatus 60 and the dispenser 40 are electrically connected to a controller 70 using wires or in a wireless manner, the controller 70 being designed and configured in such a way that the application of the paste material 30 can be carried out in an automated manner.

[0046] FIG. 5 shows a smallest component 21a, a small component 21b and two large components 22 which are in each case connected to the substrate 20 via paste material 30.

LIST OF REFERENCE NUMERALS

[0047] 10 Paste stencil [0048] 11a Smallest through opening [0049] 11b Small through opening [0050] 12 Large through opening [0051] 20 Substrate [0052] 21a Smallest component [0053] 21b Small component [0054] 22 Large component [0055] 30 Paste material [0056] 40 Dispenser [0057] 50 Selection apparatus [0058] 60 Paste printing apparatus [0059] 61 Squeegee [0060] 70 Controller [0061] 100 System