JP3739856B2 - Cream solder screen printing apparatus and screen printing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cream solder screen printing apparatus and a screen printing method for printing cream solder for soldering electronic components on a substrate.
[0002]
[Prior art]
The cream solder screen printing device arranges the screen mask on the substrate and slides the squeegee on the screen mask to pass the cream solder onto the circuit pattern electrode of the substrate through the pattern hole opened in the screen mask. Is to be printed.
[0003]
[Problems to be solved by the invention]
When sliding the squeegee on the screen mask, it is necessary to press the squeegee against the screen mask. This pressing force is called printing pressure. If the printing pressure is too large, when the squeegee slides on the screen mask, cream solder in the pattern hole tends to be removed, resulting in insufficient amount of cream solder printed on the substrate. On the other hand, if the printing pressure is too small, the cream solder is not sufficiently filled in the pattern holes, and the amount of the cream solder is insufficient. Therefore, when the cream solder is printed on the substrate, the printing pressure must be set appropriately.
[0004]
By the way, when the squeegee is slid on the screen mask, the cream solder on the screen mask rolls, so the squeegee receives a reaction force in the direction of rising from the cream solder, that is, a reaction force in the direction of reducing the printing pressure. .
[0005]
In this case, the higher the sliding speed of the squeegee, the more intensely the cream solder rolls, so the reaction force also increases. Therefore, it is desirable to change the force for pressing the squeegee against the screen mask according to the sliding speed. Specifically, since the reaction force (lifting force) increases as the sliding speed increases, it is desirable to increase the pressing force applied to the squeegee as the sliding speed increases. Of course, this reaction force varies depending on the type of cream solder (particularly the viscosity of cream solder).
[0006]
Accordingly, an object of the present invention is to provide a cream solder screen printing apparatus and a screen printing method capable of optimally controlling the magnitude of the printing pressure in accordance with the sliding speed of the squeegee.
[0007]
[Means for Solving the Problems]
The cream solder screen printing apparatus of the present invention includes a screen mask disposed on a substrate, a squeegee that slides on the screen mask while rolling the cream solder on the screen mask, and a slide that slides the squeegee. Data on the relationship between the moving means, the pressing force applying means for applying a pressing force against the screen mask to the squeegee, and the magnitude of the pressing force for obtaining the optimum printing pressure. A control unit having a memory that is obtained and registered, in order to counter the reaction force in the lifting direction that the squeegee receives by the rolling , according to the sliding speed of the squeegee by driving the sliding means, The magnitude of the pressing force applied to the squeegee by the pressing force applying means increases as the sliding speed of the squeegee increases. Kusuru so on, in which the control unit is adapted to control the pressing force imparting means.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, by increasing the magnitude of the pressing force applied to the scan Chigi the faster sliding speed of the squeegee, and maintained appropriately the size of the printing pressure, print an appropriate amount of the cream solder on the substrate be able to.
[0009]
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a screen printing apparatus for cream solder according to an embodiment of the present invention, and FIG. 2 is a relationship diagram of the sliding speed, pressing force, and printing pressure of the squeegee.
[0010]
In FIG. 1, reference numeral 1 denotes a substrate, which is positioned by clamping from the left and right by a substrate guide 2. A screen mask 3 is disposed on the substrate 1. The screen mask 3 is provided with pattern holes 4 corresponding to circuit pattern electrodes (not shown) formed on the upper surface of the substrate 1. Reference numeral 5 denotes a cream solder placed on the screen mask 3.
[0011]
A feed screw 6 is disposed above the screen mask 3. Reference numeral 7 denotes a motor that rotates the feed screw 6. A nut 8 is screwed to the feed screw 6. A frame 9 is coupled to the lower portion of the nut 8. A cylinder 10 is installed upside down on the frame 9. A squeegee holder 12 is coupled to the lower end of the rod 11 of the cylinder 10, and the squeegee holder 12 holds a squeegee 13. When the rod 11 of the cylinder 10 moves up and down, the squeegee 13 also moves up and down. That is, the cylinder 10 is a means for moving the squeegee 13 up and down. When the feed screw 6 is rotated by driving the motor 7, the nut 8 moves along the feed screw 6, whereby the squeegee 13 slides on the screen mask 3. That is, the feed screw 6, the motor 7, and the nut 8 serve as sliding means for the squeegee 13.
[0012]
Reference numeral 20 denotes a control unit to which an input unit 21 such as a keyboard is connected. Reference numeral 22 denotes a compressor, which is connected to the cylinder 10 via a pressure adjusting unit 23 such as an electropneumatic regulator and an up / down switching valve 24. The control unit 20 controls the motor 7, the pressure adjustment unit 23, the up / down switching valve 24, and the like. When the compressor 22 is driven and the ascending / descending switching valve 24 is switched to the ascending side, the fluid is sent from the tube 25 to the lower part of the cylinder 10 and the rod 11 and the squeegee 13 ascend. When the ascending / descending switching valve 24 is switched to the descending side, the fluid is sent from the tube 26 to the upper portion of the cylinder 10 and the rod 11 and the squeegee 13 are lowered. At this time, the control unit 20 controls the pressure adjusting unit 23 to change the descending force of the squeegee 13, that is, the pressing force pressing the lower end portion of the squeegee 13 against the screen mask 3. That is, the cylinder 10, the compressor 22, the pressure adjustment unit 23, and the up / down switching valve 24 serve as a pressing force applying unit that presses the squeegee 13 against the screen mask 3.
[0013]
In the above configuration, when the squeegee 13 is grounded on the screen mask 3 and the motor 7 is driven to rotate the feed screw 6, the nut 8 moves laterally along the feed screw 6. As a result, the squeegee 13 slides on the screen mask 3 and the pattern hole 4 is filled with the cream solder 5. Next, when the substrate 1 is relatively lowered from the screen mask 3 and separated, the cream solder 5 filled in the pattern holes 4 is transferred onto the circuit pattern electrodes of the substrate 1. Thus, the cream solder 5 is printed on the substrate 1.
[0014]
Next, a method for changing the pressing force for pressing the squeegee 13 against the screen mask will be described. In FIG. 1, when the squeegee 13 is slid rightward, the cream solder 5 rolls in the direction of the arrow. At that time, the squeegee 13 receives the reaction force in the floating direction, that is, the reaction force in the direction of reducing the printing pressure, due to the rolling of the cream solder 5, and the reaction force is larger as the sliding speed is higher. As described above.
[0015]
Therefore, the relationship between the sliding speed of the squeegee and the magnitude of the pressing force for obtaining the optimum printing pressure is obtained in advance by a test operation. Figure 2 is a squeegee sliding speed of which is obtained by the test operation, I pressing force of the magnitude of the relationship diagram der required for optimum printing pressure, as is apparent from FIG. 2, the squeegee 13 as the sliding speed of the fast, we are increasing the pressing force. Then, the data of this relationship diagram is registered in the memory provided in the control unit 20, and the pressure adjustment unit 23 is controlled by the control unit 20 in accordance with the sliding speed, and the squeegee 13 is set so as to obtain the optimum printing pressure. Press against the screen mask 3. In FIG. 2, the difference between the pressing force and the printing pressure is the reaction force applied to the squeegee 13 by the cream solder 5. Since the data shown in FIG. 2 differs depending on the type of cream solder 5, a test operation is performed in advance for each type of cream solder 5, and the relationship shown in FIG. 2 is obtained and registered in the memory.
[0016]
【The invention's effect】
According to the present invention, by increasing the magnitude of the pressing force applied to the scan Chigi the faster sliding speed of the squeegee, and maintained appropriately the size of the printing pressure, print an appropriate amount of the cream solder on the substrate be able to.
[Brief description of the drawings]
FIG. 1 is a side view of a cream solder screen printing apparatus according to an embodiment of the present invention. FIG. 2 is a squeegee sliding speed, pressing force, and mark of the cream solder screen printing apparatus according to an embodiment of the present invention. Pressure relationship diagram [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Board | substrate 3 Screen mask 4 Pattern hole 5 Cream solder 6 Feed screw 7 Motor 8 Nut 10 Cylinder 13 Squeegee 20 Control part 22 Compressor 23 Pressure adjustment part 24 Up / down switching valve

Claims (2)

A screen mask disposed on the substrate; a squeegee that slides on the screen mask while rolling the cream solder on the screen mask; a sliding means that slides the squeegee; A pressing force applying means for applying a pressing force, and a control unit including a memory in which data on a relationship between the sliding speed of the squeegee and the magnitude of the pressing force for obtaining the optimum printing pressure is obtained in advance and registered. And the pressing force applying means applies the squeegee to the squeegee according to the sliding speed of the squeegee driven by the sliding means. The control unit applies the pressing force so that the magnitude of the pressing force increases as the sliding speed of the squeegee increases. Cream solder of the screen printing apparatus being characterized in that so as to control the unit. A screen mask disposed on the substrate; a squeegee that slides on the screen mask while rolling the cream solder on the screen mask; a sliding means that slides the squeegee; A pressing force applying means for applying a pressing force, and a control unit including a memory in which data on a relationship between the sliding speed of the squeegee and the magnitude of the pressing force for obtaining the optimum printing pressure is obtained in advance and registered. In order to counter the reaction force in the floating direction that the squeegee receives from the rolling, the controller controls the squeegee to increase the pressing force as the sliding speed of the squeegee increases. A screen printing method of cream solder characterized by the above.

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