JP2015157418A - Printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify an amount of change in mask tension with an inexpensive configuration.SOLUTION: A printing device S includes: a mask M; a squeegee 35; a squeegee motor 51 for displacing the squeegee 35 in a separating direction and an approaching direction with respect to the mask M; a substrate support device 100 having a lifting unit 150 for displacing a printed circuit board P in a separating direction and an approaching direction with respect to the mask M; a detection unit 211 for lowering the squeegee 35 from a state of being in contact with the mask, and detecting a pressing down amount Dx of the squeegee 35 when a current value I of the squeegee motor 51 becomes a predetermined preset value X1; a calculation unit 212 for calculating an amount of change ΔD of the pressing down amount Dx by comparing the pressing down amount Dx detected by the detection unit 211 with a reference value; and a specification unit 213 for specifying the amount of change W of mask tension N from the amount of change ΔD of the pressing down amount Dx calculated by the calculation unit 212.

Description

  The present invention relates to a technique for specifying the amount of change in mask tension.

  Japanese Patent Application Laid-Open No. 2004-228561 describes that the axial load of the squeegee lifting shaft is detected by a load cell, and the mask tension is calculated based on the relationship between the detected axial load and the amount of depression of the mask.

JP 2011-189673 A

The conventional method is expensive because an expensive load cell is required for measuring the mask tension. In addition, the measurement result is not utilized for plate separation control for the purpose of providing a mask tension measurement method.
The present invention has been completed based on the above situation, and aims to specify the amount of change in mask tension with an inexpensive configuration and to utilize the amount of change in mask tension for plate separation control. To do.

  The present invention is a printing apparatus for printing solder on a printed circuit board overlaid on the lower surface of the mask by supplying paste-like solder to the upper surface of the mask and then scraping the upper surface of the mask with a squeegee. And a substrate having a squeegee motor that displaces the squeegee in a direction away from and approaches the mask, and a lift unit that displaces the printed board in the direction away from and toward the mask. A support unit; a detection unit that lowers the squeegee from a state of being in contact with the mask; and a detection unit that detects a push-down amount of the squeegee when a current value of the squeegee motor reaches a predetermined setting value; and the detection unit A calculation unit that calculates the amount of change in the depression amount by comparing the depression amount detected by the reference value with the reference value, and the depression calculated by the calculation unit Than the variation amount, and a specifying unit that specifies the amount of change in the mask tension. According to this configuration, the amount of change in mask tension can be specified without using an expensive load cell.

  The present invention is a printing apparatus for printing solder on a printed circuit board overlaid on the lower surface of the mask by supplying paste-like solder to the upper surface of the mask and then scraping the upper surface of the mask with a squeegee. And a substrate having a squeegee motor that displaces the squeegee in a direction away from and approaches the mask, and a lift unit that displaces the printed board in the direction away from and toward the mask. A support device, a detection unit that lowers the squeegee from a state in contact with the mask and detects a current value I of a squeegee motor when the amount of depression of the squeegee reaches a predetermined set value; A calculation unit that calculates a change amount of the current value by comparing a current value to be detected with a reference value, and a change amount based on the change amount of the current value calculated by the calculation unit. And a specifying unit that specifies the amount of change in the tension. According to this configuration, the amount of change in mask tension can be specified without using an expensive load cell.

As an embodiment of the printing apparatus, the following configuration is preferable.
A change unit configured to change a pattern separation control pattern of the printed circuit board with respect to the mask according to a change amount of the mask tension; According to this configuration, when the mask tension is changed, the plate separation control pattern is changed, so that the solder removability can be maintained at the same level as that for the non-defective product.

  An informing unit is provided for informing the replacement of the mask when the amount of change in the mask tension is greater than a threshold value. It is possible to prevent the occurrence of printing defects due to a decrease in mask tension.

  According to the present invention, the amount of change in mask tension can be specified with an inexpensive configuration. Also, the printing quality is improved by utilizing the change amount of the mask tension for the plate separation control.

Front view of the printing apparatus applied to the first embodiment Diagram showing the electrical configuration of the printing device Top view of the mask The figure which shows the identification method of the amount of change of mask tension A graph showing the relationship between current value I and squeegee push-down amount D Conversion table of mask tension change amount W Graph showing the relationship between stencil separation time and printed circuit board descent amount Illustration of separation operation The flowchart figure which shows the change sequence of plate separation control pattern Conversion table of mask tension change amount W

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. In the following description, the left-right direction in FIG. 1 is the X-axis direction, the direction orthogonal to the paper surface in FIG. 1 is the Y-axis direction, and the up-down direction is the Z-axis direction.

1. Configuration of Printing Apparatus S and Printing Operation The printing apparatus S includes a base 10 having a flat upper surface, a frame 10A provided on the outer peripheral side of the base 10, a support member 20, a squeegee head support frame 40, and a mask M. A squeegee 35, a substrate support device 100, a controller 200, and the like.

  As shown in FIG. 1, a pair of support members 20 are installed on both sides in the X-axis direction in the frame 10A. The support member 20 extends in the Y-axis direction on the base 10, and a rail 23 extending in the Y-axis direction is provided on the upper surface thereof.

  The squeegee head support frame 40 has a shape that is long in the X direction so as to straddle the left and right support members 20, and is disposed on the upper side of the support member 20. A squeegee 35 is attached to the center of the squeegee head support frame 40 in the X-axis direction while being supported by the squeegee head 31. The squeegee 35 has a horizontally long shape extending horizontally in the X-axis direction. The squeegee 35 prints the solder on the printed circuit board by scratching the upper surface of the mask and extending the solder.

  And the receiving part 43 fitted to the rail 23 is provided in the lower surface both sides of the squeegee head support frame 40, and the squeegee head support frame including the squeegee 35 is operated by operating the Y-axis moving mechanism (not shown). The whole 40 reciprocates in the Y-axis direction along the rail 23.

  The squeegee head support frame 40 is provided with a lifting device 50 that lifts and lowers the squeegee 35. As shown in FIG. 2, the lifting device 50 includes a squeegee motor 51, a lifting shaft (screw shaft) 53, and a transmission belt 55. The transmission belt 55 is hung between the motor shaft 51A of the squeegee motor 51 and a nut 53A that is screwed onto the outer periphery of the squeegee lifting shaft 53, and converts the power of the squeegee motor 51 into movement in the Z-axis direction. , Transmitted to the squeegee lifting shaft 53. Since the squeegee 35 is fixed to the shaft end of the squeegee lifting shaft 53, the squeegee lifting shaft 53 and the squeegee 35 are moved together with the squeegee lifting shaft 53 in the Z-axis direction (the direction away from and approaching the mask M). Direction).

  The squeegee motor 51 is provided with a current sensor 51B and an encoder 51C, and can detect the current value I of the squeegee motor 51 and the rotation amount of the squeegee motor 51.

  In the mask M, a stencil 7 is fixed to the bottom surface of the mask frame 5 via a tensioner 6 made of an elastic material such as rubber (see FIG. 3). The stencil 7 is a flat thin plate, and a large number of printing openings 7a for printing solder are formed on the plate surface. The mask M has a structure in which both sides in the X direction are fixed by the mask holding device 45 in a state where the mask frame 5 is placed on the mounting plate 21 provided inside the support member 20.

  As shown in FIG. 1, the substrate support apparatus 100 is configured by stacking a table 110, a table 120, a table 130, and a table 140 in order from the bottom. More specifically, four Y rails 11 extending in the Y-axis direction are installed on the base 10. The first stage table 110 is on the Y rails 11 while fitting rail receiving portions provided on the lower surface of the table.

  The first-stage table 110 has a horizontally long shape extending in the X-axis direction, and two X rails 115 extending in the X-axis direction are installed on the upper surface of the table. Then, on the X rails 115, the second-stage table 120 is on the rail receiving portion provided on the lower surface of the table. From the above, the substrate support apparatus 100 can be horizontally moved to an arbitrary position on the base 10 by operating the first table 110 and the second table 120 in combination.

  A third stage table 130 is mounted on the second stage table 120 via a rotation mechanism 125, and the third stage table 130 and the fourth stage table are operated by operating the rotation mechanism 125. 140 can be rotated. Thus, the relative positional relationship between the mask M and the printed board P can be adjusted by making the table rotatable.

  The fourth-stage table 140 is a support table that supports the printed circuit board P, and a pair of support members 145 are provided on the table. The pair of support members 145 are opposed to each other in the X direction, and are configured to support the printed circuit board P with both ends of the substrate sandwiched from both sides in the X direction. In addition, the substrate support device 100 is provided with an elevating device (an example of the “elevating unit” of the present invention) 150 so that the table 140 can be raised and lowered.

  As shown in FIG. 2, the lifting device 150 includes a table motor 151, a lifting shaft (screw shaft) 153, and a transmission belt 155. The transmission belt 155 is hung between a motor shaft 151A of the table motor 151 and a nut 153A screwed to the outer periphery of the table lifting shaft 153, and converts the power of the table motor 151 into movement in the Z direction. This is transmitted to the table lifting shaft 153. Since the table 140 is fixed to the shaft end of the table elevating shaft 153, the table 140 is moved together with the table elevating shaft 153 in the Z direction (in the direction away from and toward the mask M) by driving the table motor 151. Direction).

  The controller 200 has a function of controlling the printing apparatus S, and includes a CPU 210, a memory 220, and a display unit 230. The squeegee motor 51 and the table motor 151 are electrically connected to the CPU 210, and the squeegee motor 51 and the table motor 151 can be controlled by outputting a control signal from the CPU 210.

  Further, the CPU 210 includes a detection unit 211 that detects the depression amount Dx of the squeegee 35, a calculation unit 212 that calculates a variation amount ΔD of the depression amount Dx, and a specification unit 213 that identifies the variation amount W of the mask tension N from the variation amount ΔD. A changing unit 215 for changing the pattern separation control pattern of the printed circuit board P and a notifying unit 217 for notifying the replacement of the mask are provided.

  The memory 220 stores data necessary for specifying the change amount W of the mask tension N, specifically, data of the push-down amount Do and data of the conversion table shown in FIG. Also, a program for executing a plate separation control pattern change sequence, which will be described later, and execution data of each plate separation control pattern (plate separation distance, descent speed of the printed circuit board P during plate separation operation, print during plate separation operation) The descending acceleration of the substrate P) is stored.

  Next, a printing operation by the printing apparatus S will be briefly described. In order to print solder on the printed circuit board P, first, the printed circuit board P to be printed is supported on the support member 145. Thereafter, the lifting device 150 is operated to lower the table 140 to the lowered position. Next, the substrate support apparatus 100 is moved to move the print substrate P to be printed to a printing position below the stencil.

  Then, after moving to the printing position, the lifting device 150 is operated to raise the table 240 from the lowered position to the raised position, and the printed circuit board P is placed on the lower surface of the stencil 7.

  After the paste-like solder is supplied onto the stencil 7 by the solder supply device, the squeegee 35 is lowered and brought into contact with the upper surface of the stencil 7, and then the squeegee 35 is reciprocated in the Y-axis direction to remove the solder. When stretched, the solder is embedded in the printing opening 7 a of the stencil 7, and the solder can be printed at a desired position on the printed circuit board P.

  When the solder printing is completed, the lifting / lowering device 150 is operated again to lower the table 140 from the raised position. As a result, the printed circuit board P descends integrally with the table 140 and is released from the stencil 7. After that, by moving the substrate support apparatus 100 from below the mask M, it is possible to take out the printed printed circuit board P.

2. Mask tension and plate separation control As shown in FIGS. 2 and 3, the mask M has a structure in which a stencil 7 is fixed to the bottom surface of the mask frame 5 via a tensioner 6 made of an elastic material. When the tensioner 6 deteriorates over time, the mask tension (the tension (tension) of the stencil 7 by the tensioner 6) N decreases. When the mask tension N is lowered, the plate separation of the printed circuit board P is deteriorated, so that the solder removability with respect to the printing openings 7a is lowered, and the print quality may be lowered. Here, “separation” means that the printed circuit board P is separated from the state where it is overlaid on the mask M.

  Therefore, the printing apparatus S specifies the amount of change W of the mask tension N with respect to the non-defective mask M by the following method. The “non-defective mask” is an undegraded mask in which the mask tension N maintains an initial value.

W = N-No (1) Formula N: Mask tension No: Mask tension of non-defective mask W: Change amount of mask tension N

  More specifically, first, as shown in FIG. 4A, the squeegee 35 is lowered from an upper position on the stencil to a contact position where the tip of the squeegee contacts the upper surface of the stencil 7. Thereafter, as shown in FIG. 4B, the squeegee 35 is lowered and the stencil 7 is pushed in, and the push-down amount Dx of the squeegee 35 when the current value I of the squeegee motor 51 reaches the set value X1 is detected. To do.

  Then, a change amount ΔD of the push-down amount Dx of the squeegee 35 based on the non-defective mask M is calculated from the following equation (2). The amount Do of pushing down the non-defective mask M corresponds to the “reference value” of the present invention. In addition, it is assumed that the push-down amount Do is measured in advance (data has been acquired).

ΔD = Dx−Do (2) Formula ΔD: Change amount of the push-down amount Dx of the squeegee 35 Dx: Push-down amount of the squeegee 35 when the current value I reaches the set value X1 Do: Push-down amount of the squeegee 35 when the current value I reaches the set value X1 (non-defective mask)

  As shown in FIG. 5, the correlation graph of the current value I and the push-down amount D is in the order of a mask requiring replacement (small mask tension), an aged deterioration mask (during mask tension), and a non-defective mask (large mask tension). The inclination is small.

  The change amount (reduction amount) W of the mask tension N with respect to the non-defective mask M has a correlation with the change amount ΔD of the push-down amount Dx, and tends to increase as the change amount ΔD increases.

  Therefore, the change amount W of the mask tension N based on the non-defective mask M can be specified using data indicating the correlation between the change amount ΔD and the change amount W.

  In the present embodiment, the conversion table shown in FIG. 6 (a table in which the change amount ΔD and the change amount W are associated with each other) is used as the data indicating the correlation, and the change amount ΔD calculated by the equation (2) The change amount W of the mask tension N is specified by referring to the conversion table shown in FIG.

  For example, as shown in FIG. 6, if the change amount ΔD is “ΔD1”, the change amount W of the mask tension N is “W1”. Note that the conversion table of FIG. 6 shows, for example, a preliminary test that measures the push-down amount Dx for each mask (non-defective mask, deteriorated mask) with a known mask tension N, and the change amount ΔD and the change amount W of the mask tension N. It can be obtained by examining the relationship.

  In the present embodiment, the plate separation control of the printed circuit board P is performed based on the change amount W of the mask tension N. When the mask tension N decreases, the reaction force of the mask M decreases. For this reason, when the printed board P is lowered from the state of being overlaid on the mask M, the mask M is not separated from the lowered printed board P, and the mask M is largely bent while being in close contact with the printed board P, and the plate separation time T becomes longer. The solder detachability with respect to the printing opening 7a has a correlation with the plate separation time T, and tends to become worse as the plate separation time T becomes longer.

  For this reason, in the present embodiment, a plurality of plate separation control patterns having the following three elements (a) to (c) as parameters are provided. Then, by changing the plate separation control pattern according to the change amount W of the mask tension N, the plate separation time T of the deteriorated mask in which the mask tension N is reduced is made equal to the plate separation time T of the non-defective mask. In this way, even when a deteriorated product mask having a reduced mask tension N is used, the solder removability can be secured and the printing quality can be maintained.

(A) Plate separation distance (Descent distance of printed circuit board P from the start of plate separation to completion of plate separation)
(B) Lowering speed of printed circuit board P during plate separation operation (lowering speed of lifting shaft 153)
(C) Lowering acceleration of printed circuit board P during plate separation operation (lowering acceleration of lifting shaft 153)

  In the example of FIG. 6, a total of five patterns of the plate separation control pattern 0 for the non-defective mask and the plate separation control patterns 1 to 4 for the deteriorated product mask are set. Therefore, the mask tension change amount W is large. Accordingly, one of the plate separation control patterns is selected from the five patterns.

  Further, the plate separation control patterns 1 to 4 of the deteriorated mask are determined based on the plate separation control pattern 0 of the non-defective mask, and the descending amount of the printed circuit board P and the plate separation distance at each time point are compared with those of the non-defective mask. Is set longer.

  For example, as shown in FIG. 7, when the plate separation control pattern “0” of the non-defective mask is compared with the plate separation control pattern “1” of the deteriorated mask, the plate separation control pattern “ In the case of “0”, the descending amount of the printed circuit board P is “Lo1”, whereas in the case of the plate separation control pattern “1” of the deteriorated product mask, the descending amount of the printed circuit board P is “Ls1”. The amount of lowering of the printed circuit board P is larger in the plate separation control pattern “1” of the deteriorated product mask. At time t2, the plate separation control pattern “0” for the non-defective mask has the lowering amount of the printed circuit board P “Lo2”, whereas the plate separation control pattern “1” for the deteriorated product mask. On the other hand, the lowering amount of the printed circuit board P is “Ls2”, and the lowering amount of the printed circuit board P is larger in the plate separation control pattern “1” of the deteriorated product mask. The plate separation distance of the non-defective mask plate separation control pattern 0 is “Lo3”, whereas the plate separation control pattern 1 of the deteriorated product mask is “Ls3”. The plate separation control pattern “1” is larger.

  When the descending amount of the printed circuit board P is large, the deflection amount E of the stencil 7 increases as shown in FIG. 8, and the reaction force F of the mask M trying to move away from the printed circuit board P increases. Therefore, it is possible to compensate for the decrease in the mask tension N, and the force that the deteriorated product mask M tries to separate from the printed circuit board P during the plate separating operation can be set to be equivalent to that for the non-defective product.

  Therefore, the deteriorated mask M and the printed circuit board P can be separated at the same timing as the non-defective mask M, and the plate separation time T of the deteriorated mask M can be made substantially coincident with the plate separation time T of the non-defective product. I can do it.

  Note that the larger the change amount (decrease amount) W of the mask tension, the worse the plate separation becomes. Therefore, the plate separation distances of the plate separation control patterns 1 to 4 are set longer as the variation amount W is larger. Similarly, the descending amount of the printed circuit board P at each time point is set longer as the change amount W is larger.

3. Process for Changing Plate Separation Control Pattern FIG. 9 is a sequence for changing the plate separation control pattern executed at the start of production. The change sequence is composed of S10 to S130. First, in S10, the mask M used for production is clamped by the mask holding device 45. Note that the mask M used for production is the same as that used in the previous production.

  After the mask M is clamped in S10, next, in S20 to S50, processing for specifying the change amount W of the mask tension N is performed. Specifically, the CPU 210 first drives the squeegee motor 51 to lower the squeegee 35 from an upper position above the stencil to a contact position that contacts the upper surface of the stencil 7 (S20: FIG. 4a).

  Thereafter, the CPU 210 drives the squeegee motor 51 to further lower the squeegee 35 from the contact position. Thereby, the squeegee 35 pushes the stencil 7 of the mask M downward.

  The detection unit 211 of the CPU 210 monitors the detection value of the current sensor 51B, and stops the squeegee motor 51 when the current value I of the squeegee motor 41 reaches the set value X1. Then, based on the output value of the encoder 51C that detects the rotation amount of the squeegee motor 51, the pressing amount Dx of the squeegee 35 when the current value I reaches the set value X1 is detected (S30).

  Thereafter, the CPU 210 re-drives the squeegee motor 51 to raise the squeegee 35 and separate it from the stencil 7 (S40). Thereafter, the calculation unit 212 of the CPU 210 reads the non-defective mask push-down amount Do from the memory, and subtracts the non-defective mask push-down amount Do from the push-down amount Dx of the squeegee 35 to calculate the change amount ΔD of the push-down amount Dx. (S50, equation (2)).

  Then, the specifying unit 213 of the CPU 210 specifies the change amount W of the mask tension N by referring to the conversion amount ΔD calculated in FIG. 6 (S60).

  Thereafter, the CPU 210 performs a process of displaying the change amount W of the mask tension N on the display unit 230 (S70) and a process of comparing the change amount W of the mask tension N with the threshold value U (S70). The “threshold value U” is a limit value of the change amount W of the mask tension N. If the change amount W is less than the threshold value, the print quality can be maintained.

  If the change amount W of the mask tension N is smaller than the threshold value U, a YES determination is made in S80, and then the process proceeds to S90. In S90, the CPU 210 displays a message such as “Mask M is normal” on the display unit 230. Thereafter, the process proceeds to S100, and the CPU 210 performs a process of comparing the change amount W of the mask tension N with the previous value.

  If the amount of change W is the same as the previous value, a YES determination is made in S100, and then a process of printing solder on the printed circuit board P is started. Then, after the printing process is completed, the CPU 210 applies the previous “plate separation control pattern” and executes the plate separation operation of the printed circuit board P.

  On the other hand, if the change amount W of the mask tension N specified in S60 is different from the previous value, NO is determined in S100, and the process proceeds to S110. In S110, the changing unit 215 of the CPU 210 changes the plate separation control pattern of the printed circuit board P to the plate separation control pattern corresponding to the change amount W. Then, the process which prints solder on the printed circuit board P is started. Then, after the printing process is completed, the CPU 210 applies the changed “separation control pattern” and executes the separation operation of the printed circuit board P.

  While the mask M used for production is maintained in a non-defective state, the change amount W of the mask tension N specified in S60 is “0”, and YES is determined in the processes of S80 and S100. Therefore, the plate separation operation of the printed circuit board P is executed by applying the “plate separation control pattern 0”.

  When the mask tension N of the mask M used for production decreases due to aged deterioration, the change amount W of the mask tension N specified in S60 becomes “W1” or “W2”, and the change amount W is changed from the previous value. Change. Then, if the change amount W is less than the threshold value U, a YES determination is made in S80, a NO determination is made in S100, and the plate separation control pattern corresponding to the change amount W is changed. Therefore, after the mask tension N of the mask M used for production decreases due to deterioration over time, the plate separation operation of the printed circuit board P is executed by applying the “plate separation control pattern 1” or “plate separation control pattern 2”. Is done.

  Then, when the aging further progresses, the change amount W of the mask tension N specified in S60 eventually becomes larger than the threshold value U. Then, a NO determination is made in S80, and the process proceeds to S120. When the process proceeds to S120, the notification unit 217 of the CPU 210 transmits a display command to the display unit 230, and the display unit 230 displays a warning prompting the replacement of the mask M in response to the display command. Thereafter, an operation of replacing the mask M is performed in S130. After the replacement of the mask M, the process returns to S10, and each process is performed according to the procedure described above.

4). Explanation of Effects According to the printing apparatus S, the change amount W of the mask tension N is specified based on the change amount ΔD of the push-down amount Dx of the squeegee 35. This eliminates the need for a load cell.

  Also, according to the printing apparatus S, the plate separation control pattern is changed when the change amount W of the mask tension N changes. Therefore, it is possible to maintain the solder removability at the same level as that of the non-defective product.

  Further, according to the printing apparatus S, when the change amount W of the mask tension N exceeds the threshold value U, the replacement of the mask M is notified. Therefore, it is possible to prevent the occurrence of printing defects due to the decrease in the mask tension N.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIGS.
The second embodiment is different from the first embodiment in a method for specifying the change amount W of the mask tension N with reference to the non-defective mask M.

  More specifically, first, as shown in FIG. 4A, the squeegee 35 is lowered from an upper position on the stencil to a contact position where the tip of the squeegee contacts the upper surface of the stencil 7. Thereafter, as shown in FIG. 4B, the squeegee 35 is lowered and the stencil 7 is pushed in, and the current value Ix of the squeegee motor 51 at the time when the depression amount D of the squeegee 35 reaches the set value X2, Detection is performed by the detection unit 211 of the CPU 210.

  Then, a change amount ΔI of the current value Ix based on the non-defective mask M is calculated by the calculation unit 212 of the CPU 210 from the following equation (3) (see FIG. 5).

ΔI = Io−Ix (3) Equation ΔI: Change amount of current value I Ix: Current value when squeegee 35 push-down amount D reaches set value X2 Io: Squeegee 35 Current value when the amount of push-down D reaches the set value X2 (non-defective mask)

  The change amount (decrease amount) W of the mask tension N based on the non-defective mask M is correlated with the change amount ΔI of the current value Ix, and tends to increase as the change amount ΔI increases.

  Therefore, the change amount W of the mask tension N based on the non-defective mask M can be specified using data indicating the correlation between the change amount ΔI and the change amount W.

  In the present embodiment, the conversion table shown in FIG. 10 (a table in which the change amount ΔI and the change amount W are associated with each other) is used as the data indicating the correlation, and the change amount ΔI calculated by the expression (3) By referring to the conversion table shown in FIG. 10, the specifying unit 213 of the CPU 210 specifies the change amount W of the mask tension N.

  For example, as shown in FIG. 10, if the change amount ΔI is “ΔI1”, the change amount W of the mask tension N is “W1”. The conversion table in FIG. 10 shows, for example, a preliminary test for measuring the current value Ix for each mask (non-defective mask, deteriorated mask) with known mask tension N, and the variation ΔI and the variation of the mask tension N. It can be obtained by examining the relationship of W.

  According to the printing apparatus S of the second embodiment, the change amount W of the mask tension N is specified based on the change amount ΔI of the current value Ix. This eliminates the need for a load cell.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the first embodiment, the conversion table (correspondence table) in FIG. 6 is illustrated as an example of data indicating the correlation between the change amount ΔD and the change amount W. In the second embodiment, the conversion table (correspondence table) in FIG. 10 is illustrated as an example of data indicating the correlation between the change amount ΔI and the change amount W. In addition to the conversion table (correspondence table) exemplified in the first and second embodiments, the data indicating the correlation may be a graph or a mathematical expression indicating the correlation. In the first embodiment, the current sensor 51B is used to detect the current value I. However, the current detection method may be other methods. For example, it may be obtained from a drive circuit or the like that controls the current value I supplied to the squeegee motor 51.

  (2) In the first embodiment, the change amount ΔD of the push-in amount Dx and the change amount W of the mask tension N are calculated based on a non-defective mask (an undegraded mask whose mask tension maintains the initial value). . In the second embodiment as well, the change amount ΔI of the current value Ix and the change amount W of the mask tension N are calculated based on the non-defective mask M. The method of taking the reference is not limited to the examples of the first and second embodiments, and any mask M having a known mask tension N value may be used in addition to the non-defective mask M.

0 to 4 ... Plate separation control pattern 5 ... Mask frame 6 ... Tensioner 7 ... Stencil 35 ... Squeegee 50 ... Lifting device 51 ... Squeegee motor 100 ... Substrate support device 140 ... Table 150 ... Elevating device (corresponding to "elevating part" of the present invention)
210 ... CPU
211 ... Detection unit 212 ... Calculation unit 213 ... Specification unit 215 ... Change unit 217 ... Notification unit Dx ... Press-down amount Do ... Press-down amount (reference value)
ΔD ... Change amount Ix ... Current value Io ... Current value (reference value)
ΔI ... change amount N ... mask tension W ... change amount U ... threshold X1, X2 ... set value M ... mask P ... printed circuit board S ... printing device

Claims (4)

After supplying paste-like solder to the upper surface of the mask, the upper surface of the mask is scraped with a squeegee to print the solder on the printed circuit board superimposed on the lower surface of the mask,
The mask;
The squeegee;
A squeegee motor for displacing the squeegee with respect to the mask in a direction of leaving and approaching the mask;
A substrate support device having an elevating part that displaces the printed circuit board in a direction away from and approaching the mask;
A detection unit that detects the amount by which the squeegee is pushed down when the current value of the squeegee motor reaches a predetermined set value by lowering the squeegee from the state in contact with the mask;
A calculation unit that calculates the amount of change in the depression amount by comparing the depression amount detected by the detection unit with a reference value;
And a specifying unit that specifies a change amount of the mask tension from a change amount of the pressing amount calculated by the calculation unit. After supplying paste-like solder to the upper surface of the mask, the upper surface of the mask is scraped with a squeegee to print the solder on the printed circuit board superimposed on the lower surface of the mask,
The mask;
The squeegee;
A squeegee motor for displacing the squeegee with respect to the mask in a direction of leaving and approaching the mask;
A substrate support device having an elevating part that displaces the printed circuit board in a direction away from and approaching the mask;
A detecting unit that lowers the squeegee from a state in contact with the mask and detects a current value of the squeegee motor when the amount of depression of the squeegee reaches a predetermined setting value;
A calculation unit that calculates a change amount of the current value by comparing a current value detected by the detection unit with a reference value;
And a specifying unit that specifies a change amount of the mask tension from a change amount of the current value calculated by the calculation unit.   The printing apparatus according to claim 1, further comprising: a changing unit that changes a plate separation control pattern of the printed board with respect to the mask according to a change amount of the mask tension.   4. The printing apparatus according to claim 1, further comprising: a notification unit that notifies the replacement of the mask when the amount of change in the mask tension is greater than a threshold value. 5.

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