Arithmetic unit

Abstract

To properly compute pressure applied by a squeegee when a viscous body is printed on a substrate.SOLUTION: An arithmetic unit computes pressure applied by a squeegee on the basis of cycle time that is time required for performing printing processing to a single substrate with a viscous body and a substrate size that is a linear dimension of the substrate in a movement direction of a squeegee that prints the viscous body on the substrate trough a through-hole of a mask in the printing processing.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a calculation device that calculates the printing pressure of a squeegee that prints a viscous material on a substrate through a through hole in a mask in a printing process. [Background technology]

[0002] A printing machine that prints a viscous material on a substrate by sliding a squeegee over the upper surface of a mask having through holes formed therein is described in the following Patent Documents. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-150073 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present specification is to appropriately calculate the printing pressure of a squeegee when a viscous material is printed on a substrate. [Means for solving the problem]

[0005] In order to solve the above problems, this specification discloses a calculation device that calculates the printing pressure of the squeegee based on the cycle time, which is the time required to perform a viscous material printing process on one substrate, and the substrate size, which is the length dimension of the substrate in the direction of movement of the squeegee that prints the viscous material on the substrate through a through hole in a mask during the printing process. Effect of the Invention

[0006] According to the present disclosure, the printing pressure of the squeegee when printing a viscous material on a substrate can be appropriately set. [Brief description of the drawings]

[0007] [Figure 1]FIG. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a perspective view showing a cleaning mechanism. [Figure 4] FIG. 4 is a cross-sectional view showing a cleaning mechanism. [Diagram 5] FIG. 2 is a block diagram showing a control device. [Figure 6] 1 is a graph showing the relationship between printing speed and print quality. [Figure 7] 1 is a graph showing the relationship between printing pressure and print quality. [Figure 8] 1 is a graph showing the relationship between printing speed and printing pressure. [Figure 9] 1 is a graph showing the relationship between squeegee angle and print quality. [Figure 10] 1 is a graph showing the relationship between plate detachment speed and print quality. [Figure 11] FIG. 11 is a flowchart showing a process for calculating a printing speed. [Figure 12] FIG. 4 is a diagram showing a moving distance of a cleaning mechanism during a cleaning operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as modes for carrying out the present invention.

[0009] A printer 10 is shown in Figures 1 and 2. The printer 10 is a work machine for printing solder paste on a circuit board. The printer 10 includes a conveying device 20, a mask holding device 22, a cleaning device 23, a squeegee device 24, a solder supplying device 26, and a control device (see Figure 5) 28. Note that Figure 1 is a diagram showing the printer 10 from a side perspective, and Figure 2 is a diagram showing the printer 10 from an above perspective.

[0010] The transport device 20 includes a conveyor device 30 and a board lifting device 32. The conveyor device 30 includes a pair of conveyor belts 34 and an electromagnetic motor (see FIG. 5) 36 that rotates the conveyor belts 34. The direction in which the conveyor belts 34 extend is called the X direction, the direction horizontally perpendicular to the X direction is called the Y direction, and the direction perpendicular to both the X direction and the Y direction is called the Z direction. A circuit board 38 is supported by the pair of conveyor belts 34, and is transported in the X direction by driving the electromagnetic motor 36. The board lifting device 32 is disposed between the pair of conveyor belts 34, and supports the circuit board 38 supported by the pair of conveyor belts 34 from the bottom surface of the circuit board 38 via support pins 40, and lifts and lowers the circuit board 38 at a predetermined position.

[0011] The mask holding device 22 is for holding the mask 50 in a fixed manner. The mask 50 is made of a metal, for example, a stainless steel sheet, and has a plurality of through holes (not shown). The mask holding device 22 has a mask support table 52 arranged above the transport device 20, and a mask holding mechanism 54 arranged on the upper surface of the mask support table 52. An opening (not shown) smaller than the outer edge of the mask 50 is formed in the center of the mask support table 52, and the mask 50 is placed on the mask support table 52 so as to cover the opening. The mask 50 placed on the mask support table 52 is held in a fixed manner by the mask holding mechanism 54. The mask holding mechanism 54 has an adjustment device 56 for adjusting the position of the held mask 50 in the X and Y directions, and for adjusting the rotation angle around a vertical line with the center of the mask as the axis.

[0012] The opening formed in the mask support stand 52 is larger than the circuit board 38. The circuit board 38, which has been transported to a predetermined position by the transport device 20, is raised by the substrate lifting device 32 so that it comes into close contact with the lower surface of the mask 50 held by the mask holding device 22. The circuit board 38, which is in close contact with the lower surface of the mask 50, is lowered by the substrate lifting device 32 so that it moves away from the lower surface of the mask 50.

[0013] The cleaning device 23 also has a slide device 60 and a cleaning mechanism 62. The slide device 60 includes a pair of slide rails 66 and a slider 68. The pair of slide rails 66 are disposed between the transport device 20 and the mask holding device 22 in the vertical direction so as to extend parallel to each other and in the Y direction. The slider 68 is slidably held by the pair of slide rails 66, and slides in the Y direction by the operation of an electromagnetic motor (see FIG. 5). Note that the slide rails 66 do not overlap with the substrate lifting device 32 of the transport device 20 in the vertical direction, and the slider 68 moves from above the substrate lifting device 32, so that the circuit substrate 38 is lifted by the substrate lifting device 32 without coming into contact with the cleaning device 23.

[0014] 3 and 4, the cleaning mechanism 62 has a casing 70, a pair of winding shafts 71, 72, a cleaning head 73, a suction device (see FIG. 5) 74, and a spray device (see FIG. 5) 76. The casing 70 is generally box-shaped and is fixed to the upper surface of the slider 68 in a position extending in the X direction. The length of the casing 70 in the X direction is longer than the length of the circuit board 38 in the X direction. The pair of winding shafts 71, 72 extend in the X direction and are attached to the casing in a position facing each other in the Y direction. The winding shaft 71 is disposed inside the winding shaft 71 and is held by the casing 70 so as to be rotatable about its axis. A cleaning sheet 77 is wound around one winding shaft 71 of the pair of winding shafts 71 and 72, and an edge of the cleaning sheet 77 wound around the winding shaft 71 is wound around the other winding shaft 72 of the pair of winding shafts 71 and 72. As a result, the cleaning sheet 77 is stretched between the pair of winding shafts 71 and 72. The other winding shaft 72 of the pair of winding shafts 71 and 72 rotates around its axis by the operation of the electromagnetic motor 78. As a result, the cleaning sheet 77 wound around the winding shaft 71 is wound around the winding shaft 72 by the operation of the electromagnetic motor 78. The length of the cleaning sheet 77 in the X direction is substantially the same as the length of the circuit board 38 in the X direction.

[0015] The cleaning head 73 is generally shaped like a rectangular parallelepiped rod and is disposed between the pair of winding shafts 71 and 72 in a position extending in the X direction. The length of the cleaning head 73 in the X direction is slightly larger than the length of the cleaning sheet 77 in the X direction. The cleaning head 73 is raised and lowered between a standby position (solid line in FIG. 4) and a cleaning position (dotted line in FIG. 4) by the operation of the lifting device 79. As a result, when the cleaning head 73 rises to the cleaning position, the cleaning sheet 77 suspended between the pair of winding shafts 71 and 72 is lifted above the upper end of the casing 70 by the cleaning head 73. On the other hand, when the cleaning head 73 descends to the standby position, the cleaning sheet 77 suspended between the pair of winding shafts 71 and 72 is lowered to the position of the upper end of the casing 70. The suction device 74 is built into the cleaning head 73 and sucks air from the upper surface of the cleaning head 73. The spray device 76 is a device that sprays a solvent onto a cleaning sheet 77 that is stretched between a pair of winding shafts 71, 72.

[0016] As shown in FIG. 1 and FIG. 2, the squeegee device 24 includes a squeegee moving device 80, a pair of squeegees 82, 84, and a squeegee lifting device 86. The squeegee moving device 80 includes a pair of slide rails 88 and a slider 90. The pair of slide rails 88 are arranged above the mask holding device 22 so as to be parallel to each other and extend in the Y direction. The slider 90 is slidably attached to the pair of slide rails 88, and slides in the Y direction by the operation of an electromagnetic motor (see FIG. 5) 92. Each of the pair of squeegees 82, 84 is generally plate-shaped and made of a flexible material. The pair of squeegees 82, 84 face each other and are arranged so as to extend in the X direction, and are held by the squeegee lifting device 86 below the slider 90. The squeegee lifting device 86 raises and lowers the pair of squeegees 82, 84 individually.

[0017] Solder supply device 26 is a device that supplies cream solder, and a discharge port 96 for discharging cream solder is formed on the bottom surface of solder supply device 26. Solder supply device 26 is fixed to approximately the center of the side surface in the Y direction of slider 90. As a result, solder supply device 26 can be moved to any position in the Y direction by operation of squeegee moving device 80.

[0018] As shown in Fig. 5, the control device 28 includes a controller 100 and a plurality of drive circuits 102. The plurality of drive circuits 102 are connected to the electromagnetic motors 36, 70, 78, 92, the board lifting device 32, the adjustment device 56, the suction device 74, the spray device 76, the squeegee lifting device 86, and the solder supply device 26. The controller 100 includes a CPU, a ROM, a RAM, and the like, and is mainly a computer, and is connected to the plurality of drive circuits 102. As a result, the operation of the conveying device 20, the squeegee device 24, and the like is controlled by the controller 100. The controller 100 is also connected to an information processing device 110. The information processing device 110 is used to calculate the moving speed of the squeegees 82 and 84, that is, the printing speed, as will be described in detail later.

[0019] In the printer 10, with the above-mentioned configuration, the circuit board 38 is transported to a predetermined position and is raised by the board lifting device 32 so that it comes into close contact with the lower surface of the mask 50 held by the mask holding device 22. The mask 50 has through holes (not shown) formed in accordance with the pattern of the pads, etc., of the circuit board 38. Then, cream solder is applied to the mask 50, so that the cream solder is printed on the circuit board 38 through the through holes in the mask 50.

[0020] Specifically, the circuit board 38 is carried into the printer 10 by the conveyor device 30 and transported to a predetermined position. At this time, the slider 68 of the cleaning device 23 is retracted from above the board lifting device 32. Then, the circuit board 38 is lifted by the operation of the board lifting device 32. As a result, the circuit board 38 is in close contact with the lower surface of the mask 50. Next, the solder supply device 26 supplies cream solder to the upper surface of the mask 50. Next, one of the pair of squeegees 82, 84 is lowered by the squeegee lifting device 86, and the tip of the lowered squeegee contacts the upper surface of the mask 50. Then, the squeegee is moved in the Y direction by the squeegee moving device 80, and the cream solder is scraped off by the squeegee. At this time, the cream solder is filled inside the through holes of the mask 50 and printed on the circuit board 38. Next, when the solder paste is printed on the circuit board 38, the circuit board 38 is lowered by the operation of the board lifting device 32. As a result, the circuit board 38 on which the solder paste is printed is separated from the mask 50. In other words, a so-called plate-detaching operation of the circuit board 38 is performed. Then, when the circuit board 38 is lowered and placed on the conveyor belt 34 of the conveyor device 30, the conveyor device 30 is operated to carry it out of the printer 10. This completes the printing operation on one circuit board 38.

[0021] In addition, in the printer 10, the mask 50 is cleaned every time the cream solder is printed on a predetermined number of circuit boards 38. In detail, when the printing work of the cream solder on the predetermined number of circuit boards 38 is completed, the slider 68 of the cleaning device 23 moves below the opening of the mask support base 52. Then, the cleaning head 73 in the cleaning mechanism 62 of the cleaning device 23 rises to the cleaning position. As a result, the cleaning sheet 77 stretched between the pair of winding shafts 71, 72 is lifted by the cleaning head 73, enters the opening of the mask support base 52, and comes into contact with the lower surface of the mask 50. Then, the slider 68 of the cleaning device 23 slides in the Y direction, and the lower surface of the mask 50 is wiped by the cleaning sheet 77 in contact with the lower surface. As a result, the lower surface of the mask 50 is cleaned.

[0022] The cleaning of the mask 50 includes dry wiping cleaning, cleaning using a solvent (hereinafter referred to as "wet cleaning"), and cleaning using the suction device 74 (hereinafter referred to as "suction cleaning"), and any of these multiple types of cleaning can be performed. In detail, the dry wiping cleaning is a cleaning performed in the above-mentioned procedure, and the lower surface of the mask 50 is wiped with the cleaning sheet 77 in a dry state. In addition, in the wet cleaning, before the cleaning head 73 is raised, the spray device 76 sprays the solvent onto the cleaning sheet 77. Then, as the cleaning head 73 is raised, the cleaning sheet 77 soaked with the solvent comes into close contact with the lower surface of the mask 50, and as the slider 68 slides, the lower surface of the mask 50 is wiped with the cleaning sheet 77 soaked with the solvent. In addition, in the suction cleaning, the suction device 74 is operated before the cleaning head 73 is raised, or after the cleaning head 73 is raised and comes into close contact with the lower surface of the mask 50. As the slider 68 slides, the underside of the mask 50 is wiped by the cleaning sheet 77. At this time, air is sucked from the upper surface of the cleaning head 73, so that the air is sucked from the underside of the mask 50 through the cleaning sheet 77 that is in close contact with the underside of the mask 50. Air is sucked in. As a result, while the underside of the mask 50 is being sucked, the underside of the mask is wiped with the cleaning sheet 77. Note that in suction cleaning, no solvent is sprayed onto the cleaning sheet 77, and the underside of the mask 50 is wiped with the cleaning sheet 77 in a dry state.

[0023] In this way, in the printer 10, the cream solder is printed on the circuit board by the squeegees 82 and 84, and the mask 50 is cleaned every time the cream solder is printed on a predetermined number of circuit boards 38. For this reason, it is necessary to set the printing conditions of the cream solder and the cleaning conditions of the mask. Here, the printing conditions of the cream solder include a number of conditions such as the moving speed of the squeegee, the angle of the squeegee, the printing pressure of the squeegee, and the speed at which the circuit board is separated from the mask after the cream solder is printed (the plate separation speed), but these multiple conditions are not independent of each other but are related to each other. In other words, for example, if the printing speed is changed without also changing the printing pressure, there is a risk that the cream solder will remain unscraped on the mask, and the printing quality of the cream solder on the circuit board will deteriorate. For this reason, in the conventional method, an expert sets the printing conditions based on the transferred amount and shape of the cream solder, the inspection results of the printed state of the cream solder, and the like. In this case, as described above, since multiple conditions such as printing speed and printing pressure are related to each other, an expert adjusts the multiple conditions such as printing speed and printing pressure relatively based on the amount and shape of transferred solder paste, and the inspection results of the printed state of the solder paste. However, in order to check the printing conditions adjusted by the expert in this way, the solder paste is printed on the circuit board according to those printing conditions as a preliminary step. If the printing conditions are not appropriate and the print quality is poor, the circuit board is discarded, which increases production costs. In addition, only an expert can relatively adjust multiple conditions such as printing speed and printing pressure, which creates problems such as securing and training experts.

[0024] For this reason, for example, a method of statistically analyzing the printing results to estimate the printing conditions is conceivable, but it takes a huge amount of time to obtain the printing results required for the analysis. Also, for example, a method of printing cream solder on multiple circuit boards according to multiple printing conditions and estimating the optimal printing conditions from the inspection results is conceivable. However, since it is necessary to actually print cream solder on the circuit boards, many circuit boards will be wasted. Also, for example, if the printing speed is limited to three types, low speed, standard speed, and high speed, and the printing pressure is limited to three types, low pressure, standard pressure, and high pressure, and the printing process on the circuit boards is performed by combining these printing conditions, it does not take much time to analyze the printing results and the number of wasted circuit boards can be reduced. However, if the setting conditions such as the printing speed are limited to about three types in this way, an experienced person will ultimately be required to fine-tune the setting conditions. In view of this, the cycle time, the size of the circuit board, the squeegee angle, the type of squeegee, and the mask cleaning settings are simply input into the information processing device 110, and the information processing device 110 calculates the optimal printing conditions such as the printing speed and printing pressure.

[0025] In detail, the slower the printing speed, the more the cream solder can be suitably filled into the through holes of the mask 50, and therefore, as shown in FIG. 6, the slower the printing speed, the better the printing quality of the cream solder on the circuit board. For this reason, a slower printing speed is preferable when considering the printing quality. However, when considering the cycle time, a faster printing speed is preferable. Therefore, when the cycle time is set in advance, it is preferable to set the slowest printing speed within a range that satisfies the set cycle time. Also, the higher the printing pressure, the more cleanly the cream solder can be scraped off, and therefore, as shown in FIG. 7, the higher the printing pressure, the better the printing quality of the cream solder on the circuit board. For this reason, a high printing pressure is preferable when considering the printing quality. However, when the cream solder printing process is performed with a high printing pressure, the load on the mask 50 increases and the mask 50 is easily damaged, so in consideration of this, a low printing pressure is preferable. Therefore, it is preferable to set the lowest printing pressure that can scrape off the cream solder. In other words, by setting the lowest printing pressure that can scrape off the cream solder, the printing quality is compromised to some extent, while the slowest printing speed within a range that satisfies the cycle time is set. Setting the print speed improves and ensures print quality. Therefore, the lowest printing pressure at which the solder paste can be scraped off is proportional to the print speed, as shown in Figure 8. In other words, the relationship between the lowest printing pressure F at which the solder paste can be scraped off and the print speed v is expressed by the following linear equation. F=αv+β

[0026] In addition, the smaller the squeegee angle, the more the cream solder can be pressed downward, and therefore, as shown in FIG. 9, the smaller the squeegee angle, the better the printing quality of the cream solder on the circuit board. However, the squeegee angle is a fixed value depending on the printing machine, and is generally considered to be around 60 degrees. However, the squeegee angle affects the slope (α) and intercept (β) in the linear equation showing the relationship between the printing pressure F and the printing speed v described above. For this reason, the slope (α) and intercept (β) according to a predetermined squeegee angle are set in advance through experiments. Note that the slope (α) and intercept (β) change not only depending on the squeegee angle but also depending on the type of squeegee, for example, a metal squeegee or a urethane squeegee, so the slope (α) and intercept (β) are set in advance through experiments according to not only the squeegee angle but also the type of squeegee. This allows the printing pressure F and the printing speed v to be set according to the squeegee angle and the type of squeegee.

[0027] Furthermore, the faster the stencil removal speed, the more the circuit board can be removed from the mask while preventing the cream solder printed on the circuit board from losing its shape, and therefore the faster the stencil removal speed, the better the print quality, as shown in Fig. 10. For this reason, a fast stencil removal speed is preferable when print quality is taken into consideration. Also, a fast stencil removal speed is preferable when cycle time is taken into consideration. For this reason, the stencil removal speed is set to a value close to the fastest within the operable range of the board lifting device 32, which operates when removing the circuit board from the mask.

[0028] On the premise of the above, the information processing device 110 calculates the optimal printing conditions such as printing speed and printing pressure. The process of calculating the optimal printing conditions such as printing speed and printing pressure in the information processing device 110 will be described in detail below with reference to the flowchart shown in FIG. 11. First, the cycle time T, the size y of the circuit board, the squeegee angle θ, the type of squeegee, and the mask cleaning setting are input to the information processing device 110 (S10). The cycle time T is the time required to perform the printing process of the cream solder on one circuit board, and is the time from when the circuit board is carried into the printer to when it is carried out from the printer. The size y of the circuit board is the length dimension of the circuit board in the Y direction. The squeegee angle θ is selected from among 50°, 55°, 60°, and 65°, and the type of squeegee is selected from among metal and urethane. The cleaning settings are set to the presence or absence of suction, the presence or absence of solvent, and whether or not to save cleaning paper.

[0029] Then, when the input of the cycle time T, the size y of the circuit board, the squeegee angle θ, the type of squeegee, and the cleaning settings of the mask is completed, the cleaning time tc is calculated based on the cleaning settings, etc. (S12). In detail, when the cleaning settings are set to no suction and no solvent, the dry wipe cleaning is performed for a distance y' corresponding to the size y of the circuit board. That is, the cleaning mechanism 62 moves in one direction in the Y direction by a distance y' corresponding to the size y of the circuit board with the dry cleaning sheet 77 in contact with the lower surface of the mask. Note that, when the cleaning mechanism 62 moves in the Y direction with the cleaning sheet 77 in contact with the lower surface of the mask, it is necessary to move a distance y' obtained by adding a distance equivalent to the dimension A of the cleaning mechanism 62 in the Y direction to the size y of the circuit board 38, as shown in FIG. 12. For this reason, the distance y' corresponding to the size y of the circuit board is calculated according to the following formula. y'=y+A

[0030] In this way, when the distance y' corresponding to the size y of the circuit board is calculated, the cleaning time tc when no suction and no solvent are set is calculated according to the following formula: tc=(y' / vc)+cleaning time The moving speed of the cleaning mechanism 62, that is, the cleaning speed vc, is set in advance. The cleaning-related time is the total time required for operations required for cleaning, such as the time to move the cleaning mechanism 62 to the cleaning start position, the time to move the cleaning mechanism 62 to the retreat position after cleaning is completed, the time to raise and lower the cleaning head 73, the time to apply the solvent, and the time to take up the cleaning sheet 77.

[0031] In addition, when the cleaning settings are set to "no suction" and "with solvent", dry wiping cleaning is performed on the outward path for a distance y' corresponding to the size y of the circuit board, and then wet cleaning is performed on the return path for a distance y' corresponding to the size y of the circuit board. That is, first, the cleaning mechanism 62 moves in one direction in the Y direction for a distance y' corresponding to the size y of the circuit board with the cleaning sheet 77 in a dry state in contact with the lower surface of the mask. Then, after that, the cleaning mechanism 62 moves in the other direction in the Y direction for a distance y' corresponding to the size y of the circuit board with the cleaning sheet 77 soaked in the solvent in contact with the lower surface of the mask. Therefore, when the cleaning settings are set to "no suction" and "with solvent", the cleaning mechanism 62 moves back and forth for a distance y' corresponding to the size y of the circuit board. In addition, when the cleaning settings are set to "with suction" and "without solvent", suction cleaning is performed on the outward path for a distance y' corresponding to the size y of the circuit board, and then dry wiping cleaning is performed on the return path for a distance y' corresponding to the size y of the circuit board. That is, first, the cleaning sheet 77 in a dry state comes into contact with the lower surface of the mask, and the cleaning mechanism 62 moves in one direction in the Y direction by a distance y' corresponding to the size y of the circuit board while the suction device 74 is operating. Then, after that, the cleaning mechanism 62 moves in the other direction in the Y direction by a distance y' corresponding to the size y of the circuit board while the cleaning sheet 77 in a dry state comes into contact with the lower surface of the mask. Therefore, even when the cleaning settings are set to have suction and no solvent, the cleaning mechanism 62 moves back and forth by a distance y' corresponding to the size y of the circuit board. Therefore, when the settings are set to have no suction and have solvent, and when the settings are set to have suction and have no solvent, the cleaning time tc is calculated according to the following formula. tc = (2y' / vc) + cleaning time

[0032] In addition, when the cleaning settings are set to include suction and solvent, suction cleaning is performed on the forward path for a distance y' corresponding to the size y of the circuit board, wet cleaning is performed on the return path for a distance y' corresponding to the size y of the circuit board, and then dry wiping cleaning is performed on the forward path for a distance y' corresponding to the size y of the circuit board. That is, first, the cleaning sheet 77 in a dry state contacts the lower surface of the mask, and the cleaning mechanism 62 moves in one direction in the Y direction for a distance y' corresponding to the size y of the circuit board while the suction device 74 is activated. Then, after that, the cleaning mechanism 62 moves in the other direction in the Y direction for a distance y' corresponding to the size y of the circuit board while the cleaning sheet 77 soaked in the solvent contacts the lower surface of the mask. Furthermore, after that, the cleaning mechanism 62 moves in one direction in the Y direction for a distance y' corresponding to the size y of the circuit board while the cleaning sheet 77 in a dry state contacts the lower surface of the mask. Therefore, when the cleaning settings are set to include suction and solvent, the cleaning mechanism 62 moves one and a half times back and forth for a distance y' corresponding to the size y of the circuit board. Therefore, when suction and solvent are set, the cleaning time tc is calculated according to the following formula. tc = (3y' / vc) + cleaning time

[0033] Next, once the cleaning time tc has been calculated, the time required for printing the cream solder on the circuit board with the squeegee (hereinafter referred to as the "squeegeeing time") t is calculated according to the following formula (S14). t=T-(tc / N)-th-ts Here, the cycle time T is input in S10, and the cleaning time tc is calculated in S12. th is the time required for the stencil removal operation (hereinafter referred to as the "stencil removal time"), that is, the time required to remove the circuit board from the mask. As described above, the stencil removal speed is set to a value close to the fastest value within the operable range of the board lifting device 32 that operates when removing the circuit board from the mask. The distance by which the circuit board descends during the stencil removal operation (hereinafter referred to as the "stencil removal distance") and the acceleration at which the circuit board descends (hereinafter referred to as the "stencil removal acceleration") are also set in advance. For this reason, the stencil removal time is calculated based on the stencil removal speed, the stencil removal distance, and the stencil removal acceleration. ts is the time obtained by adding the time required to carry the circuit board into the printer 10, transport it to the work position, and carry it out of the printer 10 from the work position, the time required to lift the circuit board, and the time required to eject the cream solder onto the upper surface of the mask. Since these times can be measured or estimated in advance, the time ts obtained by adding them is set in advance. Furthermore, N is the interval at which the mask is cleaned, that is, the cleaning interval at which the mask is cleaned every time the viscous material is printed on N substrates, and once this cleaning interval N is determined, the squeegee time t can be calculated according to the above formula. Therefore, the cleaning interval N is set to 10 natural numbers from 1 to 10, and the squeegee time t is calculated according to the above formula according to each of the 10 cleaning intervals N. That is, 10 squeegee times t are calculated, including the squeegee time t (N=1) when the cleaning interval N is 1, the squeegee time t (N=2) when the cleaning interval N is 2, the squeegee time t (N=9) when the cleaning interval N is 9, and the squeegee time t (N=10) when the cleaning interval N is 10.

[0034] In this way, when the squeegee time t is calculated according to each of the 10 cleaning intervals N from 1 to 10, the printing speed v is calculated according to the following formula based on each squeegee time t (S16). v=[(t / 2)-{(t4 / 4)-(s / a)}1 / 2]a Here, the squeegee time t is calculated in S14 according to each of the 10 cleaning intervals N. s is the distance when the cream solder is printed on the circuit board by the squeegee, that is, the printing stroke, and is a value obtained by adding the run-up distance α to the size y of the circuit board. The run-up distance α is preset. a is the acceleration of the squeegee when the cream solder is printed on the circuit board by the squeegee, and is preset. Therefore, 10 printing speeds v are calculated according to the squeegee time t calculated according to each of the 10 cleaning intervals N. That is, 10 printing speeds v are calculated, including the printing speed v (N=1) when the cleaning interval N is 1, the printing speed v (N=2) when the cleaning interval N is 2, the printing speed v (N=9) when the cleaning interval N is 9, and the printing speed v (N=10) when the cleaning interval N is 10.

[0035] Next, when the printing speed v is calculated according to each of the 10 cleaning intervals N from 1 to 10, the printing pressure F is calculated based on each printing speed v in accordance with the following formula (S18). F=αv+β Here, the slope (α) and intercept (β) are preset according to the squeegee angle θ and the type of squeegee, as described above. Therefore, the slope (α) and intercept (β) are specified based on the squeegee angle θ and the type of squeegee input in S10. Then, according to the above formula of the specified slope (α) and intercept (β), 10 cleaning intervals from 1 to 10 are set. A printing pressure F is calculated according to each of the cleaning intervals N. That is, ten printing pressures F are calculated: printing pressure F (N=1) when the cleaning interval N is 1, printing pressure F (N=2) when the cleaning interval N is 2, printing pressure F (N=9) when the cleaning interval N is 9, and printing pressure F (N=10) when the cleaning interval N is 10.

[0036] Next, when the printing pressure F is calculated according to each of the 10 cleaning intervals N from 1 to 10, it is determined whether or not cleaning paper is saved in the cleaning settings input in S10 (S20). Then, if a cleaning setting indicating that cleaning paper is not saved is input (S20: NO), a printing speed v with the smallest cleaning interval N among the printing speeds operable in the printing press 10 is selected (S22). Here, the fastest printing speed vMAX of the squeegee in the printing press 10 is set in advance. Therefore, a printing speed equal to or lower than the fastest printing speed vMAX is specified from the 10 printing speeds v calculated in S16. As a result, a printing speed operable in the printing press 10 is specified. Then, a printing speed v with the smallest cleaning interval N among the specified printing speeds is selected. Specifically, for example, if print speed v(N=3), print speed v(N=4),...print speed v(N=9), and print speed v(N=10) are identified as operable print speeds, the print speed with the smallest cleaning interval N among those print speeds, that is, print speed v(N=3), is selected.

[0037] Also, when a cleaning setting for saving cleaning paper is input (S20: YES), the printing speed v with the largest cleaning interval N that is equal to or smaller than the set limit value among the printing speeds that can be operated by the printing machine 10 is selected (S24). Here, the set limit value is set for each squeegee angle θ. Specifically, for example, the set limit value is set to 2 for the squeegee angle θ (50°), and the set limit value is also set to 2 for the squeegee angle θ (55°). The set limit value is set to 4 for the squeegee angle θ (60°), and the set limit value is set to 6 for the squeegee angle θ (65°). Then, a printing speed equal to or smaller than the fastest printing speed vMAX is identified from the 10 printing speeds v calculated in S16. This identifies the printing speeds that can be operated by the printing machine 10. Then, the printing speed v with the largest cleaning interval N that is equal to or smaller than the set limit value among the printing speeds that can be operated by the printing machine 10 is selected. Specifically, for example, when print speed v(N=3), print speed v(N=4), print speed v(N=9), and print speed v(N=10) are specified as the operable print speeds, and the squeegee angle θ is 60°, the cleaning interval N that is equal to or less than the set limit value 4 is 3 or 4, so print speed v(N=4) is selected. Also, for example, when print speed v(N=3), print speed v(N=4), print speed v(N=9), and print speed v(N=10) are specified as the operable print speeds, and the squeegee angle θ is 50°, there is no cleaning interval N that is equal to or less than the set limit value 2. In such a case, an error screen is displayed on the display device (not shown). This is because the cycle time T input in S10 is too short, and the print speed calculated according to that cycle time T is too fast, so that the cleaning interval according to the operable print speed exceeds the set limit value. Therefore, a comment is displayed on the error screen to inform the operator that the input cycle time T is short and that a cycle time T longer than the input cycle time T should be re-input. When the error screen is displayed, the process returns to S10, and the operator re-inputs the cycle time T, etc. This causes the process from S10 onwards to be executed again.

[0038] Then, when a printing speed v is selected in S22 or S24, the selected printing speed v, the cleaning interval N corresponding to the printing speed v, the printing pressure F corresponding to the printing speed v, the plate release setting, and the cleaning operation are output from the information processing device 110 to the controller 100. The plate release setting is the plate release speed, plate release distance, and plate release acceleration used when calculating the plate release time th in S14. Also, the cleaning operation is selected from dry wiping cleaning, wet cleaning, and suction cleaning according to the cleaning setting input in S10. Then, when the controller 100 receives the printing speed v, cleaning interval N, printing pressure F, plate release setting, and cleaning operation, it executes the cream solder printing process and mask cleaning based on the received printing speed v, cleaning interval N, printing pressure F, plate release setting, and cleaning operation.

[0039] In this way, by simply inputting the cycle time T, substrate size y, squeegee angle θ, squeegee type, and cleaning settings into the information processing device 110, the optimal printing speed, printing pressure, and other printing conditions, as well as cleaning intervals according to whether or not cleaning paper should be saved, are automatically calculated. This makes it possible to solve the above-mentioned problems of securing and training skilled personnel and increasing production costs.

[0040] In the above embodiment, the circuit board 38 is an example of a board. The mask 50 is an example of a mask. The squeegees 82 and 84 are an example of a squeegee. The information processing device 110 is an example of a computing device. The cream solder is an example of a viscous material. The maximum printing speed vMAX is an example of an allowable limit speed.

[0041] The present invention is not limited to the above embodiment, and can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. Specifically, for example, in the above embodiment, the plate detachment speed is set to a value close to the fastest value within the operable range of the substrate lifting device 32, but depending on the type of viscous material, etc., if the plate detachment speed is too fast, the quality may deteriorate, so the speed can be set to any value depending on the type of viscous material, etc.

[0042] In the above embodiment, if the cycle time T input to the information processing device 110 is too short, an error screen is displayed to prompt the user to re-input the cycle time T, but a range of cycle times that can be input may be set on the input screen for the cycle time T. This makes it possible to prevent an extremely short cycle time T from being input.

[0043] Also, in the above embodiment, for example, when the cleaning mechanism 62 performs dry wiping cleaning and wet cleaning, the dry wiping cleaning is performed on the outbound path, and then the wet cleaning is performed on the return path. On the other hand, the cleaning mechanism 62 may only move while performing the cleaning operation on the outbound path, and the return path may simply move without the cleaning operation. That is, for example, the cleaning mechanism 62 moves from the front to the back of the printing press 10 while performing dry wiping cleaning (outbound path). Next, the cleaning mechanism 62 leaves the mask and moves from the back to the front of the printing press 10 (return path) (movement without cleaning operation). Next, the cleaning mechanism 62 moves from the front to the back of the printing press 10 while performing wet cleaning (outbound path). The cleaning time tc at that time is calculated according to the following formula. tc = (2y' / vc) + (y' / vi) + cleaning time It should be noted that vi is the moving speed of the cleaning mechanism 62 when only moving without performing a cleaning operation, that is, the moving speed of the cleaning mechanism 62 on the return path.

[0044] In addition, in the above embodiment, the printing speed v, printing pressure F, etc. are calculated in the information processing device 110, but the printing speed v, printing pressure F, etc. may be calculated in the controller 100. In other words, the controller 100 may function as the calculation device of the present invention.

[0045] Furthermore, in the above embodiment, cream solder is used as the viscous material, but various viscous materials can be used as long as they can be printed on the circuit board by a squeegee. [Explanation of symbols]

[0046] 38: Circuit board (substrate) 50: Mask 82: Squeegee 84: Squeegee 110: Information processing device (arithmetic device)

Claims

1. A calculation device that calculates the printing pressure of the squeegee based on a cycle time, which is the time required to perform a printing process of a viscous material on one substrate, and a substrate size, which is the length dimension of the substrate in the direction of movement of the squeegee that prints the viscous material on the substrate through a through hole in a mask during the printing process.

2. 2. The computing device according to claim 1, wherein the printing speed of the squeegee is calculated based on the cycle time and the board size, and the printing pressure of the squeegee is calculated based on the calculated printing speed.

3. 3. The calculation device according to claim 2, wherein the printing pressure of the squeegee is calculated based on the printing speed by using a linear equation that expresses that the printing pressure of the squeegee is proportional to the printing speed.

4. The calculation device according to claim 3 , wherein the linear expression has a slope and an intercept that are set in accordance with a squeegee angle.

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