JP2016072462A - Component suction head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely suck a component while shortening a cycle time of component suction in a component suction head in which vacuum suction of the component is performed by a nozzle.SOLUTION: A component suction head includes: a vertically movable nozzle 32 for sucking and picking up a component from a component supply part; vertical moving means for vertically moving the nozzle 32; negative pressure supply means which supplies a negative pressure for sucking the component by the nozzle 32; a landing detection sensor for detecting that the nozzle lands on the component when moving the nozzle 32 downward for sucking the component; and control means for controlling the vertical moving means and the negative pressure supply means. The control means stores landing timing when the landing timing detection sensor detects that the nozzle 32 lands on a component P1 in first component suction, and sets timing for starting operation of the negative pressure supply means on the basis of the landing timing in next component suction.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a component suction head that is suitably used in a surface mounter that mounts a component (electronic component) such as an IC chip on a substrate.

  In general, a surface mounter moves a component suction head above a component supply unit, and causes a nozzle provided in the component suction head to move down and ascend, thereby vacuum-sucking the component to the lower end of the nozzle. Then, the component suction head is moved above the substrate, and the nozzle is lowered and raised again to mount the component at a predetermined coordinate position on the substrate.

  In such a component suction head, the vacuum suction of the component by the nozzle is realized by supplying a negative pressure to the nozzle, specifically, the operation of the negative pressure supply means. However, even if the negative pressure supply means starts its operation (operation to supply negative pressure to the nozzle) by switching the valve or the like, it can supply a predetermined negative pressure (for example, about 85 kPa) necessary for component suction. It takes a certain amount of time (for example, about 18 ms, hereinafter referred to as “negative pressure preparation time”). Therefore, when the operation of the negative pressure supply means is started when the nozzle has landed (touched) on the component, it is necessary to wait for the negative pressure preparation time, resulting in an increase in tact time.

  Therefore, Patent Document 1 proposes a technique for starting the operation of the negative pressure supply means at a timing earlier than the timing at which the nozzle is positioned at an appropriate position for component suction by an amount corresponding to the aforementioned negative pressure preparation time. . That is, Patent Document 1 intends to shorten the tact time corresponding to the negative pressure preparation time by controlling the start of operation of the negative pressure supply means.

  However, in Patent Document 1, the operation start timing of the negative pressure supply means is set with reference to the timing at which the nozzle is positioned at an appropriate position for component suction. In other words, the timing at which the nozzle is positioned at an appropriate position for picking up the component is a calculation timing at which the nozzle lands on the component, and there may be a deviation from the timing at which the nozzle actually lands on the component. For example, if the actual upper surface height of the component in the component supply unit is different from the calculated set value, there is a difference between the calculated landing timing and the actual landing timing.

  In addition, in order to obtain the calculation landing timing, it is necessary to input various design values such as the height of the top surface of the part design. Since human input is involved in the input, input errors based on human errors are required. Can happen. In this case, of course, there is a difference between the calculated landing timing and the actual landing timing.

  In the above-mentioned Patent Document 1, if there is a difference between the calculated landing timing and the actual landing timing, there is a possibility that troubles such as component adsorption mistakes may occur. In other words, if the calculated landing timing is later than the actual landing timing, the nozzle will land on the component before the negative pressure preparation time elapses, so that a suction error may occur due to insufficient suction power. When the negative pressure preparation time has elapsed after landing, the tact time increases. On the other hand, if the calculated landing timing is earlier than the actual landing timing, the suction force acts before the nozzles land on the component, so that there is a possibility that the component is mistakenly sucked before landing, resulting in a suction error.

JP-A-8-298395

  SUMMARY OF THE INVENTION The problem to be solved by the present invention is to make it possible to reliably suck a component while shortening the tuck time of the component suction in a component suction head that vacuum-sucks the component with a nozzle.

  According to one aspect of the present invention, a vertically movable nozzle that picks up and picks up a component from a component supply unit, a lifting and lowering unit that lifts and lowers the nozzle, and a negative pressure that causes the nozzle to suck a component. A pressure supply unit; a landing detection sensor that detects that the nozzle has landed on the component when the nozzle is lowered to adsorb the component; and a control unit that controls the lift unit and the negative pressure supply unit. The component suction head, wherein the control means stores the landing timing at which the landing detection sensor detects that the nozzle has landed on the component at the time of the first component suction, and at the time of the next component suction, at the landing timing. There is provided a component suction head for setting the operation start timing of the negative pressure supply means.

  As described above, in the present invention, the operation start timing of the negative pressure supply means is set based on the actually measured landing timing detected by the landing detection sensor at the time of the first component suction, so that the tact time of component suction can be shortened and reliably Can absorb parts.

  In the present invention, the operation start timing of the negative pressure supply means is until the negative pressure supply means can supply a predetermined negative pressure after the operation starts with respect to the landing timing (actually measured landing timing). It is preferable to set the timing earlier by an amount equivalent to the time (corresponding to the negative pressure preparation time). By setting in this way, the tact time of component adsorption can be shortened most. Note that the above-described portion corresponding to the negative pressure preparation time is not a strict one but includes a concept that can be said to be substantially equivalent to the negative pressure preparation time.

  In the present invention, the control means can set a lowering profile of the nozzle by the elevating means based on the landing timing (actually measured landing timing). Thus, by setting the nozzle descending profile based on the actually measured landing timing, it is possible to set an optimum descending profile toward the nozzle landing, which contributes to a reduction in tact time. The descending profile can be set so that the nozzle stops based on the actually measured landing timing. Here, stopping the nozzle based on the landing timing includes not only stopping the nozzle at the time of landing timing but also including stopping after a predetermined time from the landing timing in order to secure a predetermined pushing amount. It is.

In the present invention, the landing timing measured at the time of the first component pick-up can be used continuously at the next component pick-up, but the actual landing timing changes with the passage of time or when the component supply unit changes. There are things to do. Therefore, it is preferable to update the actually measured landing timing at an appropriate timing. Specifically, the landing timing is actually measured and updated at the following timing (1), (2) or (3), and after the update, the operation of the negative pressure supply means is started using the updated landing timing. It is preferable to set the timing and the lowering profile of the nozzle.
(1) At the time of picking up a component every time or at the time of picking up a component every predetermined number of times (2) When there is a change in the component supply unit (for example, at the time of picking up a component immediately after the change)
(3) When the nozzle does not land on the component at the currently applied landing timing (for example, at the time of component adsorption immediately after that)

  Among these, from the viewpoint of improving the certainty of each part suction, it is most preferable to measure and update the landing timing at each part suction.

  As described above, according to the present invention, in a component suction head that vacuum-sucks a component with a nozzle, it is possible to reliably suck the component while shortening the tact time of component suction.

It is a perspective view which shows the whole structure of the component adsorption | suction head by the Example of this invention. FIG. 2 is an explanatory view showing a mechanism for lowering a spindle (nozzle) in a Z direction in the component suction head of FIG. 1. It is explanatory drawing which shows the structure around a pressing tool in the mechanism which descend | falls the spindle (nozzle) of FIG. 2 to a Z direction. FIG. 2 shows a state in which the spindle (nozzle) is lowered by the pressing tool shown in FIG. 2, (a) shows a state in which the spindle (nozzle) is in an initial position, and (b) shows a state in which the spindle (nozzle) is lowered. Indicates. It is a perspective view which expands and shows the cross section of the nozzle part with which the lower end of the spindle was mounted | worn. It is a figure which shows typically the change of the light reception amount of an optical fiber sensor when a nozzle lands. The example of control of Z servo motor by a control part (control means) is shown. It is a figure which shows notionally an example of a negative pressure supply means. FIG. 3 is an explanatory diagram conceptually showing the operation of a nozzle when picking up a component according to an embodiment of the present invention, where (a) shows the first component picking, (b) shows the second component picking, and (c) shows the third time. The operation of the nozzle at the time of component adsorption is shown.

  Hereinafter, embodiments of the present invention will be described with reference to examples in which the component suction head of the present invention is applied to a surface mounter.

  FIG. 1 is a perspective view showing the overall configuration of a component suction head according to an embodiment of the present invention.

  A component suction head 10 shown in the figure is a rotary head type component suction head, and a rotary head 30 is attached to a fixedly arranged head body 20 so as to be rotatable in the R direction around a vertical axis. A plurality of spindles 31 are arranged at equal intervals along the circumferential direction of the rotary head 30, and a nozzle 32 that sucks and holds components is attached to the lower end of each spindle 31.

  The rotary head 30 rotates in the R direction by driving an R servo motor 21 installed in the head body 20. Each spindle 31 rotates in the T direction around its axis by driving a T servo motor 22 installed in the head body 20. Further, the head main body 20 is provided with a Z servo motor 23 for raising and lowering the spindle 31a at a specific position in the Z direction along the axial direction. Since a mechanism for rotating the rotary head 30 in the R direction by driving the R servo motor 21 and a mechanism for rotating the respective spindles 31 in the T direction by driving the T servo motor 22 are well known, description thereof will be omitted. A mechanism for lowering the spindle 31a by driving the Z servo motor 23 will be described below.

  FIG. 2 is an explanatory view showing a mechanism for raising and lowering the spindle 31a in the Z direction in the component suction head 10 of FIG. A motor shaft of the Z servo motor 23 arranged in the head body 20 is connected to a screw shaft 24a of a ball screw mechanism 24, and a nut 24b is attached to the screw shaft 24a. And the pressing tool 25 is connected with this nut 24b. Therefore, the drive of the Z servo motor 23 moves the pressing tool 25 in the Z direction together with the nut 24b.

  Only one pressing tool 25 is provided on the head body 20 side. When the spindle 31 is lowered, the spindle 31 to be lowered (spindle 31a at the specific position) is selected by moving the spindle 31 relative to the pressing tool 25, and the spindle is lowered by lowering the pressing tool 25. 31a is lowered. In this embodiment, as shown in FIG. 3, the spindle 31 is moved with respect to the pressing tool 25 by rotating the rotary head 30 in the R direction, and the spindle 31a immediately below the pressing tool 25 is lowered. However, the configuration in which the spindle 31a at the specific position is selected and lowered is not limited to this, and the spindle to be lowered by moving the pressing tool may be selected. Further, there may be two or more specific positions.

  Returning to FIG. 2, the optical fiber sensor 40 is connected to the nut 24 b to which the pressing tool 25 is connected via a connection bar 26 and a spline nut 28 fixed to a spline shaft 27 fixedly provided on the head body 20. Are connected. That is, the optical fiber sensor 40 is provided integrally with the pressing tool 25. Therefore, when the pressing tool 25 moves in the Z direction by driving the Z servo motor 23, the optical fiber sensor 40 moves in the Z direction in conjunction with this. This is shown in FIG. 4A shows a state where the spindle 31a is in the initial position, and FIG. 4B shows a state where the spindle 31a is lowered by the pressing tool 25 shown in FIG. The spindle 31 is always urged toward the upper initial position by an elastic body 33 (see FIG. 2) composed of two coil springs.

  The optical fiber sensor 40 has a light emitting part and a light receiving part incorporated on the same axis together with an optical fiber and a lens, and its configuration itself is well known. In this embodiment, as shown in FIG. 2, the optical fiber sensor 40 is disposed obliquely above the nozzle 32 mounted on the lower end of the spindle 31 via a coil spring 34 (elastic body). And the light emission part of the optical fiber sensor 40 emits light P diagonally downward toward the reflective surface 32a of the outer peripheral upper surface of the nozzle 32 shown enlarged in FIG. The light P is received as reflected light by the light receiving portion of the optical fiber sensor 40.

  Here, as described above, the nozzle 32 is attached to the lower end of the spindle 31 via the coil spring 34. Therefore, when the nozzle 32 at the lower end of the spindle 31 is lowered due to the lowering of the spindle 31, the coil spring 34 is compressed, and the vertical position of the nozzle 32 with respect to the spindle 31 is changed. Specifically, the nozzle 32 moves relatively toward the lower end side of the spindle 31.

  On the other hand, the light P emitted from the light emitting portion of the optical fiber sensor 40 is focused on the reflecting surface 32a in the initial state where the nozzle 32 is not landed by the lens 40a shown in FIG. Therefore, when the nozzle 32 is landed and its vertical position is changed, the amount of reflected light reflected by the reflecting surface 32a is reduced, and the amount of light received by the light receiving portion of the optical fiber sensor 40 is reduced (FIG. 6). reference). In this embodiment, the decrease in the amount of received light is detected by the sensor unit 40b of the optical fiber sensor 40. The sensor unit 40b determines that the nozzle 32 has landed when the received light amount has decreased by a predetermined amount, for example, when the amount is less than or equal to the threshold A shown in FIG. 6, and issues a landing detection signal.

  In this specification, “nozzle landing” means that the lower end of the nozzle is landed on the upper surface of the component in the component adsorption (pickup) process, and the component held on the lower end of the nozzle in the component mounting process. Is a concept including both landing on the upper surface of the substrate.

  In the above configuration, the surface mounter having the component suction head 10 sucks and picks up a component from the component supply unit by the nozzle 32 attached to the lower end of the spindle 31 and transfers it onto the printed circuit board. Mount in place.

  At the time of component adsorption and mounting, as described with reference to FIG. 2, the pressing tool 25 presses the upper end surface of the spindle 31a positioned directly below the holding tool 25, and the spindle 31a is lowered in the Z direction. . Thereafter, when the nozzle 32 at the tip of the spindle 31a lands, the coil spring 34 is compressed and the vertical position of the nozzle 32 with respect to the spindle 31a is changed as described above, and the amount of light received by the light receiving portion of the optical fiber sensor 40 is changed. Decrease. And the sensor part 42 of the optical fiber sensor 40 emits a landing detection signal. This landing detection signal is transmitted to the control unit (control means) 50 shown in FIG. When receiving the landing detection signal, the control unit 50 stops the Z servo motor 23 that lowers the pressing tool 25. Thereby, the descending stroke of the nozzle 32 is appropriately controlled, and the nozzle 32 is accurately landed.

  FIG. 7 shows an example of control of the Z servo motor 23 by the control unit 50. FIG. 7 shows temporal changes in the lowering speed and lowering stroke of the nozzle 32 by driving the Z servo motor 23, that is, the lowering profile of the nozzle. The design value of the downward stroke is 8 mm.

  As shown in FIG. 7, the control unit 50 increases the descending speed at the beginning of the descending, and then gradually decreases the descending speed when the stroke reaches 3 mm (first height position), and further the stroke reaches 6.7 mm. When (second height position) is reached, the Z servo motor 23 is controlled so that the descending speed becomes constant. When the nozzle 32 lands and receives a landing detection signal from the optical fiber sensor 40, the control unit 50 stops the Z servo motor 23. FIG. 7 shows three patterns, that is, when the actual lowering stroke is 8 mm as designed until the nozzle 32 is landed, when it is larger than the designed value (8 mm) (9 mm), and when it is smaller (7 mm). In either case, however, the lowering stroke is appropriately controlled, and the nozzle 32 is accurately landed.

  Next, the operation of component adsorption according to the present invention will be described.

  In the present invention, the adsorption of the component is realized by supplying a negative pressure to the nozzle by the negative pressure supply means, and the mounting of the component is realized by supplying a positive pressure to the nozzle.

  FIG. 8 is a diagram conceptually illustrating an example of the negative pressure supply means. The negative pressure supply means 60 shown in the figure uses a spool valve, so that positive pressure supply can be performed in addition to negative pressure supply, and switching between negative pressure supply and positive pressure supply is possible. . That is, the negative pressure supply means 60 switches the negative pressure supply path 64a and the positive pressure supply path 64b by linearly moving the spool 63 by the rotation of the lever 62 connected to the rotation shaft 61 of the motor. Do. The negative pressure supply path 64a is connected to a negative pressure supply source such as a vacuum pump, and the positive pressure supply path 64b is connected to a positive pressure supply source such as a positive pressure air tank.

  FIG. 8A shows a state in which the nozzle is connected to the positive pressure supply path 64b, and a positive pressure is supplied to the nozzle. From this state, when the lever 62 is rotated to move the spool 63 upward as shown in FIGS. 8B and 8C, the nozzle is connected to the negative pressure supply path 64a, and the negative pressure is applied to the nozzle. Is supplied. Thereafter, the lever 62 is returned to the initial position as shown in FIG.

  Next, the operation of the nozzle during component suction according to the present invention will be described.

  FIG. 9 is an explanatory diagram conceptually showing the operation of the nozzle at the time of component suction according to the embodiment of the present invention. FIG. 6A shows the operation of the nozzle at the time of the first component suction, (b) at the second component suction, and (c) the nozzle operation at the third component suction.

  Since the timing at which the nozzle 32 lands on the component in the component supply unit 70 is unknown at the time of the first component suction, the following operation procedure is performed.

(1) The nozzle 32 is lowered until the landing of the nozzle 32 is detected by the optical fiber sensor 40 in accordance with a predetermined lowering profile as described with reference to FIG.

(2) When the landing of the nozzle 32 is detected by the optical fiber sensor 40, the control unit 50 stores the landing timing (for example, the height of the nozzle at the time of landing). This landing timing can be specified based on the encoder value of the Z servo motor 23, for example.

(3) In parallel with the above (2), the negative pressure supply operation of the negative pressure supply means 60 described with reference to FIG.

(4) Even if the negative pressure supply means 60 starts the negative pressure supply operation, the negative pressure preparation time t of about 18 ms is required as described above in order to be able to supply the predetermined negative pressure necessary for component suction. Therefore, the control unit 50 stands by in a state where the nozzle 32 remains on the component P1 until the negative pressure preparation time t has elapsed.

(5) When the negative pressure preparation time t has elapsed, the control unit 50 raises the nozzle 42. Thereby, the component P1 is picked up.

  The operation procedure at the time of the second part suction is as follows.

(1) The control unit 50 calculates and sets the negative pressure supply operation start timing of the negative pressure supply means 60 based on the actually measured landing timing stored at the time of the first component suction. Most preferably, the timing of starting the negative pressure supply operation is set to a timing earlier by the time corresponding to the negative pressure preparation time t than the actually measured landing timing, as shown in FIG. 9B.

(2) The nozzle 32 is lowered according to a predetermined lowering profile as in the case of the first component suction.

(3) When the negative pressure supply operation start timing set in (1) is reached, the negative pressure supply operation of the negative pressure supply means 60 is started.

(4) When the landing of the nozzle 32 is detected by the optical fiber sensor 40, the controller 50 stops the lowering of the nozzle 32. At this time, since the negative pressure preparation time t has elapsed, the nozzle 32 can immediately pick up the component P2. Further, the control unit 50 updates and stores the landing timing measured at the time of the second component suction from the one at the time of the first component suction.

(5) For the purpose of control, the control unit 50 raises the nozzle 32 after a specified time has elapsed since the landing of the nozzle 32 was detected. Thereby, the component P2 is picked up.

  At the time of the third component suction, the control unit 50 calculates and sets the negative pressure supply operation start timing of the negative pressure supply means 60 based on the landing timing updated at the second component suction. Thereafter, the operation procedure is the same as the second time, and this is repeated after the fourth time.

  As described above, in the present invention, the operation start timing of the negative pressure supply means 60 is set based on the actually measured landing timing detected by the optical fiber sensor 40, so that the component can be securely attached while reducing the tact time of component adsorption. Can be adsorbed.

  Further, in the present invention, the actually measured landing timing is obtained, and based on this, the descending profile of the nozzle 32 can be optimally set. For example, if the nozzle is set to stop based on the actually measured landing timing, the region where the descending speed is constant in the descending profile shown in FIG. 7 can be substantially eliminated, and the tact time can be further shortened.

  In the above-described embodiment, the landing timing is measured and updated every time the parts are picked up. However, the present invention is not limited to this, and the landing timing may be measured and updated every time the parts are picked up. Good. In addition, the update of the landing timing is particularly necessary when there is a change in the component supply unit. Therefore, the landing timing may be updated at least at the time of picking up the component immediately after the change. The change of the component supply unit includes, for example, a change in tape lot when a tape feeder is used as the component supply unit, splicing for connecting a succeeding tape to a preceding tape, and the like.

  Further, the update of the landing timing may be performed at the time of component suction immediately after the nozzle does not land on the component at the currently applied landing timing. When the nozzle does not land on the component at the currently applied landing timing, there is a deviation from the actual landing timing, so there is a high need for updating the landing timing. The fact that the deviation from the actual landing timing can be immediately detected is one of the features of the present invention that includes the landing detection sensor (optical fiber sensor 40). Note that when the nozzle did not land on the part at the currently applied landing timing, it was landed before the currently applied landing timing and after the currently applied landing timing. It is a concept that includes both.

  In the above embodiment, the sensor unit 40 b of the optical fiber sensor 40 is provided separately from the control unit 50, but the function of the sensor unit 40 b can be incorporated into the control unit 50. In the embodiment, the optical fiber sensor 40 is used as a non-contact sensor that detects the landing of the nozzle 32. However, other non-contact sensors such as a magnetic sensor may be used.

  The present invention is also applicable to component suction heads other than the rotary head type. Furthermore, the present invention can also be applied to a component suction head of a work device other than the surface mounter.

10 Component adsorption head 20 Head body 21 R servo motor 22 T servo motor 23 Z servo motor (lifting means)
24 ball screw mechanism 24a screw shaft 24b nut 25 pressing tool 26 connecting bar 27 spline shaft 28 spline nut 30 rotary head 31, 31a spindle 32 nozzle 32a reflecting surface 33 elastic body 34 coil spring (elastic body)
40 Optical fiber sensor (landing detection sensor)
40a Lens 40b Sensor part 50 Control part (control means)
60 Negative pressure supply means 61 Motor rotating shaft 62 Lever 63 Spool 64a Negative pressure supply path 64b Positive pressure supply path

Claims (7)

A nozzle that can be moved up and down for picking up and picking up a component from the component supply unit, a lifting and lowering means for lifting and lowering the nozzle, a negative pressure supplying means for supplying a negative pressure for the nozzle to suck the component, and a component Therefore, a component suction head comprising: a landing detection sensor that detects that the nozzle has landed on a component when the nozzle is lowered; and a control unit that controls the lifting unit and the negative pressure supply unit,
The control means stores the landing timing at which the landing detection sensor detects that the nozzle has landed on the component at the time of the first component suction, and at the next component suction, based on the landing timing, the negative pressure supply means A component suction head that sets the timing for starting operation.   The operation start timing of the negative pressure supply means is set to a timing earlier than the landing timing by an amount corresponding to the time until the negative pressure supply means can supply a predetermined negative pressure after the operation starts. The component suction head according to claim 1.   The component suction head according to claim 1, wherein the control unit sets a lowering profile of the nozzle by the lifting unit based on the landing timing.   The component lowering head according to claim 3, wherein the descending profile is set so that the nozzle stops based on the landing timing.   5. The component suction head according to claim 1, wherein the control unit updates and stores the landing timing at each time of component suction or at a predetermined number of times of component suction.   5. The component suction head according to claim 1, wherein the control unit updates and stores the landing timing when the component supply unit is changed. 6.   5. The component suction head according to claim 1, wherein the control unit updates and stores the landing timing when the nozzle does not land on the component at the landing timing. 6.

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