JPH0314238B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an apparatus for constructing an electronic circuit by mounting electronic components, particularly leadless small electronic components (so-called chip components), on a board.

(b) Prior Art There are generally two methods for mounting small leadless electronic components on a circuit board. The first method, as described in Japanese Patent Application Laid-open No. 57-177592, uses the adhesive force of paste solder to attach components to a board, and then heats the board for reflow soldering. As described in Japanese Patent Application Laid-Open No. 58-39094, parts are attached to a substrate by the adhesive force of the adhesive, the adhesive is cured by heating or ultraviolet irradiation to temporarily fix the parts, and then the parts are fixed by a solder bath. This is used for soldering. An example of an apparatus for attaching components to a substrate can be found in Japanese Patent Laid-Open No. 57-48293. Paste solder or adhesive is usually applied to the board side. As a coating method, JP-A-Sho
A screen printing device such as that described in Japanese Patent No. 58-60595 is often used. In the case of adhesive, there is also a proposal to apply it to the component side. Tokukai Akira
An example is the device described in Japanese Patent No. 55-78594.

(c) Problems to be solved by the invention When a component is attached to a board using the adhesive force of paste solder or adhesive, the component may be damaged before proceeding to the next process (solder reflow or adhesive hardening). may fall off. Possible causes of such insufficient adhesion are as follows.

(A) The amount of paste solder or adhesive applied was too small.

(B) It takes time from application to parts installation.
A dry film formed on the surface of the paste solder or adhesive.

(C) The printing position of paste solder or adhesive has shifted.

(D) The positional relationship between the component mounting head and the board has shifted.

(E) The positional relationship between the component mounting head and the component held there has shifted.

The above CDE occurs due to malfunction of the positioning mechanism. For products that apply adhesive to the parts themselves, there is no chance of them falling off due to CDE, but A.
B is still relevant. In any case, parts that do not have sufficient adhesion may fall off when the board is moved, resulting in the occurrence of defective boards.

(d) Means for Solving the Problems In the present invention, a plurality of vacuum suction type component mounting heads are arranged around the index table. The mounting head moves from the component suction process to the component mounting process. A suction determination process is placed after the component mounting process, and at least the period from the component suction process to this suction determination process is defined as the suction operation period of the mounting head. In the suction determination step, it is checked whether the mounting head is still suctioning the component even though the component has been pressed against the board.

(E) Effect If the adhesion force is insufficient, the component once pressed onto the board will be pulled off from the board again by the suction force of the mounting head. Subsequently, in the suction determination step, it is determined that the mounting head is still suctioning the component, and the apparatus exits the normal operation mode.

(f) Example In the figure, 1 is an index table that rotates around a vertical axis. As shown in Figure 6,
The index table 1 consists of an upper table 2 and a lower table 3, both of which are fixed to a vertical index shaft 4. The index shaft 4 is supported in a hanging state by a bearing portion 6 of a support beam 5, and is connected to an index device main body 7 on the beam. The inside of the index shaft 4 is an air intake passage 8 communicating with a vacuum source (not shown). Now, the index table 1 rotates in steps of 45 degrees, and eight work stations are arranged around it, and eight arms 9 are made to protrude radially from the lower table 3. There is. The arm 9 is supported by a slider 10 vertically mounted around the lower table 3, and is movable in the vertical direction. The slider 10 is pulled up by a spring 11 stretched between it and the upper table 2 until it hits a stopper bolt 12 screwed into the upper table 2. The slider 10 has an outwardly projecting roller 13.
is the tappet 1 at the parts suction station.
It receives the pressing action of 4. Similar tappets are placed at the component mounting station and other necessary stations, all of which are moved up and down by cam action.

Arm 9 supports a mounting head 15 at its tip.
The mounting head 15 is hollow, has a hose 16 connected to its upper end, and has a suction nozzle 17 protruding from its lower end. The nozzle 17 is adapted to be slidable relative to the mounting head 15 and is normally pushed into the extended position by a spring 18. hose 16
The other end is connected to a valve 19 fixed to the upper table 2. The valve 19 is connected to the intake path 8 through a hose 20, and is used to turn the suction power ON and OFF. The valve 19 is opened and closed by a lever actuator 21 having a roller at its tip. That is, when the actuator 21 is pushed down, the valve is open, and when not, the valve is closed. The actuator 21 is controlled by a movable cam 23 that is moved up and down by an air cylinder 22 at the station.
, the fixed cam 2 fixed to the bearing part 6
Perform according to 6. Fixed cam 26 is air cylinder 2
The movable cam 23 also serves as a support member for the fixed cam 26, and when lowered, the movable cam 23 forms a plane substantially continuous with the fixed cam 26. Since each valve 19 is arranged in a lagging position with respect to the mounting head 15 to which it belongs, the movable cam 23 is also in a position offset from the station to which it belongs.

Reference numeral 27 denotes a carrier tape for supplying parts arranged on the parts suction station. The tape 27 is made by dropping flat hexahedral parts 28 one by one into holes punched out at regular intervals in a cardboard base, and sealing both sides with plastic film. It will be peeled off just before the position. On the other hand, the board 3 is placed on the component mounting station.
An XY table 31 on which 0 is placed is arranged, and a parts collection box 32 is arranged at the suction determination station. 33 is a device for determining the orientation of components placed on the station. This consists of a photocoupler, placed at a height such that its optical path crosses directly below the successfully suctioned part. Reference numeral 34 denotes a suction determination device disposed in the suction determination station, which is composed of a photocoupler like the component orientation determination device 33, and detects whether any component is suctioned to the mounting head 15, regardless of whether it is in a normal or abnormal orientation. The sensor is placed at a height where this can be detected.

Next, the action will be explained. 1 and 2 show the behavior of the mounting head 15 at the station, . . . at a particular point in time. In the component suction station, the movable cam 23 is initially in the raised state as shown in FIG.
5 has not started suction (FIG. 6 corresponds to this state). When the tappet 14 pushes down the slider 10, the nozzle 17 of the mounting head 15 hits the component 28. After being hit, the movable cam 23 descends as shown in FIG. 1, and the nozzle 17 starts suctioning (FIG. 7 corresponds to this state). During this time, the station...
In the mounting head 15 located at , , the valve 19 is kept open by the action of the fixed cam 26, and suction is maintained. At the station, an attitude determining device 33 inspects the attitude of the component 28. If the component 28 is attracted in a normal posture as shown in FIG. 1, it is determined that there is no problem because the component 28 will not cast a shadow on the light beam of the photocoupler. At the component mounting station, the slider 10 descends and the component 28
is pressed against the substrate 30. Paste solder or adhesive is screen printed at predetermined locations on the board 30, and its adhesive force allows the component 28 to stick to the board 30.
Attach to. At the suction determination station, the suction determination device 34 examines whether the component 28 is suctioned onto the mounting head 15 or not. If the component 28 is not detected as shown in FIG. 1, there is no problem. The operation now advances to the next stage. That is, the slider 10 of the station rises and each mounting head 15 begins to move to the next station. Movable cam 23
The actuator 21 that was pushing the fixed cam 26
The next actuator 21
Waiting for.

Next, the operation when the posture determining device 33 discovers an abnormality in the suction posture of a component will be explained with reference to FIG.
If the component 28 is attracted from the side, that is, in an upright position, it will block the light beam of the orientation determining device 33, and it will be determined that the orientation is abnormal. When the mounting head 15 for which this determination has been made is next moved to the component mounting station, it does not perform a lowering operation and moves directly to the suction determination station. When the device temporarily stops at the suction judgment station and then moves to the next station, the actuator 21 of the valve 19 separates from the fixed cam 26, the suction of the mounting head 15 is cut off, and the component 2
8 falls into the collection box 32.

Next, the operation when mounting of the component 28 fails due to insufficient adhesive strength of the paste solder or adhesive will be explained with reference to FIG. The mounting head 15 is first determined at the station that there is no abnormality in the posture of the component. Therefore, the slider 10 is lowered at the component mounting station. However, because the amount of paste solder or adhesive applied was too small, or because the component 28 was pressed in a position shifted from the applied location, the adhesive force of the paste solder or adhesive could not hold the component 28 in place. If this is not sufficient, the next time the slider 10 rises, the component 28 will be lifted up while being attracted to the mounting head 15. Subsequently, when the mounting head 15 moves to the suction determination station, the suction determination device 3
4 catches the presence of part 28. The fact that the presence of the component 28 is recognized by the suction determination device 34 even though the orientation determination device 33 determines that there is no problem with the component orientation means that the component 28 has failed to be installed at the component placement station. The electronic component mounting device leaves the normal operation mode. The control flow during this period is shown in FIG. In the case of the embodiment, escaping from the normal operation mode means stopping the entire device. The operator is thereby informed of the attachment failure and takes recovery measures. Specifically, the board on the X-Y table 31 is replaced with a new one, and the index table 1 is rotated at the station without causing the slider 10 to fall, so that each mounting head 15 is not attracted. All the parts are thrown into the collection box 32. After all the mounting heads 15 have discarded the parts, normal operation is resumed and parts are mounted on the new board 30 from the beginning.

(g) Effects of the invention CCD is used as a means of determining the quality of circuit boards.
Visual systems using cameras and the like have been put into practical use. However, such systems are expensive. Furthermore, since the board on which parts have been mounted is inspected using a pattern recognition method, although defective boards are eliminated, the work carried out after a mounting error occurs requires less time and parts. It turns out that everything was in vain. In contrast, the present invention provides a low-cost device for preventing the occurrence of defective boards. Furthermore, since it is possible to immediately know the fact that a component has not adhered to the board after the occurrence, time and component losses can be kept to a minimum.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, and Figs.
4 is a flowchart of control, FIG. 5 is a top view of the index table, and FIGS. 6 and 7 are partial vertical sectional views showing different operating states of the station. 28...Electronic component, 30...Circuit board, 1...
Index table, 15...component mounting head,...component suction station,...component mounting station,...suction judgment station,
19... Valve, 23, 26... Cam (valve control means), 34... Adsorption determination device.

Claims (1)

[Scope of Claims] 1. In a device for attaching electronic components to a circuit board using the adhesive force of paste solder or adhesive, a plurality of vacuum suction type component mounting heads are arranged around the circuit board, and these heads are an index table that sequentially moves from a component suction process to a component mounting process and further to a suction determination process; a valve provided on the index table to switch between suction and non-suction of each of the mounting heads; Valve control means that sets the suction operation period of the mounting head from the process to the suction determination process, and inspects the presence or absence of component suction in the suction determination process, and detects whether or not the mounting head is activated even though the suction operation is performed in the component placement process. An electronic component mounting device characterized by comprising a suction determining means for taking the device out of a normal operation mode when a component remains suctioned.