JP3233053B2 - Method for measuring height of nozzle of transfer head in electronic component mounting apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the height of a transfer head nozzle in an electronic component mounting apparatus.

[0002]

2. Description of the Related Art For example, an electronic component mounting apparatus described in Japanese Patent Application Laid-Open No. 61-256691 or Japanese Patent Application Laid-Open No. 3-289197 is provided with an electronic component supply unit at the lower end of a nozzle of a transfer head. The picked-up electronic component is picked up by vacuum suction and mounted at a predetermined coordinate position on the substrate.

[0003] The nozzle of the transfer head moves up and down when picking up electronic components or mounting electronic components on a substrate. In this case, if there is a deviation in the vertical movement stroke, a pickup error or a mounting error occurs, so that the vertical movement stroke of the nozzle must be accurately controlled. For this purpose, it is necessary to accurately know the height of the origin of the nozzle provided in the electronic component mounting apparatus.

Therefore, in this type of electronic component mounting apparatus, after assembling the transfer head, the height of the nozzle is measured, and the measurement result is registered in the memory of the control unit. And when operating the electronic component mounting equipment,
The vertical movement stroke of the nozzle is controlled based on the registered height.

FIG. 5 is an explanatory view of a method for measuring the height of a nozzle of a transfer head of a conventional electronic component mounting apparatus. 1 is a dial gauge and 2 is a reference plate. The lower surface of the reference plate 2 is a height reference surface. Reference numeral 3 denotes a transfer head of the electronic component mounting apparatus, and reference numeral 4 denotes a nozzle. A nut 6 is connected to a block 5 that holds the transfer head 3, and a feed screw 7 is screwed into the nut 6. Therefore, when the motor 8 is driven and the feed screw 7 is rotated, the transfer head 3 moves up and down.

After assembling the transfer head 3 to the electronic component mounting apparatus, the height of the lower end of the nozzle 4 is measured as follows. First, an operator holds the dial gauge 1 and reads the scale of the dial gauge 1 by applying the tip of the arm 1 a to the lower surface of the reference plate 2. Next, dial gauge 1
The tip of the arm 1a is applied to the lower end of the nozzle 4 to read the scale. The difference between the two readings is registered as an offset value in the memory of the control unit. When the electronic component mounting apparatus mounts the electronic component, the vertical movement stroke of the nozzle 4 is determined based on the offset value.

[0007]

However, in the conventional method described above, the operator must hold the dial gauge 1 and carefully touch the lower surface of the reference plate 2 and the lower end of the nozzle 4 to measure the respective heights. Therefore, there is a problem that the operation is extremely troublesome, and that the measured value is easily varied by the operator.

Accordingly, an object of the present invention is to provide a method for measuring the height of a transfer head in an electronic component mounting apparatus capable of simply and accurately measuring the height of the lower end of a nozzle.

[0009]

[0010]

According to a first aspect of the present invention, there is provided a method for measuring the height of a nozzle of a transfer head in an electronic component mounting apparatus. Driving the up-down moving means to lower the transfer head so that the lower end of the electronic component vacuum suction nozzle protruding downward from the transfer head lands on a pressure measuring device; and The pressing force is increased, and the lower end of the nozzle is pressed strongly against the pressure measuring instrument.In this state, while monitoring the output of the pressure measuring instrument, the vertical movement means is driven to raise the transfer head. Determining the height of the nozzle when the output of the pressure measuring device decreases.

[0011]

According to the present invention, the height of the lower end of the nozzle of the transfer head can be determined quickly and accurately.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a transfer head and a nozzle height measuring device of an electronic component mounting apparatus according to an embodiment of the present invention. FIG. 2 is a partially enlarged front view of the transfer head of the electronic component mounting device. 3 is a flowchart of the operation of measuring the height of the nozzle of the transfer head of the electronic component mounting apparatus, and FIG. 4 is a view showing the measurement results of the height of the nozzle of the transfer head of the electronic component mounting apparatus.

In FIG. 1, a mounting section 11 is provided on the front surface of a block 10, and a transfer head 12 is mounted on the mounting section 11. The transfer head 12 has a nozzle 13 for vacuum-sucking electronic components. Block 10
A cylinder 14 as a pressurizing means is provided on the front surface of the transfer head 12, and a lower end of a rod 15 of the cylinder 14 is in contact with an upper surface of the transfer head 12. The cylinder 14 is connected to a regulator 16 which is a pressure adjusting means.

A nut 17 is connected to the block 10, and a vertical feed screw 18 is screwed into the nut 17. When the motor 19 drives and the feed screw 18 rotates,
The nut 17 moves up and down along the feed screw 18, whereby the block 10 also moves up and down. That is, the nut 17,
The feed screw 18 and the motor 19 are means for moving the nozzle 13 up and down. 20 is a motor driver. The regulator 16 and the motor driver 20 include a CPU as a control unit.
21. Reference numeral 22 denotes a load cell as a pressure measuring device provided below the nozzle 13. The load cell 22 is installed at a position where the height of the upper surface becomes a design value.

Next, a method of measuring the lower end of the nozzle 13 will be described with reference to FIGS. First, initially, cylinder 1
4 is set to a minimum (see step 1 in FIG. 3 and timing t1 in FIG. 4). In this state, the motor 19 is driven to lower the transfer head 12 at the standard speed (medium speed) until the lower end of the nozzle 13 lands on the upper surface of the load cell 22. 4 is a timing when the lower end of the nozzle 13 lands on the upper surface of the load cell 22. This descending stroke is calculated in advance from a design value or the like, and is immediately known. FIG. 2 shows the state at this time.

As shown in FIG. 2, the pressure of the cylinder 14 is set to a minimum, and the pressing force applied by the rod 15 of the cylinder 14 to the transfer head 12 is extremely weak. The transfer head 12 lands softly on the upper surface, and the transfer head 12 slightly floats from the mounting portion 11 (see the gap G).

Next, the pressure of the cylinder 14 is increased to the maximum, and the lower end of the nozzle 13 is pressed strongly against the upper surface of the load cell 22 (step 3). T3 in FIG. 4 is the timing at this time. Next, the transfer head 12 is raised at a low speed while monitoring the output of the load cell 22 (step 4).

The height at which the output of the load cell 22 suddenly drops to zero, that is, the height (Zactual) of the lower end of the nozzle 13 at the moment when the lower end of the nozzle 13 separates from the upper surface of the load cell 22, is recorded. At the timing t4 in FIG. 4, the output of the load cell 22 instantaneously decreases to 0 at the moment when the nozzle 13 separates from the load cell 22. This height (Zactual) is registered as a unique value of the nozzle 13 in a memory (not shown) attached to the CPU 21. As described above, if the nozzle 13 is strongly pressed against the load cell 22 and the nozzle 13 is slowly lifted in this state to measure the height when the nozzle 13 separates from the load cell 22, the nozzle 13 and the load cell 22 are reduced. The height of the nozzle 13 can be accurately measured without rattling. The nozzle 13 is a load cell 22
If the height at the time of landing is measured, the nozzle 13 and the load cell 22 rattle due to the impact at the time of landing,
Accurate measurement cannot be expected.

Next, the transfer head 12 is returned to its original height at a standard speed (step 6). Then, the difference between Zactual and the design value is registered in the memory as an offset value (step 7). Thereafter, the pressure of the cylinder 14 is returned to the initial state (minimum). Thus, the measurement of the height of the lower end of the nozzle 13 ends.

The electronic component mounting apparatus in which the height of the lower end of the nozzle 13 has been measured and registered as described above is thereafter provided for actual operation to mount electronic components.
The electronic component mounting apparatus picks up the electronic component provided in the electronic component supply unit and mounts the picked-up electronic component on the substrate by moving the nozzle 13 up and down. The height is obtained from the offset value, and the vertical movement stroke of the nozzle 13 is determined from the height of the origin. Note that a voice coil motor or the like can be used as the pressurizing means in addition to the cylinder.

[0021]

According to the present invention, the height of the lower end portion of the nozzle of the transfer head can be quickly and accurately determined, and based on the result, the vertical movement stroke of the nozzle can be accurately controlled while controlling the electronic component. Can be implemented. Also, since the cylinder pressure is set low and the nozzle is lowered, even if the nozzle lands at a high speed at a high speed, the impact at the time of landing does not rattle the nozzle or damage the pressure measuring device. Therefore, the measurement operation can be performed more quickly by lowering the nozzle at a high speed. Furthermore, since the cylinder pressure is increased and the lower end of the nozzle is pressed strongly against the pressure measuring instrument, the nozzle is raised to determine the height at which the output of the pressure measuring instrument decreases,
The height of the nozzle can be accurately measured without play.

[Brief description of the drawings]

FIG. 1 is a front view of a transfer head and a nozzle height measuring device of an electronic component mounting apparatus according to an embodiment of the present invention.

FIG. 2 is a partially enlarged front view of a transfer head of the electronic component mounting apparatus according to one embodiment of the present invention;

FIG. 3 is a flowchart of an operation of measuring the height of the nozzle of the transfer head of the electronic component mounting apparatus according to the embodiment of the present invention;

FIG. 4 is a measurement result diagram of the height of the nozzle of the transfer head of the electronic component mounting apparatus according to the embodiment of the present invention;

FIG. 5 is an explanatory view of a method for measuring the height of a nozzle of a transfer head of a conventional electronic component mounting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Block 11 Placement part 12 Transfer head 13 Nozzle 14 Cylinder 15 Rod 16 Regulator 17 Nut 18 Feed screw 19 Motor 21 CPU 22 Load cell

Claims (1)

(57) [Claims] An apparatus for driving a vertical movement means to lower a transfer head and to project downward from the transfer head after setting a small pressing force of a pressing means for applying a pressing force to the transfer head from above. Landing the lower end of the nozzle for electronic component vacuum suction on the pressure measuring device, and increasing the pressing force of the pressurizing means to strongly press the lower end of the nozzle against the pressure measuring device. Driving the vertical movement means while monitoring the output of the measuring instrument to raise the transfer head, and determining the height of the nozzle when the output of the pressure measuring instrument sharply decreases. A method of measuring the height of a nozzle of a transfer head in an electronic component mounting apparatus.