JPH11121989A - Component mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a component-mounting method by which the mounting speed of components can be increased and the shock given to the components can be minimized. SOLUTION: In a component-mounting machine, which moves a nozzle in the vertical direction by means of a VCM(voice coil motor) 12, the impulsive forces applied to mounted components can be minimized by limiting the quantity of a torque developed by the VCM 12 by detecting that the VCM 12 has approached a position which is on this side of a set position by a moving amount which has been set in advance in a system controller 16, based on the information supplied from a position detector and limiting the value of the electric current made to flow to the VCM 12 at this timing, when the VCM 12 is positioned to a lower position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component mounting method for an electronic component mounting machine.

[0002]

2. Description of the Related Art In recent years, electronic component mounting machines have been required to have high precision and high productivity. In particular, a component transfer unit (hereinafter, referred to as a head unit) for picking up components of a multifunctional component mounting machine and performing mounting operations on a substrate. The technology development aiming at high speed and high accuracy using XY robots has been developed due to the high degree of freedom in the component supply form, the wide range of mountable components, and the high mounting accuracy with a simple configuration. Is being done. In recent years, XY
A robot that adopts a linear motor to increase the speed and adjust the pressure at the time of component mounting by controlling the pressure of a mechanism for moving a component suction nozzle up and down has also been developed.

[0003] Further, a mechanism for moving the nozzle up and down is also required to be driven at a high speed.
As in M, a device that directly drives the nozzle up and down at high speed has also been realized. In addition, high rigidity and lightweight nozzle parts have been developed by the development of various material technologies.

[0004] Referring to the drawings, the structure of the nozzle portion of the above-described conventional component mounting machine will be described. FIG.
FIG. 2 is a schematic view showing a structure of a nozzle portion of a conventional component mounter. In FIG. 6, 1 is a nozzle tip, 2 is a nozzle body, 3 is a spring, and 4 is a nozzle holder. When a component is sucked or mounted with the conventional component mounter configured as described above, the nozzle is slightly pushed in and positioned slightly, and the nozzle tip 1 is released by the spring 3 to keep the suction state stable. The parts were pressed and adsorbed by the pressure.

[0005]

However, in the above configuration, since the allowable pressure / impact value differs depending on parts, several types of nozzles having different spring strengths are prepared.
There has been a problem that the nozzle must be replaced every time a part is changed. In recent years, a method of using a pneumatic spring and controlling its strength with an electropneumatic regulator has also been used, but it also has problems such as time loss and responsiveness of pressure switching and a complicated system configuration. I have.

[0006] In addition, recently, VCMs have been developed which use VCMs above and below the nozzles to detect the contact of the nozzles with components and then change the current to control the pressure.
It is necessary to perform a search operation to detect the position where the nozzle comes into contact, and there is a problem that the use of a machine that requires high speed suction and mounting is limited. In view of the above problems, the present invention can increase the mounting speed,
An object of the present invention is to provide a component mounting method for minimizing impact on components.

[0007]

A component mounting method according to the present invention comprises: a nozzle for sucking and holding a component for transferring the component;
A voice coil motor (hereinafter, referred to as VCM) as an up / down axis for vertically moving the nozzle, an input / output control device for controlling the suction and exhaust of the nozzle, a positioning control of the VCM, and a torque based on the amount of current flowing through the VCM. V to control
A component of a printed circuit board having a component transfer head including a CM controller, a system controller that instructs the VCM controller to perform positioning control / torque control, and a position detector that detects an elevation position of the VCM. In the mounting machine, when the VCM control device positions the lowering position of the VCM, the position detector detects that the VCM detects the suction target position (Z).
When the system controller detects that it has reached the preceding position (Z-Δd) by a predetermined distance (Δd), the system controller restricts the maximum current flowing to the VCM to a predetermined value and mounts or absorbs the current. It is characterized by the following.

According to the above configuration of the present invention, when the VCM that moves the nozzle up and down is positioned down, the system control device detects from the position detector that the VCM has reached the previous position by the preset amount of movement. By limiting the current value flowing through the VCM at this timing, the amount of torque generated by the VCM can be limited, and the impact force on components to be mounted can be minimized.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided a nozzle for sucking and holding a component for transferring the component,
A voice coil motor (hereinafter, referred to as VCM) as an up / down axis for vertically moving the nozzle, an input / output control device for controlling the suction and exhaust of the nozzle, a positioning control of the VCM, and a torque based on the amount of current flowing through the VCM. V to control
A component of a printed circuit board having a component transfer head including a CM controller, a system controller that instructs the VCM controller to perform positioning control / torque control, and a position detector that detects an elevation position of the VCM. In the mounting machine, when the VCM control device positions the lowering position of the VCM, the position detector detects that the VCM detects the suction target position (Z).
When the system controller detects that it has reached the preceding position (Z-Δd) by a predetermined distance (Δd), the system controller restricts the maximum current flowing to the VCM to a predetermined value and mounts or absorbs the current. When positioning the VCM that moves the nozzle up and down, the system controller detects from the position detector that the VCM has reached the position before the VCM by a predetermined movement amount. And the amount of current flowing to the VCM at this timing is limited, thereby limiting the amount of torque generated by the VCM immediately before the nozzle comes into contact with the target object and minimizing the impact force on the component to be mounted. Has the ability to.

According to a second aspect of the present invention, a value for limiting the maximum current flowing through the VCM is preset in the VCM control device according to a distance between the position of the VCM and a target position for sucking and mounting. The component mounting method is characterized in that the limiting current value continuously changes from the position of -Δd). In addition to the effects of the invention according to claim 1,
By continuously changing the limit value of the current value flowing to the VCM, the maximum amount of generated torque of the VCM is continuously changed, and the shock to the mounted components can be reduced without causing torque shortage or overshoot during positioning. Has an effect that can be minimized.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a system configuration diagram according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view showing the structure of a VCM, FIG. 3 is an operation flow diagram when components are mounted, and FIG. It is a schematic diagram of a transition of a value.

In FIG. 1, reference numeral 11 denotes a nozzle for sucking a component, 12 denotes a voice coil motor (hereinafter referred to as VCM) for vertically moving the nozzle, 13 denotes a magnescale which is a position detector for detecting the vertical position of the VCM, 14 Is a VCM control device for controlling the position and current of the VCM, 15 is an input / output control device for controlling the intake and exhaust of the nozzle, and 16 is a system control device for integrally controlling the VCM control mechanism and the input / output control device.

As shown in FIG. 2, the main body 12 of the VCM is composed of a coil 17, a bobbin 18 wound with a coil, a magnet 19, and a linear shaft 20. When a DC current flows through the coil 17 of the VCM, a magnetic field is generated, and the magnet 19 attached to the shaft 20 generates a force according to the direction of the magnetic field, and the shaft 2 operates. At this time, the force generated in the shaft 20 is proportional to the value of the current flowing through the coil.

FIG. 3 shows an operation flow when the VCM is lowered and components are mounted, and the operation of the mounting method of the present invention will be described with reference to FIG. Assuming that the thickness of the component is t, the distance between the mounting surface and the origin position of the nozzle is L, and the nozzle pushing amount at the time of mounting is d, the VCM is positioned at the origin height with the component sucked. In step # 1, the system controller 16 sets the V
The CM target position is calculated as L−t + d. Step #
In step 2, the limiting current value is determined based on the pressure f applied to the nozzle at the time of mounting preset in the system controller 16, the proportional constant α of the current flowing to the VCM and the generated torque, and the weight g including the nozzle of the VCM movable part. Find i in the following equation,

[0015]

I = (f−g) / α In step # 3, the position Lt−d at which the limit current is switched
At the same time, the limiting current i is transferred to the VCM control device as a parameter of the positioning command to instruct the operation. Step # 4
The VCM control device controls the positioning of the VCM to L−t + d as instructed.
When the position of M has not reached Ltd, it is confirmed on the magnescale 13 that when it has reached Ltd,
In step # 6, the current value in the direction in which torque is applied in the direction of pushing the nozzle while limiting to Lt + d is limited to i. At this time, the current value in the reverse direction (the direction in which the nozzle is pulled up) is not limited. As shown in the schematic diagram of FIG.
When positioning at L−t + d, when the current limitation is not applied (a) and when the current limitation is applied (b), after contacting the component (a), V (as shown by the dotted line)
Current flows to the limit performance of the CM controller, and extremely large impact and pressure are applied to the parts. On the other hand, in (b), the current limit is already applied when the parts come into contact with each other.

In step # 7, when the positioning is completed, the input / output control unit cuts off the picking-up of the component.
At 8, the VCM is driven to raise the nozzle. During this time, in step # 9, the Magnescale detects that the position of the VCM has passed Lt-d, and in step # 10, the current limit is released. As described above, according to this embodiment, the amount of torque generated by the VCM is reduced by limiting the value of the current flowing to the VCM immediately before the nozzle comes into contact with the target object to a predetermined value. Shock at the time of wearing
The pressure can be limited to a specified value. (Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings.

FIG. 5 is a table showing the relationship between the remaining distance to the target position and the limited current value preset in the VCM control device used in the present invention. The operation is the same as that of the first embodiment, except that in step # 5 and step # 6, the set position detection and the single current limitation are performed in the first embodiment. In the embodiment, as shown in FIG. 5, the current value to be limited is gradually changed according to the remaining distance to the target position.

As described above, by continuously changing the current value to be limited, it is possible to minimize the impact on components to be mounted without insufficient torque or overshoot during positioning. In the second embodiment, the distance to the target position is used as a factor for changing the limit current value. However, the factor for changing the limit current value may be a speed from the start of positioning deceleration.

Although the switching position of the limiting current is Lt-d in the above embodiment, the switching position can be appropriately changed by using another numerical value as the value of d.

[0020]

As described above, the first invention of the present invention relates to a component mounting machine for moving a nozzle up and down by a VCM.
When performing the downward positioning, it is detected by the information from the position detector that the system controller has reached the previous position by the moving amount set in advance, and by limiting the current value flowing to the VCM at this timing, It is possible to limit the amount of torque generated by the VCM and minimize the impact force on components to be mounted.

According to a second aspect of the present invention, the maximum characteristic torque of the VCM is continuously changed by continuously changing the limit value of the current flowing through the VCM depending on the speed and the position when the VCM is lowered and decelerated. It is possible to minimize the impact on components to be mounted without insufficient torque or overshoot during positioning. In addition, according to the present invention, since a spring is not attached to the tip unlike the conventional nozzle, the nozzle can be shared with the case of performing full-scale load control, the number of nozzle types and the number of nozzle changes can be reduced at the same time I do. Further, since the structure is simple, maintenance such as replacement of parts due to aging of the spring is not required.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram in a first embodiment.

FIG. 2 is a cross-sectional view illustrating a structure of a VCM according to the first embodiment.

FIG. 3 is an operation flow when components are mounted in the first embodiment.

FIG. 4 is a schematic diagram showing a change in a current flowing through a VCM in the first embodiment.

FIG. 5 is a remaining distance-restricted current value correspondence table set in the VCM control device according to the second embodiment.

FIG. 6 is a structural view of a conventional nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Nozzle 12 VCM 13 Magnescale 14 VCM control device 15 Input / output control device 16 System control device 17 Coil 18 Bobbin 19 Magnet 20 Shaft

Claims (2)

[Claims] 1. A nozzle for sucking and holding a component for transferring a component, a voice coil motor (hereinafter, referred to as VCM) as an up / down axis for vertically moving the nozzle, and controlling suction and exhaust of the nozzle. An input / output control device, a VCM control device for performing positioning control of the VCM and a torque control based on an amount of current flowing through the VCM, a system control device for instructing the VCM control device for positioning control and torque control, When the VCM control device positions the VCM lowering position, the position detector detects that the VCM detects the suction target when the VCM controller determines the lowering position of the VCM. When the system control device detects that it has reached the position (Z-Δd) in front of the position (Z) by a preset distance (Δd) from the position (Z), Component mounting method characterized by adsorbing or implemented to limit to a preset value the maximum current supplied to the VCM. 2. A value for limiting a maximum current flowing through the VCM is preset in the VCM control device according to a distance between a position of the VCM and a suction mounting target position, and is limited from the position of (Z-Δd). 2. The component mounting method according to claim 1, wherein the current value changes continuously.