JPH03291998A - Electronic component mounting device - Google Patents

Abstract

PURPOSE:To improve positional correcting accuracy of an electronic component mounting device and then to improve a mounting accuracy by settling the central position of an electronic component sucking nozzle and the central position of a printed board camera at an interval corresponding to integer number of times of a nominal lead of a ball screw contained in each shaft with respect to X-axis and Y-axis directions. CONSTITUTION:An electronic component sucking nozzle 6 and a camera 8 for detecting the central position of a land 7 on a printed board 5 are mounted on a device head 2, and the leads of screw grooves 11X, 11Y of two ball screws 10X, 10Y of a transmission and reduction gear are both set to 150mm at the X-axis and Y-axis of a robot 1. An axis of the nozzle 6 and an optical axis at the end faced at least to the board 5 of a land detecting camera 8 are directed perpendicularly to the surface of the board 5, and the positional relationship of both the axes in the coordinates on the surface of the board 5 is set to intervals DELTAX1, DELTAY1 of integral multiple (Nx1 times) of the nominal X axis lead in X direction and integral multiple (Ny1 times) of the nominal Y lead in Y direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an orthogonal robot and an electronic component mounting device.

[Conventional technology]

Conventionally, in an electronic component mounting apparatus in which a mounting head is mounted on an orthogonal robot, a printed circuit board photographing device is attached to the mounting head along with an electronic component mounting nozzle, and a mounting target terminal board printed on a printed circuit board, i.e. , the mark indicating the reference position of the land or board is photographed before mounting, the position and attitude deviation of the land or mark within the plane of the printed circuit board is detected, and the mounting command coordinates are determined based on the detected values. The values were corrected.

Correction by detecting the position and orientation of the land can be achieved, for example, by vacuum suctioning the electronic component from the supply device using an electronic component suction nozzle, moving the mounting head using an orthogonal robot to transport the electronic component to the top of the printed circuit board, and then placing the electronic component on the printed circuit board. Position the orthogonal robot so that the optical axis of the photographing device is almost directly above the land, photograph the land, calculate corrected coordinate values with the control device of the electronic component mounting device or the control device of the photographing device, Next, the orthogonal robot positions the electronic component suction nozzle at the corrected coordinate value. Alternatively, all the lands printed on - pieces of printed circuit boards are photographed in advance in sequence, and the detection results are stored in the storage device in the form of the position deviation or corrected coordinate values of each land, and each electronic component is It was also possible to take the procedure of positioning the electronic component suction nozzle to a corrected position when installing it.

On the other hand, correction by detecting the position of a mark on a printed circuit board involves photographing the mark after the board is positioned at a fixed position.
Deviations in the position and orientation of the printed circuit board are calculated based on the position detection values of multiple marks, and all mounting command coordinate values on the printed circuit board are corrected by coordinate conversion to match this deviation, and then the electronic components are suctioned. , the procedure was to perform the mounting operations one after another.

The first step to detect this land is to find the operating point position of the end effector and the target of the workpiece in a Cartesian robot with two axes, X and Y, using a general ball screw as a transmission mechanism. Detection of relative displacement with a point position The same procedure was used when performing work after detecting the X-axis direction and Y-axis direction and correcting the relative displacement.

A method of detecting the position of a land pattern on a printed circuit board using a camera or the like placed above the printed circuit board is described in, for example, Japanese Patent Laid-Open No. 62-287108, as well as the method described in Japanese Unexamined Utility Model Publication No. 55-147775. , Utsukai Showa 62-55
Similar devices are also described in Japanese Unexamined Patent Publication No. 370, Japanese Utility Model Application Publication No. 62-60071, and the like.

[Problem to be solved by the invention]

The above-mentioned conventional technology is capable of determining the position of the orthogonal robot (in the strict sense based on the definition) with regard to the positional relationship between the electronic component suction nozzle and the photographing device, especially in the plane parallel to the surface of the printed circuit board. In order to reduce the influence of accuracy, the distance between the electronic component suction nozzle and the imaging device was arranged to be as small as possible. However, especially when using an orthogonal robot with a built-in ball screw in the transmission device, the positioning error is not necessarily proportional to the distance between the electronic component suction nozzle and the photographing device, so the above arrangement is not optimal. This point was not considered.

An object of the present invention is to improve the position correction accuracy of an electronic component mounting apparatus using an orthogonal robot having a built-in ball screw in the transmission device, and thus to improve the mounting accuracy.

[Means to solve the problem]

In order to achieve the above object, the present invention provides that the center position of the electronic component suction nozzle and the center position of the printed circuit board photographing device are
They were installed at intervals corresponding to an integral multiple of the nominal lead of the ball screw built into each axis in the X-axis and Y-axis directions.

[Effect]

One component of the positioning error of a ball screw is called "wobble." Figure 5 is JIS B119
2-1987r Precision Ball Screw" is an explanatory diagram of the lead accuracy of the ball screw, and the "wobble" shown in the diagram is
is a quantity defined as "the maximum width of the difference between the measured value of the axial advance of the nut corresponding to any rotation angle and the reference value within one rotation of the screw shaft". In addition, in many cases, actual measurement diagrams in which the rotation angle of the ball screw is plotted on the horizontal axis and the difference between the axial advance of the nut (cumulative actual lead) and its reference value (cumulative reference lead) are plotted on the vertical axis. The waveform has a period of one rotation of the shaft, and may be sinusoidal. Therefore, when using a ball screw with such characteristics, if the screw shaft fixed to the drive source rotates exactly an integral number of times and the nut advances a distance that is an integral multiple of the lead, then regarding the motion of this period, Since the phases before and after rotation are the same, it is expected that positioning errors due to vibrations in this period will be minimized.

The position correction procedure using the apparatus of the present invention can be performed in exactly the same manner as the conventional methods described above. With the configuration of the present invention, the difference between the command coordinate values of the orthogonal robot when photographing a land or mark on a printed circuit board and when mounting an electronic component is a value equal to an integral multiple of the lead plus a minute correction amount of several hundred microns at most. , the phase of vibration is almost the same at both positioning points of the mounting head, and the influence of vibration is canceled out.

〔Example〕

An embodiment of the present invention will be explained with reference to FIG. The electronic component mounting apparatus includes a robot 1 having two orthogonal x and y axes, a mounting head 2 provided as a load of the robot 1, and a supply device 3 such as a tray feeder, stick feeder, tape feeder, etc. that supplies electronic components. , a conveyor 4 , and a printed circuit board 5 positioned on the conveyor 4 .

The device head 2 is attached with an electronic component suction nozzle 6 and an imaging device 8 for detecting the center position of the land 7 on the printed circuit board 5. Drive sources 9X are provided on the X-axis and Y-axis of the robot 1, respectively.

9Y and ball screw IOX, which is a transmission device and reduction device.

10Y is built-in. These two ball screws IO
X and 10Y thread grooves 11 X, 11 Y (7) IJ
- The length of both stations is 15m.

The axis of the electronic component suction nozzle 6 and the land detection photographing device 8
The optical axis at least at the end facing the printed circuit board 5 is
Both axes are oriented perpendicularly to the surface of the printed circuit board 5, and the positional relationship between the two axes in terms of coordinates on the surface of the printed circuit board 5 is an integral number (NXI) times the X-axis nominal lead in the X direction and an integral number (NXI) times the X-axis nominal lead in the Y direction. Interval that is an integer (Nyl) times the Y-axis nominal lead, Δx1.
ΔY1 is placed. The numerical value is, for example, N x s
=2 tN y 1 = 5, ΔXt=3
Set 0m+, ΔYi=75y. NXI, or
There is no problem even if one of the values of N y 1 is O, and in fact, it is more desirable.

The electronic component 12 is vacuum-sucked from the supply device 3 by the electronic component suction nozzle 6, the mounting head 2 is moved by the orthogonal robot 1, the electronic component 12 is transported to the sky above the printed circuit board 5, and the land detection photographing device 8 The optical axis of is land 7
The orthogonal robot 1 is positioned so as to come to the expected position, the land 7 is photographed, and the corrected coordinate values are sent to the control device 13 (not shown) of the electronic component mounting device or the control device 14 (not shown) of the photographing device. Then, the orthogonal robot 1 positions the electronic component suction nozzle 6 at the corrected coordinate value. In addition to this correction, in many cases, the displacement of the electronic component 12 with respect to the axis of the electronic component suction nozzle 6 is detected by some other means and used for coordinate correction of the commanded position.

According to this embodiment, the difference between the command coordinate values of the orthogonal robot 1 when the land detection photographing device 8 photographs the land 7 of the printed circuit board 5 and when the electronic component 12 is mounted on the printed circuit board 5 is as follows. Thread groove 11X.

Integer multiple (Nxi times,
N3/L times) plus a minute correction amount of several hundred microns at most obtained by calculating the difference in displacement between land 7 and electronic component 12, so the phase of vibration at both positioning points of the mounting head is
They are the same, and the influence of the vibration component is canceled out. Therefore, the accuracy of position correction is improved compared to conventional devices that did not take such consideration, and the accuracy of mounting the electronic component 12 is thereby improved.

A second embodiment of the present invention will be described with reference to FIG.

The mounting head 2 is attached with an electronic component suction nozzle 6 and a photographing device 16 for detecting a mark 15 printed on the surface of the printed circuit board 5.

The axis of the electronic component suction nozzle 6 and the optical axis of the mark detection photographing device 16 at least at the end facing the printed circuit board 5 are both oriented perpendicularly to the surface of the printed circuit board 5. The positional relationship between both axes in the coordinates on the surface of 5 is an integer (NX2) times the X-axis nominal lead in the X direction,
Interval in the Y direction that is an integral number (Nyz) times the Y-axis nominal lead, Δ
X2°ΔY2 is set. The value is, for example, NX
2=4. As N3/2:3, ΔXz=60 kaku, ΔY2
=45no.

By detecting the positions of a plurality of marks 15 (minimum two) using the mark detection photographing device 16, deviations in the position and orientation of the printed circuit board 5 can be calculated.

According to this embodiment, the difference in the command coordinate values of the orthogonal robot 1 when the mark detection photographing device 9116 photographs the mark 15 on the printed circuit board 5 and when the electronic component 12 is mounted on the printed circuit board 5 is as follows. Thread groove 11X.

Integer times (NX2 times,
Nyl times) plus a minute correction amount of several hundred microns in height obtained by calculating from the position and posture deviation of the printed circuit board 5 and the displacement of the electronic component 12, so at both positioning points of the mounting head. The phases of the vibrations are almost the same, and the influence of the above-mentioned vibration components is canceled out. Therefore, the accuracy of position correction is improved compared to conventional devices that did not take this consideration,
This has the effect of improving the mounting accuracy of the electronic component 12.

A third embodiment of the present invention will be described with reference to FIG.

The mounting head 2 includes an electronic component suction nozzle 6, a photographing device 8 for detecting the land 7, and a photographing device 16 for detecting the mark 15.
is attached. The reason why the photographing devices are provided separately is that the fields of view and resolution values required for detecting the land 7 and the mark 15 are greatly different from each other.

The distance between the optical axis of the photographing device 8 for land detection and the axis of the electronic component suction nozzle 6 is set to ΔX1 as in the first embodiment of the present invention.
= 30 m+, ΔYt = 75 am, and the distance between the optical axis of the photographing device 16 for mark detection and the axis of the electronic component suction nozzle 6 is set to ΔX2 = 60 nm as in the second embodiment of the present invention.
, ΔY2: 45 mm.

According to this embodiment, the operating methods of the above-mentioned two embodiments of the present invention can be used appropriately depending on the type of electronic component, specification values of mounting accuracy and mounting speed, etc., so that more flexible electronic components can be obtained. The mounting work can be carried out, and the accuracy of position correction is improved compared to conventional devices that do not take such considerations into consideration.This has the effect of improving the accuracy of mounting the electronic component 12.

A fourth embodiment of the present invention will be explained with reference to FIG.

Robot F has two axes, X and Y, which are orthogonal to each other.
The operating section of the robot 17 includes an end effector 18 and an
A photographing device 20 is attached for detecting one side of the workpiece 19 placed parallel to the Y plane. The X-axis of the robot 17 and the Y-axis, which is the load of the X-axis, are as follows:
Drive sources 21X and 21Y, and ball screws 22X and 22Y serving as transmission and deceleration devices are built in, respectively. The nominal lead of the screw groove 23X of the ball screw 22X is 20 mm, and the nominal lead of the screw groove 23Y of the ball screw 22Y is 15 mm. The operating axis of the end effector 18 and the optical axis of the photographing device 20 for detecting the work object are both provided parallel to a coordinate axis (Z-axis) orthogonal to the X-axis and the Y-axis, and the interval between them is in the X-axis direction. The length is set to be an integral multiple of 20no, and the length is set to be an integral multiple of 15m in the Y-axis direction.

In this embodiment, the electronic component mounting operation in other embodiments is replaced with handling and processing work of the work object 19,
Applications to various tasks can be considered by replacing the electronic component gripping nozzle 16 with the end effector 8.

Similar to the other embodiments, this embodiment also has the effect of improving the accuracy of position correction of the end effector 18 compared to conventional devices that did not take such consideration, and by extension improving the operation accuracy of the robot 17. There is.

〔Effect of the invention〕

If the present invention is applied to an electronic component mounting device, the moving distance of each axis of the orthogonal robot between the time of photographing a land or mark and the time of mounting will be an integral multiple of the wabo call lead, and The positioning error is minimized.Therefore,
Position correction accuracy can be improved, and as a result, electronic component mounting accuracy can be improved.

[Brief explanation of drawings]

Fig. 1 is a perspective view of one embodiment of the present invention, Fig. 2 is a perspective view of a second embodiment of the invention, Fig. 3 is a perspective view of a third embodiment of the invention, and Fig. 4 is a perspective view of a third embodiment of the invention. FIG. 5, a perspective view of the fourth embodiment of the present invention, is an explanatory diagram of the lead accuracy of the ball screw. 1... Cartesian robot, 2... Mounting head, 3...
Supply device, 4... Conveyor, S... Printed circuit board,
6...Electronic component suction nozzle, 7...Land, 8...
・Land detection photographing device, 9X, 9Y-drive source, IOX
, IOY... Ball screw, 11X, , IIY... Thread groove, 12... Electronic component, 13... Control device for electronic component mounting device, 14... Control device for photographing device, 15...
Mark, work 6... Photographing device for mark detection, 17... Robot, ], 8... End effector, ↓9... Work object, 20... Photographing device for detecting work object, 21X,
21Y... Drive source, 22X, 22Y-... Ball screw, 23X. Figure 1 'JIA31211 Figure 2 Imaguchi

Claims (1)

[Claims] 1. Using a ball screw as a transmission mechanism, at least
An orthogonal robot having two Y axes, a mounting head movably supported by the orthogonal robot, an electronic component suction nozzle attached to the mounting head, and a printed circuit board photographing device attached to the mounting head. In the electronic component mounting apparatus, the center position of the printed circuit board photographing device with respect to the center position of the electronic component suction nozzle is in the X-axis direction, the Y-axis direction,
An electronic component mounting device characterized in that or both of these are installed at a distance that is an integral multiple of the nominal lead of the ball screw.