DE102008059490B3 - Assembly head for assembling member with substrate, has mechanical arm for picking and holding member, and pneumatic tubes used as rigid connecting tubes and mutually plugged on connecting positions to be connected - Google Patents

Abstract

The head has a mechanical arm (11) for picking and holding a member (3), and a pneumatic unit (12) for loading preset pressure (p1) to the mechanical arm. A pneumatic tube (13) is mounted on an assembly head. Another pneumatic tube (14) is partially guided in an interior of the mechanical arm and connected with the former pneumatic tube. The pneumatic tubes are used as rigid connecting tubes and mutually plugged on connecting positions (A-B) to be connected. A flow rate sensor determines a volume flow in the former pneumatic tube.

Description

The The invention relates to a placement head for loading of substrates with components and a placement with such Placement.

In the placement technique be with the help of placement machines Substrates, usually printed circuit boards, equipped with components. For this will be usually placement heads used, which by means of a positioning of the placement in a plane are movable parallel to a plane of the substrate and to record of components or positioning of the components on the substrate are formed. With the help of such a design placement The components are picked up by so-called feeders, too a placement area of the placement machine, in which the to be equipped Substrate is provided, transferred and predefined placement positions deposited on the substrate.

nowadays will be equipped of printed circuit boards mostly the SMT method (Surface Mounted Technology) is used. This is done before the actual placement process first the solder material in the form of solder paste on the contact points on the Applied top of the circuit board, for example by means of Stencil printing can be done. Next are the components placed on their respective predefined placement positions on the printed circuit board, the components pass through the sticky solder paste at their respective Position are held on the substrate. Subsequently, will the circuit board in a soldering oven transported where the solder paste is melted, leaving between the components and the circuit board made a conductive contact becomes.

to Handling of the components has sucked by vacuum largely enforced. With the help of a vacuum pipette, which on the placement head is arranged, a component of the feeder by suction taken and while the transfer to his respective placement position. By Turn off the vacuum or over blow with compressed air, the device can be transferred from the vacuum pipette to the substrate become. To pick up and settle a device is the vacuum pipette relative to the placement head in the direction of the to be loaded PCB formed displaceable. Furthermore, the vacuum pipette for angular positioning of a held component about its longitudinal axis to be turned around. Here, a rotary feedthrough is used, which the axial and or rotational movement of the vacuum pipette relative to the placement head compensates, wherein for sealing the rotary feedthrough a touching Seal element is used. For the most accurate angular positioning possible to be able to realize the rotational movement of the pipette tip must be largely free of feedback, d. H. without torque transmission on the pipette tip, done. However, by the contacting sealing element a noticeable torque during a rotary movement of the vacuum pipette generated, whereby the accuracy of the positioning is significantly impaired.

From the US 6,298,547 B1 is a placement known, which has a suction pad, which is mounted on a hollow shaft. The interior of the hollow shaft constitutes a suction channel. The hollow shaft is displaceably mounted in the axial direction relative to a housing of the placement head. An axial displacement of the hollow shaft can be generated by means of a vertical drive, which is located in the housing. Furthermore, by means of a rotary drive, a rotational movement of the hollow shaft and thus also of the plugged suction pad about the longitudinal axis of the shaft can be generated. The interior of the housing is a pneumatic line, which is pneumatically coupled via a formed in the shaft side opening with the suction channel. By means of a pneumatically coupled to the housing blowing device, a short-term overpressure in the suction channel can be made via the lateral opening, so that an electronic component held by the suction pad is dropped. The a xiale displaceability of the hollow shaft has the disadvantage that within the placement head a comparatively large space for the hollow shaft must be available.

It Therefore, the object of the present invention to provide a placement head, which are realized within a compact design can.

These Task is by the placement head as well the placement machine solved according to the independent claims. advantageous Embodiments are the subject of the dependent claims.

The placement head according to the invention according to claim 1 comprises a gripper, which is designed for receiving and holding a component, and a pneumatic unit, which is provided for acting on the gripper with a predetermined first pressure. In this case, the pneumatic unit to a pneumatic first line, which is arranged on the placement head, and a pneumatic second line, which is at least partially guided within the gripper and coupled to the first pneumatic line. The pneumatic first line and the pneumatic second line are each designed as a rigid connection pipe. The two connecting pipes are plugged into each other for coupling at a junction, so that the first and the second pneumatic line are mutually displaceable and rotatable to realize an axial and / or rotational movement of the gripper relative to the placement head. According to the invention, the connection point is determined by an overlap between a first end section of the first line and a second end section of the second line.

Of the Gripper is relative to the placement head rotatable about its own central axis and along the central axis slidably mounted. With the help of two nested pipes is a simple way a coupling between two pneumatic lines, here between a pneumatic first line of the placement and a rotatable and axially movable pneumatic second Management of the gripper, realized. Depending on the air gap between The two connecting pipes is doing a relative movement the two connecting pipes to each other a very low torque as well as a very low axial force and associated with it clearly improved wear behavior achieved. Due to the low transmitted torque between stationary and moving pipe is a significantly higher accuracy the rotational positioning of the gripper reachable.

to Realization of the coupling of the two connecting pipes is irrelevant whether the connecting pipe of the pneumatic first line in the second line is plugged or vice versa. The air gap between the two nested connection tubes can be up to 50 microns; advantageous manner the air gap around the 30 μm.

Farther Is it possible, the pneumatic second line at least partially as a bore within a cylindrical the body form the gripper. In this case it is beneficial to the Outside surface of the cylindrical Body in such a way to edit that as possible friction arm in the connecting pipe of the pneumatic second line slides.

In an advantageous development of the placement head has the pneumatic Unit a flow sensor which is used to determine a volume flow rate in the pneumatic first line is formed.

With Help such a flow sensor is it is possible, for example Determine if a component is held at the top of the gripper is: this is the air flow through the suction line of the gripper certainly. Is a component at the top of the gripper, so the air flow rate is relatively low; If no component is present, the air flow rate is corresponding increased. To this Way is a sensor for monitoring the presence with little effort created a held device.

This Sensor has about it addition, the advantage that it is not in the area of the hook tip, on which the component is held, must be arranged, but can be formed in the pneumatic first line. This on the one hand has the advantage that no space in the area of the hook tip is required. On the other hand, the sensor is moving of the gripper relative to the placement head not moved, whereby the moving mass is reduced. The positioning accuracy is thereby significantly improved.

In a further advantageous embodiment of the placement is the connection point within a third tube of the pneumatic A unit which is used to set a second pressure around an outer edge area the connection point is provided around arranged.

is in determining the volume flow rate in the pneumatic first Line with the help of the flow sensor high accuracy is required, leakage effects can make the measurement result clear influence. Such a leakage point constitutes the connection point dependent on the air gap between the two nested connecting pipes - is: is the air gap too low, so occur in a relative movement of the Torque and axial forces on both connecting tubes, which increase the accuracy affect the rotational positioning of the gripper; is the air gap too big, so is when loading the pneumatic first line with Low pressure air leakage from outside the Junction pulled, what the measurement accuracy of the flow sensor negatively influenced. To compensate for the leakage effect is now arranged around the joint around a third pipe. prevails inside and outside the pneumatic unit of the same pressure, no leakage can occur. Therefore, the internal pressure of the third pipe is at the value of the first one Pressure, which prevails within the pneumatic unit, adjustable. The accuracy of the flow sensor is thereby clear improved.

In a further advantageous embodiment of the placement is the third pipe to guide the connecting pipe of the pneumatic second line at a Rotary and / or axial movement of the gripper formed.

In addition to the actual task of the third tube to adjust the second pressure around the connection point, the third tube can also be used to guide the connecting tube of the pneumatic contribute to the second line; the accuracy of the positioning in both the rotary and the axial movement can be improved.

In a further advantageous embodiment of the placement the pneumatic first line has a branch point over which the third tube with the pneumatic first line so pneumatically is coupled, that the first pressure equal to the second pressure corresponds.

The Branch point provides an easy-to-implement option represents the second pressure within the third tube - d. H. around the junction - on the value of the first pressure, which corresponds to the internal pressure of the pneumatic first line corresponds to adjust. The pressure of the pump, which Connected to the pneumatic first line is connected to the Branching branch in two lines branches: one is with the connecting pipe the first line, the other connected to the third pipe. On this way lies at the junction both within the first and second line as well as outside the same pressure level at. A leakage flow through the connection point is therefore no longer possible.

In a further advantageous embodiment of the placement is the flow sensor arranged between the connection point and the branching point, one as possible high measuring accuracy of the flow sensor to reach. Because leakage effects at the junction with the help excluded from the third tube, the equivalent with the help of the flow sensor measured volume flow equal to the air volume in the pneumatic second line and thus at the top of the gripper.

In a further advantageous embodiment, the placement of several Gripper on, each gripper its own pneumatic unit assigned.

Does the placement head have more than one Gripper, so it is advantageous for improving the positioning accuracy, assign each of the grippers their own pneumatic unit.

Of the Placement machine according to the invention for loading of substrates with components has a mounting head, which after a the claims 1 to 7 is formed.

Regarding the advantages of such placement is at this Place on the statements refer to the advantages of the placement head according to the invention.

in the Following are embodiments of the fitting head with reference to the attached Figures closer explained. In the figures are:

1 a schematic representation of a placement in a plan view,

2 a schematic representation of a placement head in a side view,

3a and 3b schematic representations of possible embodiments of the pneumatic unit,

4 a schematic representation of a preferred embodiment of the pneumatic unit.

In the different figures of the drawing are the same parts always provided with the same reference number. The description applies to all drawing figures, in which the corresponding part can also be seen.

1 schematically shows the general structure of a placement machine 1 for loading substrates 2 with components 3 , which for receiving the placement head according to the invention 6 suitable is. The placement machine 1 has a cross member 7 which extends in a y-direction and is fixedly connected to a machine frame (not shown). At the cross member 7 is a portal arm 8th attached, which extends in the x direction and displaceable in the y direction on the cross member 7 is attached. crossbeam 7 and porch arm 8th together form the positioning system 9 , wherein an orthogonal reference frame is formed by the x-axis and the y-axis. At the portal arm 8th is the placement head 6 arranged, which by means of a suitable drive 21 in x-direction along the porch arm 8th can be moved. Furthermore, a transport route 4 for transporting the substrates 2 in a placement area of the placement machine 1 intended. Side of the transport route 4 are near the placement area feeders 5 arranged which the construction elements 3 at their respective pick-up positions 22 provide.

For loading a substrate 2 this is about the transport route 4 transported to the placement area. The from the feeder 5 provided electrical components 3 be from the placement head 6 picked up and transferred to the placement area, where they are on their respective placement positions on the substrate 2 be positioned.

In 2 is the placement head 6 shown schematically in a side view. He has a holding device 10 for picking up and holding a component 3 on, relative to a main body of the placement head 6 in a z-direction ver slidable. However, it is also possible instead of the holding device 10 the entire placement head 6 on the portal arm 8th (please refer 1 ) in the z-direction movable to arrange. At one the substrate 2 facing the end of the holding device 10 is a gripper 11 , which is designed here by way of example as a suction gripper with a suction end located free end. Via a pneumatic line 19 is the gripper 11 acted upon by negative pressure. With the help of the negative pressure is on the male component 3 exerted a force in the negative z-direction, whereby this is sucked and held. The negative pressure is generated by means of a vacuum source (not shown) and can by means of a pressure control unit 18 be set to an appropriate value. The vacuum source and the pressure control unit 18 can do this both at the placement head 6 as well as at the placement machine 1 be arranged.

To be able to determine if a component 3 at the top of the gripper 11 is held, has the placement head 6 a flow sensor 15 on, which directly into the vacuum line 19 is integrated and thus represents a flow meter, wherein the flow sensor 15 together with the vacuum line 19 a pneumatic unit 12 forms. In this way, the air flow through the vacuum line 19 and thus at the top of the suction pad 11 be determined. Is a component at the top of the suction pad 11 on, so the suction port is at least largely closed and the resulting air flow rate relatively low; If no component is present, air is sucked through the suction opening - the air flow rate assumes a correspondingly greater value. Furthermore, with the help of the flow sensor 15 from a sudden change in the air flow rate also a loss of a component 3 , for example during transport. With the help of a control device 20 which to the flow sensor 15 is connected, appropriate information can be displayed on suitable displays of the placement machine 1 being represented.

On This way is space-saving and with little effort a sensor for monitoring created the presence of a held device. optical Become a presence control systems of a held device thereby replaced.

In the 3A and 3B are possible embodiments of the pneumatic unit 12 schematic shown. The pneumatic unit 12 has a pneumatic first line 13 and a pneumatic second line 14 which are each designed as a rigid connection pipe and inserted into one another at a connection point AB. The reference point A marks an outer edge region of the connection point AB, which limits the connection point AB of the two nested connection pipes with respect to an outer environment, whereas the reference point B represents an inner edge region of the connection point AB within the two connection pipes. At a free end of the second line 14 is a gripper 11 arranged, which is designed as a suction pad. To generate defined pressure conditions, the pneumatic unit 12 via the pneumatic first line 13 connected to a pump, which generates vacuum or overpressure as needed.

The 3a and 3b differ in principle in which of the two connecting pipes is inserted into the other connecting pipe. In this case, the outer diameter of the slimmer, inner connecting pipe is always slightly smaller than the inner diameter of the outer connecting pipe, resulting in a clearance fit between the two nested connecting pipes. This is necessary to ensure the mobility of the two connection pipes relative to each other with the lowest possible transmission of force and torque. It should be noted that the game does not turn out too large to the required positioning accuracy of the gripper 11 not to endanger. In this way, a smooth axial and / or rotational movement of the gripper 11 be realized at the same time high positioning accuracy.

Due to the clearance fit between the connecting pipes, there is an air gap (shown hatched) at the connection point AB, through which a pressure equalization between a pressure ρ ₁ or ρ ₃ in the interior of the pneumatic unit 12 and an ambient pressure ρ ₀ can take place. However, this effect affects the pressure conditions inside the pneumatic unit 12 , Therefore, the pneumatic unit indicates 12 in the region of the junction AB, a third pipe 16 on which the second line 14 partially encloses from outside and also forms a clearance with this, so that a smooth axial and / or rotational movement of the second line 14 is ensured at the same time high positioning accuracy speed. The third pipe 16 can with the help of a pressure control unit 18 be subjected to a second pressure ρ ₂ . In this way, the second pressure ρ ₂ is adjustable around the outer edge region A of the connection point AB.

If the second pressure ρ _{2 is set} to a value which corresponds to the pressure at the inner edge region B of the connection point AB, no pressure compensation takes place between the outer edge region B and the inner edge region A because of the already existing pressure equilibrium. This corresponds to the first pressure ρ ₁ in the gripper area 11 equal to the pressure ρ ₃ in the first pneumati rule 13 ,

4 shows a preferred embodiment of the pneumatic unit 12 , The pneumatic unit 12 again has a pneumatic first line 13 and a pneumatic second line 14 on, which are each designed as a rigid connection pipe. As already in 3a shown is the first line 13 at the junction AB by means of a clearance fit such in the second line 14 plugged that the mobility of the two connecting pipes relative to each other as easily as possible, ie with the least possible transmission of force and torque, can be realized. Furthermore, the pneumatic unit 12 a third pipe 16 on which the second line 14 partially encloses from outside and also forms a clearance with this, so that a smooth axial and / or rotational movement of the second line 14 can be guaranteed at the same time high positioning accuracy.

For determining a volume flow rate of the pneumatic first line 13 is a flow sensor 15 integrated into the pneumatic first line. Furthermore, the third tube 16 at a branch point 17 for setting a defined second pressure ρ ₂ within the third tube 16 with the first line 13 pneumatically coupled. In this way, the same pressure prevails within the third tube around an outer edge area as in the pneumatic first line 13 - Especially in the region of the inner edge region B. A pressure equalization between the outer edge region B and the inner edge region A along the joint AB does not take place because of the pressure equilibrium produced in this way.

For sucking a component 3 with the help of the gripper 11 , which in turn is designed as a suction pad, is the pneumatic unit 12 subjected to negative pressure. Due to the pressure parity between the internal pressure and the external pressure around the connection point AB, no pressure compensation takes place between the inner edge region B and the outer edge region A. This ensures that by means of the flow sensor 15 exactly the volume flow rate of air is measured, which is also at the top of the gripper 11 is pulled as suction air. However, due to the clearance fit between the third tube 16 and the pneumatic second line 14 Leakage air along the clearance in the third tube 16 drawn. But there the flow sensor 15 however between the junction AB and the branch point 17 is arranged in the first line, the drawn leakage affects the measurement result of the flow sensor 15 Not. In this way, the presence of a device 3 be very accurately detected and monitored.

1

automatic placement

2

substratum

3

module

4

transport distance

5

feeders

6

placement

7

crossbeam

8th

port alarm

9

positioning

10

holder

11

grab

12

pneumatic unit

13

first management

14

second management

15

flow sensor

16

third pipe

17

branching point

18

Pressure control unit

19

pneumatic management

20

control device

21

drive

22

collection position

FROM

junction

A

outer edge area

B

internal border area

ρ ₀

ambient pressure

ρ ₁

first print

ρ ₂

second print

Claims (8)

Placement head ( 6 ) for loading substrates ( 2 ) with components ( 3 ), with - a gripper ( 11 ), which is used for receiving and holding a component ( 3 ), - a pneumatic unit ( 12 ), which for applying the gripper ( 11 ) is provided with a predetermined first pressure (ρ ₁ ), which - a pneumatic first line ( 13 ), which at the placement head ( 6 ), and - a pneumatic second line ( 14 ) which at least partially within the gripper ( 11 ) and with the first pneumatic line ( 13 ), characterized in that - the pneumatic first line ( 13 ) and the pneumatic second line ( 14 ) is in each case designed as a rigid connecting pipe, and - that the two connecting pipes for coupling at a connection point (AB) are inserted into one another, so that the first and the second pneumatic line ( 13 . 14 ) are mutually displaceable and rotatable to an axial and / or rotational movement of the gripper ( 11 ) relative to the placement head ( 6 ), wherein the connection point (AB) by an overlap between a first end portion of the first line ( 13 ) and a second end portion of the second line ( 14 ) is determined. Placement head according to claim 1, characterized in that the pneumatic unit ( 12 ) a flow sensor ( 15 ), which for determining a volume flow rate in the pneumatic first line ( 13 ) is trained. Placement head according to one of claims 1 or 2, characterized in that the connection point (AB) within a third tube ( 16 ) of the pneumatic unit ( 12 ) arranged to set a second pressure (ρ ₂ ) around an outer periphery (A) of the joint (AB). Placement head according to claim 3, characterized in that the third tube ( 16 ) for guiding the connecting pipe of the pneumatic second line ( 14 ) during a rotational and / or axial movement of the gripper ( 11 ) is trained. Placement head according to one of claims 3 or 4, characterized in that the pneumatic first line ( 13 ) a branch point ( 17 ), over which the third tube ( 16 ) with the pneumatic first line ( 13 ) is pneumatically coupled such that the first pressure (ρ ₁ ) is equal to the second pressure (ρ ₂ ). Placement head according to claim 5, characterized in that the flow sensor ( 15 ) between the connection point (AB) and the branch point ( 17 ) is arranged. Placement head according to one of claims 1 to 6, characterized in that the placement head ( 6 ) several grippers ( 11 ), each gripper ( 11 ) a separate pneumatic unit ( 12 ) assigned. Placement machine ( 1 ) for loading substrates ( 2 ) with components ( 3 ), characterized in that the placement machine ( 1 ) a placement head ( 6 ) according to one of claims 1 to 7.