Method and device for monitoring electric components in a pick-and-palce device for substrates

• US 20030055528A1
• Filed: 09/27/2002
• Published: 03/20/2003
• Est. Priority Date: 03/28/2000
• Status: Active Grant

• Current Assignee: ASM Assembly Systems GmbH & Co. KG (Partnertec BV)
• Original Assignee: Siemens AG
• Inventors: Burger, Stefan, Duebel, Rainer
• Granted Patent: US 6,870,622 B2
• Time in Patent Office: Days
• US Class Current: 700/214
• CPC Class Codes: H05K 13/0812 the monitoring devices being integrated in the mounting machine, e.g. for monitoring components, leads, component placement

Abstract

The invention relates to a method and to a device for monitoring electric components in a pick and place device for substrates. The underside of a pick-up (2) is monitored by an optical scanning means (7) during the pick-up phase and during the placing phase of a component (10). A lift drive (3) for the pick-up (2) is provided with a position sensor (5) that is linked with a control device (6). The scanning means (7) emits and receives a scanning beam (22) oriented transversally to the direction of lift and is likewise coupled with the control device (6), thereby allowing to monitor the underside of the pick-up (2) in a direct time-related manner with the picking and placing of the component (10). The various lift positions are saved and compared when a threshold value of the received scanning beam (22) is exceeded so that the inventive device also allows for a monitoring of the height of the component.

Claims

1. A method for checking electric components (10) in a pick-and-place device for substrates (13),

the components (10) being handled by a pick-and-place head (1) of the pick-and-place device which is made to travel in a working plane (x-y),

a pick-up (2) for the components (10) being displaced in the pick-and-place head (1) perpendicularly in relation to the working plane (x-y) by means of a lift drive (3) between a transporting position and a functioning position,

the component (10) being sucked against an underside of the pick-up (2),

the component (10) being raised by the pick-up (2) from a pick-up position into the transporting position and, after the pick-and-place head (1) has been made to travel into a placement position, is lowered onto the substrate (13) into the functioning position,

the positional relationship between the component (10) and the pick-up (2) being checked by an optical scanning means (7) of the pick-and-place head (1),

the component (10) being brought by the lifting movement of the pick-up (2) into the active range of at least one scanning beam (22) of the scanning means (7) oriented transversely in relation to the lifting direction,

in the transporting position, the underside of the pick-up (2) being located above the scanning beam (22), and

the the pick-and-place head (1) having a control means (6), which checks the lifting position of the pick-up (2), characterized

in that the scanning means (7) is coupled to the control means (6),

in that the scanning means (7) is activated in a phase before and a phase after the suction attachment of the component (10),

in that the control means (6) detects the presence or absence of the component (10) on the pick-up (2) from the scanning values of the scanning means (7),

and in that the control means (6) assesses scanning values remaining the same between the two phases as operating errors.

2. The method as claimed in claim 1, characterized in that the scanning means (7) is activated during the picking-up and during the placing of the component (10).

3. The method as claimed in claim 1 or 2, characterized

in that, in the transporting position, the underside of the component (10) is raised above the height level of the narrowly focused scanning beam (22),

in that, in its functioning position, the underside of the pick-up (2) is displaced under the height level of the scanning beam (22),

in that the lift drive (3) has a displacement-measuring means (5) for determining the lifting position of the pick-up (2),

in that the displacement-measuring means (5) is coupled to the control means (6),

in that the lifting means is activated during the raising and/or lowering of the component (10), and

in that the control means (6) ascertains the position in height of the underside of the component (10) or of the pick-up (2) from the changes in the scanning values during the crossing of the undersides and from the respective lifting position of the pick-up (2).

4. A device for checking electric components (10) in a pick-and-place device for substrates (13), in particular as claimed in one of claims 1 to 3,

the pick-and-place device having a pick-and-place head (1) which can be made to travel in a working plane (x-y) and is intended for handling the components (10),

a pick-up (2) for the components (10) being mounted in the pick-and-place head (1) such that it can be displaced perpendicularly in relation to the working plane (x-y) by means of a lift drive (3) between a transporting position and a functioning position,

it being possible for the component (10) to be sucked against the underside of the pick-up (2),

it being possible for the component (10) to be raised by the pick-up (2) from a pick-up position into the transporting position and, after the pick-and-place head (1) has been made to travel into a placement position, it being possible for it to be lowered onto the substrate (13) into the functioning position,

the pick-and-place head (1) having an optical scanning means (7) for checking the component (10) on the pick-up (2) and

the scanning means (7) receiving at least one scanning beam (22) which is oriented transversely in relation to the lifting direction and is narrow in the lifting direction, and

in the transporting position, the underside of the pick-up (2) being located above the scanning beam (22),

the pick-and-place head (1) having a control means (6) for keeping a control check on the lifting movement of the pick-up (2), characterized

in that the scanning means (7) is coupled to the control means (6),

in that the scanning means (7) can be activated in a phase before and a phase after the suction attachment of the component (10),

in that the control means (6) can detect the presence or absence of the component (10) on the pick-up (2) from the scanning values of the scanning means (7),

in that the control means (6) assesses scanning values remaining the same between the two phases as operating errors.

5. The device as claimed in claim 4, characterized

in that, in the transporting port position of the component (10), the scanning beam (22) is arranged under the underside of said component,

in that, in its functioning position, the underside of the pick-up (2) is located underneath the sharply focused scanning beam (22),

in that the lift drive (3) has a displacement-measuring means (5) for determining the lifting position of the pick-up (2),

in that the displacement-measuring means (5) is coupled to the control means (6),

in that the lifting means can be activated during the raising and/or lowering of the component (10), and

in that the control means (6) can ascertain the position in height of the underside of the component (10) or of the pick-up (2) from the changes in the scanning values during the crossing of the undersides and from the respective lifting position of the pick-up (2), and from this can calculate the height of the component (10).

6. The device as claimed in claim 5, characterized

in that the scanning means (7) is formed as a forked light barrier with a bow-shaped carrier for the optical functional parts (for example 8, 9), and

in that the scanning beam (22) is arranged by deflecting means near the underside of the scanning means (7) facing the substrate (13).

7. The device as claimed in claim 4, 5 or 6, characterized

in that the pick-and-place head (14) designed in the manner of a turret has a stator (15), on which a rotor (16) is mounted such that it can rotate step by step,

in that the rotor (16) is provided with a multiplicity of pick-ups (17) distributed in a circular manner,

in that the pick-up (17) can be lowered and raised by the lift drive (19) in a lifting station (20) of the pick-and-place head (14),

in that the scanning means (31) fastened to the stator (15) is assigned to the lifting station (20), and

in that the stator (15) of the pick-and-place head (1) is provided outside the lifting station (20) in addition to the scanning means (7) with an optics station (18) for ascertaining the position of the component (10) on the pick-up (2).

8. The device as claimed in claim 7, characterized

in that the scanning beam (22) is oriented in the direction of rotation of the components (10).